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PROGRESS

FLYING MACHINES

BY OCTAVE CHANUTE

Being a Facsimile of The Whole of The First 1894 Edition
including original illustrations.

With Foreword
by
Alan B. Shepard
Admiral US. Navy, Retired

Lorenz & Herweg, Publishers Long Beach, CA., 1976

 
ISB N 0-916494—00—4
EfiGlNEERlNG LlBRARY

FOREWORD

From primitive times man has watched the birds and yearned to
fly. Ancient fables and ballads down through the years tell of this
quest. Yet only during the century past, have we left our plodding
earthbound existence to crisscross the world by air—~to fly at supersonic
speeds—to make distant trips into outer space, where I and others
have walked on the moon.

This classic book, Progress in Flying Machines, was first published
in 1894 by a remarkable man of vision—Octave Chanute. He was
a noted engineer who encouraged scientists, mechanics, and dreamers
to keep trying to master the secrets of the birds. There was no question
in his mind that human flight could be accomplished—it was only
a matter of time.

It was Chanute to whom the Wright Brothers wrote in 1899 for
information on gliders—how to build them and where to fly them.

Chanute was a genius who might well be called the “Father of
Aviation.” Because of the influence of his experiments, his lectures
and his published works, he compiled this pioneer compendium of
all current knowledge on building and operating what he called “flying
machines.”

The last paragraph of this book deserves mention first because it
explains the reasons for publishing this book, and for republishing
it today.

“Let us hope that the advent of a successful flying machine, now
only dimly forseen and nevertheless thought to be possible, will
bring nothing but good into the world; that it will abridge distance,
make all parts of the globe accessible; bring men into closer relations
with each other, advance civilization; and hasten the promised era
in which there shall be nothing but peace and good will among
all men.”

Rear Admiral Alan B. Shepard,
United States Navy (Ret.)

Astronaut

First man in outer space
 

OCTAVE CHAN UTE.
About the author—a man who made a difference.

Octave Chanute (pronounced sha-noot) was a three time catalyst
in the birth of aviation. He caused people to act and things to happen
by what he did, what he wrote, what he said. A true scientist, an
inventive engineer, a friend and mentor to the Wright Brothers, he
helped shape our modern age.

Born in Paris, in February, 1832 Chanute emigrated to the United
States at age six with his parents and was educated in New York
City private schools. Railroading attracted him and at age seventeen
he began the practice of his profession as a civil engineer, under
John B. Jervis, Chief Engineer. After ten years in various jobs with
the Hudson River Railroad and Western lines, he became Chief
Engineer of the Chicago 8c Alton Railroad. This despite no formal
schooling in engineering. He remained with the Chicago 8c Alton
Railroad until 1867. During this period he designed and built the
Chicago Stockyards as Chief Engineer.

In 1867 Mr. Chanute went to Kansas City, Missouri and as Chief
Engineer he was in charge of building the bridge across the Missouri
River at that point. From 1868 to 1873 he was in charge of building
four railroads in Kansas and he also designed and built the Union
Stockyards in Kansas City. In 1873 he went with the Erie Railroad
as Chief Engineer and remained with the line until 1883. Then in
the six years, 1883—1889, he worked as a private consulting engineer,
specializing in the construction of iron railroad bridges. In 1889 he
moved to Chicago and set up at the request of several railroad
companies, facilities for the preservation of timbers by the use of
chemicals. This was to remain his principal means of support.

His success only spurred on his fascination with the principles and
application of flight, beginning in 1889 with his study of the Lilienthal
brothers’ experiments.

Two years after his now—classic tour de force, “Progress in Flying
Machines,” was published (1894), he began his own gliding experi-
ments—past the age of sixty. Chanute and his assistants made literally
hundreds of glides from 95 feet on Lake Michigan sand dunes,
tabulating results and recording observations on the strength and
variations of air currents. His was the discovery of landing “tail low,”
gained from watching sparrows. These experiments progressed into
design of a 5-p1aned glider which evolved into the bi-plane that became
the model for the Wright Brothers glider.

In 1901, Chanute visited the Wrights’ camp at Kitty Hawk, watching,
encouraging, note-taking. Wilbur and Orville never failed to acknowl—
edge his key role in their own success, for it was Chanute’s masterpiece
of research and exposition—all of it in the following pages—that
unlocked many doors and paved a path for the Wright Brothers.

Moreover, in Paris in 1903, it was Chanute’s inspiring lecture on
the Wrights’ success to the cream of Europe’s engineers that proved
to be a turning point in the revival of European aviation.

His last treatise, “Recent Progress in Aviation,” was published in
April, 1910, seven months before his death.
 
INDEX TO ILLUSTRATIONS.

 

Those mar/étd with a * have been tested by experiment.

FXG. PAGE
1 Sir G. Cayley, 1809. Diagram of bird gliding ................. . ..... .. 6
2 Leonardo da Vinci, 1500. Wing-flapping device ...................... 11
3 *Besnier, 1678. Alleged artificial wings ............................. . 12
4 *Marquis de Bacqueville, 1742. Alleged artificial wings ............. 14
5 *Bourcart, 1866. Experimental feathering wings .................. .. 15
6 *Dandrieux, 1879. Experimental figure of 8 wings .................. 15
7 *Degen, 1812. Umbrella-like, valvular wings ....................... 18
8 *Letur, 1852. Parachute-like wings ....................... . ....... . 19
9 *De Groof, 1864. Winged parachute ............ . ................... 20

1o Bréant, 1854. Valvular-flapping wings.. ............................ 21

11 *Le Bris, 1857. Flapping wings ..................................... . 22

12 Gérard, 1784. Flapping wings ........................................ 24

13 Struvé and Telescheff, 1864. Multiple-flapping wings ................. 25

14 *Kaufmann, 1867. Aerial steam machine .............. . ............. 26

15 Prigem, 1871. Machine, like dragon fly ............................ 27

16 *Jobert, 1871. Artificial bird ............. .. ...................... .. 28

17 *Pénaud, 1872. Artificial bird ................... . ....... . .......... 28

18 *Hureau de Villeneuve, 1872. Artificial bird. . ....................... 29

19 *Jobert, 1872. Artificial bird .................................... 3o

20 *Pichancourt, 1889. Artificial bird ................................... 31

21 De Louvrié, 1877. Flapping wings, “ Anthropornis.”.. ............ 32

2: *Frost, 1890. Steam bird machine ................................. 34

23 *Trouvé, 1870. Artificial bird, driven by explosives .............. . .. 36

24 Method of starting Trouvé's bird ..................................... 37

25 *Launoy and Bienvenu, 1784. Ascending superposed screws ........ 49

26 Cossus, 1845. Project for screw flying machine ....... . . . . ........... 51

:7 *Bright, 1859. Superposed screws under a balloon ................... 52

28 *Ponton d’Amecourt, 1863. Steam driven superpOsed screws .......... 54

29 *Pénaud, 1870. Superposed flying screws ....................... .. 55

3o Pomes and de la Pauze, 1871. Project for flying screw ................ 57

31 *Dieuaide, 1877. Experiment with superposed screws ................ 59

32 Mélikoff, 1877. Project for screw parachute ......................... 60

33 *Castel, 1878. Multiple superposed screws. . . . . ................ . . . 61

34 *Forlanini, 1878. Steam flying screw .......... . ................... 63

35 *Trouvé, 1886. Electric aerial screw ............................... 69

36 The sparrow-hawk’s excursion ....................................... 79

37 *Henson, 1842. The first aeroplane project. . ........................ 83

38 Aubaud, 1851. Multiplane flying-machine project .................. 87
iv

INDEX TO ILLUSTRATIONS.

FXG- PAGE
3:; Loup, 1852. Aeroplane with rotating wings .......................... 88
4o Carlingiord, 1856. Aeroplane project ............................ 89
41 *Du Temple, 1857-77. Steam aeroplane ............................. 91
42 Smythies, 1860. Aeroplane and vibrating wings. . ................... 93
43 De Louvrié, 1863. Kite-like aeroplane ............................. 94
44 D‘Esternn, 1864. Aeroplane for soaring flight .......... .. .. ...... 97
45 Claudel, 1864. Aeroplane with rotating wings ........................ 99
46 *Wenham, 1866. Experimental apparatus N0. 1 ................... 100
47 *Wenham, 1866. Experimental apparatus No. 2. . . . . . .. . . . . . . .. . 101
48 *Le Bris, 1867. Artificial albatross ................................. 105
49 Smyth, 1867. Aeroplane With lifting and driving screws .............. 111
50 Butler and Edwards, 1867. Arrow-like aeroplane ................... 112
51 *Stringfellow, 1868. Steam aeroplane (superposed) .................. 113
52 Danjard, 1871. Bi-planes, with vibrating wings .................... 116
53 *Pénaud, 1871. Experimental automatic aeroplane ................... 117
54 Pénaud and Gauchot, 1876. Preject for steam flying machine.. .. . . ... 121
55 ‘Moy, 1875. Aerial steamer ........................................ 125
56 *Moy, 1879. Military—kite aeroplane ............................... 129
57 Pomes, 1878. Project for aeroplane ................................. 135
58 *Tatin, 1879. Compressed air aeroplane .......... . ................. 138
59 *Dandrieux, 1879. Butterfly toy aeroplane .............. . ............ 142
60 *Brearey, 1879. “ Wave action” flying machine ..................... 143
61 *Mouillard, 1865. Soaring apparatus No. 3 ........................... 149
62 *Goupil, 1883. Bird-like aeroplane ................................ 155
63 Beeson, 1888. Patent soaring device ................................. 163
64 *Renard, 1889. Dirigible parachute ................................. 165
65 *Phillips, 1884—91. Experimental curved surfaces ...... .. ............ 168
66 *Grafligny. 1890. Kite-like aeroplane ................................ 173
67 *Jobert, 1887. Kite balanced With cone ....................... . . . .. 181
68 l"Maillot, 1887. Kite to sustain a man ................................ 183
69 *Simplest form of Chinese kite. ................................... 191
70 *Chinese musical kite ............................................. 192
71 *Chinese bird kite . . .. ............... . ............................. 194
72 *Chinese dragon kite ............................................... 195
73 *Lilienthal, 1891. Soaring apparatus ............................... 204
74 *Lilienthal, 1892. In full flight ..................................... 206
75 *Ader, 1891. Flying aeroplane ..................................... 231
76 I"Hargrave, 1889. Screw aeroplane driven by India rubber. .......... 221
77 *Hargrave, 1890. Flying machine No. 10 ......................... 223
78 ‘Hargrave, 1890. Flying machine NO. 12 ............................ 225
79 l"Hargrave, 1891. Flying machine No. 13 ......................... 227
80 *Hargrave, 1893. Cellular kites .................................... 229
81 *Hargrave, 1893. Cellular kites ................................... 231
82 *Maxim, 1892. Steam-flying machine ............................... 232
83 Duryea, 1892. Proposed method of experimenting. .................. 262
84 Moy, 1884. Diagram of forces—sailing boat .......................... 273
85 Moy, 1884. Diagram of forces—gliding bird ........................ 274
PREFACE.

‘

THE following pages consist of a series of articles on ‘ Prog-
ress in Flying Machines,” as distinguished from balloons,
which have been published in Tlze Railroad and Engineering
7oumal (now redesignated as Tim American Engineer), of New
York City.

The first article appeared in October, 1891, and the series
comprised 27 issues. It was at first expected to explore the
subject in six or eight articles, but investigation disclosed that
far more experimenting of instructive value had been done
than was at first supposed, and not only have these articles run
to greater length than was expected, but they have been thought
worthy of issuing in book form.

Naturally enough the public has taken little heed of the prog-
ress really made toward the evolution of a complicated prob-
lem, hitherto generally considered as impossible of solution.
It will probably be surprised to learn how much has been
accomplished toward overcoming the various difficulties in-
volved, and how far the elements of a possible future success
have accumulated within the last five years.

The writer’s object in preparing these articles was threefold :

I. To satisfy himself whether, with our present mechanical
knowledge and appliances, more particularly the light motors
recently developed, men might reasonably hope eventua‘ly to
fly through the air. He now thinks that this question can be
answered in the affirmative.

2. To save the waste of effort on the part of experimenters,
involved in trying again devices which have already failed ; and
to point out, as much as may be, the causes (f such failures. To
this end an earnest efiort was made to gather all the experi-
mental records which were accessible, and to obtain a thor-
ough understanding of them, so as to bring out clearly the
reason of the failure. The reader must be the judge as to the
measure of success which has attended this effort.

3. To furnish an account of those recent achievements which
render it less chimerical than it was a few years ago to experi-
ment with a flying machine, and to give such an understanding
of the principles involved and of the results thus far accom-
plished, as to enable an investigator to distinguish between an
inadequate proposal, sure to fail, and a reasonable design.
worthy of consrderarion, and perhaps (after due investigation
and preliminary trial) of experiment upon an adequate scale.

CHICAGO, January, 1 894.
 
FLYING MACHINES.

INTRODUCTION.

HAVING in a previous volume treated the general sub-
ject of “ Aerial Navigation,” in which a sketch was given
of what has been accomplished with balloons, I propose in
the following chapters to treat of Flying Machines proper
——that is to say, of forms of apparatus heavier than the
air which they displace ; deriving their support from and
progressing through the air, like the birds, by purely dy-
namical means. ,

It is intended to give sketches of many machines, and
to attempt to criticise them.

\Ve know comparatively so little of the laws and princi-
ples which govern air resistances and reactions, and the
subject will be so novel to most readers, that it would be
difficult to follow the more rational plan of first laying
down the general principles, to serve as a basis for dis—
cussing past attempts to effect artificial flight. The course
will therefore be adopted of first stating a few general
considerations and laws, and of postponing the statement
of others until the discussion of some machines and past
failures permits of showing at once the application of the
principles.

The first inquiry in the mind of the reader will probably
be as to whether we know just how birds fly and what
power they consume. The answer must, unfortunately, .
be that we as yet know very little about it. Here is a
phenomenon going on daily under our eyes, and it has not
been reduced to the sway of mathematical law.

There has been controversy not only about the power
required, but about the principle or method in which sup-
port is derived. The earlier idea, now abandoned, so far

I
2 FLYING MACHlNES.

as large birds are concerned, was that when they {lapped
their wings downward they produced thereby a reacting
air pressure wholly equal to their weight, and so obtained
their support. This is known asthe “ orthogonal theory,”
and has been disproved by calculations of the velocity and
resulting pressures of the wing beats of large birds, and
by the more recent labors of Professor Marey. It seems
likely that the smaller birds, who, as will be explained
hereafter, are probably stronger in proportion to their
weight than the larger birds, possess the power of deliver-
ing blows upon the air equal to a supporting reaction.
Such may be the case in the hovering of the humming-
bird and the rising vertically of the sparrow; but the latter
exertion is evidently severe, and cannot be long continued.

Mr. Drzeweicki has shown that a buzzard, beating his
wings 2% times a second, with an amplitude of 120°, could
only obtain, according to accepted formulae of air pressures,
a sustaining orthogonal reaction of 0.40 pounds or about
.15 of his weight, while if his wings are considered as in—
clined planes, progressing horizontally at a speed of 45
miles per hour, a sustaining reaction is easily figured out.

It seems quite certain that large birds cannot practice
orthogonal flight, and that they derive their support main-
ly if not wholly from the upward reaction or vertical
component of the normal air pressure due to their speed.
That they are livmg Aeroplanes, under whose inclined
wings their velocity creates a pressure which is normal to
the surface. This is confirmed by the great difficulty which
they experience in getting under way. They run against the
wind before springing into the air, or preferably drop down
from a perch in order to gain that velocity without which
they cannot obtain support from the air. Thus the sur-
faces of their wings act as aeroplanes as well as propellers,
the latter action being produced by the direction of the
stroke and the bending upward of the rear flexible portion
of the feathers.

Bird flight may be considered as comprising three
phases :

1. Starting. during which great exertion must be made,
unless gravity can be utilized.

2. Sailing, or flight proper, during which the bird
exerts his normal force, or makes use of that of the wind,
as will be more particularly explained hereafter.

3. Stopping, in which great exertion may again be re-
quired, if the headway is to be rapidly stopped, or in which
the retarding force of gravity may be brought to do the
work by simply rising to a perch.

Artificial flying machines will certainly have to conform
to these three phases of flight, by providing methods of
GENERAL PRINClPLES. 3

starting and stopping in addition to the means for per-
forming the act of flight proper.

Birds perform all their manoeuvers by regulating the in-
tensity of their action, and by changing the angles at
which they attack the air. Hence the important thing for
us to know is to ascertain what pressure exists under a
wing or, to simplify the question, under a plane surface,
when it meets the air at a certain velocity and with a cer-
tain angle of incidence.

This has been, until the recent publication of Professor
Langley’s most important labors, a subject of uncertainty,
which uncertainty he has done much to remove. We
had had glimpses of the law ; but notwithstanding
very many experiments by physicists, its numerical values
were a subject of doubt and controversy among the few
who gave any attention to the subject. It was the missing
link, which rendered nearly unavailable the little that was
known in other directions.

By the law of fluid reactions all air pressures are “ nor—
mal," or exerted perpendicularly to the surfaces against
which they bear ; now the question was: What. is the re—
lation between the pressure of a current of air of known
velocity against a thin plane surface placed at right angles
thereto, and the normal pressure of that same current
against the same plane, if the latter be inclined to the cur—
rent at an angle of incidence less than 90 degrees?

Newton impliedly gave a solution ; but experiments long
ago proved it to be wrong, although it is still taught in
the schools and given in formulas in engineering reference
books. He assumed, plausibly enough, that the propor-
tional normal pressure was in the ratio of the sine of the
angle of incidence, and when experiment showed this to
be erroneous, other formulas were proposed, the following
being a few of those which have been wrangled over :

Calling a the angle, and P the pressure on the inclined
surface, while P’ is that upon the right-angled surface, the
following were assumed to represent the relation :

P:P’sina P=P’sin2a
P = P’ sin3 a , . ,
2 sin (l P = P (5111 601.54 coaa
P = P’ ~ W .
I+Sln2a P=2P’sma

Indeed, the field seemed so open in this direction that
only two years ago I ventured to propose a formula of
my own, which I subsequently concluded to be erroneous ;
but the question seems now to be set at rest for the present
by the experiments of Professor Langley, who proposes no
formula of his own, but who shows that his results ap-
proximate very closely to the formula of Duchemin :
4 FLYING MACHINES.

APPROXIMATE PERCENTAGES OF NORMAL PRESSURE. DERIVED FROM CHART
0F EXPERIMENTS AND THEORIES. CALCULATED BY BOSSUT’S OR
DUCHEMIN’S FORMULA.

 

 

 

 

 

 

 

 

2 sin a
P=P’ — ——
1+sin2 a
Results of Proportion
Deg' °f s P L311 10 ’A Normal Lift 1) 'ft
Angle. ' ' . g y ‘ ‘ r1 '
Experlments. Pressure.
I 0.035 0.035 0.000611
1% 0.052 0.052 0.00136
2 0.070 0.070 0.00244
3 0.104 0.104 0.00543
4 0.139 0.139 0.0097
5 0-15 0.174 0.173 0.0152
6 0.207 0.206 0.0217
7 0.240 0.238 0.0293
8 0 273 0.270 0.0381
9 0.305 0.300 0.0477
10 0.30 0.337 0.332 0.0585
11 0.369 0.362 0.0702
12 0.398 0.390 0.0828
13 0.431 0.419 0.0971
14 0.457 0.443 0.1155
15 0.46 0.486 0.468 0.124
16 0.512 0.492 0.141
17 0.538 0.515 0.157
18 0.565 0.538 0.172
19 0.589 0.556 0.192
20 0.60 0.613 0.575 0.210
21 0.637 0.594 0.228
22 0.657 0.608 0.246
23 0.678 0.623 0.264
24 0.700 0.639 0.286
25 0.71 0.718 0.650 0.304
26 0.737 0.662 0.323
27 0.752 0.670 0.342
28 0.771 0.681 0.362
29 0.786 0.686 0.382
30 0.78 0.800 0.693 0.400

 

 

 

 

 
GENERAL PRINCIPLES. 5

 

 

 

 

 

 

 

 

 

D of Results of Proportion .
eg. S. P. Langley’s Normal Lift. Dnft'

Angle. .

Expenments. Pressure.
31 0.815 0.698 0.421
32 0.828 0.702 0.439
33 0.843 0-706 0-459
34 0.853 0.707 0 478
35 0.84 0.867 0.708 0.498
36 0.878 0.709 0.516
37 0.885 0.709 0.532
38 0.894 0.705 0.551
39 0.902 0.701 0.569
40 0.89 0.910 0.697 0.586
41 0.918 0.693 0.602
42 0.926 0.688 0.619
43 0.934 0.683 0.638
44 0.941 0.676 0.654
45 0.93 0.945 0.666 0.666
_ , 2 sin a
— I + sm2 a

I had already independently reached a conclusion quite
similar. Finding that my formula was incorrect, I had a
chart plotted, on which were delineated all the experi—
ments on inclined surfaces which I could learn about——
those of Hutton, Vince, Thibault, Duchemin, De Louvrié,
Skye. the British Aeronautical Society, and W. H. Dines ;
and on this chart I also had plotted the curves of the various
formulas. The whole exhibited great discrepancies, yet
by patient analysis various probable sources of error were
eliminated, and the conclusion was reached that the for-
mula last given, which I have seen variously attributed to
Bossut or to Duchemin, was probably correct.

From this formula I had computed for my own use the
accompanying table of normal pressures ; and as it seems
to be quite confirmed by Professor Langley's experiments,
and seems to promise to be of great use, I now venture to
publish it.

Once the normal pressure is known at a particular angle
of incidence, its static components in different directions
can be obtained by the laws governing the resolutions of
forces. This was shown, as early as 1809, by Sir George
Cayley, in the following demonstration, in which he in-
6 FLYING MACHINES.

geniously evades the then prevailing confusion about the
“law of the angle" by starting with the weight, of the
bird instead of its wing surface and velocity. He says :

When large birds, that have a considerable extent of wing
compared with their weight, have acquired their full velocity,
it may frequently be observed that they extend their wings, and,
without waving them, continue to skim ,for some time in a
horizontal path.

Fig. I represents a bird in this act. Let A B be a section of
the plane of both wings. opposing the horizontal current of air
(created by its own motion), which may be represented by the
line CD, and is the measure of the velocity of the bird. The
angle 8 D Ccan be increased at the will of the bird, and to
preserve a. perfectly horizontal path, without the wing being
waved, must continually be increased in a complete ratio (use-
less at present to enter into), till the motion is stopped alto-
gether ; but at one given time the position of the wings may be
truly represented by the angle 8 D C. Draw D E perpendicu-
lar to the plane of the wings. produce the line CD as far as re-
quired, and from the point E, assumed at pleasure in the line
D E, let fall E Fperpendicular to D F; then D E will repre-

E

Fig. I.

 

sent the whole force of the air under the wing—i.e., normal
pressure, which being resolved into the two forcesEF and
F D, the former represents the force that sustains the weight
of the bird, and the latter the retarding force by which the
velocity of the motion producing the current CD will be con-
tinually diminished; f? F is always a known quantity, being
equal to the weight of the bird, and hence FD is also known,
as it will bear the same proportion to the weight of the bird as
the sine of the angle 8 D C bears to its cosine, the angles D E F
and B D C being equal.

In the table, pages 4 and 5, the first column shows the
degree of the angle of incidence ; the second the result of
Professor Langley’s experiments ; the third the proportion
or percentage which the normal pressure at that angle
bears to the pressure atthe same velocity of the same plane
GENERAL PRINCIPLES. 7

at right angles to the current; while the fifth and sixth
columns show the resolutions of this normal pressure,
being the force which sustains the weight of the bird ver—
tically as against gravity, which is here termed the “ Lift ;”
and the retarding force against horizontal motion, which
is here termed the “ Drift.” They are calculated by mul-
tiplying the normal pressure by the sine and by the cosine
of the angle.

In order to obtain the aggregate normal pressure, or the
lift and the drift, upon any thin plane surface, it is simply
necessary to multiply its area by the pressures per square
foot, which are given (approximately) in the ordinary
tables of wind velocities, and this again by the percen—
tages given in the table.

The angles are only given up to 45°, as more than this
would be useless to the general reader; and it will be
noted that there is an angle of maximum uplift at about
36°. This results from the factthat the normal pressure
is continually increasing, while the cosine of the angle is
continually diminishing, but not equally. so that their
product reaches a maximum, as stated. This is confirmed
by the results of Professor Langley’s experiments, as re-
corded on page 58 of his “ Experiments in Aerodynamics.”

It should be borne in mind that the table only purports
to apply to thin planes one foot square, and hence is given
as containing only approximate percentages of normal
pressures. For other shaped planes, for curved surfaces,
and for solids the percentages may be different, because a
great many anomalies have been found in experimenting
upon air resistances, and we yet know painfully little
about them.

For instance, the following may be mentioned :

I. For high velocities, such as those of projectiles, the
resistances do not vary as the square of the speed, as as-
sumed in ordinary tables ; they more nearly approach the
cube of the velocity. _

2. If a thin plane be exposed to a current of air, at right
angles thereto, the pressure on the plane is not uniform
over all its surface, but is greatest at the center.

3. Plane surfaces of equal areas but of different shapes
(square, oblong, triangular, etc.) are found to receive
slightly different pressures at the same speed. Moreover,
the average pressure per square foot varies with mere
variation of size on the same shaped planes.

4. The pressure upon an inclined elongated surface will
vary for the same speed, whether it be exposed longi-
tudinally or transversely to the current.

5. Holes may be cut in thin planes without reducing the
aggregate pressure in proportion to the surface cut away.
8 FLYING MACHINES.

Moreover, the aggregate pressure may be made to vary by
simply changing the position of the holes.

6. Inclined planes may be superposed without diminish-
ing the sum of their separate individual pressures, pro—
vided they are properly spaced with regard to the angle of
incidence. If too close, they will interfere with each
other, but the amount of such interference will vary with
the speed.

7. Perfectly horizontal planes, free to fall, have their time
of falling much retarded if in rapid horizontal translation.

8. The weight remaining the same, the force requisite
to sustain inclined planes in horizontal motion diminishes
instead of increasing, when the velocity is augmented.

9. If the plane be gradually inclined to the current. the
point of maximum pressure will move forward toward the
front edge as the angle of incidence diminishes. The
position as given by Joe'ssel’s law is shown by the
formula :

C: (0.2 + 0.3 sin a) L,

in which C represents the position of the center of press—
ure, L the length, and a the angle of incidence, the
formula indicating that the position of the center of press-
ure varies from 0.5 to 0.2 of the distance from the front
to the center of the plane.

Of these anomalies, the 6th, 7th and 8th were experi-
mentally determined by Professor Langley ; and he partly
confirmed the 9th. as well as giving strong confirmation to
the results of Duchemin 0n the “ law of the angle” pre—
viously mentioned. The 8th is especially important, and
its consequences are pointed out by Mr. Langley in the
following words :

The most important general inference from these experi-
ments, as a whole, is that, so far as the mere power to sustain
heavy bodies in the air by mechanical flight goes, such mechani-
cal flight is possible with engines we now possess, since effec-
tive steam-engines have lately been built weighing less than IO
lbs. to I H.P., and the experiments show that if we multiply
the small planes which have been actually used, or assume a
larger plane to have approximately the properties of similar
small ones, 1 H.P., rightly applied, can sustain over 200 lbs. in
the air, at a horizontal velocity of over 20 meters per second
(about 45 miles an hour), and still more at still higher velocities.

These general remarks chiefly apply to thin plane sur-
faces, such as might be used in flying machines, but mere
thickness plays an important part; for in asolid body,
with the same area of exposed head surface, the pressure
will be varied by the depth, and especially by the form of
the body in the rear. Thus curved surfaces and solids
GENERAL PRINCIPLES. 9

have quite different coefficients of pressure from thin flat
planes, and theoretical estimates of their resistances have
hitherto proved to be quite wrong.

Indeed, it may be said with respect to curved surfaces
and solids, that a glimpse has been caught of a still more
mysterious phenomenon. It is known that certain shapes,
when exposed to currents of air under certain ill-under-
stood circumstances, actually move toward that current
instead of away from it. Thus a hollow sphere impinged
upon by an air jet will move up toward it instead of away.
The lower disk in Professor VVillis’s apparatus, when
blown upon, moves against the current toward the upper
disk. Dr. Thomas Young proved, in 1800, that a certain
curved surface suspended by a thread approached an
impinging air current, instead of receding from it. M.
Goupil found, in experimenting, that a suspended hollow
shape was first blown out, to a horizontal position by a
wind of sufficient velocity, and then, when that velocity
increased, actually drew into the wmd for an instant and
slackened the tension on the cord. It is also said that cer—
tain forms of windmills wear more on the front stop than
on the back stop of their axle of rotation ; so that there
seems to be a mysterious action, which some French ob-
servers, who have been watching birds soar, have, for
want of a better term. called their“ Aspiration,” by which
a body acted upon by a current may actually draw for-
ward into that current against its direction of motion.

Thus it is seen that in such complicated matters theory
cannot progress in advance of experiment, and the
extreme importance of those experiments hitherto tried,
or hereafter to be tried by a physicist possessing the
ability of Professor Langley, will in part be appreci—
ated.

Science has been awaiting the great physicist, who, like
Galileo or Newton, should bring order out of chaos in
aerodynamics, and reduce its many anomalies to the rule
of harmonious law. It is not impossible that when that
law is formulated all the discrepancies and apparent
anomalies which now appear, will be found easily ex-
plained and accounted for by one simple general cause,
which has been hitherto overlooked.

Thus far, Professor Langley seems to have experimented
upon plane surfaces only, and to have measured chiefly
what has been termed in the table here given the “ lift.”
and the “drift" at various angles. His conclusions
therefrom are veryimportant ; but the “ drift’r will not be
the sole resistance to be encountered, for the sustaining
surfaces of a flying machine must not only have a certain
thickness, to give them the necessary strength and rigid-
IO FLYING MACHINES.

ity, but there will be friction of air upon them, and there
must be a solid body or hull to contain the machinery
and the cargo.

Thus the elements of resistance are three in num-
ber :

I. The hull resistance.

2. The drift.

3. The skin friction.

Of the skin friction Professor Langley says that it is ap-
parently so small that it may be neglected without mate—
rial error; and he has given the measure of the “ drift”
as the result of his experiments.

The head or hull resistance will probably be found to be
the chief element which will limit the possible speed of
flying machines. It will probably grow as the square of
the velocity, thus requiring the power exerted to vary as
the cube of the speed, but will be modified by a series of
coefficients, due to the shape of the solid body, just as
some birds are swifter flyers than others of the same
weight, in consequence of their difference in shape.

Hence the power required to drive such a machine can
only be approximated at present; but this will be more
particularly discussed when treating of the areas of sup—
porting surfaces and speed of birds, for the reader may be
impatient to be told something of what has been attempted
by man.

Inventors, in their ignorance of the laws of air reactions
and resistances, have proposed all sorts of devices for
compassing artificial flight and experimented with not a
few; so that Mr. E. Dieuaide, of Paris, upon making a
study of the subject, published in 1880 an illustrated
chart,* in which he delineated the more remarkable ma-
chines which had been proposed for aerial navigation with-
out the use of balloons. This chart contains some 53
figures; and from this, as well as from the book of M.
Gaston Tissandier on Aerial Navigationflr which contains
much accurate information, the following has been chiefly
compiled, in which it will be attempted not only to give an
account of what has been proposed, so far as the meager
data will permit, but also to critcise the machines with the
light of our present knowledge, and to endeavor to point
out why they failed. Failures, it is said, are more in-
structive than successes ; and thus far in flying machines
there have been nothing but failures.

These various machines, diverse as they are, may rough-

* Taéleau d’Aw‘az‘z'on. Représentant tout ce qui a été fait de remarquable
sur la navigation Aérienne sans Ballons. Published by the author.

‘l‘ La Navigation Ae’rz‘emze. Par Gaston Tissandier. Hachette et Cie;
octavo, 334 pp.
WINGS AND PARACHUTES. II

1y be classed under the three following heads, according to
the intentions and theories which were held by their
authors, as to the most efficacious way of deriving support
from the air.

A. Wings and parachutes.

B. Screws to lift and propel.

C. Aeroplanes.

A.———WINGS AND PARACHUTES.

THE earlier adventurers upon aerial enterprises pos-
sessed little accurate knowledge of the properties of air.
They had only their observations of the birds as a guide,
and knew of no motive power save that derived from mus-
cular energy; hence their thoughts first turned to flapping
wings, to be propelled by their own exertions. Some few,
as we shall see, have considered the force of the wind, but
it is only since the age of steam that artificial motors of
any kind have been proposed for flying machines.

The well—worn legends of antiquity, concerning Dada-
Zus, Aéarz’s, Ara/girls, etc., may be passed over without
comment. They merely indicate how the problem of
artificial (light appealed to the imagination of men from
the earliest periods, but some curious traditions will be
mentioned, indicating partial successes in soaring flight,
when we come to treat of aeroplanes.

About the first authentic account which we have of a
proposal to provide man with flapping wings seems to be
due to Leonardo (fa Vz'ncz', the painter, sculptor, architect,
and engineer. He is said not only to have experimented
with aerial screws made of paper, and to have designed a

 

FIG. 2.—LEONARDO DA VINCI—Igoo.

parachute, but also to have seriously contemplated build-
ing an apparatus to propel a pair of wings, of which sev-
eral sketches have been found in his note-books.

The first sketch shows a wing, actuated by the arms,
I 2 FLYING MACHINES.

but Dd Vz'ncz', becoming aware, upon reflection, that all
possible muscles of man must be brought into play to act
effectually upon the air, designs in the second and third
sketches an apparatus in which the wings are to be waved
downward by the legs and lifted up by the arms. The
third sketch is represented in fig. 2. In this Da Vinci
only shows the legs in place, so as not to obscure the con-
struction of the parts. The date is probably about the
year 1500. The construction is simple, and might not
prove altogether inefficient did the muscles of man pos-
sess the same energy and rapidity of action as do those of
birds in proportion to their respective weights. It is not
known just how far Da Vinci elaborated his idea, but he
never put it to practical test, and it is chiefly mentioned
here as a curious forerunner of actual experiments.

The first wing experiment reported by tradition seems
to be that of a French tight—rope dancer named Allard,
who, under the reign of Louis XIV., announced that he
would fly from the terrace at Saint Germain toward the
woods of Vesinet in presence of the king. It is probable
that he had previously succeeded in gliding short dis-
tances, but upon trial before the court his strength failed
him; he fell near the foot of the terrace, and he was
grievously hurt.

This probably occurred about the year 1660, and in
I678 a French locksmith named Benzz'er constructed a

  
   

 

   
    

yumnmltlltllllll
I /////

ill“ V /
I \t \ \ \ a“
\\\ \ Mm; \
\\ /\\

FIG. 3.——BESNIER—1678.

pair of oscillating wings, approximately represented in
fi . 3.

gThe apparatus consisted of two bars of wood hinged
over the shoulders, and carrying wings of muslin, ar—
ranged like folding shutters, so as to open flat on the
down stroke and fold up edgewise on the up stroke. They
were alternately pulled down by the feet and by the arms,
in such wise, that when the right hand pulled down the
WINGS AND PARACHUTES. I3

right wing, the left leg pulled down the left wing, and so
on, thus imitating the ordinary movements in walking.

Besm'er did not pretend that he could rise from the
ground or fly horizontally through the air. He only tried
short distances; having begun by jumping off from a
chair, then from a table, then from a window-sill, and
next from a second story, and finally from the garret, on
which occasion he sailed over the roof of an adjoining
cottage. He gradually grew more expert, sold his first
pair of wings to a mountebank, who performed with them ,
at the fairs, and he expected with his second pair to fly :
across moderately wide rivers by starting from a height, E
but it is not known whether he ever performed this feat. ‘

The illustration is evidently an imperfect sketch made
from a description ; for the hinging at the shoulder is not
shown, the attachment for pulling down the wings with
the legs is evidently inefficient, and the supporting sur-
faces are entirely inadequate. The four wings are appar-
ently each 3 ft. by 2 ft; say, an aggregate of 24 sq. ft. in
area, while in the table of birds, to be given hereafter, it
will be seen that the duck, which has the smallest bearing
surface in proportion to its weight, measures 0.44 sq. ft.
to the pound, and at this rate a man, weighing, say, 150
lbs., would require wings aggregating 66 sq. ft. in area. It
is probable that Besm’er had even more than this, that he
took short downward flights aided by gravity, but that be
utterly failed when he undertook to go considerable dis—
tances.

It is not stated whether the Marquis de Bouquet/ilk had
engaged in similar preliminary practice when he an-
nounced, in 1742, that he would, on a certain day, fly
across the river Seine from his mansion, situated in Paris
on the quav at the corner of the Rue des Saints Peres, and
alight in the Tuilleries, a distance of 500 or 600 ft. A
large crowd having assembled on the appointed day, the
marquis, with large wings attached to his hands and to
his feet, launched himself into space from the summit of
a terrace jutting out from one side of the mansion.

For a space he seemed to get along well, but soon his
movements became uncertain, he faltered, and then he fell,
alighting upon the deck of a washerwomen’s barge a short
distance out. into the stream. He broke his leg in the fall,
and never attempted the feat again.

The Marquis de Bacquew'Z/e was judicious in trying the
experiment over a water—bed, for could he have held out
but a few feet further he would probably have escaped
with a mere ducking. He probably glided about 120 ft.
with most violent exertions, and fell when his strength
became exhausted. Fig. 4, which is probably incorrect,
14 FLYING MACHINES.

represents the traditional apparatus with which this feat
was attempted. The surfaces measure about 24 ft. in
area, and are quite insufficient to sustain the weight of
a man.

Aware of this experiment of De Bacguem’lle and of its
consequences, the Abbe’Desforges, a canon of the church at
Sainte-Croix at Etampes, invented, in 1772, a flying chariot,

 

Fm. 4.—-—DE BACQUEVILLE—x742.

with two wings and a small horizontal sail or aeroplane at-
tached, whicn from contemporary descriptions seem to
have measured about 14.5 sq. ft. in aggregate area. He
expected to rise from a height of a few feet above the
ground, and to fly horizontally by rapidly beating his
wings. Upon actual tr1al, the machine being held aloft
by four men, the Alybé tlapped Violently, but utterly failed
to start off. Indeed, some of the accounts say that the
action of the wings pulled him down instead of up, so
that he got a harmless tumble when the men let go.

In 1781, Blane/lard, who subsequently became a fervent
aeronaut, and who was the first to cross the British Chan-
nel in a balloon, constructed near Paris a flying chariot
with four wings, measuring in the aggregate some 200
sq. ft. in area. He never exhibited the apparatus in pub-
lic, having probably ascertained by private experiment
that he was unable to move the Wings rapidly enough to
produce any useful effect.

These last two experiments, taken in connection with
those previously mentioned, exhibit fairly well the two
horns of the dilemma that confront inventors who en-
deavor to provide man with wings to be worked by his
own muscular power. Either those wings have to be
relatively small, in order to permit their being waved rap-
idly—and then they do not afford sufficient supporting
area—orif they are made to approximate to the proportion
which generally obtains with birds, or about one square
foot to the pound, they become so large that the man does
not possess the muscular power to wave them at any
adequate speed.

Ideas, however, die hard, and we may disregard some-
’WlNGS AND PARACHUTES. 15

what the chronological order of date, in order to follow
the evolution of the small-wing idea, which each fresh in-
ventor fancies has been incorrectly worked out by his
predecessors.

Of these was Bourcart, who in 1866 experimented with
the apparatus shown in fig. 5, It consisted of four wings
with a feathering action, so that it presented the edge to
the air upon the up stroke and the broad side upon the

 

FIG. 5.———BOURCART-—1866.

down stroke, but the results were insignificant, and the
experiment was abandoned. The supporting areas meas-
ure approximately some 36 sq. it., but are only effective
upon the down stroke.

In 1873 Professor Peliz'grew published his work on
“Animal Locomotion," in which he called attention to
the fact that birds in flapping flight, flex their wings so as
to resemble a screw propeller, and that the tips describe a
figure of 8 motion. This led to the inference that man
had not succeeded in raising himself with wings because

 

 

 

 

 

 

 

 

FIG. 6.-—D ANDRIEUX—1879.

he had not hit upon the right motion, and in 1879 Dam-
drz'eu-x constructed an apparatus in which the wings were
attached to an oblique axle, so as to describe a figure of
8 movement. This is represented in fig. 6, and there
16 FLYING MACHINES

being but two wings in place of four, the supporting sur-
faces measure about 32 sq. ft. in area. The result was
not satisfactory; a partial alleviation of the weight was
obtamed, but nothing like human flight or the hope of it.

A much more successful experiment had, however, pre-
viously been made at the first Exhibition of the Aeronauti—
cal Soctety of Great Britain, held at the Crystal Palace, in
London, in 1868. Mr. Charles Sflencer exhibited an ap-
paratus consisting of a pair of wings measuring each
15 sq. ft. in area, to which was attached an aeroplane
measuring 110 ft. more, and also a tail like a boy’s dart,
and a longitudinal keel-cloth to preserve the equilibrium,
the whole weighing 24 lbs. and givmg a sustaining sur—
face ot 140 sq. ft. As Mr. Spencer was an athlete, he
was enabled, by taking a preliminary run down a little hill,
to accomplish short horizontal flights of 120 to 130 ft., in
which he was wholly sustained by the air. He weighed
140 lbs., and his apparatus, which, it Will be noted from
the description, differed from those which propose “ Wings
for man” by the addition of an aeroplane, measured 0.85
sq. ft. to the pound, or about the proportion of the larger
soaring birds. The experiments attracted great attention
at the time, but were not sufficiently encouraging to war-
rant pursuing the matter further.

At the same exhibition Mr. W. Giéson showed a
machine consisting of two pairs of wings, worked by the
hands and feet together, so as to impart a feathering
movement similar to that of birds. He stated that in a
former machine, having only one pair of wings of lighter
construction, their action upon the air during a vigorous
down stroke was sufficient to raise the. man and machine ;
but no practical demonstration was given, and although
the inventor stated that he was then engaged in construct-
ing a more perfect machine, nothing more has been heard
of it.

Notwithstanding these many failures, the idea does not
seem to be dead yet, for in September, 1890, Mr. W.
Quartermam, who exhibited an explosion engine for
aerial purposes in 1868, in which the motive power was
derived from the gases generated from a species of rocket
composition, wrote a letter to the London Engineer, in
which he stated that he had abandoned his attempts to
procure a light and energetic motor from hydrocarbonous
matter, in favor of man’s weight and muscular power,
which he considers preferable, and was then engaged in
experimenting with an apparatus consisting of four wmgs,
formed after the stag beetle type, each 10% ft. long by 29: ft.
wide, opposing 90 sq. ft. of expanse of surface to the air.
This ar angement weighed 3501bs., including 212 lbs. for
WINGS AND PARACHUTES. 17

the weight of the operator, who by working both handles
and treadles, thus bringing all his muscles into action as
well as his weight, was enabled to wave the wings, which
are 25 ft. from tip to tip, so as to produce a double stroke
for every single stroke of his body on the motive shaft. He
describes the result as resembling that of domestic iowls
flapping their wings without lifting themselves from the
ground, but is of opinion that the uplifting force was
greater than his weight of 212 lbs., and believes that
further improvements in the mechanism, with more skilful
workmanship, might produce an ascensive force greater
than the whole weight of 350 lbs. This may well be
doubted, for not only will it be shown hereafter that the
energy of man must be less than that of birds, but none
of the latter fly with so small a bearing surface in propor-
tion to the weight—0.26 square foot to the pound—as in
Quan‘ermam’s apparatus.

It has been suggested, however, that umbrella-like sur-
faces might prove more effective than wings, and increase
the uplift to be derived from the air. Such contrivances
were experimented upon by Sir George Cay/5y, who con-
structed, about 1808, a pair of wings which appear from
the drawings to have been a fabric stretched tightly over
a dished frame, this framework consisting of two ribs at
right angles to each other, bent and tied across so as to
secure rigidity. This double umbrella contained 54 sq. ft.
and weighed only 11 lbs., and the inventor says: “ Al-
though both these wings together did not compose more
than half the surface necessary for the support of a man
in the air, yet during their waft they lifted the weight of
9 stone” (1261bs.). It is not stated with what speed they
were waited nor with what power, but that the result did
not promise to provide “ Wings for man” may be inferred
from the fact that Sir George Cayley, in a very valuable
series of articles in Nz'c/zo/szm’s journal for 1809 and
1810, starts out with the assertion that, in order to accom-
plish aerial navigation, “it is only necessary to have a
first mover which will generate more power in a given
time, in proportion to its weight, than the animal system
of muscles.”

The next experiments with umbrella-like wings attracted
attention all over Europe. They were carried on by
f. Degm, a clockmaker of Vienna, from 1809 to 1812,
with the apparatus shown in fig. 7. It consisted of two
wings 8% ft. wide and 22 ft. across in the aggregate, each
being shaped somewhat like a poplar or an aspen leaf.
They were stretched upon an umbrella-like frame and
thoroughly braced back, both above and below, to a cen-
tral stick by a number of small cords. The supporting

2
18 FLYING MACHINES.

surfaces consisted of bands of taffeta so attached as to
have a valvular action, in order to imitate the supposed
action of the feathers of birds, and the total supporting

 

 

 

 

 

 

 

 

 

_ ”:52;
FIG. 7.—DEGEN—1812.

surface was 130 sq. ft., while the weight, without the
operator, was stated at 20 lbs.

With this apparatus 05(ng was stated, in 1809, to have
risen to a height of 54 fr., by beating his wings rapidly, in
presence of a numerous assembly in Vienna, and all the
newspapers began to publish accounts of the performance.

These descriptions failed to mention one important ad—
dition. Began was also attached to a small balloon capa-
ble of raising 90 lbs., so that the uplift exerted by the
wings was only 70 lbs. of the 160 lbs. weight of the oper—
ator and his apparatus.

In 1812 Began went to Paris to exhibit his invention.
He then stated that. the balloon was of no sort of utility in
obtaining headway, but that it was necessary as a counter-
poise to maintain his equilibrium and to lighten his
muscular efforts. He evidently expected by the action of
his wings to drag the balloon along in still air while it
lifted part of his weight.

He gave three public exhibitions in Paris, but unfor-
tunately for him, as there was wind upon each occasion, he
was blown away, and on the third attempt he was attacked
by the disappointed spectators, beaten unmercifully, and
laughed at afterward as an impostor.

The umbrella idea had, however, previously proved to
be of value for parachutes, and in 1852 Lctur devised the
apparatus shown in fig. 8, with which he expected to
direct himself through the air. by means of the wings and
tail, tirSI starting from an elevation.

In 1854 he ascended from Cremorne Gardens in London,
suspended about 80 ft. below a balloon manoeuvred by
Mr. Adam, the areonaut, who was assisted by a friend.
Lez‘ur performed several evolutions in the air by means of
his wings, none of them apparently very conclusive; but
in coming down near Tottenham, the wind carried the
apparatus violently against some trees, and poor Lez‘ur
received injuries which resulted in his death.
WINGS AND PARACHUTES. 19

His apparatus measured about 660 sq. ft. in bearing
surface, and had he been entirely detached from the bal—
loon, it is possible that he might have reached the ground
in safety ; but it is evident that his wings would have been

 

 

FIG. 8. —LETUR——1852.

of little service in enabling him to obtain more than a
slight horizontal direction.

Undeterred by this sad fate, a Belgian shoemaker
named De Groof designed, in 1864, an apparatus which
was a sort of cross between beating wings and a parachute.
His plan was to cut loose with it from a balloon, and to
glide down in a predetermined direCtion by manoeuvring
the supporting surfaces. He endeavored to make a
practical experiment, both in Paris and in Brussels,
but it was only in 1874 that he succeeded in doing so in
London.

The apparatus is shown in fig. 9. It consisted of two
wings, each 24 ft. long, moved by the arms and the
weight of the operator, and of a tail 20 ft. long, which
could be adjusted by the feet.

De (3700f first went up on June 29, 1874, from Cremorne
Gardens, London, attached to the balloon of Mr. Sim-
mons. He came down safely, and claimed to have cut
loose at a height of I,ooo ft., but it was subsequently
stated by others that in point of fact he had not, upon
this occasion, cut loose at all, but had descended still
attached to the balloon. In any event. he went up again
on July 5 following, with the same aeronaut, and on this
occasion he really did cut loose.
20 FLYING MACHINES.

The result, was disastrous. As soon as, in the descent,
pressure gathered under the moving wings, they were
seen to collapse together overhead and to assume a verti-
cal position, when De Groof came down like a stone, and
was killed on the spot.

Had the wings been prevented from folding quite back,
by means of suitable stops, the descent might not have

 

FIG. 9.——DE GROOF~1864.

proved fatal. The area of the wings and tail, as extended
horizontally, is said to have amounted to 220 sq. ft., while
the weight of the man and machine was 350 lbs., or at the
rate of 0.65 square foot to the pound. This corresponds
to a pressure of 1.54 lbs. to the square foot, which would
be generated by a velocity of 25.7 ft. per second, or a free
fall from a height of 10.3 ft.; an unsafe distance for an
ordinary person, but not for a trained acrobat.

Ordinary parachute practice is said to allow from 2 to
3 sq. ft. per pound, corresponding to velocities in falling
of 14.7 to 12 ft. per second.

It was the most. egregious folly for Letur and De Groof,
as well as for Cat/sing, who was killed in 1836 in an ex-
periment with a parachute shaped like an inverted um-
brella, to attempt a descent with an apparatus preViously
untried to test its strength and behavior. A few prior
experiments, with a bag of sand, instead of the man, would
have exhibited the action that was to be expected.

Another class of inventors of ”wings for man” have
endeavored to secure safety by the use of large bearing
surfaces. The first of these was probably, Meant/gin,
‘WINGS AND PARACHUTES. 2 I

architect to the Prince of Wales, in 1784, who proposed
an apparatus shaped like the longitudinal section of a
spindle, separated into two wings, by a hinge at the center.
It measured nearly 200 sq. ft. in area, and probably was
never tried, but if it had been, it is quite certain that a
man could never have imparted to the wings sufficient
velocity to perform any useful effect.

The next proposal of this class was that of Bre’am‘, who

 

FIG. Io.—~BRE’ANT——1854.

designed in 1854 the apparatus shown in fig. IO. It con-
sisted of two wings, each measuring about 54 sq. ft. in
area, and provided with three valves to relieve pressure
on the up stroke. The down stroke was to be produced
by the joint action of the feet and hands, and the wings
were to be drawn back by elastic cords. It is not known
whether it was ever tried, but it would have proved in—
effective if it had been.

The next. design was that of Le Eris in 1857, which is
exhibited by fig. II. By noting the little man working
the levers in the center, the proportions of the apparatus,
which seems to have measured some 550 sq. ft. in area,
will be appreciated. It is said to have been experimented
with in a small model, in which levers pulled down the
wings which were then drawn back by springs, but it did
not succeed in rising into the air, as was hoped by the
inventor.

Before proceeding to describe other designs for winged
machines, to be driven by artificial motors instead of
muscular power, it may be well to call attention to the
fact that not only has every attempt of man to raise him—
self on the air by his own muscular efforts proved a com-
plete failure, but that there seems to be no hope that any
22 FLYING MACHINES.

amount of ingenuity or skill can enable him to accomplish
this feat.

It has been argued that there is no proof that, weight
for weight, a man is comparatively weaker than a bird,
and that, inasmuch as he can raise his weight in walking
up a stairway, he should be able to raise it by acting upon
the air with a suitable apparatus. The weak point about

 

FIG. IL—LE BRIS—1857.

this argument is not only that the weight and bulk of such
an apparatus become a surcharge on the muscular power
of the man, as would be, for instance, the case were an
artificial pair of wings applied to an ostrich, but that
among the birds themselves the power to rise vertically
unaided does not exist for the larger species. These have
to resort to various artifices, such as running against, the
wind or dropping from a perch, in order to gain that
initial velocity which enables their surfaces to derive sup—
port from the air, and this probably furnishes a good
reason why no flying birds exceed some 50 lbs. in weight ;
for small animals must possess more energy in proportion
to their size than large ones.

Assuming that the speed of contraction in the muscles
of two similar birds of different sizes is the same, it is
evident that the work done per unit of time will be in ratio
to the sectional area, or as the square of the dimensions,
while the weight to be moved will vary as the cube of the
dimensions ; hence the rate of increase between the energy
and the weight will be:

2 ——-—- 3‘ —
l/Energy varies as l/weight,

 
WINGS AND PARACHUTES. 23

or to put it in the shape of formulas which shall express
the relative energy 0t animals of the same class :

g ——-— 1.5 / ~—

E oc 1/20 0: Viv 0c W

These being all merely different ways of writing it.

Hence we see that the energy of birds will only increase

as the 7“; power of their weight, and that there will be

an increase of size beyond which they will not be able to
deveIOp the work required for a start;*

But man is also at alurther disadvantage. Not only
do birds have an enormous muscular development, but
their muscles contract at a much more rapid rate than
those of other animals. Were men, therefore, not already
relatively weaker than smaller animals, in consequence
of the physical law which has been stated, they would still
be unable to develop energy fast enough to rise on the air
with a pair of wings. They can raise their weight, it is
true, but not as quickly as the birds. They can run up a
stairway at the rate of about 3 ft. per second, while the
sparrows rise up vertically at thricevthat speed, and fly hori»
zontally at 22 ft. per second.

While the inventors who experimented with flapping
wings, with which they tried to raise themselves on .the
air by muscular effort. doubtless had it in mind eventually
to substitute artificial motors, if only they could catch the
trick by which the bird flies, there have been a few others
who have at the outset. designed flapping wings, to be
moved by some primary artificial motor. As they gener-
ally knew of no such motor, within admissible limits of
weight in proportion to its energy, such designs have re-
mained mere projects, and but few experiments have been
made.

The proposal of Ge’rara’, in 1784, shown in fig. 12,
seems to have been among the first. It apparently pro—
vides, in addition to the body and wings, for a steering
arrangement in front, and for leet with springs to land
upon. The inventor omitted to state in his printed de-
scription what motive power he intended to use, but an
inspection of the drawing suggests the conjecture that the
apparatus was to be propelled in part by escaping gases,
like a rocket, and in part by flapping the wings through
the medium of a gunpowder engine; proposals and ex-
periments with such motors antedating, as is well known,

 

mite

*'l bus a bird of :0 lbs weight can do no more work In a given time than
50/: 13. 57 similar birds each weighing I lb. ,or a bird of I 000 lbs. , did such a
one exist could only develop the same number of foot- -pounds per minute as
the aggregate of 100 analogous birds, each of 1 lb. weight.
24 FLYING MACHINES.

those with the steam—engine. Be this as it may, soon
after the success of the locomotive engine on the Liver-
pool & Manchester Railroad, Mr. F. D. Artz’ngslall en-
deavored to compass an aerial locomotive. He con-

 

 

FIG. 12.—GI::RARD—I784.

structed a very light steam—engine, suspended it by a cord
from the ceiling, and to the piston-rod he attached wings,
which were so constructed that they opened somewhat like
a Venetian blind on the up stroke and closed during the
down stroke, moving through an arc of 800. When steam
was turned on the wings worked vigorously, but the
machine jerked up and down, rushed from side to side,
and, in fact, performed all kinds of gymnastic movements
except flight. This experiment was terminated by the
explosion of the boiler, and a second attempt, in which it
was intended to use four wings instead of two, in order
to keep up a continuous buoyancy, resulted in a second
explosion ; after which the experiments were abandoned.
In 1868 Mr. Ariz'ngsz‘a/l, in a communication to the
Aeronautical Society of Great Britain, stated the weak
point in his various experiments to have been the lack of
suitable equilibrium.

Every experimenter with aerial apparatus has doubtless
encountered the difficulty of obtaining in a machine that
equilibrium which the bird maintains by instinct, and
also of deriving continuous support from the flapping of
one pair of wings. These are probably the reasons which
led Struvé and Telesc/zej’ to design, in 1864, the appa—
ratus shown in fig. 13, in which five pairs of wings are
attached to a central plane. The only description accessi-
ble to the writer states that the wings were moved by
human force acting upon a spring, but it is evident that
WINGS AND PARACHUTES. 25

the apparatus was intended to be driven by artificial
power, if the designers could only find one sufficiently
light for that purpose. That they did not succeed in this

 

 

 

 

FIG. 13.—STRUVE’: & TELESCHEFF —1864.

seems to be a fair inference from the fact that the machine
was not tested by experiment.

At the Exhibition of 1868, of the Aeronautical Society
of Great Britain, Mr. I. Palmer exhibited a pair of wings
(to be driven by power) attached to a rotating axle, and
so arranged that they expanded in the descent and closed
in the ascent, like the action of a duck's foot in swim-
ming; this motion being obtained in a remarkably simple
manner by a roller running on an eccentric cam, which
could be instantaneously changed in position, so as to
convert the vertical lifting power into one of horizontal
force. It does not seem to have been applied to any flying
machine.

At the same exhibition Mr. I. M Kaufman”, engineer
of Glasgow, exhibited the working model represented in
fig. 14, which was intended as the precursor of an aerial
steam machme weighing 7,000 or 8,000 lbs. The appa-
ratus consisted of a steam boiler and engine, mounted
upon wheels, and propelled by two long wings, which.
during the down stroke, were set at. an inclined direction
backward. and were caused to turn at a forward angle
during the up stroke. The main portion of the weight
was to be sustained by superposed aeroplanes, and hence
the machine should perhaps be described under that head,
but itis here included under the head of wings, because of
the mode of propulsion. The model weighed 42 lbs., and
during the experiments with it its boiler, owing to its
26 FLYING MACHINES.

small size, was not fired, steam being supplied from an
independent boiler. With steam pressure at 150 lbs. to
the inch, the wings made a short series of furious flaps,
and one of them suddenly gave way about 2 ft. from its
base, upon which the other one failed also. The inventor
stated that he was then engaged in the construction of a
larger machine on the same principle, but since then

 

 

 

 

 

FIG. I4.—KAUFMANN—1867.

nothing more has been heard of it. He proposed to secure
stability by letting down or raising up a long “ pendule"
with telescopic jomts, so as to adjust the center 0t gravity
and keep the machine in a horizontal position, but it may
well be doubted whether this would have proved effective.

At a meeting of the British Aeronautical Society, in
1871, Mr. R. C. fay exhibited a model to illustrate a
method which he proposed in order to use wings of any
length and weight without loss of power. This consisted
of two pairs of oscillating wings moving on the same
shaft. it was expected that the forces generated by their
motion would hold the machine is equilibrium, and that
one pair of wings would be aided by the current of air,
or whirlpool, produced by the movement of the other
pair. This does not seem to have answered, for in 1877
the same inventor presented a model to the same society,
illustrating a method of obtaining a figure of 8 or sculling
action with one pair of wings, but at the same time
Mr. fay candidly stated that “although he had made a
great many experiments, he had not. yet succeeded in
making a propeller (wings) sufficiently simple and effective
for practical purposes.”

It is said that about the same time an ofilz'cz'an of Leipsic
made a small steam bird, mounted on a globular steam
boiler and actuated by a cylinder of 2 in. stroke, working
wings 32 in. long. This machine would rise vertically
3 ft., the wings making about three beats during the
flight, but the boiler limited the performance. It con-
tained spirits of wine only sufficient for 38 seconds, and
the apparatus was but a toy.

In 1871 Przgent designed the apparatus shown in fig. 15,
WINGS AND PARACHUTES. 27

which was evidently suggested by the dragon-fly ; this is
a favorite idea with aviators, who, as we have seen
already, have proposed the combination of two pairs of
wings over and over again. It was intended to be driven
by steam, but although in that same year [May had pro-
duced a steam-engine and boiler weighing but 27 lbs. per
horse power, and Slrz'izgfellow, in 1868, has shown one
claimed to weigh but I3 lbs. per horse power (both applied
to aeroplanes). no attempt seems to have been made to
experiment with Prz'gezzt’s device. The fact is, that even
the weight of the engines mentioned was too great, for it
did not include the fuel and water, which for a non-con-

 

FIG. 15.—PRIGENT——187I.

densing steam-engine would amount to about 26 lbs.
more horse power fer flour, and this did not compare
favorably with the motive power of birds. The pigeon,
for instance, is known, both by dynamometric experiment
and computation, to develop in ordinary flight from 160
to 425 foot-pounds of energy per minute for each pound of
his weight, and as his pectoral muscles, which consti-
tute lzz‘s engine, generally compose $3 of his weight, we
have for the weight of Izz's motor from

33,000 X 10 :181bs.to 33.000 x 10
425 X 43 160 x 43

per horse power developed, including the fuel which
enables him to fly for 10 to 12 hours at a stretch.

Hopeless, therefore, of accomplishing anything practi-

cal with steam-engines, experimenters with wings next

turned their attention to springs or reservoirs of energy

of various kinds, and with these they have succeeded in

devising a number of toys which fly creditably for a few

seconds. Clock springs were first tried, but they were

found to be unduly heavy, and in 1871/0557! brought out

 

 

= 48 lbs.
28 FLYING MACHINES.

his first mechanical bird, shown in fig. 16, driven by india-
rubber in tension. The wings were arranged so as to
change their plane automatically while flapping, in order
to imitate the flexions of the natural wings, and the equilib-

 

FIG. 16.——JOBERT—187I.

rium was secured by adjusting the center of gravity so
as to correspond with the center of pressure due to the
angle of flight.

In 1872 Pe’mzud, who had already succeeded (1870 and
1871) in compassing flight with the superposed screws and

 

FIG. 17.—PENAUD—1872.

with the aeroplane, which will be noticed hereafter, by
the force of twisted rubber, applied the same motor to a
WINGS AND PARACHUTES. 29

mechanical bird, which is shown in fig. 17. The wings
beat straight down, and the propulsion is obtained from
the fiexion of their outer edges produced by the reaction
of the air. The bird is unable to rise from the ground,
but upon being thrown off the hand it first descends some
2 ft., and then, having acquired the initial velocity needed
for support, it flies for a distance of 50 ft. in 7 seconds,
rising at the same time about 8 or 9 ft. above the point of
departure, the equilibrium being perfectly maintained by
the tail.

Simultaneously with this M. Human: de Vz'lleneuve, the
permanent Secretary of the French Aeronautical Society,
brought out his mechanical bird, which is shown in fig.
18. In this the plane of the wings is inclined at an angle
of 45°, and the power is obtained from twisted rubber. In
consequence of the peculiar motion of the wings, this
model was able to start. direct from the ground, but owing

 

 

FIG. 18.—HUREAU DE VILLENEUVE—x872.

to the limited power of the rubber spring it only rose to
the height of 4 ft., and then descended, forming a para-
chute. It was subsequently modified so that it would fly
horizontally for a distance of 24 ft., at a velocity of 20
miles per hour.

M. De Vz'ZZmeuve has been promoting aviation by
flapping wings for the past 25 years. He has, first and
last, designed something like 300 experimental models, so
that his garret is a complete aviary of artificial birds. He
built, some years ago, a huge steam bird on the model of
a bat. Being aware that there was at that time no suffi-
ciently light and reliable steam—engine with its boiler to
furnish the power required, he placed only the engine 0n
30 FLYING MACHINES.

the bird, and connected it by a hose with a boiler on the
ground. Upon trial, as soon as the steam was turned on
the wings beat violently, and the apparatus rose with the
inventor aboard. He grew nervous for fear that he would
get beyond the length of his hose, and shut off steam sud—
denly, upon which the bird fell and smashed one of its
wings. It is still in existence, and the inventor is await-
ing the development of a very light motor in order to
resume his experiments with this great bird, which is
some 50 ft. across.

In 1872 M./0berz‘ brought out his second mechanical
bird, shown in fig. 19. This is driven by twisted rubber,
as being more manageable than rubber in tension, and
consists of four wings beating alternately in pairs—as a
horse trots—-—in order to produce continuous and uniform
support and equilibrium, instead of the jerking motion
observable in other apparatus. This flew fairly well, but
a measurement of the foot-pounds developed and of the
results obtained, in this as well as in the three other
mechanical birds previously described, led to the inference
that there was great waste of power, as compared with
that of birds. This was attributed to the rigidity of the

I

   

FIG. 19,—JOBERT—-1372.

front edge of the wings in all these models, and accord—
ingly in 1876 Talm took the problem up again and suc-
ceeded, by a double eccentric working two levers con-
nected to the front edge of the wing, in giving it a twist—
ing motion similar to that of the bird. His apparatus
flew some 65 ft., with rather less weight of rubber.

In 1889 Pz'c/zancourz‘ carried the matter still further in
the mechanical bird shown in fig. 20, in which there is a
‘W'INGS AND PARACHUTES. 31

 

 

 

FIG. 2o.—PICHANCOURT—ISSQ.

triple eccentric, each one actuating a lever fastened to a dif-
ferent point in the wings. His larger models, measuring
173; in. from tip to tip of wings, and weighing 1% 02., are
said to have flown up to a height of 25 ft. and to a dis-
tance of 70 ft. against a slightly adverse wind.

Now here ar no less than six artificial birds, each with
a somewhat different wing—motion, and they all fly, when
urged by the energy stored in twisted rubber. The ques-
tion, therefore, occurs why practicable machines, to carry
passengers, cannot be built by substituting some prime
mover for the rubber; and the answer is that all these
models are so wasteful of power that there is no motor
known sufficiently light, in proportion to its energy, to
take the place of the rubber. The best that seems to have
been done with the latter was to obtain a flight of 7 sec—
onds with flapping wings, and with the expenditure of
energy at the rate of 600 foot-pounds per pound of twisted
rubber. As there are 550 foot—pounds per second in a horse
power, a primary motor, wz'l/z 2'15 szz/fijfilz'es, should in the
same proportion weigh no more than :

600
7 X 550
and there are none such known in practical operation.

: 6.4 lbs. per horsepower,
32 FLYING MACHINES.

Undeterred by this disheartening fact, M. De Lam/72k?
designed, in 1877, the apparatus shown in fig. 21, which
he calls the “ Anthropornis,” and which consists of a pair
of wings, resembling those of the swallow, fastened to a
hull mounted upon wheels, and intended to be actuated
by a steam-engine or a petroleum motor. A spring is to
contribute to the downward stroke, and is to be raised by
the motor on the up stroke. M. De Louvrz'e’ is a veteran

 

 

 

 

FIG. 21.—DE LOUVRIEL1877.

in promoting aviation, and his writings show a better
understanding and firmer grasp of the question than most
of those which have been published on this intricate sub«
ject. He had proposed, in 1863, a sort of kite-like flying
machine, which will be noticed under the head of Aero-
planes, and it is said that, in 1888, he presented his latest
views before a commission of the French Academy of
Sciences, supplementing them with certain experiments,
from which he drew the conclusion that an apparatus
capable of carrying four passengers needed no more than
3 horse power to drive it at the rate of 67 miles per hour.
It may be inferred that the French Commission was not
convinced, from the fact that no action has been taken upon
the proposal.

In the United States very few experiments seem to have
been made with flapping wings, and no records of them
are attainable. Investigation is, therefore, limited to such
proposals as have been patented, and it is found that,
aside from balloons, less than 30 flying machine patents
have been taken out, of which four are for flapping wings.

The first of these, in order of date, seems to have been
the proposal of Mr. W. F. Quméy, who patented, in 1869,
an apparatus to be operated by man power, consisting of
a pair of side wings and a tail, all to be flapped by a series
of cords attached to the operator, who is encased in a
cuirass which maintains the wings at about the height of
his waist. The surfaces shown in the drawings are quite
insufficient to sustain the weight, and in 1872 Mr. Quz’nby
‘WINGS AND PARACHUTES. 33

took out another patent for a modification of his apparatus,
in which he added dorsal surfaces, so that the wings and
the tail were continuous and reSembled the supporting
surfaces of a bat. The arrangement for imparting motion
was ingenious butfutile, because of the inefficiency of mus-
cular power, which has already been stated.

In 1876 Mr. F. X. Laméoley patented a framework
shaped like the wings of a bird, and covered with a wire
netting to which birds’ feathers were fastened so as to
give a valvular action. Human power vsas relied upon to
impart motion through a trapeze-bar and platform, and of
course it would prove inadequate.

In 1877 Mr. M. H. Murre/Z patented an apparatus con-
sisting of a pair of pivoted side wings and a tail, to be
also operated by man power. The wings were furnished
with slats similar to those of a Venetian blind to close on
the down stroke, and open when going up. An investi-
gation of what others had attempted would probably have
saved the inventor some misspent time and ingenuity.

So little has been effected with flapping wings that a
number of American inventors seem to have turned their
attention to various arrangements of revolving vanes.
Of these A. P. {(627}; patented, in 1870, an aerial car with
paddle-wheels revolving in a transverse plane, for the pur-
pose of lifting and propelling. Thomas Green patented,
in 1873, an apparatus with two wheels, each with four
revolving blades passing through the air flatwise on the
down stroke and edgewise on the up, and M H Baldwin
patented, in 1890, an aerial vessel in which weight is to
be supported by a set of wheels containing feathering
vanes; the wheels revolving in opposite directions on
longitudinal shafts. All of these are worthless, as is also
the patent of 1. M. W/zeeler of 1887, which covers the
arrangement of a number of oscillating frames superposed
to each other on a mast, and carrying slats similar to
those of a Venetian blind; these varlous devices only
being mentioned to illustrate how ingenuity has been
wasted upon mechanical details, while scarcely any atten-
tion seems to have been given to the deVISing of the light-
est possible motive power. Each fresh inventor of winged
machines is apt to imagine that his predecessors did not
succeed because they did not hit upon the right method
of imitating the complicated and swift motions of the
birds. Thus Mr. [1. Syrian, of Australia, communicated
to the British Aeronautical Society, in 1888, that experi-
ment and observation had convinced him that the tips of
the bird's wings describe, when viewed from the side, the
outline of an inverted cone with rounded base, instead of
the figure of 8 motion described by Dr. Pettigrew and

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FLYING MACHINES.
i WINGS AND PARACHUTES. 35

Professor Marcy. He had accordingly made a model,
driven by clockwork, to test the truth of his theory. This
model was not capable of free flight (steel springs and
clockwork being much heavier than rubber, in proportion
to their stored energy), but when suspended at the end of
a counterweighted lever, resting upon an upright support
with a ball—and-socket joint, it flew in a circumference of
about 12 ft. by the flapping action of the wings. By
slightly modifying the stroke of either wing it was made
to fly from right to left or from left to right. By altering
the guide-rods, which governed the direction of the stroke,
it could be made to fly upward at any desired angle, but
the important, the vital question of an efficient motor was
left untouched by the inventor.

Still, earnest attempts are occasionally made in the
direction of light motors. At the meeting of the British
Aeronautical Society, in 1890, a photograph was shown of
a steam-bird machine, designed and built by Mr. E. P.
Frost, which is represented in fig. 22. The wings, which
are 30 ft. from tip to tip, are in exact imitation of those
of the crow, and the various positions which they assume
during a stroke are shown in the picture. The weight of
the machine, including engine and boiler, is about 650 lbs.
It. was expected to carry in addition the weight of a man
in the air, but it was said that the maker of the engine
failed in his contract to secure the necessary power, and
the apparatus did not fly.

At the same meeting Mr. H. Middleton, who has been
advocating for several years winged apparatus as supe-
rior, in his judgment, to aeroplanes, exhibited two bird
machines, one weighing 20 lbs., with a wing-spread of
nearly 12 ft., and the other of between to and 12 lbs.
weight with a wing-spread of some 9 ft. He also
showed an aeroplane weighing somewhat over 20 lbs.,
with sustaining planes of 14 ft. across and a screw of 4 ft.
diameter, in order to compare its performance with those
of the bird machines. Only the smaller of these latter
was shown in action, but its balance was not properly
adjusted, and although it raised itself from the sustaining
horizontal rope during the first few strokes, it soon rested
again upon the rope, and on the pressure being raised
during a subsequent run, the right wing broke and ter-
minated the experiment.

The aeroplane, being similarly suspended, moved along
the rope at a moderately good pace, but without raising
itself on the air, and that experiment was brought to an
untimely end by the rupture of a joint on the propeller
shaft.

Probably the most original conception ever presented
36 FLYING MACHINES.

for a flying machine is that of M. G. Trouvé, who has
just revived (1891) the proposal for his mechanical bird,
which was first presented to the French Academy of

FIG. 23i—TROUVE—187o.

 

Sciences in I870. This is shown in fig. 23, and consists
of two wings, A and B, connected together by a “ Bour-
don" bent tube, such as is used in steam gauges. The
peculiarity of this tube, as is well known, is that as pres—
. WINGS AND PARACHUTES. 37

sure increases within it the outer ends move apart, and
as pressure diminishes they return toward each other.
M. Tram/é increases the efficiency of this action by plac—
ing a second tube within the first, and in the experimental
model he produces a series of alternate compressions and
expansions by exploding 12 cartridges contained in the
revolver barrel 1), which communicates with the tube.
This produces a series of energetic wing strokes which
propel and sustain the bird in the air in connection with
a silk sustaining plane indicated at C.

The manner of starting the bird is equally ingenious
and peculiar, and is shown in fig. 24. The bird is sus-
pended from a frame by a thread, which, being attached
to the hammer, keeps the latter off the cap. A second
thread holds the bird back from the perpendicular, while
a common candle A and a blow-pipe flame 8 complete the
preparations. Upon the thread being burned at A the bird
swings forward from position I to position 2, where the
suspending thread is burned by the blow-pipe B, the
hammer falls on the cap, an explosion ensues, the wings
strike downward violently, and the bird flies on an upward
course, as shown in posntion 3. Then the gases escape
from the Bourdon tube, this recovers its shape, raises the
wings and actuates two pawls which rotate the revolver
barrel and work the hammer, so that afresh explosion

 

FIG. 24.—STARTING TROUVE’S BIRD.

occurs and the bird continues to fly. When the 12
cartridges are exhausted the bird glides gently to the
ground, being sustained by its wings and aeroplane as by
a parachute. It has thus flown 75 to 80 yards.
38 FLYING MACHINES.

This motor is evidently very simple and very light, and
for a practical flying machine M. Tram/é proposes to
substitute for the cartridges a supply of compressed
hydrogen gas, which, when mixed with about three parts
of air, becomes an explosive mixture to be fired by the
electric spark. Thus the motor would derive the greater
portion of its power direct from the atmosphere as wanted,
there would be no danger of premature explosion as with
fulminates, and, hydrogen being only 1-14— the weight of air,
the weight and the equilibrium of the apparatus would
vary but little when supplies became exhausted. More-
over, it is probable that no cooling agent would be re-
quired, as in ordinary gas engines, because the tube ex-
poses so great a surface that it is to be expected that the
heat would pass into the air while under motion, and that,
as there is no piston to be lubricated, a moderate heating
would not prove objectionable.

M. Trauvé started out with the assumption that a
motor for aerial navigation should not weigh over 8 lbs.
to the horse power. He presented to the French Academy
of Sciences, in 1886, an electric motor, weighing but 7.7
lbs. per horse power, working an aerial screw, which will
be more fully noticed when that subject is treated, and on
August 24 last (1891) he deposited with the same body a
sealed letter containing the drawings and description of
an aeroplane and screws, which, he confidently believes,
provide a final solution for the problem of aerial naviga—
tion, and which will also be noticed under the head of
Aeroplanes.

Meanwhile other inventors are also working in the same
field, and the English papers have contained sundry para-
graphs, within the last few months, concerning a flying
machine some 45 ft. across, in the form of a bat, which is
being built in Coventry for Major Moore, of India. It is
to be driven by an electric motor, but the descriptions do
not make it clear whether this is to be by beating wings
or with fixed wings, as in an aeroplane. The cost in-
curred is stated at over $5000, and the trial is to take
place at the Crystal Palace. Should this take place in
time, it will be noticed, as well as the great apparatus
now being completed by Mr. Maxim, when we come to
discuss aeroplanes.

It will be seen from the foregoing statements of what
has been accomplished with beating wings, that the prin—
cipal questions are those of motive power and of propor—
tion of surfaces to weight, and the reader will probably
first inquire as to what is really the power developed by
birds in their flight. The answer must unfortunately be,
that it is not accurately known. A great many computa—
.\VINGS AND PARACHUTES. 39

tions have been made, based upon more or less plausible
assumptions, but none of these computations can be abso-
lutely accepted as correctly based upon indisputably meas-
ured data.

This ceases to be surprising when we consider that there
is no creature so willful, so swift, and so easily affrighted
as the bird, and that once in the air, he will not lend him-
self to be measured experimentally. Mathematicians have,
therefore, partly resorted to conjectures for their data.
Thus Napier assumed that a swallow weighing 0.58 oz.
must beat his wings 2,100 times per minute while going
33;,~ miles per hour, in order to progress and sustain his
weight, and that it therefore expended 1%; of a horse power.
In point of fact, the bird only beats about 360 times a minute,
and is chiefly sustained by the vertical component of the
air pressure on the under side of the wings and body, due
to the speed, instead of by the direct blow of the wings
downward, as supposed in the orthogonal theory already
alluded to.

Other mathematicians, starting from the fact that a
weight falls about 16 ft. during the first second, and in so
dropping does work, have assumed that a bird in hori—
zontal flight, being then sustained, performs a certain
fraction of this work. It is evident, however, that if the
bird does not drop, the fraction assumed is purely arbi-
trary, and that such calculations must be quite worthless.

Experiments to measure directly the power expended
have proved failures, and resort has been had to indirect
measurements.

Thus Dr. W. Smyth, of Edinburgh, succeeded in meas—
uring with a dynamometer the strain exerted by a 12—02.
pigeon while flexing its wings, when excited by a current of
electricity, and found it capable of raising 120 lbs. one
foot high in a minute, or at the rate of 160 foot-pounds per
pound of bird. Professor Marey performed the same ex—
periment on the buzzard and on the pigeon, and ascer—
tained the contractile strength of their muscles to be 18.46
and 19.91 lbs. to the square inch respectively ; * but as
he was unable to measure satisfactorily the rapidity with
which the muscles contracted, he did not calculate the
foot—pounds.

Mr. Alexander, starting with the assumption that a
2-lb. pigeon makes 180 completed strokes per minute,
each stroke with an amplitude ot 1.5 ft. at the center of
pressure, calculates the power exerted as being 2 X 180 X
1.5 —_~ 540 foot-pounds per minute, or at the rate of 270
foot-pounds per pound of bird. This is plausible ; but the

* “ Vol des oiseaux," page 92.
4O FLYING MACHINES.

most satisfactory computations are those made by Pénaud
from observations of the direct velocity of ascent of various
birds. From these he concludes that the pigeon, for in-
stance, expends for rising 579 foot-pounds per minute, and
that the proportion of horse power to weight is as follows :

For the peacock, one horse power for every 66 lbs.

‘1 0‘ pigeon, It (I (6 57 1‘
‘6 L‘ Sparrow. II (I IL (6 ‘6 48% ‘l
(( 6‘ Sea ple’ ‘l ‘G l‘ (I (l 26 ((

This, however, is merely the work of elevation, such as
would be performed upon a solid support, in addition to
which the bird has to overcome the resistance of the air to
his motion, and to derive support from this mobile fluid.
Pénaud calculates that this additional work amounts to
over 1,000 foot-pounds per minute, so that the total work
done by the pigeon in rising to a perch 35 ft. above the
ground amounts to 1,650 foot-pounds per minute, or 1
horse power for every 20 lbs. Moreover, it must be remem—
bered that the pectoral muscles of birds, which constitute
their motor, comprise but one-quarter to one—sixth of their
total weight, so that in this particular case the relative
weight of the motor is only about 5 lbs. per horse power
for the force exerted in rising.

These are formidable figures, but they cease to be dis—
couraging when we reflect that the effort of rising is evi-
dently a maximum, and that birds seldom perform it in a
nearly vertical direction except for short distances, and that
the exertion is clearly so severe that the feat is usually per—
formed only by the smaller birds, which, as previously ex—
plained, must possess greater energy in proportion to their
weight than those exceeding a few ounces. Heavy birds
can only rise at angles less than 45°, and even then they
exert for a short time far more than their mean strength,
the latter being, for all animals, only a fraction of the
maximum possible effort. Thus man, who is usually esti-
mated as capable of exerting 0.13 horse power for 10
hours, can develop 0.55 horse power for 2% minutes, and
nearly a fall horse power for 3 or 4 seconds ; and it seems
probable that similar proportions obtain for birds, the
emergency effort being three or four times the average
performance, and the possible maximum about twice as
great as the emergency effort.

Pénaud states that the ring—dove dispenses in full flight
217 foot-pounds per minute; but he does not give fig—
ures for this, so that they can be checked. Goupil esti—
mates the work done by a pigeon weighing 0 925 lbs. at
1,085 foot-pounds per minute in hovering and 119 foot-
pounds per minute in flight ; but the latter is arrived at by
WINGS AND PARACHUTES. 4I

reasoning from analogy. It is evident that the power
exerted in horizontal flight is much less than that required
for rising or for hovering; but until a bird is taught to
tow behind him some dynanometric arrangement at a
regular rate of speed, and on a level course, it will be diffi-
cult to settle exactly what are the feet-pounds expended in
ordinary performance.

In 1889 Captain de Labouret, an expert in the solution
of balistic problems. analyzed mathematicallytwo series of
photographs of a gull weighing 1.37 lbs., and just starting
out in flight with 5 wing beats per second, as obtained by
by Professor Marey with the chrono-photographic proc—
ess. The calculations showed that the bird expended in
this act an average of 3,152 foot-pounds per minute, or
2.303 toot-pounds per pound of his weight; and as Pro—
fessor Marey shows that from his other observations of
the reduced amplitude and rapidity of the wing beats, the
same bird does only expend in full flight % of the effort re—
quired at starting, the conclusion may be drawn that the
gull in full flight expends some 460 foot-pounds per min—
ute for each pound of his weight.

This estimate seems plausible to me, and agrees with
my own figures, but it is not accepted by all aviators. The
Revue S'cz'mz’zfigue of November 28, 1891, contains two
articles disputing the conclusions—one by Mr. V. Tatin,
an expert aviator, who claims that the accelerations of the
bird have been erroneously calculated ; that the center of
pressure under the wing is g of the distance from its root
instead of ,2, as usually assumed, and who figures out from
the velocity of this new center of pressure, and from the
known trajectory that the bird in tull flight only expends
from 33 to 197 foot~pounds per minute for each pound of
his weight.

The second article is by Mr. C. Richet, the editor of the
Revue Scz'em’z'fique, who, having ascertained the volume
of carbonic acid exhaled by a bird at rest, assumes, from
experiments on other animals, that in full flight he will
give out three times as much, and that the difference repre-
sents an effort of 105 foot-pounds per minute per pound of
bird.

These two articles, being the most recent computations
by earnest students of the subject, are here mentioned
chiefly to illustrate how greatly aviators vary in estimates
of the power expended, and how many elements have to
be assumed in making such computations.

In the absence of direct measurements, and of positively
satisfactory computation by others, of the feet-pounds ex—
pended in horizontal flight, I believe that an approxima—
tion may be obtained by analyzing and calculating the
42 FLYING MACHINES.

various elements which combine to make up the aggregate
of the resistance to forward motion in horizontal progres-
sion; and as this method promises to be useful in com—
puting the power required by artificial flying machines, I
venture to set it out at some length, applying it to the
domestic pigeon as being more convenient to compare
with the results of the calculations of others. For this
purpose two dead pigeons were selected, weighing as near
as practicable I 1b. each. and their dimensions were ac—
curately measured as follows :

Cross SECTION AND HORIZONTAL PROJECTION OF PIGEONS.

 

 

 

 

Pigeon No. I. Pigeon N0. 2.
Largest cross section of body .............. 4.9 sq. in. 5.3 sq. in.
“ “ “ edge of wings..... 5.02 “ “ 4.88 “ “
Weight of bird, freshly killed .............. I lb. 0.969 lb.
Horizontal area of both spread wings ...... 90.35 sq. in. 99.86 sq. in.
“ “ “ body projected ........ 22.49 “ “ 24.0! “ “
“ “ “ tail spread. ......... 19.72 “ “ 27.17 “ “
132.56 sq. in. 151.04 sq. in.

 

 

 

These dimensions all require the application of coeffi-
cients in calculating their action upon the air. Thus the
wings are concave, and give a greater sustaining power
per square foot than a flat plane ; the body is convex, and
affords less than a plane, while the tail is slightly concave,
but partly ineffective from its position. Previous experi—
ments have indicated that, in the aggregate, the support—
ing power is about 30 per cent. more than that of a flat
plane of equal area, so that in the calculations which fol—
low the supporting surfaces will be assumed at 1.3 sq. ft.
to the pound instead of the I square foot to the pound
which the average of the measurements seems to indicate.

It will be remembered that experiments with parachutes
indicate a coefficient of resistance of 0.768 for the convex
side and of 1.936 for the concave side, as compared with
the plane of greatest cross section.

The cross sectional area of the body is assumed at 5
square inches or 0.03472 of a square foot. and to this a co-
efficient is applied 0f one—twentieth of a flat plane, or 0.05,
in consequence of its elongated, fusiform shape. This
agrees well with experiments on the hulls of ships of
“ fair" shape.

The cross sectional area of the wings is also taken at 5
square inches, or 0.03472 of a square foot; but the co—
efficient here assumed is about one-seventh, or 0.15, in con-
WINGS AND PARACHUTES. 43

sequence of its shape, which is ogival, or rather something
like only half of a Gothic arch.

The friction of the air is omitted, as being entirely too
small to affect the results in a case where so many co-
efficients have to be approximated.

The angle of flight is ascertained by selecting from the
table previously given of air reactions, the coefficient
which will give the nearest approximation to a sustaining
“lift” to support the weight, and from this angle the
“ drift" is obtained to calculate the resistance of the sur—
face.

The velocity V is in feet per minute, and the pressure P
on a plane at right angles to the current by the Smeaton
formula is in pounds per square foot. The following are
the calculations:

20 miles per hour—V : 1760 ft. P : 2 lbs.

 

Lift, 12°, 1.2, x 2 x 0.30 = 1.014 lbs. sustained.
Resistance. Power.
Drift, 12°, 1.3 x 2 x 0.0828 = 0.21520 lb. X 1760 = 378.7 ft. lbs.
Body resistance, 0.03472 x 2 X 0.05 :- 0.00347 “ x 1760 = 6.1 ”
Edge wings, 0.03472 x 2 x 0.15 = 0.01040 “ X 1760 = 18.3 “
0.22907 lb. 403.1 ft. lbs.

30 miles per hour—V : 2640 ft. P : 4.5 lbs.

 

Lift, 5°, 1.3 x 4.5 X 0.173 :: 1.012 lbs. sustained.
Resistance. Power.
Drift, 5°, 1.3 X 4.5 x 0.0152 = 0.08892 lb. x 2640 = 234.7 ft. lbs.
Body resistance, 0.03472 X 4.5 X 0.05 = 0.00781 “ x 2640 : 20.6 “
Edge wings, 0.03472 x 4.5 x 0.15 = 0.02343 “ X 2640 = 61.9 “
0.12016 lb. 317.2 ft. lbs.

40 miles per hour—V: 3520 ft. P = 8 lbs.

 

 

Lift, 3°, 1.3 X 8 X 0.104 = 1.082 lbs. sustained.
Resistance. Power.
Drift, 3°, 1.3 X 8 x 0.00543 2 0.05647 lb. X 3520 : 198.7 ft. lbs.
Body resistance, 0.03472 x 8 X 0.05 = 0.01389 “ x 3520 1: 48.9 “
Edge wings, 0.03472 X 8 X 0.15 : 0.04166 “ x 3520 2 146.6 “
0.11202 lb. 304.2 ft. lbs.

50 miles per hour—V = 4400 ft. P: 12.5 lbs.

Lift, 2°, 1.3 x 12.5 X 0.07 = 1.137 lbs. sustained.
Resistance. Power.
Drift, 2°, 1.3 x 12.5 X 0.00244 : 0.03965 lb. x 4400 = 174.5 ft. lbs.

“ kfi

Body resistance, 0.03472 x 12.5 x 0.05 = 0.02170
Edge wings, 0.03472 x 12.5 x 0.15 = 0.06510

x 4400 = 95-5
x 4400 : 286.5

£6 (E

 

0.12645 lb. 556.5 ft. lbs.
44 FLYING MACHINES.

60 miles per hour—V = 5280 ft. P: 18 lbs.

 

Lift, 1%°, 1.3 x 18 x 0.052 = 1.217 lbs. sustained.
Resistance. Power.
Drift, 1%°, 1.3 X 18 X 000136 2 0.0318 lb. x 5280 = 167.9 ft. lbs.
Body resistance, 0.03472 x 18 x 0.05 = 0.0312 “ X 5280 = 164.7 “
Edge wings, 0.03472 x 18 X 0.15 = 0.0937 “ x 5280 = 494.7 “
0.1567 lb. 8273 ft. lbs.

These figures are probably somewhat in excess of the
real facts in consequence of the adoption of slightly exces-
sive coefficients for the resistance of the body and wing
edges, which coefficients in full flight may be as much as
one-third less than those which have been estimated.

It will be noticed that, as the velocity and the conse—
quent air pressures increase, the angle of incidence re-
quired to obtain a sustaining reaction or “ lift” dimin—
ishes, and so does, therefore, the “drift” or horizontal
component: of the normal pressure, while the “ hull resist—
ance,” consisting of that of the body and edges of the
wings, is at the same time increasing. There will there—
fore be some angle at which these various factors will so
combine as to give a minimum of resistance, and this is
probably for most birds at an angle of about 3°, which in
the case of our calculated pigeon requires a speed of 40
miles per hour in order to sustain the weight.

This angle of minimum resistance depends upon the
relative proportions of the bird—-z'.e., upon the ratio be-
tween his surface in square feet per pound of weight, and
the cross section of his body and wings, as well as their
coefficient of resistance ; and so, while the angle may not
vary greatly, it needs to be ascertained for each case.
Mr. Drzewiecki has calculated that for an aeroplane ex—
posing a cross sectional area of I per cent. of its sus-
taining area (instead of the 7 per cent. which the meas—
urements show for the pigeon), the angle of minimum
resistance would be 1° 50' 45”, and that it would be the
same for all velocities. It does not follow, however, that
the minimum of power required will coincide with the mini-
mum of resistance, for the latter increases as the square,
while the power grows as the cube of the speed. The cal—
culations, therefore, show that the minimum of resistance
occurs at 40 miles per hour, while the minimum of work
done in foot-pounds is found at 30 miles per hour, and
these two favorable speeds are about those observed from
railway trains, as habitually practised by the domestic
pigeon.

The estimates of the feet—pounds per minute indicate
that the bird finds it less fatiguing to fly at 30 miles per
hour than at 20 ; that his exertions are not much greater
WINGS AND PARACHUTES. 45

at 40 miles per hour, but that at 50 miles per hour he is
expending rather more than his mean strength—the lat—
ter being probably about 425 foot-pounds per minute,
nearly an average of the first four calculations, or about
one—quarter of the maximum work done in rising, as esti—
mated by Pénaud.

A flight of 60 miles within the hour is probably a severe
exertion for the domestic pigeon, while the finer lines and
greater endurance of the carrier pigeon enable him to
maintain this speed for hours at a time ; but there is rea—
son to believe that this must be nearly the limit of his
strength, and that homing birds who have made records
of 70 and 75 miles per hour were materially aided by the
wind.

The calculations therefore appear plausible, and to agree
fairly well with the estimates arrived at with different
methods by others. They indicate that if a flying machine
can be built to be as efficient as the domestic pigeon, its
motor should develop one horse power for each 18 lbs.
of its weight, provided it can give out momentarily about
four times its normal energy, or that special devices, such
as that of running down an incline or utilizing the wind,
or some other contrivance are adopted to give it as tart and
to enable it to rise upon the air.

The next question whlch the reader will probably want
to ask, is as to the amount of supporting surfaces possessed
by birds in proportion to their weight. Upon this point a
good deal of information has been published ; and in 1865
Mr. De Lucy greatly cheered aviators by publishing a
paper in which he showed that the wing areas of flying
animals diminish as the weight increases, from some 49
square feet to the pound in the gnat to 0.44 square feet to
the pound in the Australian crane ; and from which tables
he inferred the broad law that the greater the weight and
Size of the volant animal. the less relative wing surface it
requrred.

As thus stated, the assertion is misleading. For inasmuch
as the supporting surfaces will increase as the square, and
the weight will grow as the cube of the homologous dimen—
sions, it was to be expected that wing surfaces would not
increase in the same ratio as the weight if the strength of
the parts remained the same; and in 1869 Hartings pub—
lished some tables of birds, in which be compared the
square root of the wing surface with the cube root of the
weight, and showed that their ratio became what he con—
sidered a somewhat irregular constant. Subsequent meas-
urements and tables by Professor Marey have shown that
this statement of Hartings is also slightly misleading, inas-
much as the so-called constant varies from 1.69 to 3.13, so
46 FLYING MACHINES.

that no broad law can be laid down as to any fixed relation
between the surfaces and weight of birds of various sizes.
The fact seems to be that while their structures are gov-
erned by the laws which limit the strength of materials
(bones, muscles, feathers, etc.), yet there are differences
in the resulting stresses, and in the consequent efficiency
of the birds themselves, who are thereby led to adopt
slightly different modes of flight ; and in 1884 Mullenhoff
published an able paper, in which he divided flying ani-
mals into six series, in accordance with the ratio between
their weight and their wing surface, as well as their
methods of flight. As the tables of De Lucy, Hartings,
Marey and Mullenhoff are all easily acceSSIble in print,
they will not. be repeated here ; but the following table is
considered more valuable than any of them. It has been
compiled from “ L’Empire de l’air” of Mr. Mouillard, a
very remarkable book, published in 1881, which contains
descriptions of the flight of many birds and accurate meas—
urements of their surfaces and weights.

TABLE OF SUPPORTING AREAS OF BIRDS.
MEASURED BY 1.. P. MOUILLARD.

COMPILED BY S. DRZEWIECKI.

 

 

 

 

 

 

 

i|C0rr’sp'ding

Scientific Name. Common Name. Sq. Ft. ‘Lbq' per speed fora

per Lb. Sq. Ft. plane at 30

‘Miles per hr
Nyctinomous aegypticus . . .. Bat ............ .64 0.131 i 15.9
Upupa epops ............... Peewlt ......... 3.62 0.276 23.1
Cotile rupestris ............. Swallow ......... 3.62 0.276 23.1
Budytes flava .............. Wagtail .. 3.49 0.286 23.5
Galerita cristata I .......... Lark ............ 3. 18 0.315 24.6
Caprimulgus ............... Goatsucker ..... 3. 17 0.314 24. 6
Galerita cristata II .......... Lark ............ 3.06 0.327 25.1
Accipter nisus .............. Sparrow—hawk... 3.00 0.333 25.3
Pteropus Geoffroyi .......... Bat ............. 2.79 0.362 26.2
Coracias garrulus ..... . ..... Roller .......... 2.76 0.363 26.5
Tringa canutus ............ Knot. .......... 2.64 0.380 27.0
Falco tinnunculus ......... . Falcon .......... 2.48 0.403 27.9
Passer domesticus I ..... . . . . Sparrow. ....... 2.42 0.414 28.2
Vanellus cristatus. . .. . . ..... Lapwing ........ 2.40 0.417 28 3
Passer domesticus II ........ Sparrow ....... 2.36 0.424 28.6
Cypselus apus .............. Martinet ........ 2.35 0.426 28.6
Larus Inelanocephalus I. Gull ............ 2.35 0.426 28.6
Glareola torquata ........... Glareola ........ 2.32 0.431 28.8
Larus melanocephalus IL... Gull ............ 2.30 0.435 28.9

 
WINGS AND PARACHUTES.

47

 

 

 

 

Corr’sp’ding

Scientific Name. Common Name. :2: 11:1: stqs 15:1. 25:51: :22:

Miles perhr.
Turtur aagypticus .......... Egyptian Dove. 2.27 0.441 29.2
Otus brachyotus ............ Owl............. 2.26 0.443 29.2
Strix flammea .............. ” 2.26 0.443 29.2
Milvus mgypticus....... .. . Kite ........... .. 2.19 0.457 29.7
Petrocincla cyanea ......... Blackbird ....... 2.18 0.460 29. 7
Alcedo hispada I ........... Kingfisher. . . . . 2. 11 0.475 30.3
“ “ II .......... “ ...... 2.11 0.475 30.3
Buphus minutus ............ Crane ........... 2.02 0.495 30.9
Scolopax gallinula I. . . . . . .. Snipe . 1.96 0.510 31.4
Ephialtes zorca ............ Scops ........... 1.90 0.526 31.8
Alcedo hiSpida III .......... Kingfisher ...... 1.87 0.535 32.1
Corvus aegypticus .......... Rook ........... 1.74 0.575 33.3
Astur palumbarius. . . . .. . . . Goss-hawk ...... 1.73 0.579 33 .4
Ibis falcinellus .............. Ibis.. . 1.66 0.603 34.1
Sturnus vulgarls ............ Starling ........ 1.65 0.606 34.2
Scolopax capiensis ......... Snipe .......... 1.65 0.606 34.2
Corvus corax ....... . ...... Raven .......... 1.62 0.614 34.5
Scolopax gallinula II. . ..... Snipe ........... 1.60 0.625 34.7
Philomachus pugnax ....... Water-fowl ...... 1 .48 0.634 36. I
Ardea nycticorax ........ ... Night Heron.. . . 1.43 0.700 36. 7
Ciconia alba ................ Stork ........... 1.40 0.715 37.1
Charadrius pluvialis ........ Plover ........... 1.38 0.725 37 .4
Columbia azgyptica I ........ Egyptian pigeon 1.37 0.730 37.5
Falco peregrinus ............ Falcon .......... 1.29 0.775 38.6
Rallus aquaticus ............ Rail ............ 1 .28 0.781 38.8
Pandion fluvialis. . . . . . . . Balbuzzard ...... 1 .26 0.795 39.2
Neophron percnopterus. . . . Egypt'n vulture 1 _ 18 o 848 40.4
Columba aegyptica .......... “ plgeon. 1.13 0.885 41.3
Numenius arquatus ........ Coulis .......... 1.11 0.901 41.7
Ortyx coturnix ............. Quail .......... 1.08 0.927 42.3
Recurvirostra avocetta ...... Avocetta ........ I .05 0.954 42.8
(Edicnomus crepitans ...... Plover .......... 0.926 1.079 43 6
Anas querquedula .......... Duck ........... 0.864 1.158 44.2
Pufiinus Kulhi... Shearwater...... 0.853 1.170 44.5
Gallinula chloropus ......... Water-hen. . . .. 0.765 1.307 50.3
Numenius arquatus ......... (,urlew ......... 0.761 1.312 50 .3
Pelecanus anocrotales ...... Gray Pelican. .. 0.732 1.365 51.3
Gyps fulvus ........... , . . .. Tawny Vulture. 0.679 1.473 53 .3
Otogyps auricularis ......... Oricou ......... 0.664 1.473 53.9
Pterocles exustus ........... Running Pigeon 0.664. 1.508 53.9
Procellaria gigantea ........ Giant Petrel . . . .v 0. 640 1.561 54 .9
Anser sylvestris ............ Wild Goose. . . . . 0.586 1.708 57.4
Meleagris Gallopavo ....... Turkey ....... 0.523 1.910 60.6
Anas clypeata, female ...... Duck . . . . .. . . . . 0.498 2.008 62.2
“ “ male ........ ” .. 0.439 2.280 66.2

 

 

 

 
48 FLYING MACHINES.

Mr. Mouillard adopted a more rational method than other
observers. Instead of merely measuring the surface of the
wings, he laid the bird upon its back on a sheet of paper,
projected the entire outline, and then measured the total
area from which it gains support. The compilation has
been made by Mr. Drzeweicki for a paper presented to the
International Aeronautical Congress at Paris in 1889, in
which he states the general law more accurately than his
predecessors, by calling attention to the fact that the ratio
of weight to surface will vary somewhat with the structure
of the bird, and that the result will be that those possessing
the lesser proportionate surface must fly faster in order to
obtain an adequate support at the same angle of incidence.

I have added the last column in the table, showing the
speed required to sustain the weight of a flat plane loaded
to the same proportion of weight to surface as the bird,
at an angle of incidence of 3°. This speed merely ap-
proximates to the real flight of the bird, because it takes
no account of the concavity of the wings, which, as pre-
viously explained, increases the effective bearing surface
of the animal; but it would require experimenting with
each and every bird tabulated in order to give the true and
varying coefficients.

B.—SCREWS TO LIFT AND PROPEL.

IN describing the various proposals and experiments
which have been made to compass artificial flight by
means of rotating screws, the latter will chiefly be con-
sidered as instruments from which to obtain support of a
given weight in the air. There is no question that they
can serve as propellers if the support be otherwise ob-
tained; nor that if a screw can lift and sustain its own
prime motor, it can also be made to progress horizontally,
either by inclining it at. the proper angle or by adding a
vertical screw.

It was to be expected that when inventors found how
difficult it is to obtain a lifting effect from flapping wings,
they should turn to aerial screws to sustain them in the
air. Man has succeeded in out-traveling both land and
marine animals by substituting rotary motion for the re-
ciprocating action of their limbs : the locomotive far out-
strips the horse, and the paddle-wheel and screw have, for
large vessels, SUperseded the oar, so that it seems natural
to expect that some rotating device shall be found the
preferable propeller, should aerial navigation ever be ac-
complished.

It will be seen, from the accounts which follow, that the
chief obstacle has hitherto been the lack of a sufficiently
SCREWS TO LIFT AND PROPEL. 49

light motor in proportion to its energy ; but there has re-
cently been such marked advance in this respect, that a
partial success with screws is even now a1m05t in sight.

Curiously enough, the Aerial Screw considerably ante-
dates the marine screw, although, unlike the latter, it has
not been brought into practical use. We have already
seen that Leonardo Da Vz'ncz' experimented with paper
screws, which mounted into the air, as early as A.D. 1500,
and we may add that a sketch has been found in his note
books for a proposed aerial screw machine 96 ft. in diame-
ter to be built of iron and bamboo framework, covered
with linen cloth thoroughly starched. He probably aban-
doned all idea of constructing it when his experiments
with models showed the power that would be required.

A similar proposal was made by Paucton, a learned
mathematician, in 1768, when, in a treatise upon the
Archimedean screw, he described an apparatus which he
called a “ Pterophore,” consisting of two aerial screws,
one to sustain and the other to propel, attached to a light
chair. A man seated in the chair was expected to rotate
these screws by means of gearing, and so raise himself
through the air.

The first practical experiment known. however, is that
of M. Lamzoy, a naturalist, and M. Bz'mvenu, a mechani-
cian, who jointly exhibited before the French Academy of

 

 

Sciences in 1784 the little apparatus shown in fig. 25. It
consisted of two superposed screws, about one foot in

4
50 FLYING MACHINES.

diameter, each composed of four feathers inserted in
sockets at the ends of a rotating axle. This axle was put
into motion by the unwinding of a cord fastened to the
two extremities of a bow; and the report to the French
Academy (May 1, 1784) says :

“ The working of this machine is very simple. When
the bow has been bent by winding the cord, and the axle
placed in the desired direction of flight—say vertically, for
instance—the machine is released. The unbending bow
rotates rapidly, the upper wings one way and the lower
wings the other way, these wings being arranged so that
the horizontal percussions of the air neutralize each other,
and the vertical percussions combine to raise the machine.
It therefore rises and falls back aiterward from its own
weight.”

Lamwy & Bz'mz/enu proposed also to build a large
machine, and to go up in it themselves. It is not stated
whether this was ever attempted ; but probably not, as a
brief investigation must have satisfied them that they had
no adequate primary motive power at hand to lift even its
own weight in that way, and that with a secondary or
stored power the machine would fly but for a few seconds.

Practically the same device was constructed by Sir
George Cayley in 1795, and described by him in Nichol-
son's/ourzm/ for April, 1810; but whether he reinvented
it or borrowed the idea from Lamzoy & Bimz/ezm is not
stated. He mentions it merely as a toy, and his writings
seem to indicate that he expected success to be achieved
instead with an aeroplane to be driven by some sort of
propelling apparatus, if only a sufficiently light first mover
could be contrived.

Subsequently, Deg/zen, in 1816, Sartz’, in 1823, and
Dubocfzet, in 1834, all proposed and constrUcted models
for flying machines on the vertical screw principle; but
they did not discover the necessary light motor to trans-
form their models into practical machines.

In 1842 Mr. sz'llz'fls, the inventor of the “Fire An-
nihilator,” succeeded in raising into the air an apparatus
weighing in the aggregate 2 lbs., by means of revolving
fans inclined about 200 from the horizontal. The motive
power was evolved by the combustion of charcoal, nitre
and gypsum making steam, as in the original fire an-
nihilator; and the engine consisted of rotating arms dis-
charging steam direct into the atmosphere, and thus work-
ing by reaction, being the device known as the discovery
of Hero, of Alexandria. Mr. P/zz'llifis exhibited a work-
ing model of his aerial machine at the Aeronautical Ex-
hibition in London, in 1868; and in describing his experi-
ment of 1842 he said :
SCREWS TO LIFT AND PROPEL. 51

“ All being arranged, the steam was up in a few sec-
onds, when the whole apparatus spun around like a top
and mounted into the air faster than any bird; to what
height it ascended I had no means of ascertaining. The
distance traveled was across two fields, where, after a long
search, I found the machine minus the wings, which had
been torn off from contact with the ground." This is un-
doubtedly the first machine which has risen into the air by
steam power; but the necessarily small capacity of the
generator, and the wasteful though simple method of
using the steam, limited its flight to a very iew minutes,
and removed it from the possibility of application on a
practical scale.

In 1843 Mr. Bourne, the well—known English engineer,
constructed some models of aerial screws, consisting of
large fowl’s feathers inserted in a cork, stuck on the top
of a pine stick, to which a watch spring was attached, and
succeeded in making them rise by the force of the coiled
Spring to the height of some 20 ft. ; but he recognized
that the difficulty in the way of building a really navigable
machine was to obtain “ the right motive power.”

This must also have been the conclusion of Mr. Camus,
who propOsed, in 1845, the apparatus shown in fig. 26,
which consists in three rotating aerial screws to be moved
by steam power. The design is by no means devoid of

 

FIG. 26.-—COSSUS—1845.

merit, for by hinging the outer and smaller screws, and
varying their angle with respect to the machine, the latter
can be made to travel in any direction desired, while sus-
tained by the rotation of the middle screw. It cannot be
learned that Camus tried any practical experiments, for a
simple inquiry into the weights and relative energy of the
steam engines of his day and an investigation as to the
power required to sustain his apparatus must have speed-
ily convinced him that it had better be abandoned.
52 FLYING MACHINES.

Analogous proposals were made in 1851 by Mr. Auéaud,
who combined several screws with an aeroplane ; and by
Le Brz's, who designed a car surmounted by two screws
turning in opposite directions, in order to overcome the
tendency of the apparatus to rotate on its own axis, as the
consequence of the horizontal component of the thrust of
a single screw.

It was to overcome this same objection that, in 1859,
Mr. Bright designed and patented the apparatus shown
in fig. 27, the axles of the screws consisting of tubes,
rotating in opposite directions, one inside of the other.

/.~

\

 

FIG. 27.—B RIGHT—1859.

Mr. Bright seems to have planned the machine to be sus-
pended beneath a balloon, and to be worked by man
power, in order to alter or to maintain the altitude at will,
and thus save the expenditure of ballast in rising or of gas
in descending. Its beneficial effects, however, seem to
have proved so small—solely, it may be said, from the
inadequacy of the motive power employed—that it has not
come into practical use.

These various efforts were somewhat desultory, and not
followed up by anything like scientific experiments; but
in 1863 there was in Paris a great “ boom” in projects for
navigating the air by means of aerial screws, and the
French espoused its promotion with great enthusiasm.
M. de Ponton d’Amécourt and M. de [a Landelle had
already studied the action of the screw upon the air, when,
in July, 1863, M. Nadar, a prominent photographer, in-
vited to his reception rooms the élz'te of the press, of sci-
ence, and of artists, and treated them to a first reading of
his famous “ Manifesto upon Aerial Automotion," which
appeared the next day in the press, and was republished
and commented upon throughout the whole of Europe.
SCREWS TO LIFT AND PROPEL. 53

In this manifesto, written with much eloquence, [Vadar
expressed the opinion that the principal obstruction in the
way of navigating the air was the attention which had
been given to balloons; that, in order to imitate nature,
a flying machine must be made heavier than the air. Also
that the surest means of success was the employment of
the aerial screw—“ the sainted screw,” as an illustrious
mathematician called it, which was known to be capable of
carrying up a mouse, and must, therefore, dforlz'orz', be
able to sustain an elephant.

The inanity of this argument was not apparent at the
time; and Nadar proceeded to form a syndicate to pro-
mote“ aviation" after the methods of opera bouffé. A
journal was founded—the first Aéronam‘e—43 paying sub—
scribers were obtained, and 100,000 copies of the first issue
printed. This journal expired after its fifth issue. Then
a monster balloon was built—the Gécmi—out of the ex-
hibition of whichit was expected to realize sufficient profits
to build a screw machine which should put an end to bal-
looning forever. But the Géam‘ met with all sorts of mis—
haps ; it gave no profits, and entailed losses instead,
which nearly ruined Nadar; and such experiments as
were tried with aerial screws (outside of the little toys
which were exhibited at the various meetings) demon-
strated that the utmost weight which the exertion of one
horse power could sustain, with a screw acting upon the
air. was some 33 lbs.. or. in other words, that if the ap-
paratus were to weigh one ton, it would need 67 horse
power continuously exerted to keep it afloat.

This is now clear enough to us. Assuming that in con-
sequence of the rotation at high speed a smaller surface
is required to sustain a given weight with a screw than with
reciprocating wings or fixed aeroplanes. yet the motor for
the screw would probably weigh about one-third of the
whole weight of the apparatus (instead of one-quarter, as
in the case of birds, and probably one—sixth in the case of
aeroplanes), and so the utmost weight available for the
motor of the screw and its supplies would be %; of 33 lbs., or
II lbs. to the horse power, while in 1863 there was no
primary motor known then approximating such phenomenal
lightness.

Now that Mr. Maxim has announced that he has built
a steam engine, and its generator of 950 lbs. aggregate
weight developing 120 actual horse power, or at the rate
of 8 lbs. to the horse power, it is doubtless within his
power to go up into the air with an aerial screw, and to
perform therein various evolutions; but his trips would
probably be short, and the consequences might be unpleas-
ant were the machinery to break down while he is aloft.
54 FLYING MACHINES.

He has, accordingly, with great good judgment, begun by
applying his steam engine to an aeroplane, although this
will involve greater difficulties in starting and in landing,
as well as a less immediate demonstration.

Almost the only memento which now remains of the
movement in favor of the aerial screw inaugurated by
jVaa’ar is the model of the flying machine designed by the
Vz'scoum‘ a’e Pom‘on a” Amécourt, and which is shown in
fig. 28. The following description is translated from that
at M. Tz’ssana’z’er .-

“ M. de Pom‘on d’Amécourz‘ constructed. in 1865, an
aerial screw machine worked by steam, which was ex—
pected to rise with both its motor and its steam generator.
This beautiful little model, which was exhibited at the
London Aeronautical Exposition in 1868, is exquisitely
finished. The boiler and frames are of aluminium, and

 

F16. 28.—D’AMECOURT~1853.

the steam cylinders are of bronze. The reciprocating
movement of the pistons is transmitted by gearing to a
double pair of superposed screws of 41 sq. in. surface,
one rotating in a different direction from the other. The
apparatus, which is now in the collection of the French
Societyfor Aerial Navigation, weighs, w1thout water or
fuel, 6.1 lbs. The boiler is 3% in. high and 4 in. in diame-
ter; the total height is 24% in. Unfortunately the boiler
cannot be worked at sufficient pressure; when the ma-
chine is put into motion it possesses a certain ascensional
force ; it loses weight, but it does not rise.”

The illustrated papers also published about 1865 views
 

 

SCREWS TO LIFT AND PROPEL. 55

of agreat steam flying machine, attributed to M. de [a
Lamz’e’lle. These showed a hull flanked with aeroplanes,
and surmounted with two masts, each carrying four sets
of screws, and also a partly folded umbrella, presumably
to open into a parachute. It is to be found reproduced in
most works upon aerial navigation, and in encyclopaedia
articles, and is not given here, because it possesses no
merit whatever, being probably a newspaper fancy, like
the flying ship attributed to Mr. Edison, which went the
rounds of the press some years ago, and which is also re-
produced in M. Dz'euaz'de’s chart.

M. de [a Landel/e was a persevering man, as well as one
of considerable scientific acquirements. He continued
making experiments upon screws of various shapes long
after MM. Nadar and Ponlon d’Amécourz‘ had given them
up in disgust ; and he encouraged M. Pe’mzua’, then a ris-

 

FIG. 29.—PENAUD—187o.

ing young man, to take up the study of Aviation. The
latter produced in 1870 the little apparatus shown in fig.
29. which has remained the best of its kind.

Pénaud’s flying screw, which is called by the French a
“ Hélicoptére," consists of two superposed screws rotat-
ing in opposite directions, and actuated by the force of
twisted rubber strings. The principle is the same as the
apparatus of Lamwy 65¢ Bz'mvenu and of Sir George
Cayley, but the twisted rubber is far more effective than
the bow, whether the latter be of whalebone or steel, and
this change in the motor constituted the chief merit of
Pénaud’s modification. He first experimented with rub-
ber in tension, but found that the increased weight of the
frame (to resist the strains) more than compensated for
the weaker effects of torsion, and that the latter applica-
tion enabled him to construct models which were simple,
cheap, efficacious, and not easily broken. These models,
when built in varying proportions. would either rise like a
56 FLYING MACHINES.

dart to a height of some 50 ft., and then fall down, or sail
obliquely in great circles, or, after rising some 20 or 25
ft, hover in the same spot for 15 or 20 seconds, and some—
times as many as 26 seconds, which was a much longer
flight than had ever before been obtained with screws.

For lack of a sufficiently light primary motor, Pe’naud's
further experiments in this direction brought forth no
practical results, and his apparatus has remained a toy,
which has been varied in many ways.

The most popular of such toys have been the various
single spinning screws, either of cardboard or metal,
which are attached to a spindle around which a string is
wound, and which are set in rapid rotation by briskly
pulling and unwinding the cord. These are of many
shapes, with two, three, or more arms, and of various
angles of pitch. Those with heavy rims are most effective,
sometimes rising as much as 200 ft. into the air; but they
have led to accidents and proved dangerous. In such de-
vices the source of power is not taken up into the air, as
in Pe’naud's apparatus, but it is stored in the momentum
of the screw and encircling ring (if any) by the original
muscular effort. Mr. Wen/mm measured the force ex—
pended in unwinding the coiled string by attaching thereto
a small spring steelyard, and noting the time of ascent of
a flying screw of tin plate with three equidistant vanes.
He computed that to maintain the flight of the instru-
ment, weighing 396 grains, a constant force is required of
near 60 foot-pounds per minute, or in the ratio of about
3 horse power for every 100 pounds.

Many modifications have also been made of the double
screw arrangement, which takes up its secondary motor in
the shape of twisted rubber. These have been produced
by many people ; but the cleverest are probably those of
M. Dandrz'eux, who, in November, 1879, presented before
the French Aeronautical Society * no less than 10 different
types, the best known of which is that of the butterfly,
which is still to be found in the toy shops, and which
comes to us both from Paris and from Japan. M. Dan-
drz‘eux modified the shape and proportions of the screw,
and effected a material improvement in its efficiency.

Flying screws driven by clock springs have been fre-
quently made. Such an arrangement was constructed by
Sir George Cayley, “the flying baronet,” at the begin-
ning of the century, and is described in his paper on
“ Aerial Navigation," in Vol. XV of Nz'e/zolson'sjournal.
Sometimes the attempt has been made to substitute man
power. Of such was the experiment of Mr. Mayer, a

* L’Ae’ronauz‘e, January, 1880.
SCREWS TO LIFT AND PROPEL. 57

stair-builder, who, about 1828. constructed an aerial screw
proportioned to sustain 126 lbs., and rotated it with his
own muscular power. In giving an account of the result,
forty years later, he said, naively z’l<

“The result was very flattering, though not perfectly
successful. My pecuniary resources were exhausted, and
other work in my own business being then offered to me,
ascending by wings (screws) was abandoned until a more
convenient season, and the more certain and substantial
method of making stairs, and ascending them step by step,
was substituted in its place."

Realizing the utter insufficiency of man power, or of
any known primary motor, some inventors have designed
flying screws to be worked by new-fangled motors. Of
these was the apparatus of Pomés (55)") ([6 [a Pauze, pro—
posed in 1871, and shown in fig. 30. The sustaining screw

 

FIG. 3o.—P0Mi:s & DE LA PAUZE—1871.

was inclined 56' as to obtain an oblique ascent, and appears
to have been adjustable. The steering was to be done by
a rudder, and the whole was to be worked by a gunpow—
der motor. The first requisite, therefore, was to perfect
the gunpowder engine. It is not known how much was
accomplished toward this; but the flying apparatus was
never built.

The next year (1872) M. Renoir, a member of the
French Society, proposed an apparatus consisting of two
aerial screws placed side by side in the same horizontal
plane, but with shafts capable of being moved out. of the
vertical, in order to secure movement in both directions.
They were to be driven by steam, and to rotate in op—
posite directions; and M. Renaz'r computed that the axis

* Third Annual Report Aeronautical Society of Great Britain.
58 FLYING MACHINES.

of rotation would have to be inclined 11° in order to ob
tain a horizontal course. Also, that to produce satisfac—
tory forward speed, the additional power required would
be but 10 per cent. of that required for sustaining the
weight. Aside from the main question of the motor, which
was left in abeyance, the important thing to ascertain was
the best form of sustaining screw, in, order to get the
utmost support with the least expenditure of power; so
the succeeding year, M. Renoir, having studied the results
obtained by M. Pellet with a concave screw * in a series
of experiments beginning in 1848, tried some experiments
of his own with a screw provided with a return flange or
turned edge, to prevent the centrifugal escape of the air,
of which he gave an account in the Aéronaute for April,
1873.

He drove his screw by man power, and claimed that the
results showed that a force of one horse power could sus-
tain, by means of his screw, a weight of 165 lbs. ; but Mr.
Bennet, in giving an account of these experiments to the
Aeronautical Society of Great Britain, in 1874, gave a
somewhat different account, and said :

Two years ago M. Renoir, a member of the French So—
ciety, experimented with a screw 15 ft. in diameter, with which,
by the action of his feet, he was able to lift a weight of 26 lbs.
The screw was two bladed, with an increasing pitch, the angle
of inclination being 3° at the front edge of the blade and in-
creasing to 30° at the back edge. The two blades cover the en-
tire area of the screw, and have a deep rim suspended from
them to prevent the air being driven from the circumference by
centrifugal force. M. Renoir estimated the power he developed
was about one fifth of a horse power ; but this was considered
by the members of the French Society present at the experi-
ment to be considerably below the real power exerted. As the
screw was driven by the feet, after the manner of a velocipede,
the body being in a good position for exerting its maximum
effort, the power developed was undoubtedly nearly one horse
power. A man running up a pair of stairs is able for a few
seconds to exert two horse power, and mounting a ladder placed
vertically, by the help of his hands, an ordinary man can do the
work of 1% horse power. These facts have been determined
by experiment.

While on the subject of the form of screws, it may be
well to call the attention of those who may desire to study
the subject further to an article upon “ Propulsors," by
M. Croee’ sz'nellz' (the same gentleman who lost his life in
the scientific balloon ascension of the Zem'l/e), which will
be found in the Aéronaule for April, 1870, and to another

* Ae’ronaute, March, 1870.

 
 

 

SCREWS ’1‘0 LIFT AND PROPEL. 59

by the same author on “ A Screw with Variable Pitch” in
the Aéronaute for November, 1871. Also to the remarks
on Screws by Mr. Wen/mm in the first and second reports
of the Aeronautical Society of Great Britain, and to those
of Mr. Tfiomas May, in the fourth report of the same so—
ciety. He evidently knew what he was talking about.

In 1872 Mr. Wen/mm proposed a method for varying
the pitch of the screw, which may be found in the report
of the British Aeronautical Society of that year. The
blades were to be made of some fabric, one edge being
attached to a cross arm, which was made fast to the shaft
of the screw. The other edge of the fabric was fastened
to another cross arm, so arranged as to be placed in any
position on the shaft, and firmly fixed in such position. A
coiled spring was to keep the two cross arms apart, and
thus maintain the fabric tightly stretched. If the adjust—
able arm be placed precisely in line with the fixed arm,
then the blade is parallel with the shaft, and by moving

 

 

 

 

FIG. 3I.—DIEUAIDE—I877.

the adjustable arm to one side more or less, the pitch can
be made anything desired.

The next experiments on screws were tried in 1877, by
M. Dz'euaz'de, formerly Secretary of the French Aeronauti-
cal Society, and the well—known Engineer and Patent At—
torney, whose clever c/mrl has furnished (by permission)
almost all the illustrations contained in these articles.
His apparatus is shown in fig. 31. It consisted of two
pairs of square vanes set at various angles to the line of
motion, so as to vary the pitch, and rotated in contrary
directions by gearing. The power was furnished by a
double cylinder steam-engine connected with the boiler by
a flexible hose, and the lifting power of the screws could
be accurately weighed by simply putting the apparatus on
a scale.
60 FLYING MACHINES.

The results of the experiments seemed to show “that
this double screw could not, in consequence of the losses
of power due to the gearing, exert a lifting force greater
than that of 26.4 lbs. per horse power.” This agrees
closely with the results of the experiments of Géflard with
a single screw ; he having found that6 horse power would
lift with a screw 165 lbs. at the rate of 3.28 ft. per second,
or say 27.5 lbs. per horse power, from which he deduced
the conclusion that the aerial screw gave out but 18 per
cent. of the power exerted to drive it.

The next apparatus to be noticed was not experimented
with, so far as the writer has ascertained, but was a pro—
posal of great oddity and originality patented in 1877 by
M. MéZi/amj’. Engineer and graduate of the school of. the
“ Ponts—et~Chaussées.” It is shown in fig. 32, and con—
sisted in a sort of screw parachute composed of “ two
hyperbolic paraboloids united by their concavities into a

 

FIG. 32.—MELIKOFF——I877.

sort of cone or pyramid with a rectangular base in projec-
tion.” This was to be furnished with a series of zones,
shown in section in the figure, to act upon the air; and
this arrangement, the one resembling a spear-head in the
figure, was expected to screw itself up into the air and to
act as a parachute in coming down. It was to be rotated
by a gas turbine, consisting of eight curved chambers, into
each of which charges of the vapor of ether mixed with air
were to be successively exploded by an electric Spark, and
the charges allowed to expand in doing work. The sur—
faces were to be kept cool by melting ice and by heating
the resulting water. This ice and the supply of ether
 

SCREWS TO LIFT AND PROPEL. 61

were to be carried in the recipient shown just below the
parachute, the turbine being shown lower down; this
motor was expected to work also an ordinary screw with
three arms, geared on a short axle, from which screw
horizontal propulsion was expected. Below all is shown
the car for the operator.

M. Mé/z'faofldesigned his apparatus to carry up one man,
and estimated its total weight at, 374 lbs. Of this the ap—
paratus proper was to absorb I08 lbs., the gas turbine was
to weigh 92 lbs., its supplies for one hour were to amount
to 40 lbs., and the operator was to be of 134. lbs. weight.
The rotating surface was to measure 87 sq. ft. in area,
thus giving a proportion of 4.3 lbs. to the sq. ft., which
seems entirely too small, although claimed to be calculat—
ed from the tables of air pressures given by T/zz'baulz‘.
The turbine was to be of 4 horse power, being thus esti-
mated to weigh 23 lbs. per horse power, and it was to
consume per horse power per hour 3.3 lbs. of ether and 8.7
lbs. of ice for cooling the parts, thus showing a slight dis-
crepancy from the aggregate of 40 lbs. of supplies esti—
mated as required for one hour.

The apparatus as a whole is scarcely worth experiment-
ing with, and has been chiefly described because of its
oddity ; but the weight and power of the projected gas tur-
bine seem to have been worked out with some care, and it
might be worth while to take the subject up again, in
order to ascertain whether it is practicable to construct a
rotary gas motor weighing as little as 23 lbs. to the horse
power.

The next experiment to be noticed was tried by M. Cas-
161, a mechanical engineer, in 1878. He wanted to deter-

 

 

 

 

 

FIG. 33.—-CASTEL—-I878.

mine the amount of mechanical work required to sustain
a motor in the air, and built the apparatus shown in fig.
33. It consisted of eight double screws rotated in opposite
directions by a double-cylinder compressed-air engine,
62 FLYING MACHINES.

mounted upon wheels and fed with compressed air through
a long, very light rubber hose. The weight of the whole
apparatus was 49 lbs., of which 22 lbs. was in the screws
and their machinery. The screws were 3 93 ft. in diame-
ter, and weighed 1.32 lbs. each.

Experiments were repeatedly tried, but they came to an
early ending by the apparatus rising upon the air, taking
a sheer, and smashing itself against the wall of the room.
M. Caste! did not publish the results accomplished in the
way of lifting a measured number of pounds per horse
power developed ; but he stated that he “ nolonger had
the confidence which he once possessed in screws as
future instruments of aviation. Elastic surfaces with an
alternating action to impart Vibratory motion to the air
now seem preferable to screws to solve the problem of
aerial navigation with an apparatus heavier than the air."
He estimated from an examination of the muscles of birds
and of the amount of work which those muscles were able
to give out, that the bird in full flight expended not more
than 24 foot-pounds per minute for each pound of his
weight, so that a bird, if he weighed 220 lbs., would only
expend a maximum of 0.16 horse power.

Now, we have already seen that the average power of
a man is 0.13 horse power, and that although he weighs
less than 2201bs., he cannot fly with wings by his muscu—
lar efforts, so that the estimate must be erroneous.

M. Caste! proposed to build a petroleum motor to drive
his proposed wing apparatus, but he probably found him—
self unable to keep within the necessary limits of weight.

A simpler apparatus than M. Casiel’s accomplished
much better results, for in the same year (1878) Professor
For/anim', an Italian civil engineer, launched into the air
the second steam apparatus which has flown With its con—
tained supply of steam ; the first having been that of Mr.
Phi/Zips, already described. Fig. 34 shows the flying
screw arrangement experimented with by M. For/am'm'.

It is composed of two double-bladed screws, of which
the lower one is rigidly fixed to the steam-engine, while
the upper one rotates; the result being that the lower
screw furnishes a fulcrum upon the air, while the upper
one furnishes the ascending power. The whole apparatus
thus slowly rotates upon its own axis; but this feature.
which would be very objectionable in a really navigable
apparatus, could be ehminated by rotating both screws in
inverse directions.

The upper screw was worked by a double cylinder steam
engine of )1 horse power, supplied with steam from super—
heated water contained in a depending hollow globe after
the manner of the well-known fireless locomotive, the initial
SCREWS TO LIFT AND PROPEL. 63

pressure being some 120 to 160 lbs. per sq. in. It was the
original design of M. For/dizz'm' to send up his apparatus
with a steam boiler attached, fired by 200 minute alcohol
flames ; but this proved too heavy to be lifted by the ma-
chine, and he substituted the hollow globe, tested to an
internal pressure of 225 lbs. per sq. in., which, being two-
thirds filled with water, is simply laid upon a fire until the
desired pressure is obtained ; when, on being withdrawn,
the throttle-valve which admits steam to the cylinders is
opened, and the apparatus rises.

It has been repeatedly tested, and its best performance
seems to have been to rise to a height of 42 ft. and to re-
main 20 seconds in the air. M. Forlam'm' expressed the
intention of following it up with an improved apparatus,
of which he had the design, and with an engine of 2 horse
power ; but it is stated that he has not had the leisure to
carry out this intention.

The total weight of the original apparatus was 7.7 lbs.,
and the aggregate area of the screws was 21.5 sq. ft., thus
giving a bearing surface of about 2.8 sq. ft. per pound.
The weight of the steam-engine proper was 3.52 lbs. and
that of the screws 1.32 lbs. The hollow globe, charged
with water, weighed 2.20 lbs., and the steam-gauge and
connections weighed 0.44 lbs. more, leaving 0.22 lbs. for
other accessories. It Will be noticed that the engine, the

 

FIG. 34 —FORLANlNl—1878.

boiler and the gauge weigh about 80 per cent. of the
whole, which proportlons could not be expected to obtain
in a navigable apparatus ; but, on the other hand, a larger
steam—engine and boiler would weigh less in proportion to
its power than the minute one thus experimented with, in
which steam was very wastefully used in consequence of
the relatively very large proportion of radiating surfaces.
M. Forlam'izz' designed. a self-generating steam boiler,
64 FLYING MACHINES.

which he expected to weigh but 13.2 lbs. per horse power ;
but it is not known to have been constructed.

This, then, is the best that has hitherto been done with
steam. A model screw machine weighing 7.7 lbs. has
risen 42 ft. into the air and flown for 20 seconds, but with—
out taking up a self—generating steam boiler. The power
developed ranged from 7,800 to 10,850 foot pounds per
minute, and the total weight sustained was at the rate of
26.4 lbs. per horse power.

Some time about the year 1880 Mr. Edison—the great
Edison—at the instance of Mr. James Gordon Bennett,
made some preliminary experiments to promote aerial
navigation. He began very judiciously by trying to ascer—
tain what could be done with the aerial screw as a pro-
peller. For this purpose he is reported to have placed an
electric motor of 10 (P) horse power, connected with a ver—
tical shaft surmounted with rotating vanes upon a platform
scale, and to have connected it by a wire with a source of
electric powerv—the object being to ascertain how much
the whole could be lightened by the action of the vanes
upon the air.

He rigged upon the shaft first one kind of propeller. and
then another, until he had tried all that he could think of ;
the best being a two-winged fan with long arms.

He is reported as saying that the best results obtained
were to lighten the apparatus some four or five pounds of
its total weight of 160 lbs., but the amount of power de—
veloped is not stated. This must have been quite small,
and Mr. Edison must have been unfortunate in his selec—
tion of the screws to be tried, for we have seen, by the
experiments of others, that a motor of IO (if it was really
this) horse power ought to lift 260 lbs. It is no wonder
that he is reported as saying that. “ the thing never will
be practicable until an engine of 50 horse power can be
devised to weigh about 40 lbs.”

It is understood that somewhat similar experiments
were tried by Mr. Dudgezm, the celebrated maker of
hydraulic jacks. He tested the lifting effect of various
forms of screws when rotated by steam power, and, like
Mr. Edison, he stopped in disgust. when he found how
small was the lift in proportion to the power expended.

There may have been other experiments with lifting
aerial screws in the United States, but they have not come
to the knowledge of the writer. In point of fact, such
aerial devices do not seem to have received much attention
from inventors, and there have been but few patented pro—
posals therefore in the United States.

In 1876 a patent was taken by Mr. Ward, of San Fran-
cisco, for an aerial vessel in which the supporting and the
SCREWS TO LIFT AND PROPEL- 65

propelling power was to be furnished by a series of fan
blowers. The fans furnishing the support were placed on
horizontal shafts and the exhaust opened downward, so that
the reaction would act against the force of gravity, while
the fans which produced the horizontal motion were also
arranged on horizontal shafts at the rear, the air being
conducted to them through a duct. from the front. and ex-
haust being to the rear, so that the reaction would force
the vessel forward.

In 1877 Mr. Ward took out further patents, in which
the apparatus was somewhat modified, but the general
principles remained the same. It is believed that he tried
some experiments; but no record of them has been met
with by the writer, and a letter to the inventor has re-
mained unanswered.

The same idea, but in a modified form, has quite lately
(1892) been patented by Mr. Walker, of Texas ; and per-
haps experiments will be tried to test the lifting effect of
air blasts under favorable circumstances ; but as the effi-
ciency of a screw, when used as a fan, is stated at only 35
per cent., while its efficiency as a propeller is stated at 70
per cent., it seems a question whether air blasts can be
advantageously used in aerial navigation.

It may be pointed out here that there is a considerable
difference between the fan blower and the screw propeller
—a difference which should be more thoroughly under-
stood by inventors. The most efficient fan blower is a
machine which will produce the strongest current of air
with any given expenditure of power. The best screw
propeller is the machine which will produce the least cur»
rent. If a screw propeller could be so arranged that it
would not put the air in motion at all, then there would be
no “ slip," and the machine would be as efficient as a loco-
motive running on a dry rail, in which case all the power
is expended upon the vehicle. In the case of afan blower,
or in the case of a steamboat moored to the wharf, and
with its engines in operation, all of the power is expended
in moving the fluid. It is all wasted in slip. In the case
of the steamboat advancing throughthe surrounding fluid,
or of the aerial machine, if it ever gets under way, a part
of the power is expended in putting the craft in motion and
another part in putting the fluid in motion, and the latter
power is inefficient; it is the “slip.” The best screw,
therefore, is the one which shall expend the greatest part
of the applied force upon the craft and the least upon the
fluid. It is the screw which will create as little move-
ment. as possible in the fluid in which it operates.

In 1879 Mr. Quz‘nby patented a device consisting of two
sets of screw-like sails, one set to raise the machine and

5
66 FLYING MACHINES.

the other to propel it. The drawing shows a light frame—
work with two screws, each with two blades of fabric,
one set on a vertical mast, and the other upon an inclined
mast. The screws were to be driven through rope gear-
ing by some source of power.

In the same year Mr. Gremough also patented an ap-
paratus, which should better, perhaps, be noticed under the
head of aeroplanes, but which differed from this type by
having lifting screws imbedded in the surface of the aero-
plane, in order to obtain a lifting action upon first getting
under way, after which, by sailing at an angle, both sus-
taining and propelling effect could be obtained from the
screws, with, however, the possible addition of a vertical
screw to give increased forward motion. This inventor is
understood to have tried some preliminary experiments of
details, and as a result thereof to be awaiting the develop-
ment of a light motor before undertaking to realize his
conception upon a navigable scale.

In 1885 Mr. Foster patented an air ship consisting of
two screws, four-bladed, side by side, on separate verti—
cal shafts, which latter can be thrown at an angle by rea—
son of a flexible portion connecting with the main driving
shaft, so that the thrust may both lift and propel the ap-
paratus. The main shaft was to be driven by the feet of
an operator sitting below and half way between the two
screws. These screws are apparently some 8 ft. in diame—
ter, and the man power relied upon is evidently inade—
quate, so that it is quite safe to say that if the apparatus
was ever tried it did not succeed in rising.

In 1886 and 1887 some experiments were tried at the
Royal Dock Yards in Copenhagen, for the purpose of de-
termining the relative efficiencies \of screws operating
in water, and those which should operate in the air.
The experiments were in connection with marine, and not
with aerial navigation; but it was found that not only
would the aerial propeller develop as great a thrust as the
water propeller, in proportion to the energy consumed,
but that under certain conditions it would do slightly more,
and greater thrusts per horse power were attained than in
any prev10us experiments.

These very important results, for which most of our read-
ers will be unprepared, warrant noticing the experiments
at some length. They were described in a paper by H. C.
Vogt, read before the British Association in 1888, and
the first seems to have consisted in the careful measure-
ment by Mr. Frem'nges, of Copenhagen, of the thrust and
work done by a largish flying screw, two-bladed, I ft. in
diameter and I ft. pitch, weighing 0.35 lbs. With 70
revolutions per second, it will rise 200 ft. into the air, and
SCREWS TO LIFT AND PROPEL. 67

Mr. Frem'nges determined the efficacy or work done to be
63 per cent. of the kinetic energy imparted by the arm of
the operator. At 52 revolutions per second, requiring the
expenditure of 100 foot-pounds, the thrust oi the screw
against a stop was 6 lbs., and its efficiency therefore was
6 X 550

100
the measurements of Mr. Wen/1am and others.

The first dock-yard experiments were undertaken by
Messrs. Da/zlstrom 69¢ Lolzman, and consisted in fitting
out a launch 20 ft. long and 5% ft. beam with an aerial
screw propeller of canvas 8% ft. in diameter, having 24
sq. ft. of area distributed over two ordinary canvas sails,
the pitch of which could be varied. The engine was 1%
horse power. Measured by a spring balance, the thrust of
the air propeller was, in calm weather, 36.7 lbs. per indi-
cated horse power, or the same as that of a water-screw
turned by the same power. In windy weather this thrust
was augmented through 75 per cent. of the directions in
which the wind could blow, thus illustrating the fact that
if a current of air be blowing across the blades the effi-
ciency of a propeller will be increased, because many
more particles of air will be acted upon in the same space
of time than in a calm. This fact promises important
consequences for an aerial screw in propelling, should a
true flying machine ever be compassed, for then the ad-
vancing screw would constantly have fresh particles of air
to work upon, and there would be a reduction in the slip
which necessarily must occur when its thrust is measured
in a fixed position.

The next experiment was tried with the Government
Dock Yard launch, which was 31 ft. long and 8 ft. beam.
Its ordinary water screw was removed, and an air pro-
peller of canvas was substituted, which was 20 ft. in diame-
ter and had a total area of 250 sq. ft. This area was found
much too large, but by reducing it to about 150 sq. ft. an
average speed of nearly 7 knots was attained by the
launch, whose speed with the ordinary water screw and
the same power (11.3 indicated horse power) was a maxi-
mum of 7.3 knots per hour. There was, however, a slip
of the driving rope which was estimated as wasting about
2 horse power. and the director estimated that the speed
with the air propeller would have been 7.5 knots per hour
if the gear had worked properly. As on previous trials,
75 per cent. of the winds increased the thrust of the pro-

eller.

p The apparatus for the next experiment, which was tried
in 1887, was made by Messrs. Dam/straw 65¢ Lolzman, en-
gineers, of Copenhagen. An air propeller with three vanes

= 33 lbs. per horse power, which agrees well with
68 FLYING MACHINES.

of thin sheet steel, and an area of about 5 sq. ft., was fitted
to a boat 16 ft. long and 4% ft. beam, and rotated by man
power. It is stated to have produced a thrust of 10 lbs,
with an effort of about 100 foot-pounds, or at the astonish-
ing rate of 55 lbs. per horse power ; but it must have been
assisted by wind blowing athwart the blades, for Mr. H. C.
Vogt, in a letter published in London Engineering for
December 4, 1891, says, in discussing Aerodynamics, that
“ with I indicated horse power it is not possible to obtain
a thrust of over 40 lbs. to 45 lbs. with an air propeller—
say 50 lbs. to 60 lbs. per brake horse power on the shaft
—-just the same in whatever manner area, pitch, and revo-
lutions are varied.”

On the basis of these Copenhagen experiments Mr.

aim P. Holland, in a very interesting letter, published
in the New York Herald in November, 1890, claims that
it is even now possible to navigate the air upon the screw
principle, by simply combining things already tried and
proved by various experimenters ; and he gives the elements
of a proposed steam apparatus, weighing some 7,000
lbs., and capable of carrying two men, with supplies of
fuel, etc., sufficient to sail from 8.44 to 23.6 hours. Details
of the design and method of operation are withhe'd until
a patent can be secured. As has already been said in re-
ferring to Mr. Maxim, it is probable that such a machine
can be made to rise upon the air; but special appliances
will be required to secure safety in case the machinery
breaks down while under way, and in effecting a land-
mg.

A somewhat similar proposal is made in a pamphlet
published in 1891 by Mr. fames Means, of Boston, but he
gives only a scanty glimpse of the arrangement by which
he thinks the problem could be solved. He proposes one
screw on a vertical shaft, sustaining a car, with a pair of
widely extended vertical planes, to prevent rotation of the
apparatus, and concludes by saying: “ If you want to
bore through the air, the best way is to set up your borer
and bore."

Our knowledge of the action of aerial screws is almost
Wholly experimental; and it would seem, in the present
chaotic state of theory as applied to the screw, as if this
remark of Mr. Means was almost as comprehensive and
reliable as anything on the subject of aerial screws which
has been published up to the present time. The writer
feels quite certain that it contains in a condensed form as
much reliable detailed solid information as several mathe-
matical articles of considerable complexity which he has
consulted, and it will be seen, by closely analyzing Mr.
Means’s suggestion, that after its entire adoption in the
SCREWS TO LIFT AND PROPEL. 69

Spirit in which it is made, there would be little left to be
desired in the development of aerial screws.

Among the inventors who have most deeply and most
intelligently studied the action of screws must be mentioned
M. G. Tram/é, of Paris, whose artificial flapping bird has
already been noticed under the head of “ Wings." He
has proceeded almost wholly in the experimental way, and
he has accomplished some very remarkable results. He
began his experiments with marine screws applied to elec-
tric launches about 1881, and soon developed an electric
motor weighing but 33 lbs. per horse power (primary bat-
tery not included), which rotated an improved marine screw
some 2,400 turns per minute.*

In 1886 he exhibited to the French Academy of Sciences
a new method of constructing geometrically accurate
screws by a process so simple that any workman can
carry it out, and that the cost is very much reduced.
He has also experimented. ever since 1867, with aerial
screws, and has reached the conclusion that for the latter

 

Fm, 35.—-TROUVE—i886.

the best results are obtained when the pitch is equal to the
diameter, or a little lessnL contrary to marine practice,
where pitch is generally 1.3 times the diameter.

In 1887, at the Scientific Congress at Toulouse, and in
1888, before the French Société de Physique, M. Tram/é
exhibited the electric motor and aerial screw represented
in fig. 35. The motor is the lightest ever built, weighing

t Histoire d’un Inventeur—Barral. Page 416. 'l‘ lbz'd. Page 442.
7O FLYING MACHINES.

but 3.17 02., and developing 868 foot-pounds per minute,
or at the astonishing rate of I horse power for each 7.42
lbs. weight. It is wholly of aluminum, except the mag-
netic circuit, which is necessarily of very soft iron; and
the armature is directly connected with a very light aerial
screw, geometrically perfect, which was constructed by
the process communicated to the French Academy of Sci-
ences.

This apparatus, upon being placed in one pan of a pair
of scales, and connected with a source of electricity of 40
Watts constant delivery, lightened itself of its entire weight
by action upon the air. To make the experiment more
striking, M. Tram/e” then arranged it at the extremity of a
balanced beam, as shown in the figure, connecting it with
the electric supply through the standard, the knife edges
and the beam. Then upon turning on the current, the
screw began to revolve, and the balanced beam rose from
the position A B into the position A’ B’, with the expendi-
ture of 868 foot-pounds per minute, which M. Tram/é says
is capable of raising it at the rate of 72 it. per second.

Inasmuch as he estimates that this minute motor has
only an efficiency of 20 per cent., and that a similar one
of 50 to 100 horse power would possess an efficiency of 80
to 92 per cent., it would seem that M. Tram/é now has it
in his power to go up into the air with a pair of aerial
screws, rotating in contrary directions in order to insure
stability, moved by his wonderfully light motor, to float,
to hover, and to move about at pleasure so long as he re-
mains within the limits of length, of strength and of weight
of a connecting wire to convey the electric force from a
dynamo and steam engine, which remain on the ground,
to the electric motor and aerial screw in the air.

This, as he points out, would be of practical use on the
battle-field or in a besieged city, to observe the enemy ;
and it is not impossible that he will exhibit such an ap-
paratus at some International Exposition ; but he believes
that he has now designed a still better solution of the prob-
lem; and we shail see. when we come to treat of aero-
planes, that he made the plans for an apparatus of that
kind which seems to him to solve, both in arrangement
and motive power, the all-important question of the navi-
gation of the air.

For several years past series of experiments upon aerial
screws, both for sustaining and for propelling. have been
carried on by Commandant Renard, at the French Aero-
nautical War Establishment at Chalais. He published a
preliminary paper in the Revue de L’Aéronauz‘z‘gue, in
1889. in which he gave a description of the machine used
in testing. and of the results of the experiments with the
SCREWS TO LIFT AND PROPEL. 71

screw of the war balloon La France, which is two-bladed,
nearly 23 ft. in diameter, with an average pitch of 27.5 ft.
and a surface of about 42 sq. ft.

He found that the efficacy of this screw, or its thrust in
pounds divided by the foot—pounds exerted, varied from
48.4 lbs. per horse power at 17 turns per minute, down to
16.94 lbs. per horse power, with 48 turns per minute ; and
he calls attention to the fact that inasmuch as the thrust
increases as the square of the velocity, while the power re-
quired grows as the cube, the proper method of com—
paring the efliciencies of various forms of screws is to
compare the quotients obtained by dividing the cubes of
the thrusts by the squares of the powers.

Commandant Renard seems to have so proceeded in
comparing his experiments ; and in a paper read by him
before the French Society of Physics, in 1889, he stated
that of seven forms of screws tried up to that time, one
was much better than the others; and he added from

theoretical considerations: “ There must be a screw tor
. Thrust3 . . . .
which ~———2 = constant, is a max1mum. This IS con-
Power

firmed by experiment; and it shows, moreover, that this
maximum when plotted resembles a sharp peak, each
side of which forms a wrz'tablezfireczpz'ce. In other words,
there is a screw very much better than others, and its
form cannot be much departed from without producing
very bad aerial screws."

None of the forms of screws experimented upon are
published, save that of La France, and that this is not the
best may be inferred from the fact that Mr. Maxim, who
tested about fifty different forms of screws in his recent
experiments, says : “ The screw which gave the worst re-
sults was made exactly like those employed in the experi-
ments of the French Government.”

Mr. Maxim has published a popular account, all too
brief, of his experiments, in the Cenz‘ary Magazine for
October, 1891, but for obvious reasons does not go into
scientific details. He has expressed the intention of
eventually doing so, and this is sure to prove a very great
addition to our present scanty knowledge, for his experi-
ments on aerial screws have been more systematic and
comprehensive than any heretofore tried.

From the foregoing it will be seen that comparatively
few experiments have been made to compass artificial
flight by means of sustaining aerial screws, and that much,
very much remains to be learned concerning the best
form to be given to them, the proper area. velocity and
pitch, as well as the power required, either for sustaining
or for propelling a given weight in the air with a screw.
72 FLYING MACHINES.

Indeed, even for marine screws, our knowledge may be
said to be wholly empirical—that is to say, based on ex-
periment; and there is no mathematical theory of them
which has found general acceptance. or which connects
their action with that of plane surfaces, so as to agree
with the observed facts. Some calculations made by the
present writer seem to indicate that it may be less difficult
to do so, in the case of aerial screws ; but it must be ac-
knowledged that we really know but little about them,
and that the most that we can say at present is that while
a flying machine in which the sustaining power is to be
obtained from rotating screws is likely to require less
surface than an aeroplane to sustain the same weight, per-
haps in the proportion of about one—third, yet it is likely to
require more power than the aeroplane to obtain the same
speed of translation, and also to involve greater risks of
accidents in case of failure of any part of the machinery.

It would seem to the writer as if the true function of
aerial screws was to propel, leaving the sustaining power
to be obtained in some other way, and we will therefore
pass to the consideration of AEROPLANES.

AEROPLANES.

AEROPLANES-—i.e., thin fixed surfaces, slightly inclined
to the line of motion, and deriving their support from the
upward reaction of the air pressure due to the speed, the
latter being obtained by some separate propelling device,
have been among the last aerial contrivances to be experi-
mented upon in modern times.

The idea of obtaining sustaining power from the air
with a fixed, instead of a vibrating or a rotating surface is
not obvious, and it was not till I842 that an aeroplane, as
we now understand the term, consisting of planes to sus-
tain the weight, and of a screw to propel, was first pro-
posed and experimented with. All aviators must have oc-
casionally seen and marveled at the performances of the
soaring varieties of birds, sailing in every direction at will
upon rigidly extended wings (a performance concerning
which more will be said in the progress of this discussion),
but the flapping birds are so much more numerous and
easily observed, their action is so much easier of compre-
hension. that they have been the favorite model.

We shall see, however, in reviewing old traditions with
perhaps a new understanding, that such faint approxima-
tions to success. as have hitherto been attained with artifi-
cial flying machines, were probably accomplished with fixed
surfaces, either by gliding downward by the force of
gravity, or in soaring upon the wind like a bird.
AEROPLANES. 73

Although aeroplanes have been among the last devices
to be experimented upon, they are now the favorite ap-
paratus from which success is hoped for, and later designs
have chiefly been in this direction. The very important
labors of Professor Langley have shown that with the exer-
tion of I horse power as many as 20o lbs. can be sustained
in the air by an aeroplane, while Mr. .Maxz'm states, as
the result of his many experiments, that at least 133 lbs.
can be sustained per horse power. If we compare this
with the results of vibrating wings, which may be assumed
as supporting 77 lbs. per horse power,* or with screws,
which have been shown as affording generally 33 to 40 lbs.
per horse power—chiefly, as the writer believes, because
of the greater angle of incidence or of pitch which is re-
quired with alternating or rotating surfaces—we see that
fixed surfaces possess a marked advantage over movable
surfaces. The latter, it is true, can probably be made
somewhat smaller and hence lighter, but this advantage
is likely to be more than counterbalanced by the greater
power required to work them.

Still the fact remains that almost all experiments with
aeroplanes have hitherto been fiat failures. This is be-
lieved by the writer to result from the difIiCulty of main-
taining the equilibrium of that form of apparatus, both
sideways and fore and aft. There seems to be no very
great difficulty in obtaining proper balance and equilibrium
with flapping wings or with screw apparatus, the motion
of the parts apparently compensating to some extent for
the tendency to tilt over, but fixed aeroplanes seem much
more unstable—a single flat plane, for instance, of uni-
form weight throughout, possessing no sort of stability
whatever when in forward rectilinear motion.

Perhaps the reader will best understand this, and at the
same time obtain a glimpse of some of the laws of aerial
equilibrium under forward motion, by experimenting with
an aeroplane of his own.

Let him cut out. a strip or parallelogram of stiff wrap-
ping paper—say 15 in. long and 3 in. wide. Its sides
should be straight and parallel, and the surface a true flat
plane, free from folds or wrinkles. In this condition it
may fall flatways a short distance with tolerable steadi-
ness; but if allowed to fall edgeways, or projected for-
ward without whirling, it will at once rotate upon its long
axis, tumble over and over, and be seen to have very un-
stable equilibrium. This can be remedied with very

* Assuming a bird in horizontal flight to develop 425 ft. lbs. per minute for

33.000

each pound of his weight, the sustaining reaction will be = 77 lbs. per
. 25

 

horse power.
74 FLYING MACHINES.

slight changes ; for next paste upon one of the long edges
of the plane a strip of pasteboard % of an inch wide and
the same length as the paper plane. Part of an ordinary
pasteboard box will do very well ; but the important point
to be observed is that the apparatus shall balance on its
middle line, and at a point 28 to 30 per cent. back from its
front edge, or say, % of an inch. When the paste is dry,
make a very slight fold in the paper strip near the edge
opposite to the pasteboard strip and parallel to it. Let
this fold or crease be about % of an inch from the rear
edge, and form an angle of about 10° with the plane of the
paper. Next bend the aeroplane parallel with the short sides
and exactly in the center of the long sides, so that the two
halves shall also stand at a diedral angle of about Io° with
each other, like a very obtuse letter V, care being taken
that middle fold and the back fold shall be on the same
side of the plane. It will then be noticed that the attitude
of the apparatus somewhat resembles that of a soaring
buzzard in the air minus its tail.

It, now, this aeroplane be allowed to drop edge-ways,
with the weighted side downward, from a height of 7 ft.
or more, its behavior will be entirely different from that
in its former condition. Instead of tumbling over and
over, it will sail downward and forward upon acurve until
the increasing pressure balances the weight, and then
glide on a straight path to the floor, some 15 or 20 ft. from
the operator. It may not glide on a straight line upon the
first trial, but in that event very slight changes in the
angles of the back crease and of the middle told, and a
smoothing out of the plane will be sure to produce the de-
sired forward flight and steady glide.

Still better results can be obtained by pasting a strip of
tin % in. wide in a fold in the forward edge of a plane 4
in. wide. For this purpose it will be well to have the
strip of tin 15 in. long, and to cut the paper plane 20 in.
long by 5 in. wide, so that I in. of the latter can be folded
quite over and pasted down over the tin. The latter
should be accurately spaced 2% in. from each end, so that
the apparatus shall balance exactly on the middle line
lengthways, and 1.2 in. from the weighted edge, cross-
ways. The corners beyond the tin may be rounded off if
desired. provided care be taken notto disturb the balance.
Then by bending the apparatus very slightly in the center
of its length, and turning up the rear edge about 10° in
the same direction, an aeroplane will be produced which
will sail steadily forward in still air. sweep to the right, if
the right-hand back corner be slightly curved up. or go to
the left when the left-hand corner is similarly treated.

The principle on which this aeroplane sails is the same
AEROPLANES. 75

as that upon which the bird glides downward on out-
stretched wings. The preponderance of the weight in
front determines the angle of incidence, and brings the
center of gravity to coincide with the center of pressure,
the latter varying approximately as per Joe‘ssel law, already
given, which, however, it must be remembered, probably
only applies to square planes; the horizontal component
of the pressure (inasmuch as the plane is inclined forward)
acts in the direction of the flight, and furnishes the motive
power while the back fold supplies automatically the longi-
tudinal stability by counteracting such tendency as the
aeroplane may have to tilt fore and aft; and the diedral
angle in the middle gives lateral stability, by reacting
against the air on that side toward which the apparatus
may begin to tip.

These compensations are effective in still air, but it may
be doubted whether they are sufficient in the open air.
When a bird soars in a gusty wind (and almost all winds
are gusty and irregular in velocity near the surface of the
ground), the automatic effects obtained by the diedral
angle of the wings and the upward angle of the tail do
not seem to act quickly enough. The bird will be seen,
by observation at close range, to be almost constantly bal-
ancing himself by slight, almost unconscious movements.
He advances the tips of his wings or thrusts them back ;
he flexes one or the other, and quite often he advances or
draws back his head, or uses his legs as a pendule from
the knee joint, in order to maintain his equilibrium. All
birds are acrobats, but the soaring kind, if closely ob-
served in a gusty wind, will be seen to perform feats of
balancing more delicate and wonderful than those of any
human equilibrist.

We shall hereafter see that even if the aeroplanes experi-
mented with had been provided with adequate motors,
as they were not, this difficulty in maintaining a proper
equilibrium with fixed surfaces is probably sufficient to
account for most of the failures of experiments upon a
practical scale with that form of apparatus, and for their
abandonment by their designers, abrief trial having proba-
bly satisfied them that aside from the question of a motive
power, which they were confessedly unable to solve, they
were not yet masters of such reasonable stability and com
mand over their apparatus, as to warrant them in proceed-
ing further. Now that the all-important question of a light
motor seems to be in a fair way of being solved through
the achievements of Mr. Maxim, M. Tram/é, and others
who are known to be laboring in the same direction, the
question of the equilibrium of aeroplanes increases in
relative importance, and warrants making this somewhat
76 FLYING MACHINES.

prominent in criticising past experiments and proposals.
For this and other reasons, we shall pass in review a
number of mere designs as well as forms of apparatus which
was actually subjected to the test of experiment, and en-
deavor to inquire into the causes of failure.

Failures, it has been said, are almost as instructive as
successes, as tending to remove, if we can understand
the cause, at least one of the difficulties in the way. and
the reader will probably agree that there has been hitherto
no lack of failures in aerial experiments.

There probably have been in all ages of the world men,
whose imaginations were fired by the sight of the soaring
birds, and some who tried to imitate them. In early times
mechanical and mathematical knowledge was too crude
to render such experiments numerous, and before the in-
vention and diffusion of printing, even the records of such
failures would generally perish; but a few legends have
come down to us in abbreviated shape, which indicate
that some then celebrated attempts and failures had taken
place. No great faith can be attached to these legends,
yet some of them are curious, if considered as the relation
of attempts to sail upon the wind like soaring birds with
rigid fixed surfaces.

Passing over as too scanty of record the myths of an-
tiquity, perhaps the earliest legend of an experiment which
we may fairly suppose to have been tried with an aero-
plane is stated to be found in the somewhat fabulous
chronicles of Britain,* wherein it is related that King Bla-
dud, the father of King Lear, who is supposed to have
reigned in Britain about the time of the founding of
Rome, caused to be built an apparatus with which he
sailed in the air above his chief city of Trinovante, but
that, losing his balance, he fell upon a temple and was
killed. This is about all there is of the legend, and as even
that concerning King Lear, which Shakespeare worked up
into his tragedy, has been suspected of being a myth, it is
difficult to comment intelligently upon such a tradition ;
yet it is not impossible that King Biaa’ua’ (who was reput—
ed to be a wizard, as were all investigators in ancient
times), should have attempted to imitate the ways of the
eagle in the air, and should have succeeded in being raised
by the wind, when, for lack of the balancing science of the
bird, he should have lost his equilibrium, and with a shear,
a plunge, or a whirl have come in disaster to the ground.

A better authenticated legend seems to bethat of Simon
the Magician, who, in the thirteenth year of the reign of
the Emperor Nero (about 67 A.D.), undertook to rise tow-

* Bescherelle, Histoirqdes Ballons, x852.
AEROPLANES. 77

ard heaven like a bird in the presence of everybody.* The
legend relates that “the people assembled to View so
extraordinary a phenomenon and Simon rose into the air
t/iroug/i the assistance of Me demons in the presence of
an enormous crowd. But that St. Peter, hating offered
up a prayer, the action of the demons ceased, and the
magician was crushed in the fall and perished instantly.”

“ It seems, therefore, certain” (adds M. de Grafigny)
“ from this tale, which has come down to us without any
material alteration, that even in that barbarous age a man
succeeded in rising into the air from the earth by some
means which have unfortunately remained unknown.”

The writer has seen the feat performed by soaring birds
many times. He has seen a gull, standing upon a pile-
head within 20 ft. of him, float up into the air without.
flapping, by simply facing the wind, opening his wings to
their full extent, and keeping them rigidly extended to a
sea breeze blowing at the rate of 14.40 measured miles per
hour. The gull rose vertically about 2% ft. above the
pile-head, then drifted back about 5 ft.., still rising slightly,
when he altered by a trifle his angle of incidence, ad-
vanced against the wind, losing a little height, and was
thenceforth in full soaring activity. Many other writers
have seen the same kind of performance, including the still
more difficult feat seen by M. [Woni'l/arahL who observed
in Africa an eagle spring from the top of an ash-tree,
and without a single flap first descend from 7 to 10 ft.,
going against the wind, and upon this freshening to a
squall, rise directly and slowly some 300 ft. into the air,
while advancing against the wind some 150 ft. at the
same time.

The reader may be further interested by the account of
a somewhat similar feat, published in L’Aéronante of Oc-
tober, 1890, by Mr. C/iarles Way/tar, and which he de-
scribes as follows :

“ One day when I was close to the Aqueduct of Em, and the
wind was blowing strongly down the valley, and therefore at
right angles to the aqueduct, I saw a sparrow hawk come out
of a hole marked A (fig. 36) on the sketch,i near the top, and
on the leeward side.

“The bird left his hole and dove downward, his wings
scarcely opened, and thus reached-like a dart a point about the
center of the opening of one of the arches. At this moment,
when at 19, he stretched his wings wide open and began circling,
continued his orbits, drifting with the wind, until he attained
an elevation of 800 to 1,000 ft. At this elevation, or the point

* Grafiigny, La Navigation Aérienne, 1888.
’l‘ Mouillard, L’Empire de l’Air, 1881. Page 22.
1 See page 79 for thls sketch.
78 FLYING MACHINES.

C, the sparrow hawk folded his wings almost completely and
dove forward again upon a steep inclination, making use of the
height gained to recover against the Wind the distance which
he had drifted, and to regain his hole, into which he entered
gently, by simply opening his wings Wide when within 7 to IO
ft. of the wall.

“ It is well to observe that the bird in taking this journey,
both going and coming back, expended no muscular work
whatever, save the utterly inappreciable exertion of opening and
folding, up his wings twice.”

The legend of Simon the Magician, which has led to
the above digression, is clearly ot Christian origin, as evi-
denced by the intervention of St. Peter, who is supposed
to have been martyred in Rome about A D. 64. It. is not
known to be confirmed by any Roman record, such records
having been largely destroyed during the dark ages ; but
it the tradition be founded upon a fact, we may suppose
Simon, after some preliminary trials, to have attempted to
imitate, with a fixed aeroplane, in public, some of the evolu-
tions of a soaring bird, and being unable to perform skill-
fully the necessary manoeuvres, to have lost his equilibrium
and his life.

There is another monkish tradition of the eleventh cen-
tury concerning Oliver of Malmeséury, who in some of
the accounts is styled “ Elmerus de Malemaria," and who
was an English Benedictine monk, said to have been a. deep
student of mathematics and of astrology, thereby earn-
ing the reputation of a wizard. The legend relates * that
“ having manufactured some wings, modeled after the de-
scription that 07/22! has given of those of Dedalus, and hav-
ing fastened them to his hands, he sprang from the top of a
tower against the wind. He succeeded in sailing a dis—
tance of 125 paces ; but either through the impetuosity or
whirling of the wind, or through nervousness resulting
from his audacious enterprise, he fell to the earth and
broke his legs. Henceforth he dragged a miserable, lan-
guishing existence (he died in 1060), attributing his mis—
fortune to his having failed to attach a tail to his feet.”

Commentators have generally made merry over this last
remark, but in point of fact it was probably pretty near
the truth. To perform the manoeuvre described, of gliding
downward against the breeze, utilizing both gravity and
the wind, Oliver 0f Malmesbury must have employed an
apparatus somewhat resembling the attitude of a gliding
bird, but being unable to balance himself fore and aft, as
does the bird by slight movements of his wings, head and
legs, he would have needed even an ampler tail than the

* Bescherelle, Histoire des Ballons.
79

S.

T

AEROPLAN

 

 

 

FIG. 36.——THE SPARROVV-HA\VK’S EXCURSION.
80 FLYING MACHINES.

bird spreads on such occasions in order to maintain his
equilibrium. He would have failed of true flight in any
event, but he might have come down in safety.

A more explicit tradition of the same kind comes from
Constantinople, where, under the reign of the Emperor
Manuel Comnenns, probably about the year II78, a Sara—
cen (reputed to be a magician of course), whose name is
not given, undertook to sail into the air from the top of the
tower of the Hippodrome in the presence of the Emperor.

The quaint description of this attempt, as taken from
the history of Constantinople by Cousin, and given both
by Grafigny and by Besenerelle, so clearly describes an
aeroplane as distinguished from movable wings, and so
well indicates the difficulty of obtaining and maintaining a
proper balance with such an apparatus, that it is worth
quoting :

“ He stood upright, clothed in a white robe, very long and very
wide, whose folds, stiffened by willow wands, were to serve as
sails to receive the wind. All the spectators kept their eyes in-
tently fixed upon him, and many cried, ‘ Fly, fly, 0 Saracen !
do not keep us so long in suspense while thou art weighing the
wind !'—i.e., adjusting the angle of incidence and the equilib-
rium of the machine.

" The Emperor, who was present, then attempted to dissuade
him from this vain and dangerous enterprise. The Sultan of
Turkey in Asia, who was then on a visit to Constantinople,
and who was also present at this experiment, halted between
dread and hope, wishing on the one hand for the Saracen’s suc-
cess, and apprehending on the other that he should shamefully
perish. T/ze Saracen kept exlending lzis arms to rate/z the wind.
At last, when be deemed it favorable, lze rose into l/ze air like
a 6im’; but his flight was as unfortunate as that of femur, for
the weight of his body having more power to draw him down-
ward than his artificial wings had to sustain him, he fell and
broke his bones, and such was his misfortune that instead of
sympathy there was only merriment over his misadventure.”

This account seems to be given with such circumstance
as to preclude the idea that it is merely the idle tale of
some lover of the marvelous. We may, therefore, fairly
seek to draw some inferences therefrom, which have not
been heretofore mentioned by other writers. The first is
that the apparatus was some form of aeroplane, because it
is likened to a robe instead of a pair of wings, and also
because no mention whatever is made of any flapping
action. The only active exertion described on the part of
the operator is that of the adjustment of the apparatus to
the prevailing wind, implying that it was so adjustable
that the angle of incidence might be regulated to obtain
an ascending effect, and the center of pressure be brought
to coincide with the center of pressure to produce fore and
AERUPLANES. 81

aft equilibrium. The second inference is that the force of
the wind was the only motive power relied upon, and that
the apparatus was not blown away, but rose upon the
wind like the gull which has been already described.
This being possibly an instance of that mysterious
phenomenon of “ Aspiration” which was alluded to at
the beginning of this account of “ Progress in Flying Ma-
chines," and which will be found further exemplified when
an account is given of the various experiments _of Captain
[,3 8722's. The third inference is that the defect lay in the
maintenance of the equilibrium. That the apparatus
started off properly balanced, but that so soon as a change
occurred in the conditions, perhaps an erroneous manoeuvre
on the part of the Saracenfior perhaps a gust of wind on one
side, the aeroplane lost its balance. and disaster ensued.

Only brief allusion need be made in this discussion to
the writings of Roger Bacon, the eminent philosopher of
the thirteenth century (1214—94). He seems to have
prophesied both the balloon and the flying machine, but
not to have tried or related any experiments. His writ-
ings will be found noticed in some of the encyclopmdias,
and in \Vise’s “ History and Practice of Aeronautics,” the
latter book containing, moreover, references to the tradi-
tions which have here been mentioned, as well as to others
which have been omitted.

One of the most celebrated traditions of partial success
with a flying machine refers to f. B. Dante, an Italian
mathematician of Perugia, who toward the end of the four-
teenth century seems to have succeeded in conswucting a
set of artificial wings with which he sailed over the neigh-
boring lake of Trasimene.* We have no description of the
apparatus, but this was presumably an aeroplane, soaring
upon the wind, for we have seen abundantly that all ex-
periments have failed with flapping wings, man not hav-
ing the strength required to vibrate with sufiicient rapidity
a surface sufficient to carry his weight in the air. Moreover,
there would be a stronger and steadier wind over a lake than
over the land, and the selection of a sheet of water to ex-
periment over was very happy, as it would furnish a yield-
ing bed to fall into if anything went wrong, as is pretty
certain to happen upon the first trials. A similar selection
has been recommended by D’Esz‘erno and by [Maui/Kari
and cannot be too strongly urged upon any future inventor
who desires to make similar experiments. With adequate
extent of surfaces, and (if he goes up at all) some prudence
as to the height to which he allows the wind to carry him,
he can thus acquire some insight into the science of the

* Tissandier, La Navigation Aerienne. Bescherelle, Histoire des Ballons.

6
82 FLYING MACHINES.

birds, with no greater danger than that of numerous duck-
in 5.

Whether Dante grew overbold with some preliminary
successes, or whether he was impatient to display his
achievement before his fellow-citizens and his sovereign,
he attempted to repeat the feat in Perugia, on the occa-
sion of the marriage of Barinolomew Alw'ano with the sis-
ter of jean Pan! Baglz'onz'. Starting from the top of the
highest tower in the city of Perugia, he sailed across the
public square and balanced nz'mse/ffor a long lime in tin:
air, amid the acclamations of the multitude. Unfortu-
‘nately the iron forging which managed his left wing sud-
denly broke, so that he fell upon Notre Dame Church and
had one leg broken. Upon his recovery he seems to have
given up further experiment, but went to teach mathe—
matics at Venice, where he died of a fever before he had
reached forty years of age.

Granting the tradition to be true, the apparatus used by
Dante must have been more manageable than any of its
predecessors, for the accident is said to have been due to
a breakage instead of a loss of balance. The latter, how-
ever, must have been still deficient, or Dante would have
renewed his experiments with a stronger forging. He
may have reasoned, moreover, that as the wind does
not blow with the requisite speed every day, and he knew
of no sufficiently light motor to take its place, the use of a
soaring machine would be very limited; but it is very
unfortunate that we should have no description of the ma-
chine and its mode of operation.

Two somewhat similar experiments are alluded to in
M. G. de la Landelle’s “ Aviation," published in 1863,
but are too briefly described to give much of an idea as to
the kind of apparatus employed ; he says 2

Paul Gain’otli, an artist—painter, sculptor and architect, who
was born in Lucca in 1569, constructed wings of whalebone
covered with feathers, and made use of them several times
with success. Determining to exhibit his discovery, he took
flight from an elevation, and sustained himself pretty well in
the air for a quarter of a mile, but soon becoming exhausted,
he fell upon a roof, and his thigh-bone was broken. . .

I might also cite the article from the Malaga newspaper, the
Courier of Andalusia, which was republished in several French
journals in March, I863, stating that a peasant of the neighbor-
hood, named Francisco Orujo, was said to have sailed in the
air a distance of one league with artificial wings in less than
fifteen minutes; but why multiply examples? It is better to
deduce from these occurrences, some of which are abundantly
authenticated, useful conclusions concerning the insufficiency
of man's muscular power, and concerning the sustaining power
of an inclined plane.
AEROPLANES. 83

The writer has been thus far unable to find in other
publications fuller accounts of the last two experiments
mentioned, but it is a significant fact that the greater
number of the experimenters who are said by tradition to
have actually succeeded in floating for a short distance
on the air, were men living in warm climates, where the
soaring varieties of birds are much more numerous and
more easily observed than in variable and colder climates.
This suggests the inference that these experimenters had
been watching the soaring birds, sailing upon fixed wings
in every direction, and endeavored to imitate their evolu-
tions. With the aid of the wind they may have attained a
glimmer of success, but they failed in every instance for
lack of accurate knowledge of what constitutes the sci-
ence of the birds. Elsewhere than in warm climates the
soaring birds are so few, they so frequently have to re-
sort to flapping, that those who have not seen them sail-
ing about for hours upon fixed, extended wings, deny even
the possibility of such a. performance, and only think of
wings as oscillating surfaces ; and so when, in 1842, Han-
son patented his flying machine, the proposal to obtain
support from the fixed surfaces of an aeroplane was hailed
by many as a new and happy idea.

A top View of Henson’s apparatus is shown by fig. 37.
It consisted of an aeroplane of canvas or oiled silk

 

FIG. 37.—HENSON—I842.

stretched upon a frame made rigid by trussing, both above
and below. Under this surface a car was to be attached
containing a steam-engine, its supplies and the passen-
gers. The apparatus was to be propelled by two rotating
wheels, acting upon the air after the manner of a wind-
mill. Back of these was a tail, also covered with canvas
84 FLYING MACHINES.

or oiled silk, stretched upon a triangular frame, and
capable of being expanded or contracted at pleasure, or
moved up and down for the purpose of causing the
machine to ascend or to descend. Under the tail a rudder
was placed for steering the machine to the right or to the
left. and above the main aeroplane a sail or keel-cloth
was stretched, as shown, between the two masts which
rose from the car, in order to assist in maintaining the
course. The apparatus was to sail with its front edge a
little raised so as to obtain the required support or lift
from the air, and was to be started from the top of an
inclined plane, in descending which it was to attain a
velocity sufficient to sustain it in its further progress. the
steam-engine being only designed to overcome the head
resistance when in full tlight.

Henson's patent indicates that he believed the correct
proportions to be about 2 sq. ft. of supporting surface to
each pound of weight, this being considerably in excess of
the proportion of the large soaring birds, and that the
motor required was about at the rate of 20 H.P. per ton
of weight. His general design ev1dences careful thought
and possesses some excellent features, but the form of his
aeroplane was crude and its equilibrium especially was
deficient. Henson stated in his patent :

The following are the dimensions of the machine I am mak-
ing, and which will weigh about 3,000 lbs. The surface of the
planes on either side of the car Will measure 4,500 sq. ft., and
the tail I,500 more, with a steam-engine (high pressure) of 25
to 30 H.P.

Scaled irom the patent drawings the intended dimen-
sions of the main aeroplane appear to have been about
I40 ft. long. in the direction of motion, by about 32 ft. in
width, this being considerably larger than the great
aeroplane that Mr. Maxim has been lately constructing in
England.

Henson did not realize his intention, for Mr. F. W.
Brearey, Honorary Secretary of the Aeronautical Society
of Great. Britain, says in an article upon flying machines,
published in Popular Science Review in 1869* in describ—
ing the Henson experiments :

The fact is the machine was never constructed; for after
two abortive attempts to manufacture models at the Adelaide
Gallery, which should represent the dimensions before named,
he rejoined his friend (String/ellow) at Chard, and the two
together commenced their experiments under a variety of
forms. . . . However, in I844, they commenced the con-
struction of a model ; Henson attending chiefly to the wood or
framework and Stringfe/[ow to the power, and after many
trials adopted steam. This model, completed in 1845, meas-

* Popular Science Review, vol. 8, p. I.
Q
AEROPLANES. 85

ured 20 ft. from tip to tip of wing, by 31} ft. wide. giving 70
square feet sustaining surface in the wings, and about 10 it.
more in the tail. The weight of the entire machine was from
25 to 28 lbs. . . . An inclined plane Was constructed,
down which the machine was to glide, and it was so arranged
that the power should be maintained by a steam engine, work-
ing two four bladed propellers each 3 ft. in diameter at the rate
of 300 revolutions per minute.

A tent was erected upon the clowns, 2 miles from Chard, and
for seven weeks the two experimenters continued their labors.
Not, however, without much annoyance from intruders. In
the language of Mr. Stringfe/low.‘ " There stood our aerial
prote’ge’in all her purity— too delicate, too fragile, too beautiful
for this rough world ; at least those were my ideas at the time,
but little did Ithink how soon it was to be realized. Isoon
found, before I had time to introduce the spark, a drooping in
the wings, a flagging in all the parts. In less than ten minutes
the machine was saturated with wet from a deposit of dew, so
that anything like a trial was impossible by night. Idid not
consider that we could get the silk tight and rigid enough.
Indeed the framework was altogether too weak. The steam-
engine was the best part. Our want of success was not for
want of power or sustaining surface, but for want of proper
adaptation of the means to the end of the various parts.”

Many trials by day, down inclined Wide rails, showed a
faulty construction, and its lightness proved an obstacle to its
successfully contending with the ground currents.

The above has been given verbatim, because of the im-
portance of the experiments. Stated in plainer terms, it
means that the machine was deficient in stable equilibrium
for out-of-door experiments; that “ground currents" or
little puffs of wind would destroy the balance, and that in
falling to the ground it would get more or less injured.
That the experimenters, annoyed at the presence of spec-
tators at these mishaps, endeavored to test their machine
at night, with still less success, and finally gave it up in
disgust. Mr. Brearey then continues :

Shortly after this Hanson left England for America, and Mr.
Stringfellow, far from discouraged, renewed his experiments
alone. In 1846 be commenced a smaller model for indoor
trial, and, although very imperfect, it was the most successful
of his attempts (an illustration from a photograph is given);
the sustaining planes were much like the wings of a bird.
They were 10 ft. from tip to tip, feathered at the back edge,
and curved a little on the under side. The plane was 2ft.
across at the widest part; sustaining surface, I7 sq. ft.; and
the propellers were 16 in. in diameter, with four blades oc<u-
pying three-quarters of the area of the circumference, set at an
angle of 60°. The cylinder of the steam-engine was % in.
diameter; length of stroke, 2 in.; bevel gear on crank-shaft,
giving 3 revolutions of the propeller to I of the engine. The
86 FLYING MACHINES.

weight of the entire model and engine was 6 lbs., and with
water and fuel it did not exceed 61} lbs.

The room which he had available for the experiments did
not measure above 22 yds. in length, and was rather contracted
in height, so that he was obliged to keep his starting wires very
low. He found, however, upon putting his engine in motion
that in one-third the length of its run upon the extended wire,
the machine was enabled to sustain itself; and upon reaching
the point of self-detachment it gradually rose until it reached
the farther end of the room, where there was a canvas fixed to
receive it. Frequently during these experiments it rose after
leaving the wire as much as I in 7.

Stringfe/Zaw then went to Cremorne Gardens with the two
models, but found the accommodations no better than at home.
It was found that the larger model (Henson’s) would run well
upon the wire, but failed to support itself when liberated.
Owing to unfulfilled engagements as to room, Mr. Stringfe/low
was preparing for departure, When a party of gentlemen, un-
connected with the gardens, begged to see an experiment, and
finding them able to appreciate his endeavors, he got up steam
pretty high and started the small model down the wire. When
it arrived at the spot where it should leave the wire, it appeared
to meet with some little obstruction and threatened to come to
the ground, but it soon recovered itself and darted off in as fair
a flight as it was possible to make, to a distance of about 40
yds., farther than which it could not proceed.

Having now demonstrated the practicability of making a steam-
engine fly, and finding nothing but a pecuniary loss and little
honor. this experimenter rested for a long time satisfied with
what he had effected.

It is evident that, taught by experience, Mr. Slrz'ng-
fellow had obtained greater stability in the smaller model.
The aeroplane was shaped like the wings of a bird,
slightly curved on the underside and feathered at the back
edge, so that the elastic yielding of the feathers might
automatically regulate the fore and aft stability, like the
back fold in the paper aeroplane which has been de~
scribed; but the equilibrium was still insufficient for
experiment out-of-doors, and the important problem of
safely coming down was not solved at all, for to prevent
breakage the apparatus had to be caught in a canvas
fixed to receive it.

The sparrow-hawk, whose excursion has been described
(fig. 36), solved this last problem by simply tilting himself
back and opening his wings wide so as to stop his head-
way by increased air resistance. This possibly might be
done with a full-sized apparatus mounted by an operator,
but was scarcely practicable in a small model. To miti-
gate this difficulty Mr. Slrz'agfellow increased the sustain-
ing surface, so that it was 2.6! sq. ft. per pound, and
therefore might act like a parachute, but this largely in-
AEROPLANES. 87

creased the “ drift,” and required more power, so that
water and fuel could only be provided for a very brief
flight, and the machine cannot fairly be said to have
“demonstrated the practicability of making a steam-
engine fly."

Mr. Strz'ngfellow took the matter up again in 1868, and
made further experiments with a somewhat different ap-
paratus. which will be described in due course.

The next proposal for an aeroplane was that of Aubaua’,
in 1851, which is shown in fig. 38. It provided for a
number of supporting planes, above which rotating screws
were to furnish ascending power, while vibrating wings
were to propel. The car containing the motor was to be
beneath the planes. and equipped with legs or tubes con-
taining compressed air, in order to ease off the shocks
which might be encountered in alighting.

M. Auéaua’ seems to have reasoned that in order to
secure safety in coming down, it was necessary to arrange

 

 

 

F16. 38.-——AUBAUD—~x851.

matters so that the whole weight, or nearly the whole
weight of the apparatus, could be sustained by screws
when about alighting. This same general idea will be
found to crop out in a number of subsequent proposals
by inventors, who have believed that in order to come
down safely it is necessary to design a machine which has
enough power to start up by itself on level ground. This,
of course, requires much more power than it only hori-
zontal flight is provided for, and handicaps the inventor
in an experimental machine.

The writer has been unable to ascertain whether Auéaud
ever tested his apparatus experimentally. It seems clear
that if he did, he must have become aware that no motor
then known was sufficiently light in proportion to its
energy to raise his machine into the air with screws,
especially as he actually increased the ascending resist-
ance by placing planes beneath the screws, so that the
latter would not only have to sustain the weight, but also
to overcome the vertical air pressure resulting from the
movement. He advanced a meritorious proposal, how-
88 FLYING MACHINES.

ever, by dividing the sustaining surface into several
planes, an arrangement which we shall find (in describing
Mr. D. S. Brown's experiments) to add materially to the
stability; but even with this feature the apparatus, as
shown in the figure, is deficient in equilibrium, and would
have come to grief many times if it had been experi-
mented with.

The succeeding year Mic/2e! Loufl proposed another
form of aeroplane, which is shown both in plan and in

was

l"§‘\ ""\ ‘3;

      

  

FIG. 3o.—-LOUP —x852.

side elevation in fig. 39. It is described both by M. Dz'ezz-
aide and M. Tz‘ssandz'er as consisting of a supporting
plane propelled by four rotating wings, and provided
with a rudder, also with legs beneath the car carrying
wheels upon which the machine might roll upon alighting
on the ground, an arrangement subsequently proposed
again by many inventors.

The writer has been unable to find any record of experi—
ments tried with this apparatus (which is chiefly here fig-
ured to show the wheeled feet), and it seems difficult to
conceive of its successful operation.

In 1856 Vz'scomzz‘ Carlz'ngford patented both in England
and France the aeroplane shown in fig. 40, and resem—
bling in outline a falcon gliding downward with partially
closed wings. In the center was a car or chariot, de-
scribed by the inventor as follows 2

The aerial chariot in form is something in the shape of a
boat, extremely light, with one wheel in front and two behind.
having two wings, slightly concave, fiXed to its sides, and sus-
AEROPLANES. 89

tained by laths of a half hollow forrn pressing against them,
and communicating their pressure through the body of the
chariot from one wing to the other, and supported by cords,
whose force. acting on two hoops nearly of an oval shape,
hold the wings firmly in their position.

A tail can be raised and lowered at pleasure by means
of a cord.

The chariot is drawn forward by an ‘ aerial screw'
in front thereof, “ which screws into the air at an eleva-

/
\\

\
\p

( v

 

l ;‘
\\\\\\\\;\ \\

l

 

 

 

/,/
/ /
.77
e 9/
E
5/

"l/

 

 

 

 

 

 

 

FIG. 4o.—CARLINGFORD—1856.

tion of 45°, similar to the bird’s wing; and is turned by
means of a winch acting on three multiplying wheels.”
This screw “ is known as the Carlingford screw ; the blades
of this screw become more straight as they approach the
center, or, in other words, their edges become more direct
toward the center. . . . When a certain altitude is
attained the chariot may go several miles, perhaps 50 or
60, as it were, upon an inclined plane of air."

A novelty consisted in the mode proposed for starting
the chariot. It was proposed to suspend it by ropes be—
tween two poles, and then allow it (by drawing a trigger
suddenly) to fall upon the air and to be drawn “ forward
with great velocity by the falling of the weight in front ;”
a method which we have seen to have been subsequently
adopted by M. Tram/é in starting his bird. If the invent-
or was thoroughly assured beforehand of the stability of
his apparatus at all angles of incidence, this would be an
90 FLYING MACHINES.

elegant method of getting under way, but it would be
somewhat awkward if there was any miscalculation about
the position of the center of pressure. The writer has
found no record of any experiments with the Carlingford
apparatus.

The next apparatus to be noticed was thoroughly ex-
perimented with, and years were spent in the endeavor to
put it into practical operation. It was first patented by
M. Felix du Temple, a French naval officer, in 1857, and
is shown in fig. 4t ; the top figure representing an end
View from the rear and the lower figure being a top view.
It consisted in two fixed wings of Silk fabric, stretched by
curved spars of wood or metal, and firmly attached to a
car containing the motor. In front of this a screw was
attached with a pivoted axle, in order to draw the appa-
ratus forward. An horizontal tail hinged at the car was
to regulate the angle of incidence and of flight of the
machine, while a vertical rudder under the tail and sepa-
rate from it was to steer to the right or left.

The car was to be shaped like a boat, lightly constructed
of wood or iron ribs, and might be covered on the outside
with tarred or rubber cloth. Beneath it were to be hinged
three hollow legs, which might either be folded up or
allowed to hang down. Strong springs inside of them
were to carry rods or feet, at the outer end of which were
to be wheels to roll over the ground. These legs were to
be so adjusted in length that the apparatus should present
an angle of incidence of about 20° to the horizon, and upon
being put into forward motion, at the rate of about 20
miles per hour, by the screw, it was expected to rise upon
the air and to enter upon its flight, the latter being regu-
lated by the horizontal tail and by the vertical rudder.

The motor might be steam, electricity, or some other
prime mover, and it was estimated that 6 H.P. would be
required for an apparatus ; weighing one ton. This was a
very great underestimate, for the proposed plan of driving
the machine over the ground by means of the aerial screw
would largely increase the resistance, and suflicient speed
could not be obtained to rise upon the air.

M. Du Temflle tried many experiments with models
shaped like birds, and his patent indicates that he had
carefully considered the question of stability, for he places
the preponderance of weight toward the front of the car,
provides for a diedral angle during flight by the flexibility
and shape of the wings, and produces a slight turning up
of the rear edge by making it; flexible, all much as in the
paper aeroplane which has been described. There was a
weak point, however, in the fact that the center of gravity
was not adjustable during flight, so as to correspond with
AEROPLANES. 91

the change in the center of pressure, produced by such
alterations in the angle of incidence as might result from
the action of the tail or otherwise.

When he began with the aid of his brother, M. Louis
(in Temple, to experiment on a large scale, the inadequacy

'NV'ICI
'MHIA avuu

'lLSI-LSSI—ElrldWHL rid—'1? 'DIJ

 

of all motors then known became apparent. They first
tried steam at very high pressures, then a hot-air engine,
and finally built and patented, in 1876, a very light steam
boiler weighing from 39 to 44 lbs. to the horse power,
which appears to have been the prototype of some of the
light boilers which have since been constructed. It con-
sisted in a series of very thin tubes less than % in. in in-
ternal diameter, through which water circulated very rap-
92 FLYING MACHINES.

idly, and was flashed into steam by the surrounding
flame.

This is understood to have been applied to a slightly
modified form of the main apparatus, built in 1874 at Brest
by M. Du Temple. This was calculated to carry a man,
was 40 it. across from tip to tip, weighed about 160 lbs.,
and cost upward of $6,000, the workmanship being very fine.

Careful search by the writer through various French
and English publications has failed to discover any ac—
count of the operation of this machine, save the statement
of M. Tz'ssaizdz'er that “ notwithstanding most persever-
ing efforts, no practical results could be obtained in ex-
perimenting With this apparatus.”

In 1858 fill/fen, a French clock repairer of Villeiuif,
who had already exhibited in 1850 the first model of a fish—
shaped navigable balloon which operated with its own
motor, propeller, and steering gear, endeavored to prove
what could be accomplished with aeroplanes. He exhibit-
ed to the French Society of Encouragement for Aviation
a model weighing only 1% oz., although its aeroplane
measured 39 in. across the line of motion. It was pro-
pelled by two screws each with two arms, and the power
was furnished by the tension of a rubber band wound over
two conical spools of equal diameter, like the fusée of a
watch, in order to maintain the force uniform. The angle
of incidence was about 10°, and the apparatus proceeded
horizontally in a straight line a distance of 40 ft. in five
seconds, with an expenditure of 0.52 foot-pounds per sec-
ond.

juZZz'en proposed to build a large apparatus upon the
same principle, but he failed to obtain the requisite finan-
cial backing. He saw, clearly enough, that he must have
a light motor, and he began to experiment with elec-
tricity, seeking chiefly a light primary battery. In 1866
he announced that he had succeeded in devising an elec—
tric motor and battery weighing at the rate of 82 lbs. per
H. P. with which he expected to drive an aeroplane
through the air during an entire day; but he did not receive
the encouragement or aid of capital, and this ingenious
inventor, who had struggled all his life long with inade—
quate means, died miserably poor, in a hospital in 1877.

The singular machine patented in 1860 by Mr. Smyf/zz'es,
while quite impracticable in form, is here mentioned in or-
der to make known two novel proposals—z’.e., the utilization
of the aeroplanes as steam condensers and the proposed
means for shifting the center of gravity while in flight.
A top view is shown by fig. 42. The apparatus was to
consist of extended plane surfaces in order to furnish the
Stipport, and to be propelled by the alternating motion of
AEROPLANES. 93

wings actuated by a boiler and engine of a peculiar
kind.

The boiler was to be upright, its top view being indi-
cated by the circles at the junction of the two planes. It
was to be fitted with small vertical water-tubes, thickly
placed in a “ flame—chamber" heated by the combustion
of some volatile fluid mixed with air. Back of the boiler
an upright cylinder was to be placed to work the wings
up and down, feathering motion being imparted to the
vanes composing them (by compound levers), so that they

  
 
  

/////
/

/.

    

 

FIG. 42.———SMYTHIES—1860.

should separate slightly on the up-stroke and firmly close
on the overlap on the down-stroke.

The whole of the two aeroplanes and of the upright
boiler was to be encased in a closed flat bag of oiled silk
or other light air-tight covering—that is to say, that a
steam surface condenser was to be provideo by making a
hood, tapering on its top and bottom trorn the thin edges
at the front and rear of the apparatus to a thickness at
the center equal to the height of the boiler. This hood or
case was to be kept distended by spars and by light cords,
and the spent steam was to be exhausted therein so as to
be condensed by contact with the sides, and the water
thus produced was to drain into a reservoir at the bottom,
whence it was to be pumped back into the boiler, thus
keeping the total weight of the apparatus constant and
utilizing the same water over and over again.

The operator was to be suspended in an adjustable seat
beneath the center of gravity of the machine, and by
shifting his position sideways or fore and aft, was to guide
the machine to the right or left, or up and down through
the changes thus produced in the position of the center of
gravity and consequent angle of incidence. Elastic legs
beneath the whole were to break the fall on alighting;
94 FLYING MACHINES.

the descent being, moreover, retarded by the action of
the wings, in which both the amplitude of movement and
the overlap of the vanes or “ feathers” were under the
control of the operator through a series of cords.

This apparatus as designed was quite impracticable,
but it indicates that the inventor had been watching the
birds and had become aware of some requirements over—
looked by his predecessors, such as the necessity for ad-
justing during flight the center of gravity to coincide with
the center of pressure consequent upon changes in the angle
of incidence, in order that the equilibrium may be preserved;
the necessity for more energetic efforts and greater angles
of incidence at starting and in alighting than during hori-
zontal flight, and also the necessity for an air condenser
to liquefy the 5 team, if the latter is to be used as a motive
power, both to diminish the weight of the water required
and to keep the weight constant.

In 1863 M. de Louvrz'é, a French engineer and mathema-
tician, proposed the apparatus shown in fig. 43, which he
called an “ aeroscaphe." It consisted in a kite-like surface,
stiffened by light cords to a mast above and to the car
below, and capable of acting as a parachute, as well as of
being folded like the wings of a bird. It was intended to

 

 

 

FIG. 43.—DE LOUVRIE’——i863.

progressthrough the air either» through the agency of a
screw driven by a motor, or more directly by the reaction
upon the air of some explosive substance, such as gunpow-
der. It was submitted to the French Academy of Sci—
ences, but no experiments were made on a practical scale.

This proposal was the result of a mathematical investi-
gation of the action of air upon aeroplanes and under the
Wings of birds, which was published by M. de Lozzvrz'e’,
first in Les Monday and then in the Aéromzute,* wherein
he showed that Navz'er and other French mathematicians
had grossly overestimated the power required for flight.
He also contended that the formulas then in current use
for calculating the reactions of air upon oblique surfaces

* L’Ae’ronauz‘e, September, October and November, 1868.
AEROPLANES. 95

were erroneous, and be advanced the empirical formula
of Duane/12in, hereinbefore given, as agreeing much more
closely with the observed facts. These writings of M. (Xe
Lozwrz'é were sharply attacked by other aviators,* who
had been promoting the imitation of flapping wings, and
who denied altogether the possibility of soaring or sailing
flight of birds, so that a lively controversy ensued, which
has continued to this day, for M. de Lam/rié published in
18901L a new formula on a rational basis, of fluid action
upon oblique surfaces, which agrees very closely in its re-
sults with those of the Dnc/zenzz'n formula, and he has
also written an article on the “ Theory of Sailing Flight,”
which is to appear shortly.

The “ aeroscaphe” was practically a kite without string
or tail, and its stability would probably have been found
deficient, but M. dc Louvrz'e’ tried in 1866 some experi-
ments with a model weighing some 9 lbs. and exposing a
surface of about II sq. ft. This ran upon a car on an in-
clined plane, and the “ lift" and the “drift” were care-
fully measured by means of dynamometers. The results
of these experiments demonstrated the fact that at all
velocities and for all angles the “ drift.” or resistance of a
plane to motion is to the “ lift” or supporting pressure as
the sz‘ne of the angle of incidence to its cosine ; as indeed
was to be expected from theoretical considerations, and as
had been 1aid down in 1809 by Sir George Cayley, in the
article which has already been herein quoted.

As the sine is to the cosine, as the tangenz‘ of the angle
M. de Lam/rig” deduced from his experiments the funda-
mental formula for the resistance of aeroplanes to be

R = Wtang. @,

in which R is the resistance or “ drift," Wthe weight,
and @ the angle of incidence ; and calling L the “lift”
and P’ the normal pressure, at that angle of incidence, we
may write further :

R : Wtang. @ = P' sin. a
L = W = P/ 603. a,

which formulas furnish at once the “ drift" and the “lift”
when either the normal pressure or the weight is known.
In 1868 M. de Lozmrz'é took out a second French patent
for an aeroplane, in which he chiefly described the method
of stretching the kite sail by adjustable radiating arms.
It was to’have a flat diedral angle to provide stability side-
ways, and was to be driven by a hot air engine, but no

* 1.1—1 Eronam‘e, December, 1868 ; January and February, 1869.
'f Revue de Z’A e’ronantz'gue, Vol. 3, page 102.
96 FLYING MACHINES.

experiments seem to have been made. Since then he is
understood to have abandoned the promotion of aero-
planes, and to expect more favorable results from his
"anthropornis," which has already been noticed under
the head of “ wings and parachutes.”

It may be incidentally here mentioned that a somewhat
similar proposal for a circular kite or flat parachute was
patented in the United States by Mr. Wooton in 1866. It
must have been found, if experimented with, quite defi-
cient in stable equilibrium ; any square, round, or polygonal
surface being quite inferior in stability to the comparative-
ly long and narrow wings which form the sustaining aero-
planes ol the birds.

While it seems certain. from the shape and arrangement
of the apparatus of Car/ingford, Du Temple and De
Louvrz'é, that they had in mind the possibility of soaring
upon the wind like a bird. they all proposed some kind of
an artificial motor, and none of them was bold enough,
in the face of existing prejudice, to propose to trust to the
wind alone as a motive power. This was reserved for
Count D’Esterno, who published in 1864 a very remark-
able pamphlet* upon the evolutions and flight of birds, in
which he gave the results of his many years of close ob-
serv'ation, and formulated what he considered to be “ the
seven laws of flapping flight and the eight laws of soaring
flight.” He held that the act of flight involved the pro-
viding for three distinct and indispensable requirements-—
z'.e., equz‘liérz‘um, guz’a’anre and z'mflu/sz'on, and that the
latter could be obtained from the wind whenever it blew
strongly enough. He says in his pamphlet :

“Sailing flight labors under the disadvantage that it
cannot take place without wind ; but, on the other hand.
we can derive from the wind, when it blows, an unlimited
power, and thus dispense with any artificial motor. In
sailing (or soaring) flight, a man can handle an apparatus
to carry IO tons, just as well as one only carrying his own
weight. Whoever has seen large birds of prey sailing
upon the wind, knows that without one flap of their wings
they direct themselves as they choose, save when they
want to go dead with the wind or dead against it, on
which occasions they must either tack or sweep in cir-
CleS."

He patented in 1864 the apparatus shown in fig. 44, con-
sisting of two wings hinged to a frame at the side of a central
car, so that they could be set at any diedral angle, or even
flapped should a motor be applied. The front end of the
frame was provided with trunnions fitting in sockets insert-

* “ Du Vol des Oiseaux,” D’Estemo, 1864.
AEROPLANES. 97

ed in the car, so that the rear end of the wings could be
raised or lowered, thus altering the angle of incidence.
and incidentally moving the wings forward or backward
with respect to the car. The wings themselves were to
be rigid within the triangles next to the car, and made
flexible in the rearward portion, where the curved ribs are
shown, which latter might be made of whalebone. It was
claimed that these wings would thus be capable of three
movements, corresponding to the first three ” laws” laid
down by D'Esz‘emzo: I. An up-and-down or flapping

 

FIG. 44.—D’ESTERNO—I864.

action; 2. A forward or backward inclination, and 3. A
torsional or twisting motion. The tail was connected with
the car with a universal joint, and had also three motions
corresponding to the next three laws—viz.: 4. An up-
and-down oscillation ; 5. A lateral displacement. sideways,
and 6. Torsion. The car was provided with a movable
seat, and the operator could either sit thereon, and
shift his weight forward and back or sideways, or he
might stand up and effect the same object by swaying his
body or moving about, this action displacing the center of
gravity of the apparatus, and corresponding to the seventh
law of flapping flight, or means for the maintenance of
equilibrium ; to which for sailing flight D’Esterno added
still an eighth requirement or “ law” in aflirmingthe neces-
sity for an initial headway.

He indicates in his book that an apparatus for one man
would weigh, with the operator, approximately 330 lbs.,
and spread an equal number of square feet of horizontal
surface, 215 sq. ft. of which would be in the two wings,
each being approximately 15% ft. long by 7 ft. wide, and
he describes in his patent, mechanism somewhat crude,
chiefly consisting of ropes and drums, for producing the
various motions described.

7
98 FLYING MACHINES.

The proposed mode of actual operation is not described,
but it must have been nearly identical with the evolutions
of the sparrow—hawk in the excursion which has been de-
scribed. The apparatus would first descend in order to
obtain an initial velocity, after which, having a speed of
its own, it might utilize that of the wind. During this de-
scent the fore-and-aft plane of the wings would have to
point below the horizon, and it the reader will refer to the
various attitudes of the sparrow-hawk on fig. 36, he will
note that between points A and B his wings were scarcely
open, in order to diminish the “ drift.” Once the speed
gained, the apparatus would needs alter its center of
gravity in order to change upward the angle of incidence
and to come on a nearly level keel. If it went dead with
the wind, its relative speed would have to be great enough
to furnish support; if going dead against the wind, it
would lose headway but gain'elevation ; and it might tack
on a quartering wind or describe a series of helical orbits,
like those of the birds. If the latter were chosen, the ap-
paratus would, when it had the wind in its quarter, be
sailing into the “eye of the wind” and faster than it blew,
just as in the case of the ice boat ; while it would proba-
bly need to descend a little on the part of the circle when
it was going with the wind, and would be enabled to rise
materially when, upon facing the wind, the force of the
latter was added to its own initial velocity. Thus, at
every turn height would be gained, this being acquired
when going against the wind ; and height once obtained,
the apparatus would be able to sail in any direction by
descending.

It will be noted, however, how many delicate manoeuvres
are requisite to accomplish these evolutions: to alter the
angle of incidence. the direction, the speed, and to main-
tain the equilibrium at all times. The bird does all this
by instinct ; he performs the exact manoeuver required ac-
curately, at exactly the right time, and he is always master
of his apparatus ; but the man would be at a terrible dis-
advantage, his perceptions and his operations would be
too slow, and a single false movement might be fatal.

There probably would have been many mishaps at first
with Count D’Esterno’s apparatus had it been experiment-
ed, and being aware of this difficulty, he proposed that the
experiments should be conducted over water sufficiently
deep to break the fall, the apparatus being raised, like a
kite, by a cord fastened ashore, which the operator could
hold fast or abandon at will, while he was acquiring the
science of the birds.

At that time (1864) aviation was not in public favor, and
the very existence of soaring or sailing flight of birds was
AEROPLANES. 99

strenuously denied. It was held that there must be some
small movements of the wings, which sustained the bird in
the air, and which the observers had failed to detect, and it
was not till the subse-

quent observations of

Pénaud, Wen/mm, Basle’,

Peal, Darwin, Mouz’l— ~ \\ \

lard, and others that it \\\ ‘

was admitted that a bird ‘

might sail by the sole
force of the wind without
flapping.

Count D'Esterno's
proposal was generally
laughed at as an evidence
of mild lunacy, and
whether because of this /
reason or because he dis- .
trusted the efficacy of his
own mechanism, he did ,
not build his apparatus. // \\

This is the more to be FIG. 45.—CLAUDEL—1864.
regretted because, being

in possession of an ample fortune, he might have tried
a number of valuable experiments which, if they did
not result in success (as they probably would not), might
yet have greatly advanced the fund of knowledge upon
this intricate subject. Later on, when aviation grew in
favor, and he was urged by members of the French
Aeronautical Society, he conferred with various ingeni-
ous mechanics, and in 1883 he made an arrangement
with M.f0berl to build a soaring apparatus. This was
well under way when, in that same year, Count D’Esterno
died at the age of 77. The apparatus was never com-
pleted, and, such as it is, has been deposited in the Ex-
position Ae’ronautique.

A singular proposal was that of M. Claude], who
patented in 1864 the apparatus shown in fig. 45. This
consisted of two aeroplanes, one at the front and one back,
propelled by two wings, lozenge-shaped, and rotated upon
pivots at each apex. If they were made flexible the resist-
ance of the air would bend these wings into an elongated
screw, and some propelling effect might be produced.
They were to be driven by bevel gears set in motion by a
steam engine in the car; but it is not known whether any
practical experiments were ever tried.

In 1866 Mr. F. H Wen/2am patented the meritorious
proposal of superposing planes or surfaces above each
other, so as to increase the supporting area without in-

 

 

 

 

 

 
IOO FLYING MACHINES.

creasing the leverage. These were to be “ kept in parallel
planes by means of cords, or rods, or webs of woven fab-
ric. . . . The long edges of the surface,” made of silk
or other light material, to be placed “foremost in the
direction of motion." This system of surfaces being ar-
ranged above a “ suitable structure for containing the mo-
tive power.” If manual power was employed, the body of
the operator was to be placed in a horizonial direction,
and “ the arms or legs to work a slide or treadle from
which the connecting cords convey a reciprocating motion
to oars or prOpellers, which are hinged above the back of
the person working them."

In a very able paper, which has become classical, read
at the first meeting of the Aeronautical Society of Great

VJC\~\ ”a
4 a m a\\\ a
\ j \ /r
L \l \/5

FIG. 46.—WENHAM—1866.

 

 

 

 

Britain, in 1866, Mr. I/Ven/zam gave an account of his ob-
servations, concluding with a very valuable discussion of
the problem of flight, and with the following description
of his experiments :

Having remarked how thin a stratum of air is displaced be-
neath the wings of a bird in rapid flight, it follows that in order
to obtain the necessary length of plane for supporting heavy
weights, the surfaces may be superposed or placed in parallel
rows, with an interval between them. A dozen pelicans may
fly, one above the other, without mutual impediment, as if
framed together ; and it is thus shown how two hundred weight
may be supported in a transverse distance of only 10 ft.

In order to test this idea, six bands of stiff paper 3 ft.
long and 3 in. wide were stretched at a slight upward angle in
a light rectangular frame, with an interval of 3 in. between
them, the arrangement resembling an open Venetian blind.
When this was held against a breeze, the lifting power was very
great ; and even by running with it in a calm it required much
force to keep it down. The success of this model led to the
construction of one of a sufficient size to carry the weight of a
man. Fig. 46 represents the arrangement, being an end eleva~
tion ; a a is a thin plank tapered at the outer ends, and at-
tached at the base to a triangle, é, made of similar plank for the
insertion of the body. The boards a a were trussed with thin
bands of iron 6 c, and at the ends were vertical rods dd. Be-
tween these were stretched five bands of holland 15 in, broad
and 16 it. long. the total length of the web being 80 ft. (100 sq. ft.
of surface). This was taken out after dark into a wet piece of
AEROPLANES. IOI

meadowland one November evening, during a strong breeze,
wherein it became quite unmanageable. The wind acting upon
the already tightly stretched webs, their united pull caused the
central boards to bend considerably, with a twisting, vibratory
motion. During a lull, the head and shoulders were inserted
in the triangle, with the chest resting on the base board. A
sudden gust caught up the experimenter, who was carried some
distance from the ground, and the affair, falling over sideways,
broke up the right-hand set of webs.

In all new machines we gain experience by repeated failures,
which frequently form the stepping-stones to ultimate success.
The rude contrivance just described (which was but the work of

 

 

 

 

 

 

 

 

 

“b\,/&¢/

Z

fwd .2’7/6 Ila/7:351.

\

\ \_\j:m

 

 

 

 

31. If. /
/

 

FIG. 47.—WENHAM~1866.

a few hours) had taught, first, that the webs or aeroplanes must
not be distended in a frame, as this must of necessity be strong
and heavy to withstand their combined tension; second, that
the planes must be made so as either to furl or fold up for the
sake of portability.

In order to meet these conditions, the following arrangement
was afterward tried : a a, fig. 47, is the main spar, I6 ft. long,
1} in. thick at the base, and tapered, both in breadth and thick-
ness, to the end ; to this spar was fastened the panels I} b, hav-
ing a base board for the support of the body. Under this, and
fastened to the end of the main spar, is a thin steel tie band,
a c, with struts starting from the spar. This served as the
foundation of the superposed aeroplanes, and, though very
light, was found to be exceedingly strong; for when the ends
of the spar were placed upon supports, the middle bore the
weight of the body Without any strain or deflection ; and fur-
102 FLYING MACHINES.

ther, by a separation at the base-board, the spars could be fold-
ed back with a hinge to half their length. Above this were ar-
ranged the aeroplanes, consisting of six webs of thin holland
15 in. broad (giving 120 sq. ft. of supporting surface); these
were kept in parallel planes by vertical divisions 2 ft. wide of the
same fabric, so that when distended by a current of air, each
two feet of web pulled in opposition to its neighbor; and
finally, at the ends (which were sewn over laths), a pull due to
only 2 ft. had to be counteracted, instead of the strain arising
from the entire length, as in the former experiment. The end
pull was sustained by vertical rods, sliding through loops on the
transverse ones at the ends of the webs, the whole of which
could fall flat on the spar till raised and distended by a breeze.
The top was stretched by a lath, f, and the system kept vertical
by stay-cords taken from a bowsprit carried out in front. All
the front edges of the aeroplanes were stiffened by bands of
crinoline steel. This series was for the supporting arrange-
ment, being equivalent to a length of wing of 96 ft. Exterior
to this two propellers were to be attached, turning on spindles
just above the back. They are kept drawn up by a light
spring, and pulled down by cords or chains running over pul-
leys in the panels 5 é, and fastened to the end of a swiveling
cross-yoke sliding on the base-board. By working this cross-
piece with the feet. motion will be communicated to the pro-
pellers, and by giving a longer stroke with one foot than the
other, a greater extent of motion will be given to the cor-
responding propeller, thus enabling the machine to turn, just as
oars are worked in a rowing boat. The propellers act on the
same principle as the winds of a bird or bat; their ends being
made of fabric stretched by elastic ribs, a simple waving motion
up and down will give a strong forward impulse. In order to
start, the legs are lowered beneath the base—board, and the ex-
perimenter must run against the wind.

An experiment recently made with this apparatus developed
a cause of failure. The angle required for producing the requis-
ite supporting power was found to be so small that the crino~
line steel would not keep the front edges in tension. Some of
them were borne downward, and more on one side than the
other, by the operation of the wind, and this also produced a
strong fluttering motion in the webs, destroying the integrity of
their plane surfaces, and fatal to their proper action.

Another arrangement has since been constructed having laths
sewn in both edges of the webs. which are kept permanently
distended by cross stretchers. All these planes are hinged to a
vertical central board, so as to fold back when the bottom ties
are released, but the system is much heavier than the former
one, and no experiments of any consequence have yet been
tried with it.

It may be remarked that although a principle is here de-
fined, yet considerable difficulty is experienced in carrying the
theory into practice. When the wind approaches to I5 or 20
miles per hour, the lifting power of these arrangements is all
that is requisite, and, by additional planes, can be increased to
AEROPLANES. 103

any extent ; but the capricious nature of the ground-currents is
a perpetual source of trouble.

If Mr. Wenfiam tried any further experiments with his
apparatus, he has not, to the writer’s knowledge, published
an account of the results. They would be nearly certain
to be unsatisfactory for want of stable equilibrium. The
Wen/mm aeroplane was even more unstable than that of
the bird, and the latter is constantly in need of adjustment,
to counteract the “ ground currents" and the variations in
speed and in the angle of incidence. Moreover, the hori-
zontal position selected by Mr. Wen/mm was most; un-
favorable because unnatural to man, in directing the
movements of an apparatus ; so that as often as he might
rise upon the wind, just so often he was sure to lose his
balance and to come down with more or less violence.
The two propellers described by him would of course have
proved quite ineffective in sustaining the weight, because
man's muscular power is quite insufficient to have worked
them with a speed adequate to that purpose, but they
might have served to direct the course, had the equilibrium
of the apparatus been stable.

Indeed, the writer believes that the first care of the avia-
tor who seeks to solve the problem of flight, must be to
seek for some form of apparatus which shall be, if possi-
ble, more stable in equilibrium than the bird. The latter
is instinct with life; he meets an emergency instantly.
Man’s apparatus will be inanimate, and should possess
automatic stability. Safety is the first requisite—safety in
starting, in sailing, and in alighting, and the latter operation
must be feasible almost everywhere without special prepa-
ration or appliances before the problem can be said to be
fairly solved. It will probably prove the most difficult de-
tail to accomplish, but it does not seem impossible when
we see the feat performed by the birds so many times
every day.

Mr. Wen/law’s proposal to superpose planes to each
other in order to obtain large supporting surfaces without
increasing the leverage, and consequent weight of frame,
will probably be found hereafter to be of great value.
The French experimenter T/zz‘bauz‘ found that when two
equal surfaces were placed one be/zz‘mi l/ze other, in the
direction of fluid motion, the resistance more nearly
equaled that of the two separate surfaces than might be
supposed. Thus for two square planes, placed at a dis-
tance apart equal to their parallel sides, so as to cover
each other exactly, M. T/zibauz‘ found the resistance equal
to 1.7 times that of one single surface. When the hinder
p‘lane projected by 0.4 of its surface beyond the front
plane, the resistance was 1.95 times that of the single sur-
104 FLYING MACHINES.

face. This diminished to 1.84 times, when it became 0.9.
Beyond this it reached nearly twice the resistance.*

Professor Langley found in his experiments with super-
posed planes, 15 X 4 in., soaring at horizontal speed, that
“ when the double pairs of planes are placed 4 in. apart
or more, they do not interfere with each other, and the
sustaining power is, therefore, sensibly double that of the
single pair of planes; but when placed 2 in. apart, there
is avery perceptible diminution of sustaining power shown
in the higher velocity required for support and in the
greater rapidity of fall." 1-

We may hence conclude that there will resulta material,
indeed a great advantage in superposing planes, provided
they are so spaced as not materially to interfere with each
other, and provided also that they are arranged so as to
afford a good equilibrium.

The writer of this record of “ Progress in Flying
Machines" originally hesitated whether he should in-
clude therein the account of the experiments of Captain
Le Brz's, which is about to follow. Not because he
deemed it incredible in itself, nor because, if correctly
stated, the experiments were not most interesting and in-
structive, but because the only account of them which he
had been able to procure was contained in a novel, in
which the author, to make the book more attractive, had
mixed up a love story with the record of the aerial experi-
ments, which combination, in the present state oil dis-
belief, the writer feared might be too much for the credu—
lity of the reader. It is true that the author of the novel:
said that the account of the experiments was scrupulously
correct, and that in this, the principal object of the book,
he had endeavored to be very exact, even at the risk of
detracting from his hero. It is also a fact that the Ae’ro-
naute,§ in reviewing the book, said :

Throughout the novel are to be found absolutely historical
data concerning the artificial bird of Le 872's, his experiments,
his partial success, his mischances, and his deplorable final
failure, the latter not through a radical defect, but through
lack of method, steadiness in thought, and attention to details.

But still the writer hesitated to reproduce this tale of
an ancient mariner.

Fortunately, after a year’s seeking, he succeeded in
getting a copy of an historical book, now quite out of
print, by the same author," which gives without any em-

* Derval, “ Navigation aerienne,” 1889, p. 185.

‘i‘ Langley, “ Experiments in Aerodynamics.” p. 40.

t “Les Grandes Amours,” G. de la Landelle, 1878, page 369.
§ Ae’ronaute, March, 1879, page 86.

ll “ Dans les Airs,” G. de la Landelle, 1884, page 210.
AEROPLANES. 105

bellishments an account of Captain Le Brz‘s’s experi-
ments, and quite confirms that given in the novel, wherein
it is said to have been related “ with scrupulous exact-
ness.” From the historical work, therefore, of M. de la
Landelle, supplemented by his novel, the following ac-
count has been compiled of what seems to have been a
very remarkable series of experiments on “ aspiration."
Captain Le Brz‘s was a French mariner, who had in his
younger days made several voyages around the Cape of
Good Hope and Cape Horn, and whose imagination had
been fired by the sight: of the albatross, sporting in the
tempest; on rigid wings, and keeping up with the fleetest
ships without exertion. He had killed one of these birds,
and claimed to have observed a very remarkable phenom-
enon. In his own words, as quoted by M. de la Landelle :

I took the wing of the albatross and exposed it to the breeze ;
and lo ! in spite of me it drew forward into the wind ; notwith-
standing my resistance it tended to rise. Thus Ihad discov-
ered the secret of the bird! I comprehended the whole mys-
tery of flight.

Possessed with an ardent imagination, he early became
smitten with the design of building an artificial bird
capable of carrying him, whose wings should be con—
trolled by means of levers and by a system of rigging;
and when he returned to France, and had become the
captain of a coasting vessel, sailing from Douarnenez
(Finistere), where he was born, and where he had mar-
ried, he designed and constructed with his own hands the
artificial albatross shown in fig. 48.

 
      
 

   

  

”W
v x i»

Fm. 48.—LE BRIS—1867.

This consisted of a body in the shape of a “ sabot," or
wooden shoe, the front portion being decked over, pro-
vided with two flexible wings and a tail. The body was
built like a canoe, being 131} ft. long and 4 ft. wide at its
broadest point, made of light ash ribs well stayed, and
covered on the outside with impermeable cloth, so it could
float. A small inclined mast in front supported the pul-
leys and cords intended to work the wings. The latter
were each 23 ft. long, so that the apparatus was 50 it.
106 FLYING MACHINES.

across, and spread about 215 sq. ft. of supporting surface ;
the total weight, without the operator, being 92 lbs. The
tail was hinged so as to steer both up and down and
sideways, the whole apparatus being, as near as might
be, proportioned like the albatross. The front edge of
the wings was made of a flexible piece of wood, shaped
like the front edge of the wing of the albatross, and to
this, cross wands were fastened and covered with canton
flannel, the flocculent side down. An ingenious arrange-
ment, which Le Brz's called his rolules (knee pans),
worked by two powerful levers, imparted a rotary motion
to the front edge of the wings, and also permitted of their
adjustment to various angles of incidence with the wind.
Le Eris was to stand upright in the canoe (an excellent
position), his hands on the levers and cords, and his feet
on a pedal to work the tail. His expectation was that,
with a strong wind, he would rise into the air and repro-
duce all the evolutions of the soaring albatross, without
any flapping whatever.

Le Brz's’s first experiment was conducted on a public
road at Trefeuntec, near Douarnenez. Believing, like
Count D'Esterno, that it was necessary that the apparatus
should have an initial velocity of its own, in addition to
that of the wind, he chose a Sunday morning, when there
was a good Io-knot breeze from the right direction, and
setting his artificial albatross horizontally on a cart, he
started down the road against the brisk wind, the cart
being driven by a peasant. The bird, with extended
wings, 50 ft. across, was held down by a rope passing
under the rails of the cart and terminating in a slip knot
fastened to Le Brz’s's wrist, so that with one Jerk he could
loosen the attachment and allow the rope to run. He
stood upright in the canoe, unincumbered in his move-
ments, his hands being on the levers and depressing the
front edge of the wings, so that the wind should press
upon the top only and hold them down, their position
being, moreover, temporarily maintained by assistants
walking along on each side.

When they came to the right turn in the road the assist-
ants were directed to let go, and the driver was told to
put his horse on a trot. Then Le Eris, pressing on his
levers, slowly raised the front edge of the wings to a very
slight angle of incidence; they fluttered a moment, and
then took the wind like a sail on the under side, relieving
the weight upon the cart so much that the horse began to
gallop. With one jerk Le Brz's loosened the fastening
rope, but 10! it did not run, and the bird did not rise.
Instead of this, its ascending power counterbalanced the
weight of the cart, and the horse galloped as if at full
AEROPLANES. 107

liberty. It was afterward ascertained that the running
rope had been caught on a concealed nail, and that the
apparatus had remained firmly fastened to the cart.
Finally the rails of the latter gave way, the machine rose
into the air, and Le Brz's said he found himself perfectly
balanced, going up steadily to a height of nearly 300 ft.,
and sailing about twice that distance over the road.

But an accident had taken place. At the last moment
the running rope had whipped and wound around the
body of the driver, had lifted him from his seat, and car-
ried him up into the air. He involuntarily performed the
part of the tail of a kite ; his weight, by an extraordinary
chance, just balancing the apparatus properly at the as-
sumed angle of incidence, and with the strength of the
brisk wind then blowing. Up above, in the machine,
Le Brz's felt himself well poised in the breeze, and exulted
that he was about to pass two hours in the air; but below.
the driver was hanging on to the rope and howling with
fright and anguish.

As soon as Le Brie became aware of this state of affairs,
and this was doubtless in a very short time, he took
measures to descend. He changed the angle of incidence
of his wings, came down slowly, and manoeuvred so well
that the driver gently reached the soil, entirely unharmed,
and ran off to catch his horse, who had stopped when he
again felt the weight of the cart behind him; but the
equilibrium of the artificial albatross was no longer the
same, because part of the weight had been relieved, and
Le Brz's did not succeed in reascending. He managed
with his levers to retard the descent, and came down en-
tirely unhurt, but one wing struck the ground in advance
of the other and was somewhat damaged.

This exploit naturally caused a great deal of local talk.
Captain Le Eris was considered a visionary crank by
most persons, and as a hero by others. He was poor,
and had to earn his daily bread, so that it was some little
time before, with the aid of some friends, he repaired his
machine and was ready to try it again.

He determined this time to gain his initial velocity by
dropping from a height, and for this purpose erected a.
mast, with a swinging yard, on the brink of a quarry,
excavated in a sort of pocket, the bottom of which was
well protected from the wind. In this quarry bottom he
put his apparatus together, and standing in the canoe, it
was suspended to a rope and hoisted up aloft to a height
of some 30 ft. above the ridge, and nearly 100 ft. above the
quarry bottom. A fresh breeze was blowing inland, and
the yard was swung so that the apparatus should face
both the wind and the quarry, while Le Eris adjusted his
108 FLYING MACHINES.

levers so that only the top surfaces of the wings should
receive the wind. When he had, by trial, reached a
proper balance, he raised upward the front edge of the
wings, brought the tail into action through the pedal, and
thought he felt himself well seated on the air, and, as it
were, “aspired forward into the breeze.” At this mo-
ment he tripped the hook suspending the apparatus, and
the latter glided and sailed off toward the quarry.

Scarcely had it reached the middle of the pocket, when
it met a stratum of wind inclined at a different angle
from that prevailing at the starting-point—a vertical eddy,
so to speak—probably caused by the reaction of the wind
against the sides of the quarry. The apparatus then tilted
forward ; Le Brz's pressed on his levers to alter the plane
of the wings, but he was not quick enough. The ac-
counts of the bystanders were conflicting, but it was
thought that the apparatus next oscillated upward, and then
took a second downward dip, but in any event it finally
pitched forward, and fell toward the bottom of the quarry.

As soon as the apparatus became sheltered from the
wind it righted up, and fell nearly vertically ; but as it ex-
posed rather less than I sq. ft. of surface to each pound
of weight, it could scarcely act as a parachute, and it
went down so violently that it was smashed all to pieces,
and Le Eris, who at the last moment suspended himself
to the mast of the canoe and sprang upward, nevertheless
had a leg broken by the rebound of the levers.

This accident practically ruined him, and put an end
for 12 or 13 years to any further attempt to prove the
soundness of his theory. He had failed in both experi-
ments for want of adequate equilibrium. He fairly pro-
vided for the transverse balance by making his wings
flexible, but the longitudinal equilibrium was defective,
as he could not adjust the fore—and-aft balance as in-
stantly as the circumstances changed. The bird does
this like a flash by instinct; the man was compelled to
reason it out, and he could not act quickly enough.

M. de la Landelle makes the following comment :

He lacked the science of Dante (of Perugia), but he was in—
genious, persevering, and the most intrepid of men. He was
entirely in the right in locating himself upright. both arms and
legs quite free, in an apparatus which was besides exceedingly
well designed. None was better fitted than he to succeed in
sailing flight (val-d-wz'le) in imitation of his model, the alba-
tross.

In 1867 a public subscription at Brest enabled Le Brz's
to build a second artificial albatross, and this is the one
represented by fig. 48. It was much like the first, but a
AEROPLANES. 109

trifle lighter, although a movable counterweight was
added, intended to produce automatic equilibrium. The
apparatus when completed was publicly exhibited, and
attracted much attention ; but the inventor no longer had
the audacity of youth, and he was influenced by number-
less contradictory counsellors. He wanted to proceed as
at Douarnenez, by giving an initial velocity to his appa-
ratus, but he was dissuaded from this. He was also urged
to test his machine with ballast, instead of riding in it
himself, which at once changed all the conditions of
equilibrium, as there was no longer command over a
varying angle of incidence, and yet a first mischance led
him to resort to the method of experimenting without
riding in the machine.

M. de la Landelle relates the incident as follows :

Once only did he obtain something like an ascension, by
starting from a light wagon, which was not in motion. He
was on the levee of the port of commerce at Brest, the breeze
was light, and the gathered public was impatient, through
failure to realize that success depended wholly on the intensity
of the wind. Le Bris was hoping for a gust which should
enable him to rise ; he thought it had come, pulled on his levers,
and thus threw his wings to the most favorable angle, but he
only ascended a dozen yards, glided scarcely twiCe that dis-
tance, and after this brief demonstration came gently to the
ground without any jerk.

This negative result occasioned a good many hostile
comments, and so the inventor no longer experimented in
public; but he had further bad luck; the machine was
several times capsized at starting, and more or less in-
jured, being repaired at the cost of Le Brz‘s, whose means
were nearly exhausted. Then he tried it in ballast with
varying success, and on one occasion, the breeze being
just right, it rose up some 50 yds., with a light line attached,
and advanced against the wind as if gliding over it.
Very soon the line became slack, and the assisting sailors
were greatly astonished, for the bird, without waver, thus
proceeded some 200 yds.; but at the approach of some
rising ground, which undoubtedly altered the direction of
the aerial current, the bird, shielded from the wind, began
settling down, without jolt, very gently, and alighted so
lightly that the grass was scarcely bruised.

Encouraged by this partial success, Le Brz's tried to
reproduce the same results, but he met many mishaps, in
which the apparatus was upset and injured. At last, one
day, by a stiff northeast breeze, he installed his bird on
top of the rising ground near which it had performed so
well a few weeks before, and this time he meant to ride
in the machine himself. He was dissuaded by his friends,
I IO FLYING MACHINES.

and probably made a serious mistake in yielding to them,
for the uncontrolled apparatus was not intended to adjust
itself to a gusty wind.

At any rate, the empty machine rose, but it did not sus-
tain itself in the air. It gave a twist, a glide, and a plunge,
and pitched forward to the ground, where it was shattered
all to bits. The wings were broken, the covering cloth of
the canoe was rent to pieces, while the bowsprit in front
was broken and forced back like a dart into the canoe.

The friends claimed that if the operator had been
aboard, he surely would have been spitted and killed, but
Le 8723‘ maintained that. if he had been aboard he could,
with his levers, have changed the angle of the wings in
time to avoid the wreck; he blamed himself for having
surrendered his better judgment, and he gave way to pro-
found despair.

For this was the end. His second apparatus was
smashed, his means and his credit were exhausted, his
friends forsook him, and perhaps his own courage weak-
ened, for he did not try again. He retired to his native
place, where, after serving with honor in the war of 1870,
he became a Special consrable, and was killed in 1872 by
some ruffians whose enmity he had incurred.

Le Bris had made a very earnest, and, upon the whole,
a fairly intelligent effort to compass sailing flight by imi-
tating the birds. He finally failed for want of sufficient
pecuniary backing, and also, perhaps, for lack of scientific
methods and knowledge, for even at that day Captain
Be’léguz'c, a French naval officer, had called attention to
the importance of securing longitudinal equilibrium, the
lack of which caused the failure of poor Le 872's. Had
he secured this he might have succeeded far better. espe-
cially if he had adhered to his original conception as to .
the necessity for that initial velocity against the wind,
which served him so well upon the first trial and so ill
upon the second. Singularly enough, he does not seem in
all his subsequent experiments to have sought to give his
apparatus that forward motion of its own, which he, like
Count D’Esterno, originally held to be indispensable.
He had also proposed to carry on his experiments at sea,
from a steam vessel under way, and whatever may have
been the cause that made him give up this idea, it was a
misfortune, for his apparatus was capable of floating, he
was himself an excellent swimmer, and had he experi-
mented from a vessel under motion, not only would he
have been safe, but he would have had no lack of wind to
rise upon the air.

He seems, it the accounts given be correct, to have ex—
hibited some very remarkable phenomena of “aspira-
AEROPLANES. I I I

tion,” which we shall find reproduced in one or two ex-
periments yet to be noticed, and which the soaring birds
exhibit every day to the observer, but he was baffled by
the lack of fore-and-aft equilibrium.

In 1867 Mr. Smyt/z patented, in Great Britain, a com-
bination of aeroplanes with lifting and driving screws,
which is shown in end view by fig. 49. It consisted of a

gig-’7
%

FIG. 49.—SMYTH—1867.

 

 

cylindrical car with pointed ends. to carry the passengers
and the motor ; of two aeroplanes, or light frames covered
with silk, one at the front of the car and one at the rear,
to furnish the supporting power when driven through the
air by the propellers—one of which is shown in end view——
and of two lifting screws, one above and the other below
the car. These latter vanes were to be mounted at an
adjustable angle upon vertical shafts passing through a
tube in the car, the weight of the latter being transferred
to them by means of a disk placed on rollers. This set
of vanes was to be driven by one engine, and the hori-
zontal propellers by another, so that the apparatus could
be simultaneously lifted and driven forward if desired.

This arrangement is open to the objection that the re-
sistance of the aeroplane has to be overcome in rising, and
it is quite inferior to the proposal of Craze/ell patented in
the United States in 1862, in which he had shown a palr
of propellers (revolving 1n contrary directions), pivoted
at the car, so that they might be brought overhead to
ascend, and gradually dropped to the horizontal line to
drive the apparatus forward, at which time a pair of
aeroplanes. hinged at the car, and hanging vertically
during the ascent, was also to be brought. to a horizontal

osition to furnish a sustaining reaction.

Mr. Smyz‘lz seems to have apprehended that there might
be some difficulty with his own arrangement, for he pro-
vides in his patent for a modification, in which he dis
penses with the elevating propellers, and proposes to flap
the sustaining surfaces or modified aeroplanes.

The principal feature of novelty, however, in Mr.
Smyt/z’s proposal was in the motor, which was to be a
non-metallic apparatus, within which to explode gases to
produce motion. This was to consist of a wooden cylin-
der, lined with a water-proof coating, and containing a
series of india-rubber cells surrounded with water and
I I 2 FLYING MACHINES.

connected with each other. Inside of these cells, which
could be alternately collapsed or expanded, explosive mix-
tures of hydrogen and air were to be fired by electric
sparks, the resulting expansion driving out a folding ex-
tension of the wooden cylinder, arranged like a concer-
tina, and imparting motion to a jointed rod from which
it was conveyed to the propellers.

The object was evidently to save the weight incumbent
upon metallic engines, the patentee asserting that india-
rubber cells are not injured by exploding mixed gases in
them, so long as they are kept moist. It is probable that
experiments were made with some models of this novel
motor, but no account of them seems to have been pub-
lished. Mr. Smyt/z had described his proposed machine
at the 1867 meeting of the Aeronautical Society of Great
Britain, but had no model in the exhibition of that society
in the ensuing year, where, however, an analogous idea
was brought forward by Mr. D. S. Brown, through a
model in which the ordinary cylinder and piston ot a
steam-engine were replaced by an india-rubber cloth bag,
the alternate inflation and expansion of which produced
the stroke. It was stated that the first steam-engine con-
structed by Hancock ran on the common road with an
engine of this description, but that as the process of vul-
canizing india-rubber was not then known, the steam
speedily softened the texture and escaped through the
canvas.

Fig. 50 shows the form of aeroplane patented in Great
Britain in 1867 by Butler and Edwards, and was evidently
due to some recollection of their school-boy days, when

 

 

Fm. 50.-—BUTLER & EDWARDS—1867.

they threw paper arrows in class. The stability of these
little projectiles is quite good fore-and-aft, because the
supporting surfaces increase in area while the intensity of
the pressures diminish toward the rear, but the power
required is great, and there is probably no aviating merit
in this form. Hui/er and Edwards proposed to combine
it in a variety of ways, superposing the sustaining planes,
or placing two machines side by side, or both, and bracing
between by diagonal ties. The form here shown is the
simplest, the top planes being set at a slight diedral angle,
in order to procure lateral stability.
AEROPLANES. I 13

The motive power was to be placed in a car, forward of
the centre of figure, and capable of being moved forward
and back, so as to shift the center of gravity to corre-
spond with the center of pressure at varying angles of
flight. The power was to consist in jets of steam issuing
against the air in the rear ; but, suspecting that this would
be enormously wasteful, the patentees reserved the right
of using screw propellers, driven either by the reaction of
jets of steam issuing from curved arms (Hero's aaolipile)
or by an ordinary steam-engine, in which case the steam
was to be exhausted and condensed back into water, in
cells formed by doubling the surfaces of the planes and
thus providing hollow spaces.

We now come to a celebrated experiment, which at-
tracted great attention at the time ; not so much because
of the results obtained with the entire apparatus, for these
were unsatisfactory, but because of the unprecedented
lightness of the steam-engine in proportion to its esti-
mated power.

 

  

 
   
  
 

—;
«'fi
s, @M “’

FIG. 5 r .—9TRINGFELLOW—1868.

Mr. Sz‘rz'ngfellow, whose experiments in connection
with Henson’s machine have already been noticed, was
much impressed with Mr. Wen/Lam’s proposal for super—
posing planes, and when the Aeronautical Society of Great
Britain advertised an exhibition and offered prizes, he con-.
structed and entered two models for competition in 1868.

One of these models was the apparatus shown in fig. 51,
and consisted of three superposed planes and of a tail,
driven by a screw propeller moved by a steam-engine.
The aggregate frontage was 21 lineal feet and the sustain-
ing area of the three planes was 28 sq. ft., while the tail
added some 8 ft. more, thus making some 36 sq. ft. The
weight, including the aeroplane, engine, boiler, fuel and
water, was under 12 lbs., thus giving a proportion of
about 3 sq. ft. per pound, which was certainly ample for

8
II4 FLYING MACHINES.

support. The engine was rated at one-third of a horse-
power, but its weight is not stated.

The machine ran suspended along a wire, in the central
transept of the Crystal Palace in London. It was forced
by its propellers at great speed, but generally failed to
lift itself from the wire, although Mr. Strz'ngfel/ow said
that it occasionally did so, and was then sustained by its
superposed planes alone. This failure to rise may have
been due to the fact, stated by M. Hureau de Villeneuve,
that the axis of the screw was parallel With the sustaining
planes, so that there was no angle of incidence. but a
better explanation lies in the fact that the equilibrium
was so imperfect that it was not safe, for fear of break-
age, to liberate the machine. This, however, was done
in the basement of the Crystal Palace, after the close of
the public exhibition, a canvas being held to break the
fall, and M. Brearey, an eye-witness, says :

When freed, it descended an incline with apparent lightness
until caught in the canvas; but the impression conveyed was
that had there been sufficient fall, it would have recovered
itself. . . . It was intended at the last to set this model
free in the open country, when the requirements of the Exhibi-
tion were satisfied, but it was found that the engine, which had
done much work. required repairs. Many months afterward,
in the presence of the author (M. Brearey). an experiment was
tried in a field at Chard. by means of a wire stretched across
it. The engine was fed with methylated spirits, and during
some portion of its run under the wire, the draft occasioned
thereby invariably extinguished the flames, and so these inter-
esting trials were rendered abortive.

This apparatus (restored) is now in the National Museum
of the Smithsonian Institution at Washington, where it is
said that the engine cannot now develop anything like the
power originally claimed.

The remark has well been made that so far as concerns
the motive power, this apparatus ought to have flown.
Its weight was only that of a goose, and it was said to
have one-third of a horse-power. This may have been
overestimated, but then Mr. Maxim estimates the power
of a goose at 0.083 of a horse-power, and so there is
ample margin.

There were two reasons for the failure. In the first
place the sustaining surfaces were at least three times
those of the goose, and hence the “ drift,” Or horizontal
component of the air pressure, would be much greater in
the aggregate, so that the discrepancy in power is not as
great as at first sight appears; and in the second place.
and more important, the equilibrium was so defective
that the inventor did not dare liberate his model, while
AEROPLANES. 1 15

freedom of action is the first condition of successful ex-
periment in flight. He had done better with single planes
on the previous occasion which has been mentioned, but
the failure with superposed planes in 1868 does not neces-
sarily condemn them. It merely indicates that the sur—
faces must be of correct shape and skilfully arranged,
and, if possible, produce automatic stability. It the
equilibrium be unstable, like that of the bird, it is well
enough to have more power than the goose, but it is
much more important to possess its skill.

The second model of Mr. String/“fellow consisted in a
steam-engine, similar to that applied to the complete
apparatus, but larger. It was entered in the catalogue
thus :

Light engine and machinery for aerial purposes, about half
horse-power, cylinder 2 in. diameter, 3 in. stroke, generating
surface of boiler, 31}- ft.; starts at 100 lbs. pressure in three
minutes, works two propellers of 3 ft. diameter, about 300 revo-
lutions per minute. With 31} pints of water and 10 oz. of
liquid fuel, works about ten minutes. Weight of engine, boiler,
water, and fuel, 16;}; lbs.

Subsequently the examining jury estimated the power
at one full horse—power, the weight of the engine and
boiler alone being 13 lbs., and it. awarded a prize of $500
to Mr. Strz'zzgfe/[ow for “ the lightest engine in propor-
tion to its power, from whatever source that power may
be derived.”

With this prize money Mr. Slrz‘ngfe/Zow erected a
building over 70 ft. long, in which to experiment with a
view of ultimately constructing a large machine to carry
a person to guide and conduct it, his experience with
models having evidently impressed him with the necessity
for intelligent control of any aerial apparatus not possess-
ing automatic stability; but he was already 69 years of
age, his sight became impaired, and he died in 1883,
without having accomplished any advance on his previous
achievements.

A reference is made by M. de la Landelle in “ Dans
les airs” to an “ Essay upon the Theory of Flight,” pub-
lished in 1869 at Copenhagen by Professor Krarup-Han-
sen, giving an account of an apparatus carrying a man
who, by means of pedals, put into action horizontal wings
whose action imparted motion to the machine, but the
account is too scanty to determine whether this refers to
beating wings or to an aeroplane.

Almost the same may be said concerning a large artifi-
cial bird, whose wings covered with feathers were more
than 32 ft. across, constructed in 1845 by M. Duckesnay
x I 6 FLYING MACHINES.

and exhibited in Paris, but which does not seem to have
been tried in the open air. Somewhat more definite is
the account given of some experiments by M. Marc Seguz'n,
the. celebrated French civil engineer, who in 1846 tried
two series of experiments, one with lifting screws, and
the other with an apparatus weighing 150 lbs., with a pair
of canvas wings measuring 65 sq. ft. in area, from which
he drew rather discouraging conclusions. He, however,
tried another series of experiments in 1849, with an ap-
paratus weighing 35 lbs. and worked by a man, the total
weight, including ballast and operator being 232 lbs.
This actually left the ground, and raised up some 6 to
8 in., but the effort required was evidently so violent as
not to warrant further experimenting with man-power.
Fig. 52 exhibits an apparatus patented in 1871 by
M. Danjard. This was to consist in parachute-like sails
in front and at the rear, between which were to be placed
two sustaining aeroplanes, between which again there was
to be a pair of vibrating wings, which, in connection with

 

 

 

 

 

 

 

 

FIG. 52.——DANJAR’D-—187r.

a screw, placed behind the car, were to furnish the impul-
sion. The front parachute was to be triangular in form,
and made strong and rigid to cleave the air, while the
rear parachute and the two aeroplanes were to be made
flexible in the rear, so as to obtain a horizontal thrust from
the escaping air compressed at the front. Under the rear
parachute there was to be a rudder, to move to the right
or to the left, and the machinery and aviators were to be
in the central car. No motor is indicated save hand-
AEROPLANES. I 17

power, but, of course, any primary motor could be applied
if it were only light enough.

The apparatus is not known to have been experimented
with. Probably M. Damjard dropped a lot of paper mod-
els and found that the arrangement of planes in pairs was
more stable than a single aeroplane, and the figure is here
given to show a combination which will be seen to have
given fair stability in other experiments to be hereafter
described.

The next experiment to be mentioned was important
and quite successful upon the small scale on which it
was tried. Fig. 53 represents an aeroplane with auto-

 

FiG.r53.—PENAUD—i87r.

matic equilibrium, produced in 1871 by M. A. Pe’naud, who
called it his “ planophore," and whose artificial bird and
flying screw have already been noticed.

The motive power in this aeroplane was, as in his former
models, the force of twisted india-rubber threads, fastened
to a stick 20 in. long, and rotating a double-vaned screw
8 in. in diameter. The aeroplane, 18 in. across, by a
width of 4 in., was fastened to the main stick at about its
center, so that, through the leverage of the front end, the
center of gravity of the apparatus should be slightly in
front of the centerof surface of me sustaining aeroplane.
The outer ends of the latter were bent upward, so as to
furnish lateral stability by a. diedral angle, and the longi-
tudinal stability was secured by fastening to the main
stick, back of the aeroplane, as shown, a small pair of
wings or rudders, set at an angle of about 8° pointing
below the horizon of the main aeroplane.

This was the important feature of the apparatus, and
M. Pémma’ not only showed experimentally that it fur-
nished automatic equilibrium, but he also demonstrated*

* Ae’ramzuz‘e, January,1872. Page 4.
I I8 FLYING MACHINES.

the mathematical reasons why it should do so, in re-
establishing, through the action of the air impinging upon
this horizontal rudder set at a fixed angle, any deviation
of the aeroplane irom the horizontal line of flight. The
principle is the same as that of the rear told of the paper
aeroplane which has already been described, and the fol-
lowing account of its mode of action was given by Mr.
Bennett at the 1874 meeting of the Aeronautical Society of
Great Britain :

The center of gravity of the machine is placed a little in
front of the center of pressure of the aeroplane, so that it tends
to make the model descend an incline ; but in so doing it les-
sens the angle of inclination of the aeroplane, and the speed is
increased. At the same time the angle of the horizontal rud-
der is increased, and the pressure of the air on its upper surface
causes it to descend ; but as the machine tends to turn round
its center of gravity, the front part is raised and brought back
to the horizontal position. If, owing to the momentum gained
during the descent, the machine still tends upward, theangle 0f
the plane is increased, and the speed decreased. The angle of
the rudder from the horizontal being reduced, it no longer re-
ceives the pressure of air on its superior surface, the weight in
front reasserts its power, and the machine descends. Thus,
by the alternate action of the weight in front and the rudder
behind the plane, the equilibrium is maintained. The machine
during flight, owing to the above causes, describes a series of
ascents and descents after the manner of a sparrow.

The weight of the entire apparatus was 0.56 oz., of
which the rubber absorbed 0.17 02., or about one-third.
The surface was 0.53 sq. ft., 50 that the proportion was
nearly at the rate of 15 sq. it. per pound, and necessarily
gave a slow flight.

The apparatus was publicly exhibited in August, 1871,
to a group of members of the French Society of Aerial
Navigation, in the garden of the Tuileries, and the model,
guided horizontally by a small vertical rudder, not shown
on the figure, flew several times in a circle, falling gently
to the ground near its starting—point, when the power of
the rubber was exhausted. The speed was not quite 12 ft.
per second, or about the same as that of insects with the
same relative surface in proportion to their weight, and
the flight was 131 ft. in 11 seconds, with 240 turns of the
rubber.

Subsequently M. Pénaud measured the power con-
sumed in a very ingenious way. He found that with 60
turns of the rubber the apparatus would just hold its own
——z'.e., hover in the same spot, against a wind of 9 ft. per
second, and knowing the speed of rotation of the screw,
as well as the weight of the apparatus, he deduced the
AEROPLANES. 1 19

conclusiou that the power expended was at the rate of one
horse-power for each 81 lbs. of weight, although M.
Touc/zg, who has revised the calculations. makes it about
three times this amount—a result, of course, quite inferior
to those obtained by Professor Langley and by Mr. Maxim,
because, perhaps, of the greater proportion of surface to
weight.

M. Pe’mzua’ was a very ingenious man, and might have
accomplished great things in aerial navigation had not his
career been cut short prematurely. He was one of the
few men who have taken up the subject in his youth, for
it is a singular fact that most of the scientific students of
this inchoate research are now men of middle age, perhaps
past the dread of being considered mentally unsound, but
no longer with the ardor and the daring of youth. M.
Pénaua’, however, began before he was 20 years old, by
producing his flying screw. He had intended to enter the
French Navy, but a painful hip disease had brought him
to crutches, and left him no career but that of scientific
studies. These he directed to aerial navigation, and dur-
ing six or seven years of improved health he impetuously
investigated and experimented upon the various phases of
the problem. Not only did he produce the three forms of
apparatus which have been described, almost the first
which have practically worked, each flying upon a differ-
ent principle and all produced by one man, but he took a
very active part in the investigations promoted by the
French Society for Aerial Navigation ; making a scientific
balloon ascent, in which he was somewhat injured, de-
signing a plane table for platting the course of balloons,
a guide rope break, a delicate barometer, a balloon-valve,
a kite without a tail, balanced in the same way as his aero-
plane, a form of explosion engine, a programme for ex-
periments on air resistances, one for investigation of flight
by instantaneous photography, sincecarried out by Pro-
fessor Marcy, etc., etc., towering above his fellow-mem-
bers in discussions. in a way which must have excited
many jealousies; and he also contributed a number of
very valuable papers to the Aéronaute, in one of which he
endeavored to account for the mystery of sailing flight by
showing that ascending currents in the wind were not
rare, and were quite sufficient to explain all the phenom-
ena.

These labors finally culminated in his taking, in 1876
(in partnership with M. Gaza/202‘, a clever mechanician,
who had produced an artificial bird), a patent for the ap-
paratus shown in fig. 54, which was to be of sufficient size
to carry up two men.

It was to consist of an aeroplane somewhat in the form
120 FLYING MACHINES.

of an ellipse, built of a light framework covered both at
top and bottom with varnished silk, and stiffened by wire
stays radiating from two short masts above and from the
car below the aeroplane. The outer ends of the aeroplane
were to be flexible, or to be set at a died ral angle, In order
to produce lateral stability, and the rear portion was also
to be flexible and to bend upward, to produce the longi-
tudinal stability, this being, moreover, provided for by two
horizontal rudders, side by side, hinged at the rear, so as
to set themselves automatically at the angle required to
produce fore-and-aft equilibrium, upon the principle de-
veloped in the “ planophore.” Under these balanced
horizontal rudders a vertical rudder was to steer to the
right. or left. A car, in the shape of a light boat, was to
be rigidly attached just under the aeroplane, the steers-
man standing or sitting at the bow, with his head just
above the top of the aeroplane, and protected from the
wind by a glass box. Movable legs with rollers and
springs were to be let down to get a preliminary run on
land, or to alight in a glancing direction.

The motion was to be obtained from two propellers,
placed at the front edge of the aeroplane, and rotating in
opposite directions ; the power to be furnished by a steam-
engine—although M. Pe’naud said frankly that he knew of
none in practical operation sufficiently light for his pur-
pose. He believed it ought not to weigh more than 15 to
22 lbs. per horse-power, and hoped to get one constructed
within those limits. The engine was so to be located in
the car as to bring the center of gravity of the apparatus
one-fifth of the distance back of the front edge, and all the
steering was to be done by the helmsman through a single
lever, which might either be pulled or pushed to work the
horizontal rudders, or twisted to work the vertical rudder.

The sustaining surface of the aeroplane was to be pro-
portioned at the rate of about 0.24 sq. ft. per pound of
weight, the whole apparatus with two aviators was to
weigh 2,640 lbs., and required an engine of 20 to 30 H.P.
to fly through the air at 60 miles per hour, with an angle
of incidence of 2°.

This apparatus, the result of several years of study by
an able man who bestowed very careful thought thereon,
was never built. The writer of this does not believe it
would have succeeded if it had been experimented with,
but valuable data might have been obtained. Aside from
the difficulty about a light motive power, a difficulty now
almost removed, it may be questioned whether the general
form of the aeroplane was the best possible to glide upon
the air, and whether the longitudinal equilibrium would
have been as well preserved as in M. Pénaud’s toy model.
AEROPLANES. 12 I

If not, then a sustaining surface of only 0.24. sq. ft. per
pound would have been exceedingly dangerous. The
horizontal rudders, when left to adjust themselves, were
expected to regulate the automatic balance, but they were
also expected, when actuated by the steersman, to alter
the angle of incidence, in order to cause the apparatus to
rise or to fall. Such a change in the angle would neces-
sarily alter the position of the center of pressure, and there
was no provision for making a corresponding change in
the center of gravity, other than by the displacement of
the aviators themselves, or that of the fuel, water, or
boiler, which displacement would be nearly impracticable.

 

 

 

 

 

 

 

 

 

 

 

 

FIG. 54.—PENAUD & GAUCHOT—1876.

This was the weak point, for the pressure being then
applied at a point differing from the center of gravity,
would act with a. leverage upon the apparatus and tilt it
either forward or backward longitudinally, so that, had it
been experimented with on a practical scale, it might have
experienced a forward sheer or a plunge, either from too
great an action of the horizontal rudders in rising or in
coming down, or, as in the case of poor Le Brz's’s second
experiment, from encounter with a stratum of wind of differ-
ent horizontal direction than that for which the machine
was adjusted.

Perhaps surmising the possibility of some such action,
M. Pe’naua’ suggested that the experiments should be con-
ducted over a sheet of water. The apparatus might also
have been suspended between two very high masts, or
from a captive balloon, but probably the best results would
have been obtained by experimenting entirely clear of any
restraining supports.
122 FLYING MACHINES.

At any rate no funds were forthcoming for the construc-
tion of the full-sized machine. M. Pe’mma’ was criticised,
decried, misrepresented, and all sorts of obstacles arose
to prevent the testing of his project. He lost. courage and
hope, his health gave way, and he died in October, 1880,
before he had reached 30 years of age.

He had doubtless done much toward solving the difficult
problem of automatic stability in the air, but the French
aviators do not seem to accept M. Pénaud’s device as a
solution of the question of longitudinal equilibrium. They
claim that it consumes too much power in the constant re-
adjustment of the stability, and that in a full—sized naviga—
ble apparatus it would not act quickly enough to prevent
disaster. In September, 1890, M. Hureau do Vii/mauve
published a paper in the Aéronaute, in which he treats
the problem of.stabili‘ty as yet to be solved, and suggests
the inverted cone, as exemplified in the parachute of Cock—
ing (which failed simply by reason of f-aulty construction),
and he proposes as a possible solution of the equilibrium
in both directions, that the aviating surface shall be made
to conform to the development of an inverted cone. That
is to say, that its lines, whatever they may be in the ground
plan', shall in vertical projection follow the development
of an inverted cone, placing the center of gravity so as to
correspond with the position of the apex, and this he seems
to have illustrated with a number of working models by
cutting out various forms of birds out of an inverted cone.

Pérmua’ said that his solution was practically the same
as that of Sir George Cayley, with whose labors he was
not acquainted at the time that he hit upon the device for
his “ planophore." In his articles in Nicholson’s journal,
published in 1809 and 1810, Sir George Cayley shows that
the lateral stability is easily secured by placing the wings,
either curved or plane, at a slight diedral angle to each
other, and he lays down the principle, that in order to
secure the longitudinal stability : I. The center of gravity
must be made to occupy a position directly under the
center of pressure ; and 2. The aeroplane requires, to
steady it, a rudder in a similar position to the tail in the
bird. He then continues :

All these principles upon which the support, steadiness, ele-
vation, depression, and steerage of vessels for aerial navigation
depend have been abundantly verified by experiments, both
upon a large and small scale. I made a machine having a
surface of 300 sq. ft., which was accidentally broken before
there was an opportunity of trying the effect of the propelling
apparatus, but its steerage and steadiness were perfectly proved,
and it would sail obliquely downward in any direction accord-
ing to the set of the rudder. Its weight was 56 lbs., and it was
AEROPLANES. 1 23

loaded with 84 lbs., thus making a total of I40 lbs., or about
2 sq. ft. to I lb. Even in this state, when any person ran for-
ward in it with his full speed. taking advantage of a gentle
breeze in. front, it would bear upward so strongly as scarcely
to allow him to touch the ground, and would frequently lift
him up and convey him several yards together. . . . It
was beautiful to see this noble white bird sail majestically from
the top of a hill to any given point of the plain below it, with
perfect steadiness and safety, according to the set of its rudder,
merely by its own weight, descending in an angle of about 8°
with the horizon.

A number of very interesting experiments upon the
stability of aeroplanes were tried in 1873 and 1874 by Mr.
D. S. Brown. He had begun by seeking for a light motive
power, and his proposal for a steam-engine with an india?
rubber bag instead of a cylinder has already been noticed ;
but becoming aware of the enormous importance of stable
equilibrium, he turned his attention in that direction. He
exhibited at the meeting of the Aeronautical Society of
Great Britain, in 1873, a model consisting of two planes
of equal size, one placed before the other at some distance
and connected by a rod, which arrangement showed much
greater stability than a single plane, and he followed this
up at the next meeting, in 1874.- by exhibiting models of
what. he called his “ aero-bi-plane,” which showed still
further improvement in the stability, in consequence of
“ constructing the anterior edges or frames of the planes
rigid, and the other parts yielding or elastic.” The two
planes might. be rectangular and have their anterior edges
straight, or these might be curved to diminish the air re-
sistance, and the surfaces were placed one behind the
other in the same general plane, so that they did not, as
in the case of Pémzud’s “ planophore,” make a slight hori—
zontal angle with each other.

Mr. Brown stated that “ the aeroplane should not. be
inclined to its path of motion, but its surface should form
a direct line with it. . . . the plane being kept: at
the same elevation by slightly directing its course upward,
sufficient to compensate for any fall which may take
place." As, however, there was in the model a horizon-
tal rudder, which regulated the angle of incidence in
flight, Mr. May pointed out that the claim was a distinc—
tion without a difference. In one model the planes were
connected with each other through double rods, so as to
admit of a load, representing a car, being placed between
them, and Mr. Brown stated that: in this form it might be
termed a progressive parachute, which was only‘supported
by the air when in forward motion. When this motion
was stopped—and this might be done by bringing it sud-
124 FLYING MACHINES.

denly into a large angle with the horizon, so as to increase
the resisting surface—the model settled down to the floor.
It being, therefore, necessary that the apparatus should
start with an initial motion, this was given by an india-
rubber rope fastened at one end to a post, and at the other,
by means of a ring, to a vertical bolt inserted in the under
part of the bi—plane, so that it might be released when the
rope slackened. The experiments are described in the
report of the meeting as follows :

Mr. Brown launched several planes of different dimensions.
All showed perfect stability, and, save one or two, floated in
the air in a horizontal position across the room, a distance of
between 20 and 30 ft., and, apparently, in some instances could
have gone further without falling had not the walls intervened.
One he suddenly pressed downward in a perpendicular direction
by striking it with a stick when in the air ; this caused it to dart
forward with great velocity in a horizontal course. Mr. Brawn
considered this an illustration of true flight, as the planes were
only inclined the moment he struck the connecting-rod. Dur—
ing the flight they recovered their horizontal position and offered
no resistance to the air.

It may be noticed that this arrangement of surfaces,
which Mr. Brown referred to as “ first steps to flight.”
differs from that of M. Pémmd in making the rear plane
of the same size as that of the front, and parallel there—
with, the automatic stability being obtained through the
flexibility of the posterior edge, which acts much in the
same way as the upward inclination” of the rear plane or
rudder in Pénaud’s apparatus. Whether either of these
arrangements, thus slightly differing in construction, will
prove adequate in practical operation upon a large scale,
can only be ascertained by experiment. but it may be
stated that the British aviators have not accepted Mr.
Brown’s proposal as a solution of the problem of equili-
brium, and that some of them believe that he made a mis-
take in placing his planes parallel with each other ; “ no
change of action taking place whether the planes move
from the horizontal to 45° or to any other angle."

The next apparatus to be noticed will be found de-
scribed in most of the articles on flight in magazines and
in encyclopaedias, but the writer of these lines has been
fortunate enough to obtain from Mr. May himself still
further particulars concerning an experiment which has
well been characterized in the reports of the Aeronautical
Society of Great Britain as “ one of the most determined
attempts at solving the problem which has yet taken

lace.”

p Fig. 55 shows a front view, from a photograph, of
“ Thomas Moy's aerial steamer,” which was tried in the
AEROPLANES. I 25

open air at the Crystal Palace near London in June, 1875.
The supporting surfaces consisted in two aeroplanes, one
in front and the other behind the propelling aerial wheels ;
the planes being of linen, stretched upon bamboo canes,
and set at an angle of 10° with the horizon, the rear plane
being placed higher than the front plane, but parallel there-
with. A third steering plane, of smaller size, governed
by a horizontal wind wheel with screw vanes, was placed
in the rear to serve as a horizontal rudder. The front
plane measured 50 sq. ft.., and the after plane had 64
sq. ft. of surface ; their true size in relation to the whole
apparatus being inadequately shown in the figure, because
of the perspective, as they are seen nearly edgewise.
Between the two supporting aeroplanes were placed two
propelling aerial wheels 6 ft. in diameter, each provided

\
’ \\\\~

//
5,
/

 

 

 

 

n“

 

=.r

FIG. 55.—MOY—I875.

with six blades. These were first made of thin laths to
approximate to true helices, but were afterward made of
Scotch cambric. The blades or vanes were by a most
ingenious and simple arrangement caused to change their
angle of incidence as they rotated, so as to be “ succes-
sively caused to be inclined to the line of onward motion
of the machine, in such a manner that the blades on one
side of the neutral line will be caused to act downward on
the air with both a raising and propelling effect, while
those on the other side thereof will, in their upward
course, be impinged upon by the air with only a lifting
tendency.” This being in effect an aerial screw in which
the pitch was variable in every portion of the revolution,
and constituting the chief feature of novelty in the whole
apparatus.
I 26 FLYING MACHINES.

The steam-engine was placed between the two aerial
wheels, and ,was a marvel of lightness. The diameter of
the cylinder was 2% in. and the stroke 3 in., with 520 to
550 revolutions per minute. The heating surface was
8 sq. ft. or 2% sq. ft. per horse-power, the boiler being of
the water-tube description, and the steam pressure was
120 to 160 lbs. per square inch, the fuel being liquid and
burned in Russian lamps. The engine weighed, with the
boiler, 80 lbs, and developed fully 3 H.P., being at the
rate of 26% lbs. per horse-power. or about the same as the
1868 engine of Mr. Strz’ngfellow as rated by himself. Mr.
S/zz'll, a clever mechaniCIan, who exhibited a remarkably
light engine in 1868, was associated with Mr. May in
producing the 1875 engine, and had an interest in the
patents, so that the apparatus was also known as the
“ Moy & Shill aerial steamer.” It was I4 ft. long and
about 14. ft. wide, was mounted on three wheels, and
weighed 216 lbs., thus being proportioned at the rate of
0.53 sq. ft. of sustaining surface per pound of weight,
omitting the lifting effect of the aerial wheels, which
measured 60 sq. it. more.

The inventor estimated that at a speed of 35 miles per
hour the apparatus would be able to rise from the ground
and glide upon the air, and this estimate seems fully con-
firmed by Professor Langley’s recent experiments, which
show that the uplift on a plane surface of 114 sq. it. at an
angle of 10° would be fully 206 lbs., while somewhat
higher results are obtained from the table of “ lift” and
” drift" heretofore given herein, when taken’ in connec-
tion with Smeaton’s table of wind pressures.

After some preliminary tests a path around one of the
fountains at the Crystal Palace was selected, which had a
diameter of nearly 300 ft.; a pole was erected at the center
of the fountain, and two cords were run from the top of
the pole to each end of the machine, in order to keep it at
a uniform distance from the center. The gravel had been
rolled, and steam was got up. The gravel, however,
proved too rough, it shook the steamer and largely in-
creased the traction. Then a board walk was laid over
the path, and again steam was got up and a good run was
made around the fountain, the machine (which was only
a large model and could not carry an engineer) being
wholly propelled by the action of the aerial wheels upon
the air, acting only as drivers.

The utmost speed attained was 12 miles per hour, while
35 miles an hour was required to cause it to leave the
ground. This indicated that the resistances had been
underestimated, which resistances consisted in the traction
upon the boards, the air resistance on the framing, cordage
AEROPLANES. 1 27

and ground wheels, and-also in the “ drift” due to the
Inclination of the sustaining planes. With our present
knowledge we can say that at a speed of 35 miles per hour
(6 lbs. per sq. ft.) the latter would have been : 114 X 6 X
0.0585 : 40 lbs., and as the speed would have been 3,080
ft. per minute, the power required by the “ drift” was:
40 x 3080

33.000
ments of resistance, so that it is not strange that only 12
miles an hour was attained.

Mr. 1110}! needlessly handicapped himself in starting
from the ground by a level run. He reasoned, like many
others before and since, that “ when they were coming
down power was wanted, and, of course, power was es-
pecially wanted when they were going up,” but he en-
countered thereby, in an experimental machine, all the
additional resistance of the traction upon the boards. He
considered the propriety of launching the apparatus from
a height, or down an incline, but then this costly machine,
built wholly at his own expense, would surely have come
to grief, for he says that “the transverse stability was
better than the longitudinal stability, but both were bad,”
and unless this was first remedied, it really was not safe
to experiment.

Mr. May also placed his sustaining aeroplanes at too
obtuse an angle, for if he had simply doubled their area,
and inclined them at 5° instead of 10°, the “lift” would
have been, by the table, at 35 miles per hour: 228 X 6 X
0.173 = 236 lbs., or practically the same as before, but.
the“ drift” would have been diminished to: 228 x 6 x
0.0I52 = 20.79 lbs., or about one half of that heretofore
calculated.

Such experiments would doubtless have been tried had
ample means been forthcoming, but other things were
more pressing, for it was recognized that some modifica-
tions would be required in the steam generator, which
was provided with six Russian lamps burning methylated
spirits, and it was found that when running in the open
air, the fumes from the three forward lamps extinguished
the three after lamps, and thus reduced the power one-
half. Before even this difficulty could be remedied the
machine was seriously injured by the wrecking of the
bamboo aeroplane frames, while it was being moved sz‘ern
first across the grounds, in a fierce gale, and Mr. May then
decided to rearrange it for experiment, as to its vertical
lifting power, by substituting I2-ft. aerial wheels with
vertical axles tried under cover.

The total surface of these new aerial wheels was 160 sq.
ft., and the weight, including engine, boiler and all acces-

 

= 3.73 H.P., to say nothing of the other ele-
1 28 FLYING MACHINES.

sories, was 186 lbs. It was found that by counter-balancing
66 lbs. with levers, the wheels would lift the remaining
120 lbs., thus showing a lift of 40 lbs. per H.P., or about
the same as the best performance which has been attained
with other forms of screws.

Mr. May, as the result of his various experiments, then
proposed to build a much larger apparatus, with an engine
of I00 H.P., and capable of carrying several men, both to
avail of the diminished relative weight and resistance of
larger engines and to secure intelligent control while in
action ; but the money could not be secured for this pur-
pose. It would necessarily have cost a large sum, and at
that time (1875) not only was the whole subject of aerial
navigation generally considered as visionary, but there
was not sufficient knowledge to enable the public, or even
scientific men, to distinguish the difference between a wild
proposal, sure to fail to compass flight, and a promising
experiment which was worth following up—a condition
of affairs which has in a measure continued to this day,
and which this account of “ Progress in Flying Machines"
is partly written to remedy.

So Mr. May got no money, but he had instead “two
Chancery suits about shares in his patents, with no help
from any one ;” his experiments had brought him down
in funds, and he had to turn to hard work to live. As he
justly remarks, " Unless you can lift the last ounce of a
model, the unscientific people call it a failure, and few
can appreciate that as size and weight increase, the rela-
tive hull resistance decreases, by reason of its diminished
surface in proportion to its cubic contents.” He, how-
ever, continued to take an active interest in the subject ;
read papers at the meetings of the Aeronautical Society of
Great Britain, made private experiments with planes, both
in air and in water, as well as with methods for securing
automatic stability, and with an improved method of pro-
pulsion. V

In 1879 Mr. May exhibited at the meeting of the Aero-
nautical Society the small flying model shown in fig. 56,
which he described as a “ military kite” mounted upon
wheels and provided with propelling gear. The front plane
measured 660 sq. in. of surface, and the after plane, of
half its linear dimensions, measured 165 sq. in. They were
made of cambric, fastened to a central box-girder of thin
pine, running lengthways, and mounted on small wheels,
the aeroplanes being given a diedral angle, as shown, and
the angle of incidence fore and aft being ad1ustable. At
each end of the central stick or box-girder cross-arms were
fastened, which held in position strands of india-rubber
strings, one on each side of the central stick and parallel
AEROPLANES. I 29

therewith, the untwisting of which rotated (in opposite
directions) two screw propellers with two vanes each.
These propellers are removed in the plan and side view

 

 

 

 

 

 

 

 

 

 

 

En CZ E6 6V;
Fm. 56.—MOY-—187g.

of fig. 56, for the sake of clearness, but are shown in the
end elevation or front view.

The model weighed 24 oz., of which 34.} oz. was in the
india-rubber springs, and with 500 turns of the rubber it

9
130 FLYING MACHINES.

would run on its wheels over a smooth surface, and under
favorable circumstances would rise for a short distance
upon the air. It would, of course, fly from the hand like
Penaud's planophore, but showed, like it, great waste of
power, the supporting surfaces being at the rate of 3.82
sq. ft. per pound, and the angle of incidence required for
it to rise from the ground being 8° ; and more unfavorable
than a flatter angle, at which, however, it would not have
possessed sufficient “ lift.” Mr. May says that “ its trans-
verse-stability was very good, but its longitudinal stability
was defective, and was a perfect puzzle at that time, but
now all these troubles are overcome."

He has recently patented in England a method for auto-
matically securing horizontal stability, and it is to be hoped
that he will be enabled to renew his experiments.

Mr. May has also been an observer of soaring or “ sail-
ing” flight, and he described the sailing of the albatross
in a wind, on rigid wings, in a paper read before the
Aeronautical Society in 1869. Deeming it possible for
man to imitate this performance, but recognizing the
prodigious difficulty of reproducing the complicated shape
and arrangement of curved surfaces (not planes), with
which impulse is received from the wind, and of imitating
the exquisite balancing through which the soaring birds
perform this feat, he read a paper before the "Balloon
Society,” in 1884, in which he proposed an ingenious
method of carrying on the many experiments required,
with no greater danger than that of getting wet, by taking
a start at sea from a lifeboat on the crest of the waves in
a gale, equipped with a pair of wings and an inflated
Boynton dress. In the hope that some aviator, favorably
situated, may try this experiment, the paper, rewritten for
the pprpose, will be given in the appendix.

About the year 1875 paragraphs were floating in the
American newspapers concerning the " California flying
machine,” which was said to be under construction in San
Francisco. This was the design of Mr. Marriott, of the
San Francisco Newsletter, formerly a fellow-worker with
Mr. Strz'ngfetlow in aeronautical pursuits, and also a resi-
dent of Chard.

Mr. Marriott had already experimented in 186769 with
an elongated balloon, provided with attached aeroplanes,
from which he expected to obtain additional sustaining
power when at speed—a system which has been many
times proposed, and which is often brought forward again
by inventors who are not aware of the prior experiments.

Mr. .Marrz‘ott's balloon model was 28 ft. long, 91} ft. in
diameter, with aeroplanes extending for half its length,
and was to be driven by a light steam-engine, rotating a
AEROPLANES. I 3 I

propeller4 ft. in diameter 120 times a minute. The utmost
speed that could be obtained was five miles per hour, and
as this was not sufficient to stem the winds that constantly
prevail in San Francisco, the inventor turned his attention
to a design for an aeroplane.

This is said, in the report of the Aeronautical Society
of Great Britain for 1875, to have consisted of three planes,
superposed longitudinally, with an interval between them
of about 10 ft. In transverse length the whole structure
was to be 120 ft. fixed upon a foundation of trussed bam-
boo, the planes being unequal in size, the largest on the
top being of the above dimensions and about 40 ft. wide,
the three planes being rigidly supported by two masts
about 40 ft. high and stayed by wire rigging.

To the lower end of each mast were to be affixed small
wheels, to run down an inclined rail, in order to impart
the necessary initial velocity to the apparatus, and this im-
pulse was then to be continued by means of a steam-en-
gine enclosed in a square compartment capable of holding
the engineers. This compartment was to be located in
the center of the trussed bamboo keel. The engine was
to work four screw propellers, two of them vertical and
two horizontal, their place of working breaking up the
continuity of the longitudinal planes. The weight of the
whole machine was estimated at 1,500 lbs., including the
motive power and the engineer.

No drawings or detailed description of this aeroplane
were ever published, the inventor’s idea being to keep his
plans secret until he had made a success of the machine.
It was never completed, for Mr. Marn'otz‘ sickened and
died before the apparatus was ready for trial, and his as-
sociates did not care to risk the great outlay which would
have been necessary to test so large and expensive an ap-
paratus. The weight of the motor and the equilibrium
would have been the stumbling-blocks.

At the meeting of the Aeronautical Society of Great
Britain for 1876, M. Sénéml gave some notes on the stabil-
ity of aeroplanes of different forms, which be illustrated
with paper models, and these experiments are so easily
reproduced that the following account of them, quoted
from the report, will probably prove interesting :

He said that while planes of even width and thickness (load
uniformly distributed) revolve upon their own axes, and their
path of translation is rectilinear, the motions of triangular
planes are much more complicated. These planes are obtained
by dividing the circumference into blades of different widths.
These blades, besides revolving upon their axis, rotate also
round a vertical conic axis, whose base is upward, the vertex of
the plane describing a spiral round the conical axis.
132 FLYING MACHINES.

He found that the rate of revolution and rotation increases
in direct proportion as the base and the length of the blade de-
creases, and the length traveled over in a unit of time decreases
also in the same proportion. The shifting of the center of grav-
ity (pressure?) of these blades is most interesting. Itwas found
that the center of gravity of narrow planes was near the vertex
and on the edge of the plane, but recedes toward the base and
axis as it widens ; it also travels from the axis toward the edge
and vertex as the rate of revolution increases, and possibly
that, at high velocities of rotation, the center of gravity will be
beyond the edge. The size of blade that revolves and rotates
most steadily represents the eighteenth to the twenty-fourth part
of the circumference. He also proved that by cutting a small
plane out of the base it had the same effect as applying a weight
at that point before cutting it. The plane will then revolve and
rotate round with its base turned toward the vertical axis.

He also liberated several narrow strips of paper, showing,
while revolving, nodal and ventral sections similar to musical
strings in vibration, the number of aliquot parts increasing with
the length of the ribbons and disappearing as the width in-
creases.

M Se’ne’ml then enunciated the following law: that planes,
of whatever form, but of even thickness and rigid margin, in
order to translate steadily must carry their maximum load on
a line representing the first third part from the anterior margins
of the plane; but one can, with impunity, apply graduated
weights from that line right on to the edge, and, in some in-
stances, a good distance beyond the edge, and high rate of
speed is the result. The rate of translation increases directly
with the load placed on the different points of the graduations
from that line of the center of gravity.

While the account of the action of these paper planes is
not very clear, it is sufficiently so to permit the curious in
such matters to repeat the experiments, and these will he
found more instructive than any description of the results,
however accurately expressed. The action will be found
to be greatly modified by slightly folding the back edges
as already described.

In .1877 Mr. Barnett. of Keokuk, 1a.. patented in the
United States a flying machine somewhat similar in ar—
rangementand principle with that of Péizazm’ and Gaza/wt.
It consisted in an aeroplane something like a boy's trian-
gular kite, but with the two longitudinal halves set at a
diedral angle from the central Spine or spar, in order to
obtain lateral stability. Just under this kite a boat-shaped
car was to be affixed, carrying the motor, which was to
rotate two propellers mounted upon shafts at the front of
the apparatus, and turning in opposite directions. An
adjustable tail was to carry part of the weight and to
regulate the angle of incidence, the car being provided
with wheels so as to run over the ground until the speed
was great enough to give a sustaining reaction.
AEROPLANES. 133

This design is not without merit, but it leaves unsolved
the two principal problems concerning aeroplanes~z’.e.,
the providing a light motive power, which shall not weigh
more in proportion than that ot the birds in ordinary
flight, say 20 lbs per horse power, and the providing tor
automatic stability, which, as already explained, should
be greater for an inanimate machine than for a live bird.
The form of the triangular kite is not stable, as many a
boy has found out to his sorrow by providing an insuffi-
c1ent tail, and if the kite form is to be used, it will proba-
bly be best to experiment with shapes that fly without a
tail, some of which will be noticed hereafter.

Mr. Barmlt is understood to have tried many experiments,
extending over a period of 30 years. He first constructed a
plain flat kite some 12 it. long and loft. wide, under which
was hung a frame so as to attach and adjust the mechanism
for turning two propellers rotating in opposite directions.
This machine was not placed on wheels, but he was much
pleased with the clutch that the propellers took on the air.
Next he constructed an apparatus to carry the weight of
a man. This consisted of a kite or aeroplane of canvas
27 ft. square, from which hung a propelling arrangemert
somewhat similar to that shown by Mr. [Maxim in the Cen-
lury Magazine for October, 1891, as the manner of con-
necting the aeroplanes and attaching the screws in his ex-
perimental apparatus. This machine was placed on
wheels, being the running gear of a light spring wagon,
and as Mr. Barnez‘z‘ knew of no motor sufficiently light for
actual flight, he determined first to experiment with his
own muscular power.

The propellers were two bladed, each blade being
of oil-cloth and a sector of a circle, or like a piece from
the ordinary round pie. The operator was beneath and
rotated them through appropriate gearing. He ran the
machine along smooth country roads, but as soon as speed
was gained, the increasing air pressure, acting forward
of the center of figure, in accordance with the law of
foé‘ssel, already given, would tip up the front of the aero-
plane and disturb the equilibrium. This led the inventor
to believe that the propellers were too tar below the aero-
plane, and be altered their position, but without any better
result; the machine would still tip backward, presenting
a greater angle of incidence, and increasing the resistance.
Moreover, it would not keep to the line of the road, but,
as it was propelled, would run off to either side into the
grass, weeds or uneven ground, swerving in a way which
would have involved great danger if it had been able to
rise into the air.

Picking out a quiet evening, near dusk, the inventor de-
134 FLYING MACHINES.

termined to give it an extra good test over smooth ground,
and while apprehensive that if it left the earth it might
lurch and come to grief, he managed by “ main strength
and awkwardness” to get under conSiderable headway.
when the front end tipped up so much as to break and
splinter the main support, and the inventor came very
near getting hurt.

This terminated the experiments with that machine.
Subsequently the inventor entered it for exhibition at the
State fair as an “automatic kite," and he says quaintly
that he entered, at the same time, some samples of toma-
toes, cabbage and grapes of his own growing; received
a premium on the tomatoes and cabbage, and favorable
mention on the grapes, but concluded at the last moment
not to take the " kite" to the fair ground, as it did not
perform as he desired.

He has built two more machines of such dimensions as
to support a man within the last six or seven years, and
has tested them upon a smooth pasture, but found this,
after many weeks of trial, too rough and uneven for his
purpose. The tracks of animals, a bunch of grass, or a
corncob would check the speed, so that With all his
strength he could not arrive at sufficient velocity to leave
the ground. This is not surprising, for Professor Lang-
ley has since shown that the best that can be done with a
plane is to sustain 209 lbs. by the exertion of one horse
power, and this without any hull resistance whatever, so
that, as man cannot steadily exert much more than oneotenth
of this power, a total weight of about 20 lbs. is the maxi-
mum that he can hope to support and drive through the
air by the exertion of his own unaided strength.

Mr. Barnelt has of course experimented with a consid-
erable number of small models. He first tried clock
springs, but found them too heavy; and all would-be in-
ventors had better avoid wasting effort with them; next
he tried twisted india-rubber, and while he fdund great
irregularity in its action, he succeeded in obtaining a
number of fair flights among many failures. He experi-
mented with superposed planes, but the result was not
satisfactory. His last model. produced in 1892, resembles
his original design, and, driven by rubber bands, succeed-
ed in getting a preliminary start by running over a plat-
form 12 ft. long, slightly inclined, and flying through the
air “above the liollyhocks and other flowers" until it
struck the side of a house 30 ft. away, and 4 it. higher
than the platform.

India-rubber is a good reservoir of power to experiment
with. The flights are brief, as the power is soon spent,
but they give an opportunity of testing the equilibrium,
AEROPLANES. I 35

the proportions, and the adjustment of the parts, which
may suggest themselves to an experimenter as possibly
efficient.

An apparatus patented in France by M. P071223, in 1878,
is represented in fig. 57. It consisted in two supporting
planes in front, together with a keel plane, and a large

 

 

 

  

 

 

 

 

 

 

 

L \ _

FIG. 57.—POMES—IS78.
vane behind, to maintain the course. Two propelling
screws on the same horizontal shaft were to impart mo-
tion, and although they are shown as actuated by hand on
the figure, the same inventor had already patented, in 1871,
in connection with M. de [a Pauze, a gunpowder motor, in
which a series of charges, exploded by electricity, were
made to pass through a tube and to impinge against the
buckets of a revolving wheel, from which the motion was
to be communicated to the propellers. Neither this motor
nor the aeroplane possess merit, and indeed the latter is
about as badly arranged as it can be, for as the air press—
ures which are to sustain the weight act with a leverage
increasing toward the tips of the wings, or sustaining
planes, the latter should taper in plan from the center of
the apparatus outward, instead of tapering inward as
shown in the figure, in order to obtain a light and strong
construction. It is not known whether M. Pomés experi-
mented at all, but if he did, it must have been with very
small models, for his design is quite unsuitable for a large
one, and has been here included in order to point out the
deficiencies of such a design.

'In 1878 Mr. [infield constructed an apparatus to test
his conception of an aeroplane. It consisted of plane sur-
faces extended on a framework 40 ft. x 18 ft. at its great-
est width, and measuring about 300 sq. ft. in surface, the
weight of 'the apparatus being 189 lbs. It was mounted
upon wheels. and driven over a macadamized road by the
action of a screw propeller placed in front of the machine,
rotated at about 75 revolutions per minute by the aviator,
working a treadle and levers with cross handles. Upon
the highway, on an incline of about one in a hundred, a
136 FLYING MACHINES.

speed of 12 miles an hour was attained without any indica-
tion of a rise from the ground. Then by going down hill,
a speed of 20 miles per hour was obtained, but still with-
out perceptible effect, which is not be wondered at, for at
this speed, with an angle of incidence presumed to have
been 6°, the “ lift” would be 300 x 2 x 0.206, or, say,
123 lbs., while the weight including the aviator was over
300 lbs. It would have required an angle of 17°, at a
speed of 20 miles per hour, to have produced sufficient
“ lift," while at that angle the “ drift" alone would have re-
quired the exertion of 5 horse power, which the operator
was clearly unable to furnish, it being "most dreadful
exertion” to work the treadles at the flatter angle of inci-
dence above presumed to have been experimented.

Subsequently Mr. Lz'nfield built another machine upon a
different principle. It was 20 ft. 9 in. in length, 15 ft. in
width, and 8 ft. 3 in. high ; the sustaining surfaces being
in two frames, each 5 ft. square. Each frame contained
25 superposed planes of strained and varnished linen 18
in. wide and spaced 2 in. apart, thus somewhat resem-
bling a cupboard without front or back, and with shelves
very close together. These frames were slung on either
side of a cigar-shaped car at its maximum section, being
set at a diedral angle to each other, so that the apparatus,
could it have been seen in the air, would have resembled
a huge cigar with a pair of saddle bags attached thereto.
There was a nine-bladed screw at the front, and a guiding
vane, like the tail of a dart, behind ; the entire sustaining
surfaces in the two frames being estimated to aggregate
438 sq. ft., and the whole machine, which was mounted
on four wheels, weighing 240 lbs., to which 180 lbs. must
be added for the operator, thus providing a little over one
square foot of sustaining surface per pound.

Mr. Lz'nfiela’ was to stand between the two front wheels
and actuate two treadles to rotate the screw, which was
7 ft. in diameter; but when the time arrived for testing
the machine upon an ordinary macadamized road, it was
stated that this could not be done on account of the im—
possibility of blocking the road during the trial. This
was in a measure fortunate, for it led Mr. Lin/531d then
to arrange with a railway to mount the machine on a Hat
car and to tow it behind a locomotive. When a speed of
40 miles per hour was attained the machine rose entirely
free from the car, but was not allowed to swerve very far,
as there was a side wind blowing, and it swung very close
to the telegraph poles as it was. The tow line was some
15 ft. long, and the pull thereon was 241bs., which for a
24o-lb. machine (without the aviator) indicates an angle
of incidence of I in 10, or 6°. At this angle, and at a
AEROPLANEs 137

speed of 40 miles per hour, at which the .air pressure
would be 8 lbs. to the square foot, the total lift. for a sin-
gle plane ought to be 438 x 8 X 0,206 = 722 lbs., so that,
if the 240 lbs. of machine was just sustained, it indicates
that. the very narrow spacing (2 in.) between the super-
posed aeroplanes greatly interfered with their efficiency.

Mr. Lz'nfie/d also tested the efficiency of superposed
screws. He placed nine of them some 6 in. apart upon a
vertical shaft. These were all with two narrow blades and
3 it. in diameter, but in whatever relative position they
were placed radially, he could get no greater lift from the
nine screws than he could from the top and bottom screws
only, 4 ft. apart, the seven intermediate screws being
removed.

The idea of testing the apparatus by towing it on a rail-
way car was evidently a good one, but this disclosed such
inefficiency of lifting power and of stability as to put an
end to the experiments.

We next come to a series of very careful experiments,
tried by an able mechanician, which almost demonstrate
that artificial flight is accessible to man, with motors that
have been developed within the last two years. These
experiments were carried on by M. V. Tm‘z‘n, who was
then Professor Marcy’s mechanical assistant. He first
began with beating wings, and produced, in 1876, the arti-
ficial bird which has already been briefly noticed under
the head of “ Wings and Parachutes.” This was driven
by twisted rubber; not only did M. Tali” find that the
power required was unduly great, but he also found that
this power could not be accurately measured, the torsion
of india-rubber being erratic and stretching unequally.
He constructed a large number of mechanical birds of all
sizes and various weights; he tried many modifications
and entire or partial reconstructions, and finally conclud-
ed, after spending a good deal of time and money, to take
up the aeroplane type, to be driven by a reservoir of com-
pressed air. With this his efforts were successful almost
from the first, and he produced in 1879 the apparatus
shown in fig. 58, which is practically the first that has
risen into the air by a preliminary run over the ground.
This machine consisted in a silk aeroplane, measuring
7.53 sq. ft. in surface, being 6.23 ft. across and 1.31 ft.
wide, mounted in two halves at a very slight diedral angle,
on top of a steel tube with conical ends which contained
the compressed air. This reservoir was 4% in. in diame-
ter and 33% in. long, was tested to a pressure of 20 atmos-
pheres, and worked generally at 7 atmospheres ; its weight
was only 1.541bs., and its cubical capacity 0.28 cub. ft.
From this (the vital feature of the machine) the stored
I38 FLYING MACHINES.

energy was utilized by a small engine, with oscillating cyl-
inder, placed on a thin board on top of the tube, and con-
nected by shatts and gearing to two propellers with four
vanes each, located at the front of the aeroplane. These
propellers were I.3I ft. in diameter, and rotated in op-
posite directions some 25 turns per second, their velocxty
at the outer end being about 100 ft. per second. The
vanes were of thin bent horn set at a pitch of about 1.50
it” and they towed the apparatus forward instead of push-
ing it.

A tail of silk fabric 1.97 ft. across at the rear, by a
length of 1.97 ft., was set at a slight upward angle and

 

 

 

/
. —\ i \ \
$\\\ \ \ § 9 \\ \ \\ ‘
§ § §
\
\\\\\\ \\ \\ ‘ \\ W \

FIG. 58,—TATIN—x879.

braced by wire stays, in order to provide for the longi-
tudinal stability upon the principle advanced by Pémzua’ ,-
and the whole apparatus was placed on alight running
gear consisting first of four wheels, and subsequently of
three wheels. The total weight was 3.85 lbs., so that the
sustaining surface of the aeroplane (omitting the tail) was
at the rate of Lgs sq. ft. to the pound.

After a vast deal of preliminary testing and adjustment,
the apparatus was taken to the French military establish-
ment at Chalais-Meudon, where it was experimented with
in 1879 upon a round board platform 46 ft. in diameter.
Upon this the machine would be set upon its wheels, the
front and rear ends being fastened to two light cords car-
ried to a ring around a central stake, and the compressed
air would be turned on to the engine. The propellers
would put the apparatus in motion, and it would run from
65 to 165 ft. over the boards, until it attained a velocity
of 18 miles per hour, when it would rise into the air, still
confined radially by the two cords, and make a flight of
about 50 ft., when, the power being exhausted, it would
AEROPLANES. 139

fall to the ground, almost invariably injuring the running
gear in doing so.

The flights were not very high, but on one occasion the
apparatus passed over the head of a spectator. The angle
of incidence was 7° or 8°, and the power developed by the
engine was at the rate of 72 33 foot-pounds per second,
gross; but. as its efficiency was only 25 to 30 per cent. of the
gross power, the effective force was at the rate of 18.08 to
21.70 foot-pounds per second, or, say, at the rate of 5 foot-
pounds per second (300 foot—pounds per minute) per pound
of apparatus.

This power was measured with great care, the machine
being provided with a tiny gauge and tested repeatedly
with a dynamometer. M. Tatz'n calls attention to the fact
that the minuteness of the engine greatly diminished its
efficiency, and that with large machines it would be com-
paratively easy to obtain 85 per cent. of the gross power
developed. He draws the conclusion that his apparatus
demonstrates that 110 lbs. can be sustained and driven
through the air by the exertion of I horse power—a most
important conclusion, which will be further discussed here-
after.

To return, however, to the experiments: they are de-
scribed as follows by M. Tatz'n.*

I W|1l pass without description a series of preliminary experi-
ments which led me to modily certain details, until all condi-
tions were favorable. I then had the satisfaction of seeing the
apparatus start at increasing speed, and in a few seconds the
carriage barely touches the ground ; then it leaves it entirely at
a speed of about 18 miles per hour, which agrees closely with
the calculations. It describes over the ground a curvesimilar
to those described by small models gliding freely, and when it
comes down after its orbit, the shock is so violent as to injure
the running gear. This accident recurred upon each experi-
ment carried out under the same conditions ; the carriage was
soon destroyed, and even the propellers were injured, although
they could be repaired. 1 then tried another experiment,
which I had already attempted several times without success,
in consequence of inadequate preparation. The apparatus, the
running gear being removed, was suspended by two grooved
wheels running freely over an iron te‘egraph wire 260 ft. long,
stretched as rigidly as practicable. When the speed became
sufficient, the apparatus rose, and then one of the propellers
struck the iron wire; the front grooved wheel overtook the
machine, and the propeller was destroyed. These accidents
caused no repining, for they demonstrated that in all cases the
apparatus had completely overcome the force of gravity.

In order to continue the experiments I built a new carriage

* Ae’ranaute, September, 1880.
I40 FLYING MACHINES.

and new propellers, hoping to make them strong enough to
stand the shocks during a new set of experiments, from which
to deduce accurately the work done. The new running gear
had but three wheels, these being larger and lighter than the
old. The propellers, on the other hand, were made heavier,
but modified so as to rotate more easily. Their vanes were
made of a thin sheet of horn bent hot to the proper curvature.
The inner two-fifths from the hub conSIsted of steel wire, this
portion of a propeller requiring much force for rotation, and giv-
ing out but small effect toward propulsion; but the diameter and
the pitch were the same as formerly.

I was, unfortunately, unable to make all the experiments I
desired With this repaired apparatus. I intended to study the
results with various angles of incidence in the planes and vari-
ous pitch of the propellers ; then to study the important ques-
tion as to the best proportion between the sustaining surface
and the diameter of the propellers; and lastly the speed of
translation which will best utilize the force expended.

I was nevertheless enabled to deduce the following figures
from my experiments. These figures are not absolutely exact,
but sufficiently so to serve as a guide to others who may wish
to engage in similar work. Calling A the sustaining surface
in square meters (without the tail), and V the speed of transla-
tion in meters per second, then we may say :

Lift : 0. kg. .045 A V’.

And the motor will need to develop effective work at the rate
of 1.50 kilogrammeters per kilogramme of the weight (4.935
foot-pounds per second per pound), which corresponds to one
horse power for each 110 lbs. weight of the apparatus.

These experiments seem to demonstrate that there is no impos-
sibility in the construction of large apparatus for aviation, and
that perhaps even now such machines could be practically used
in aerial navigation.

Such practical experiments being necessarily very costly, I
must, to my great regret, forego their undertaking, and I shall
be satisfied if my own labors shall induce others to take up such
an enterprise.

The effective work done by this aeroplane having been
accurately measured, it affords a good opportunity of test-
ing the method of estimating resistances which has been
proposed by the writer in estimating the work done by a
pigeon.

The weight of M. Tatz‘n’s apparatus was 3.85 lbs. Its
aeroplane surface was 7.53 sq. ft., the angle of incidence
was 8°, and the speed was 18 miles per hour, at which the
air pressure would be 1.62 lbs. per sq. ft. Hence we
have, by the table of “ lift and drift" :

Lift, 8° = 7.53 X [.62 x 0.27 = 3.291bs.,
AEROPLANES. 141

which indicates that a small part of the weight was sus-
tained by the tail.

The hull resistances are stated by M. Tali” to have
been almost equal to that of the plane. These hull resist-
ances would consist of that of the tube, of 0.12 sq. ft. mid-
section, which, having conical ends and parallel sides, will
have a coeffiCient of about one-third of that of its mid-
section. The resistance of the wheels and running gear
will be slightly greater, but must be guessed at, as the
wheels would continue to revolve through inertia and thus
increase the resistance.

The front edge of the aeroplane, which was of split reed
and about one-eighth of an inch thick, was 6.23 ft. long;
but as the back edge of the aeroplane and the Side borders
of the tail would also produce some air resistance, we
may call the edge resistance as equal to 6 ft. in length,
by a thickness of 0.01 ft., without any coefficient for round-
ness. We then have the following estimate of resistances :

RESISTANCE OF TATIN AEROPLANE.

Drift 8° —— 7.53 X 1.62 x 0.0381 2 0.4648 lbs.
Tube — 0.12 x 1.62 —:—- 3 = 00648 “
Wheels and gear —- estimated : 0.1000 “
Edges of wings — 6 X 0.01 X 1.62 = 0.0972 “

 

Total resistance : 0.7268 “

and as the speed was 18 miles per hour, or 26.40 ft. per
second, we have for the effective power required :

Power = 0.7268 x 26.4 = 19.19 foot-pounds per second,

which agrees very closely with the 18.08 to 21.70 foot-
pounds per second said to have been effectively developed,
and is at the rate of 5 foot-pounds per pound of appa-
ratus, or of 110 lbs. of weight per horse power.

This last is the important point. Now that Mr. Maxim
has produced a steam-engine which, with its boilers,
pumps, generators, condensers, and the weight of water
in the complete circulation, weighs less than 10 lbs. to
the horse power. aviation seems to be practically possible,
if only the stability can be secured, and an adequate
method of alighting be devised.

Ocular demonstration being always more. satisfactory
than description, those readers who have been sufficiently
interested in the subject to try the experiments which have
been described with paper planes (falling by gravity) may
also like to see for themselves how an aeroplane behaves
when motive power is applied. They can probably obtain
in a shop one of the toys which have already been alluded
I42 FLYING MACHINES.

to, under the head of " Screws to Lift and Propel," as one
of the series produced in 1879 by M. Dandrieux, and
which is shown in fig. 59.

This is a true aeroplane, the wings being fixed, and the
propulsion being produced by the screw at the front, which
represents the antennae of the butterfly. This screw is
driven by the unwinding of the rubber threads, and has
practically no pitch except that produced by the yielding
of the posterior edge of the gold—beater's skin, of which
the vanes are composed. Its peculiar shape, giving a

 

FXG. 59.—DANDRIEUX——187Q.

maximum of surface near the outer end, with a rigid an~
terior edge and an elastic posterior edge, is the result of
a good deal of experiment, and may furnish a useful hint
for those desiring to experiment upon a larger scale. The
wings are also of gold-beater's skin, and instead of being
stretched tightly upon the frame, the anterior margin only
is made rigid, the rest of the surface being left quite loose.
so that it may undulate when under forward motion, as
in the case of M. Brearey’s device, which will presently
be described. This feature in construction, which differs
greatly from that which obtains in the case of birds and
AEROPLANES: 143

insects, whose wings are elastic, but do not undulate, is
said to be intended to compensate for defects in workman-
ship and equilibrium. Upon being tested in still air within
doors, the toy will be found quite erratic in flight. It will
generally go up to the ceiling, and then flutter in various
directions until the power is exhausted, and seldom twice
pursue the same course. Out—ofadoors it will rise some
20 or 30 ft., dart about, or drift with the wind, until the
rubber threads are unwound, and then glide down to the
ground sustained by its aeroplane alone.

As a matter of course the sustaining surfaces have to be
made very large in proportion to the weight, in order to
prevent injury in alighting. One of these little toys, com-
puted by the writer, weighs 86 grains or 0.0123 lbs., and
measures 50 sq. in. in aeroplane surface, or 0.3472 sq. ft. ;
this being in the proportion of 28 sq. ft. to the pound, or
about 0.7 of that of the real butterfly, which, being much
smaller, measures some 40 sq. ft. to the pound, and which

 

FIG. 60.‘—BREAREY—~1879.

in consequence is capable of but slow flight, although it
is not infrequently found by aeronauts floating about in
the upper air a mile or so above the earth, a fact to which
further reference will be made when we come to consider
the prevalence of upward trends in aerial currents.

The propulsion of a loose undulating surface was at
about the same time, somewhat differently and quite inde»
pendently, proposed by M. F IV. Brearey, the Honorary
Secretary of the Aeronautical Society of Great Britain.
He patented, in 1879, the apparatus shown in fig. 60, in
which a flexible fabric is attached to a central spine and.
to vibrating wing arms at the front, which latter beat up
and down like the wings of a bird. The effect of this
action is to throw the fabric into a state of wavelike mo-
tions, both lengthwise and in a smaller degree also later—
ally, which are said to cause the apparatus to be both sup—
ported and propelled in the air, while an adjustable tail
I44 FLYING MACHINES.

regulates the angle of incidence. The wing arms are
flexible and stayed to a bowsprit by cords, and the power
for an actual machine is to be placed in a car or body
affixed along the central spine.

M. Brearey records that he took the idea from watching
the movements of a “ skate" fish in an aquarium, which in
swimming undulated its whole body, and that he found
that when applied to propulsion in air the loose fabric
greatly added to the stability, so that the device might be
considered as a sort of dirigible parachute, which would
come down safely if the motive power became exhausted
from any cause. In the various models which he made to
illustrate the experimental lectures, With which he was ac-
customed to popularize “ the problem of flight" in Great
Britain, he used the torsion of india-rubber to produce the
revolution of the crank which vibrated the arms, thus get-
ting a dozen strokes or so, and he claimed that the smaller
model (5 ft. x 8 ft.) flew from his hand, on one occasion
at least, perfectly horizontally to the extent of 60 ft., no
angle of incidence of the apparatus being perceptible.
The larger model was 6 ft. wide by 10 ft. long, with about
16 sq. ft. of surface, and a weight of 3.1 lbs. (of which
0 44.1bs. was added ballast, which it easily carried), being
thus in the proportion of some 5.15 sq. ft. per pound ot
weight, with which the falling velocity would be about 9
ft. per second, or equal to a descent from a height of 1.27
ft., but which was nevertheless found to be too heavy to
be safely used in public experiments over the heads of an
audience. From his experiments M. Bream] drew the
following conclusions as to the possibilities of his ap—
paratus :

We are thus at liberty to contemplate the construction of an
aerial vehicle whose dimensions would suffice to maintain, in
wave-action, 600 or 700 sq. ft. of canvas, actuated by steam-
power. and capable of supporting the additional weight of a
man, whose weight, together with the machine, would certainly
not exceed 500 lbs. ; and we can contemplate the man as being
able to move a few feet backward or forward without much
affecting the stability of the machine. His descent under the
parachute action can thus be graduated at will. This can also
be effected by a cord attached to the tail, which by that means
can be elevated or depressed at pleasure. Placed upon wheels
it has, of course, yet to be ascertained what distance of pre-
liminary run would be required, assisted by the action of the
fabric, before it would rise from the ground.

Subsequently (his second American patent is dated in
1885) M. Brearey further proposed the superposition of
two or more sets of such “ wave-action" aeroplanes, and
the important addition of what he calls the “pectoral
AEROPLANES. r45

cord,” which consists in an elastic cord (or suitable
spring) attached to some point underneath each of the
lower set of wing-arms and passing underneath the
carriage, car or central spine, 50 that it may be thrown
into tension on the up stroke, and restore the power thus
stored upon the down stroke of the Wing-arms. This de-
vice is designed to imitate in its action the functions of
the pectoral muscle of a bird. The tension of this cord
or spring is regulated in accordance with the weight to
be sustained, and is said to be perfect when, upon the
whole apparatus being committed free to the air, the
wing—arms are retained at a suitable diedral angle against
the upward pressure. It follows from this action that the
up stroke, being assisted by the air pressure which sus-
tains the weight of the apparatus, expends less powerthan
the down stroke, and that nearly all the power can be
used in depressing the wing-arms to compress a wave of
air, which undulating backward and outward along the
loose fabric may assist the air pressure already due to the
forward speed, in sustaining the aeroplane, and serve at
the same time to propel it.

M. Brearejy, however, seems to have applied this “ pec-
toral cord” chiefly to those of his models which showed
the wing-action proper, and in the practical demonstra—
tion which he gave to the Aeronautical Society of Great
Britain, at its meeting in 1882, he said :

Working in the field of experiment, I am enabled to state
that the power requisite to propel and sustain a body in the air
has been greatly overestimated, even by those who took the
more favorable estimate in view of the ultimate attainment of
flight. I am not aware, however, that the true reason for the
minimum display of actual power exerted in the flight of birds
has ever been propounded. Certainly it has never before been
demonstrated by actual experiment.

The action of the pectoral muscles of the bird alone accounts
for this. Consequently the advantage would be altogether lost
in anything but a reciprocal action. The bird commits himself
to the air, and the pressure of the air underneath the wings
forces them upward. The weight of the bird is indicative of
the pressure ; and as a consequence of this automatic raising of
the wing by the pressure of the air underneath, we should im-
agine that the elevator muscle need not be strong. As a mat-
ter of fact, we find it is weak. I doubt whether any muscular
effort is made to elevate the wing at all in flight; but when not
in flight, the bird of course requires the power to elevate its
wing in preparation for it.

Committed, then, to the air, the elastic ligaments connected
with the wings are stretched to that degree which allows of the
wings being sufficiently raised for effective support without
flapping, and without, as I conceive, any muscular exertion

IO
I46 FLYING MACHINES.

upon the part of the bird. The limited power of the elevator
muscle may here come into use occasionally in aid of the under
air-pressure, and with the further effect of stretching the liga-
ments. Now it will be argued that in the downward stroke
there must be as much muscular force employed as will raise or,
at least, prevent from falling, the weight of the bird ; but this is
not so, because the reaction of these ligaments, which have
been stretched entirely by the weight of the bird, assists mate-
rially the action of the depressor muscle. . . . .

M. Brearey here produced a model having wings measuring
4 ft. from tip to tip. He showed the elastic cord underneath
the wings, but for the purpose of the first experiment be de-
tached it. He then wound up the india-rubber strands 32
times, and showed that this, although sufficient to flap the wings
with energy while held in the hand, was insuflicient to cause
the model to fly. This was demonstrated by letting the model
free. He explained its inability to fly from its want of power
to bring the wings down with sufficient force.

He now unwound the action and proceeded to wind it up
again 32 times, and attached the pectoral cord. Holding the
model in his hand, he called attention to the fact that it was
powerless to flap the wings because the two forces were in
equilibrium. It required the addition of another force to effect
flight, and he asked what that other force could be except
weight? If now it flew, he proved beyond the possibility of
doubt that weight was a necessity for flight. The model was
then set free, and flight was accomplished.

He also showed that the model would only fly without the
attached pectoral cord when wound up 40 times. With the
cord it would fly when wound up only 13 times, thus showing
the great saving in power which accrued through the action of
the pectoral cord.

M. Brearey then produced a model of his “ wave aerial ma-
chine.” having 4 sq. ft. of loose surface weighted to % lb., and
he demonstrated by its flight that the principle was equally ap—
plicable to that.

It may be questioned whether this “wave action" is
likely to prove economical of power in either sustaining
or propelling an aeroplane, for it seems diflicult to conceive
that a wave of air compressed at the front by the wing-
arms should travel back to the rear, unconfined as it is
either at the bottom or sides. Still, the loose surface may
add to the stability, as claimed for the Dandrz'eux toy,
and it would certainly diminish by its yielding the strains
that would otherwise occur at the points of attachment of
a rigid surface in an aeroplane ; but M. Brearey's wave-
action seems to be chiefly applicable as a dirigible para-
chute, and a small model upon this principle, but without
motive power, was once liberated as an experiment by
Captain Templar, from a balloon which had risen 200 ft.
AEROPLANES. 147

or 300 ft. from Woolwich Arsenal, and it traveled back
again to the arsenal, half a mile, against the wind.

It seems somewhat singular that so few efforts have been
made to devise dirigible parachutes, a system which M.
(la la Landelle constantly extolled, as constituting the first
requisite step toward eventual flight by working out the
problem of absolute stability and safety. The only one of
these devices which the writer has been able to find record-
ed is that of M. Coulurz'er, patented in France in 1875,
and this is so briefly described in the Ae’ronauz‘e for No-
vember, 1878, that its mode of operation cannot be made
out.

The “ pectoral cord" attachment is probably a valuable
device for flapping wings, as furnishing that inequality of
effort between the up and the down stroke which undoubt-
edly obtains in bird "flight. This effect was produced in a
“wave—action" model exhibited by M. Brearey at the
aeronautical exhibition of the Aeronautical Society of
Great Britain of 1885, by a “ trunk engine” designed and
built by M. Hollands, which, however, was not shown
under steam, as the boiler was only just completed in time
for the exhibition; but M Hollands said that the model
flew well, and supported weights, when the engine was
supplied with compressed air through an india—rubber
tube. He does not seem to have stated what power was
exerted.

While almost all inventors and experimenters of aero-
planes have proposed some sort of motive power, and
have found their designs paralyzed very soon by the want
of a sufficiently light motor, there have been at various
times, as already intimated, keen observers of the flight of
soaring birds, who have held that once under way in a
sufficient breeze, the performance involves no muscular
movement whatever. save in balancing, and that the wind
alone furnishes sufficient motive power (if blowing from
IO to 30 miles per hour) to enable man to soar and to
translate himself at will in any direction, even (paradoxi-
cal as it may seem) against the wind itself.

Chief among these observers in recent days stands M.
Mouz’llarzl, of Cairo, Egypt, who has spent over 30 years
in watching birds soar in tropical latitudes, and who pub-
lished, in 1881, a very remarkable book (in French),
“ L’Empire de l’Air," which should be read by all those
seriously interested in the solution of the problem of
flight. This book, the result, as the author explains, of a
passionate, vocation which began at the age of 15, is al-
most wholly a record of personal observations and deduc-
tions. Its sub-title designates it as an “ essay upon
ornithology as relating to flight,” but it is far more than
148 FLYING MACHINES.

that, for it not only describes the flight and manoeuvres of
birds, and gives good reasons for the author's belief that
they can be imitated by man, but it describes four attempts
which he has made to do so with various forms of appa-
ratus.

M. [Maui/lard underrates, perhaps, the value of mathe—
matical investigation, and he sometimes errs in his ex-
planation of physical phenomena; but his observations
are unrivaled, and theyare presented with a particuFarity
of circumstance, a vivacity and a charm which photo—
graph them at once on the mind of the reader. He begins
by explaining the difference between useful and unfruitful
observations of creatures so willful, so swift, and so shy
as the birds ; then he describes the various modes of flight
(both rowing and sailing), and the movements of the vari-
ous organs, such as the wings and the tail ; the influence
of their shape in determining the mode of progression and
the speed of the various species, and he shows conclusive-
ly that. if these organs are properly shaped therefor, the
heavier the bird the more perfectly he soars, and can, once
initial speed is gained, sail indefinite/y ufon [/ze wind
wz‘l/zouz‘furt/terflapping his wings. This is the keynote
of the book; observation after observation is described,
anecdote after anecdote is related, to impress upon the
reader that there need be no flapping whatever, if only the
wind be strong enough ; and that when there is no wind,
the soaring bird must come down to the ground or resort
to flapping, like the rowing birds.

Then the effect of ,the speed of the wind is discussed.
It is shown that certain species of soaring birds with broad
wings, such as the kites, the eagles, and the vultures can
sail upon a wind blowing at 10 to 25 miles per hour, but
must seek shelter when it increases to a gale, while the
sea-birds, with long and narrow wings, such as the gulls,
the frigate bird, the albatross, sport indefinitely in the
tempest blowing at 50 or more miles per hour. He arrives
at the conclusion that when man succeeds in imitating the
manoeuvres of the soaring birds, he will utilize the moder-
ate winds, and attain to speeds of about 25 to 37 miles per
hour.

M. Mouz'llard also passes in review the individual mode
of flight and characteristics of the various species of birds,
both the rowers and the sailers ; comprising some 13 differ—
ent types, and giving tables from his own measurements
of weights, surfaces, dimensions, etc., which have been
compiled by M. Drzewz’ec/cz', and have already been quot-
ed by the writer under the head of “Wings and Para-
chutes ;” while he finally expresses a strong opinion that
the easiest type for man to imitate is the great tawny vul-
AEROPLANES. 149

ture of Africa (Gyfls fulmu), which weighs some 1650
lbs.. and spreads some II sq. ft. of surface to the breeze.

M. Mouz’l/ard explains how, in his opinion, the manoeu-
vres of this bird can be imitated, so as to obtain both a
sustaining and a propelling effect from the wind, and he
describes (much too briefly) the four several attempts
which he had then made to demonstrate the correctness
of his theory of the possible soaring flight of an aeroplane
for man.

The third of these aeroplanes, as described in 1881, is
shown in fig. 6!. It consisted of two thin boards, proper-
ly stiffened, to which were attached ribs of “agave” wood
(an African aloe, exceedingly light and strong), which ribs
carried the fabric constituting the two wings. The two
boards were hinged vertically together (somewhat imper-
fectly) at the center, and the operator stood upright in the
central space at c, suspended by four straps attached to
the boards near the hinge; two of these straps passing
over the shoulders and two between the legs. Moreover,

   
 

/ ' ,, l"

       

 

 

Fig. 6x.——MOUILLARD——1865.

light wooden rods extended from the feet to the outer ends
of the boards, so that the angle of the wings with each
other could be varied at pleasure.

Standing upright, with this apparatus strapped on, the
hinge was about at the height of the pitof the stomach, the
arms being extended out flat upon the boards, and slipping
under straps; M. Maud/arr! trusting to such shifting of
his body within the space 6 as he could effect by resting
his weight on his arms, to produce the necessary changes
in the center of gravity of the apparatus, which were re-
quired by the changes in the angles of incidence.

The whole apparatus weighed 33 lbs., but was found
unduly light, as the parts yielded and the wood cracked
when tested with vigorous thrusts of the legs. It had been
hastily constructed, with such materials as the country
afforded, and the builder was not satisfied with it.

M. [Maui/lard gives but a scanty description of his ex-
periments with this aeroplane in “ L'Empire de l’Air,"
so little, indeed, as to suggest further inquiry; but he has
since written another book, which he entitles “ Le vol sans
150 FLYING MACHINES.

battements” (flight without flapping), which is now nearly
ready for the press, and wherein he records further ob-
servations, explains more fully his ideas and the results of
his meditations, giving freely, as he expresses it, “ all that
he knows,” and in which there is a fuller account of the
experiment in question.

From this forthcoming book M. Mouz’llard has kindly
furnished the following extract concerning the experiment
with the apparatus shown in fig. 61.

It was in my callow days, and on my farm in the plain of
Mitidja, in Algeria, that I experimented with my apparatus,
No. 3, the light, imperfect one, the one which I carried about
like a feather.

Idid not want to expose myself to possible ridicule, and I
had succeeded by a series of profound combinations and pre-
texts in sending everybody away, so that I was left all alone
on the farm. I had already tested approximately the working
of my aeroplane by jumping down from the height of a few
feet. I knew that it would carry my weight, but I was afraid
to experiment in the wind before the home folks, and time
dragged wearily' with me until I knew just what the machine
would do; so I finally sent everybody away-to promenade
themselves in various directions—and as soon as their backs
were turned, I strolled into the prairie with my apparatus upon
my shoulders. I ran against the air and studied its sustaining
power, for it was almost a dead calm; the wind had not yet
risen, and I was waiting for it.

Near by there was a wagon road. raised some 5 ft. above the
plain. It had thus been raised with the soil from ditches about
IO ft. wide, dug on either side.

Then came a little puff of wind, and it also came into my
head to jump over that ditch.

I used to leap across easily without my apparatus, but I
thought that I might try it armed with my aeroplane ; so I took
a good run across the road, and jumped at the ditch as usual.

But, oh horrors! once across the ditch my feet did not
come down to earth ; I was gliding on the air and making vain
efforts to land, for my aeroplane had set out on a cruise. I
dangled only one foot from the soil, but, do what I would. I
could not reach it, and I was skimming along without the
power to stop.

At last my feet touched the earth. I fell forward on my hands,
broke one of the wings, and all was over ; but goodness ! how
frightened I had been I I was saying to myself that if even a
light wind gust occurred, it would toss me up 30 to 40 ft. into
the air, and then surely upset me backward, so that I would fall
on my back. This I knew perfectly, for I understood the de-
fects of my machine. I was poor, and I had not been able to
treat myself to a more complete aeroplane. All’s well that
ends well. I then measured the distance between my toe
marks, and found it to be 138 ft.
AEROPLANES. I 5 I

Here is the rationale of the thing. In maling my jump I
acquired a speed of II to I4 miles per hour, and just as I
crossed the ditch I must have met a puff of 'he rising wind. It
probably was traveling some 8 to II miles per hour, and the
two speeds added together produced enough pressure to carry
my weight.

I cannot say that on this occasion I appreciated the delights
of traveling in the air. I was too much alarmed, and yet never
will I forget the strange sensations produced by this gliding.

Then M. Mouz‘llard repaired the injured aeroplane, and
he tried it again a few days later. Of this later experi-
ment he says in “ L’Empire de 1’Air” :

I had no confidence, as I have already stated, in the strength
of my aeroplane. A violent wind gust came; it picked me up;
I became alarmed, did not resist, and allowed myself to be up-
set. Ihad one shoulder sprained by the pressure of the two
wings, which folded up against each other like those of a but-
terfly when at rest.

M. Mom'llara’ then determined to make no more experi—
ments with this incomplete machine. but to build a better
one, with which he could control all the manoeuvres neces-
sary for soaring, but shortly afterward his Circumstances
led him to leave the farm and to remove from Algeria to
Cairo, Egypt. Here, in a great city, he no longer had the
facilities for experimenting that he possessed on the farm,
for he had to go out some distance to secure space and
privacy for each experiment. Then came illness ; the
former gymnast became a cripple, so that he could no
longer perform for himself the acrobatic manoeuvres
necessary to experiment with a soaring apparatus, but
still he persevered, and he describes in "L’Empire de
l’Air” the design for the fourth apparatus, of which he
began the construction in 1878, but which was interrupted
by ill—health.

Since the publication of his book in 188I, M. .Mom'llard
is understood to have been continuously engaged in per—
fecting and simplifying his proposed soaring apparatus,
and in trying experiments (by proxy) with models on a
small scale. He says that he will soon be prepared to
have the matter tested on a large scale, and that he has
never wavered from absolute convrction in the truth of the
principles which he laid down in ” L'Empire de l'Air,” in
which he expresses himself as follows :

I hold that in the flight of the soaring birds (the vultures, the
eagles. and other birds which fly without flapping) ascension is
produeea’ hy the shillful use of the force of the wind, and the steer-
ing, in any direction, is the result of shill/ulmameuwes ; so that hy
a moderate wind a man am, with an aeroplane, unprooidea’ with
152 FLYING MACHINES.

any mo/or 'wlzatever, rise up into t/ze air anda’ireet Izz'mself at will,
even against the wind z'tse/f.

Man t/zerefare am, until a rigid sz/rfaee and a frzfter/y de—
signed apparatus, repeat the exercises per/onned by Me soaring
birds in ascension and steering, and will need to expend no jone
w/uzlever, save to perform the maneeum’es required/or steering.*

“The exact shape of these aeroplanes need not be dis-
cussed in this chapter, for it will be seen further on that
there are scores of shapes and devices which can be em-
ployed, but all forms of apparatus, however dissimilar,
must be based upon this idea, which I repeat."

Ascension z's t/ze result of Me ski/[fut use of the power
of the wind, and n0 otnerforee is required.

M. Maui/lard then continues :

It will doubtless be very difficult for many persons to admit
that a bird can with a moderate wind, remain a whole day in
the air with no expenditure of power. They will endeavor to
suppose some undetermined pressures or some unseen flap-
pings. In point of fact. the human understanding does not
readily admit the above truth; it is astonished, and seeks for
all the evasions it can find. All those who have not seen say,
when ascension without expenditure of force is mentioned to
them, “ Oh, well, there were some motions which escaped your
observation."

It even occurs sometimes that a chance or superficial ob-
server, who has had the luck to see this manoeuvre well per—
formed by a bird, when he turns it over in his mind afterward
feels a doubt invading his understanding; the performance
seems so astonishing, so much against ordinary experience,
that the man asks himself w/zet/zer leis eyes did not deeei’l/e him.
For this observation, in order to carry absolute conviction,
must bear upon the performance of the largest vultures. and
they alone ; and this is the reason : it is because all the other
birds which ascend into the air by this process do not perform
the necessary decomposition of forces required in all its naked
simplicity.)L . . . .

To be convinced, a man must see ; for to see the perform-
ance even once is better than a whole volume of explanations.
Therefore, 0 reader, if you are interested in this subject, go
and see for yourself, and be edified. Go to the regions where
dwell the birds which perform these demonstrations ; and when
you have beheld them for a few instants, being already initiated
as to what to observe, comprehension will at once come into
your understanding.

Whoever has seen a boy’s kite ascen‘d into the air, and

considered that the string may be replaced by a weight,
if Only tne equilibrium be secured and maintained, will

* The italics are M. Mouz'Z/ard's own.
i The present writer has seen the feat performed by gulls many times.
AEROPLANES. I 53

have no difficulty in granting the correctness of M. .Mom'Z-
Zara”: assertion that the power of the wind is quite suffi-
cient to secure ascension, but it will not so readily be
understood how it is also sufficient to secure progression
even against the wind. It will. indeed, be conceived that
an aeroplane possessed of initial velocity can soar in a
circle in the wind like a bird, and by changing its angle
of incidence, descend somewhat when going with the wind.
and rise again in consequence of the greater “ lift" when
facing the wind. thus gaining in height at every lap, and
eventually utilizing the elevation thus gained in gliding in
any desired direction, always firo'vz'dea’ t/zaz‘ Z/ze equilib-
rz'um be maintained ; but this involves very delicate
manoeuvres, which will be further considered when we
come to sum up the results of all the experiments with
soaring devices, and indeed the subject warrants a paper
by itself. which may be placed in an appendix.

It may, however, be said here that the French aviators,
after having long doubted the reality of the performance of
sailing flight by the birds, whose evolutions they were un-
able to watch in their climate, have had so many corrobora-
ti'ons furnished to them by trustworthy witnesses, that
they now generally admit that a soaring bird can sustain
himself indefinitely on a wind, without flapping, and that
man may learn to imitate him if only a proper apparatus
be designed, and the operator possesses the necessary
knowledge and skill to work it, so as to perform the right
manoeuvres and at the right time.

But these wonderful performances'of the “ sailing birds”
are chiefly witnessed in tropical or semi-tropical regions—
those in which the steady trade winds or the regularly in—
coming sea breezes afford daily to the birds the power of
performing their evolutions in search of food. In the
more temperate regions the wind does not blow every day
with just the right intensity, the casual soaring bird is fre-
quently compelled to resort to flapping, and the would-be
inventor has his thoughts directed to some form of a power
machine; generally some combination of aeroplanes with
propelling screws, which differsa good deal from the sim—
ple. compact, and severe outlines indicated by nature.

The form of the soaring bird is reducible to three ele-
ments. First, a comparatively large body, shapely, but
unsymmetrical fore and aft, presumably the solid of least
resistance to the air ; second, a symmetrical pair of wings,
convex on top. and more or less concave beneath, with a
sinuous and stiff front edge ; and, third, a tail, which
varies greatly in its proportion among the various species.
For these features, most of the inventors have substituted
a small, boat-like body, a combination of flat planes and
154 FLYING MACHINES.

fiat rudders, both horizontal and vertical, which last is not
found to exist in the bird.

A good case in point is found in the instance of Mr.
Krueger, who patented in the United States, in 1882, a fly-
ing machine consisting in three fiat horizontal planes set
one behind the other, the front one being triangular
in plan, while the rear one might be shaped like
the tail of the swallow. These were to be adjustable,
so as to guide the machine up or down. Beneath them
was to hang a ship or vessel, and above them were to
be set still other planes, sloping like the two sides of a
roof, in order to act as a parachute. Four propelling
screws were to be arranged between the three sustaining
planes, while four adjustable keel cloths, vertically aflixed
both above and below the sustaining planes, were to steady
the course and to furnish the steering power.

No particular motive power was proposed, and no meth-
od indicated {or maintaining the stability, so that it is
quite safe to say that no experiments were ever tried with
this apparatus upon any practical scale. It has been here
mentioned to illustrate how misguided ingenuity some-
times runs to complications, while leaving untouched the
really essential requirements.

The next inventor to be noticed, M. Gouflz’l, a distin-
guished French engineer, began otherwise : by taking
thought of the motive power and of the equilibrium. After
having tried a few preliminary experiments, he designed
in detail a light steam-engine and boiler, the weight of
which he estimated at 638 lbs. for a machine of 15 horse
power gross, or 42.5 lbs. per horse power. He also de-
signed a condenser of like capacity, estimated to weigh
some 220 lbs. (15 lbs. per horse power), so that the water
could be. used over and over again ; and he then figured
that the rest of the flying apparatus, without cargo, might
weigh 242 lbs., thus making a total of 1,100 lbs., so that if
the steam-engine worked up to two-thirds of its theoretical
efficiency and developed 10 effective horse power, the total
apparatus would have been in the proportion of 110 lbs.
per horse power, but might be reduced to about 44 lbs.
per horse power through the use of aluminium instead of
other metals.

These estimates of weights of motor and condenser have
been since then more than confirmed by the achievements
of M. Maxim and other inventors, but before seeking to
realize them M. Goupz'l determined to investigate the all-
important question of equilibrium.

Both observation and mathematical considerations bad
satisfied him that much of the longitudinal stability of the
bird in the air was due to the raking shape, fore and aft,
AEROPLANES. 155

of the under part of its body, which, presenting to the air
an increasing and more effective angle of resistance when
pitching oscillations occur, tended to restore the balance
and to prevent the animal from taking either a " header"
or a “ cropper.” This he determined to test experi—
mentally, and he accordingly built, in 1883, an apparatus
similar to that represented by fig. 62 ; omitting, however,
the screw, the lower framework, and the stays to the wings.

The alar spread was 19.68 ft. from tip to tip of wings,
the length was 26.24 ft. from the head tip to the end of the
tail, and the mid-section was 26 90 sq. ft. in area, while
the sustaining surface was no less than 290 sq. ft., the
weight being 110 lbs.

It will be noticed that this was a marked departure from

 

FIG. 62.——GOUPlL—-—1883.

the ordinary aeroplane types, there being an ample body
to contain machinery, and the wings being decidedly con-
cave—convex, while other inventors have generally endea-
vored to diminish the body as much as possible and to gain
support from various combinations ofp/ane surfaces.

M. Goupz‘l’s object was to make a series of preliminary
experiments with this apparatus, in order to ascertain its
stability, the effect of the wind upon such a system, and
the resistance to be expected, as well as the sustaining
power. He accordingly applied neither motor nor screw,
but exposed it to the natural wind when blowing from 18
to 20 ft. per second, say, about 13 miles per hour, at which
velocity the resulting air pressure is generally assumed to
be 0.85 lbs. per square foot. These experiments took place
156 FLYING MACHINES.

in December, 1883, at which season the winds were quite
variable, and the apparatus was anchored by various ropes
so as to prevent it from rismg more than 2 it. from the
ground.

Exposed head on to a wind of 18 to 20 ft. per second,
the body being inclined at an angle of 1 in 10 and the
wings at x in 6 (about 10°), this apparatus lifted up clear
of the ground the weight of two men besides its own, mak-
ing a total of 440 lbs. ! The thrust or end resistance did
not exceed 17.6 lbs. M. Gaupz'l tested this several times,
and expresses himself as surprised at the low resistance to
penetration against the wind evidenced by this apparatus,
which was mounted upon two small wheels.

When the wind increased to more than 20 ft. per second
he could no longer control the machine. There being no
stays or guys to the wings, such as are shown in fig. 62,
the apparatus was twisted out of shape, and the wind took
greater effect upon the deformed side. Then a wind gust
occurred ; the efforts of five men were required to control
the apparatus, and one of the wings (constructed with
white pine) was broken.

The inclement season and other considerations of a per-
sonal nature prevented M. Gouflz’l from pursuing these ex-
periments further at that time. He had gathered valuable
preliminary data, and had caught a glimpse of a veryim-
portant fact concerning the effect of concavo-convex sur—
faces, but his own affairs had a more immediate claim
upon his personal attention.

He therefore desisted for a while and allowed the sub—
ject to remain in abeyance until he could take it up again,
but he published, in 1884. a very remarkable book, “ La
Locomotion Aérienne,” in which he advanced a number
of important and new theoretical considerations concern-
ing the solution of the problem of aerial navigation, gave
data concerning the steam—engine, the condenser, and the
various sizes of bird-like aeroplanes which he had de-
signed, and generally evinced such a grasp and compre-
hension of the question that it seems a marvel that the
book is not more frequently referred to by the French
writers on aviation.

This experiment of M. Gouflz’l opens up quite a new field
of inquiry concerning the effects of concave, bird-like sur-
faces, when exposed to an air current. Calculated by the
data which have been gathered by experiments upon plane
surfaces. the “ drift" and total resistance does not seem to
vary greatly from what might be expected, but there is an
enormous, an almost incredible increase of the lifting
power.

Thus there was said to be a total end thrust of 17.6 lbs.
AEROPLANES. 157

in the apparatus when exposed to a wind of about 13 miles
per hour, at which the a1r pressure would be presumably
some 0.85 lbs. per square foot. The angle of incrdence of
the wings was practically 10°, and we may, without seri—
ous error, assume the resistance of the body to have been
one-tenth of that due to its mid-section, while that of the
edges of the wings (presumably 0.20 ft. in average thick-
ness) would be about one—third of their plane cross-sec-
tion. As the sustalning surface was 290 sq. ft., we then
have, using the table of “litt” and “dritt” heretofore
given, the following estimate 2

RESISTANCE OF THE GOUPIL AEROPLANE.

 

Drift 10°... 290 X 0.85 X 0.0585 2 14.42 lbs.

Body ........... 26.9 X 0.85 +10 2 2.28 “

Edge of wings. 19.7 x 0.2 x 0.85 + 3 = 1.11 “
Total 17.81 “

which agrees closely with the amount said to have been
ascertained by experiment ; but when we come to calcu-
late the liiting force we have :

Lift 10° -- 290 X 0.85 x 0332 = 82 lbs.,

while the apparatus is said to have actually lifted 440 lbs.,
or more than five times as much 2

Of course various allowances must be made in consider-
ing the results of an experiment carried on in a variable
wind, and where so little motion of the apparatus (2 ft.)
could be allowed. The thrust may have been measured
while the breeze was steady, and the uplift to have oc-
curred duringawind gust, deflected possibly by surround—
ing objects so as to produce a greater angle than 10° with
the wings; still, in any case, the result of this experiment
and also of other experiments by M. P/zz’l/z'fis, which are
to be described hereafter, leads to the inference that much
greater supporting power is to be obtained from concavo—
convex surfaces than from the flat planes which hitherto
have been chiefly proposed for aeroplanes.

This increase in supporting power might indeed have
been expected from the theoretical consideration : that the
concave lower surface would produce a higher co-efficient
of pressure, while the convex upper surface would deflect
the current of air impinging at. an acute angle thereon,
and thus produce a partial rarefaction ; and also from the
much stronger practical consideration that [My 2': theway
the wings of éz’ra’s are s/zaffiea’; and yet very few experi—
ments and proposals seem to have been made with bird-
like aeroplanes.
158 FLYING MACHINES.

This neglect may possibly be due to the fact that the
proportions, the shape, the concavity and the convextty of
natural wings differ from each other among the various
species, so that the moment that we discard the flat plane,
a multitude of combinations present themselves, which
may require long and careful experimenting before the
best shape for an artificial machine is ascertained.

It is understood, however, that M. Goupz‘l has planned
a whole systematic series of such experiments to elucidate
this important matter, and that he hopes soon to be in posi-
tion to carry them on.

In March, 1884, the Ae’ronaute published a paper by M.
De Sana’erval, giving an account of some very interesting
experiments, which he had tried with a pair of artificial
wings no less than 39 ft. across and 13 ft. wide in the mid-
dle. These wings formed an aeroplane, or rzgz'd plane of
canvas, stretched upon wooden arms, which latter, how-
ever, possessed a certain flexibility.

In a first set of experiments, this aeroplane, loaded with
ballast to the amount of 176 lbs., was allowed to glide in
calm air along a cable 1,3 00 ft. long, which both support-
ed and guided it, and which was inclined ata slight angle.
It was also allowed to drop in still air from a height of 131
ft., and then still further experiments were tried with men
riding on the machine when the wind was blowing.

For this purpose the aeroplane and its operator were
suspended by a long rope from the middle of a cable,
stretched in some cases between two hills and over a
ravine, and in other cases between two high masts erected
near the sea-shore.

M. De Sanderval states that he was attached some 5 ft.
above the aeroplane and a little in front of its center of
figure, so that by pulling upon four oblique cords he was
enabled to shift his weight either forward or back, and to
the right or left at pleasure.

When the wind blew and the apparatus was restrained
by a head-rope, the effect was much the same as when glid—
ing free in calm air, with, however, the unfavorable differ-
ence that when near the ground it was less steady by rea—
son of whirling currents.

In a light wind the apparatus would rise until the sus-
pending rope became horizontal, thus relieving it of its
weight—carrying function, and the aeroplane would then
oscillate at the pleasure of the operator.

When the wind increased to 18 miles per hour therap-
paratus would sustain the operator and two assistants.

Subsequently, M. De Sander'zzal gave an account of his
experiments to the French Academy of Sciences, and this
was reprinted in the Ae’ronaule for November, 1886, with
‘AEROPLANES. 159

the somewhat uncalled-for comment that “ it is a pity that

the author should not have stated the time, the place. nor

the witnesses. as such extraordinary facts need verifying."
The following are the facts as stated :

My first apparatus consisted in two wings, each 19 68 ft.
long, thus giving an aggregate spread of 39.36 ft., by a maxi-
mum width of I3 ft. These wings Were 01 canvas, stretched
upon bamboos and upon wooden arms. The canvas was divid-
ed into a series of parallel sheets or flaps, each 4% in. wide,
and perpendicular to the dorsal l‘ne. They were suitably
fastened, and a net was stretched above them, so that they
might flap and open upon the upstroke, like the feathers of
birds, which oscillate upon the quill which divides them into
two unequal portions.

Standing upright upon a light board, and connected by straps
to a central spine, I was enabled by thrusts of the legs to de-
velop their maximum effort; but with this apparatus, which
worked quite well, I was enabled to settle but one fact, and
that is, that man cannot develop sufficient energy to sustain
himself in calm air. I therefore gave up the thought of beating
wmgs.

I then rebuilt the apparatus, transforming the Wings into a
rigid plane, and replacing the flapping strips by an unbroken
canvas.

This apparatus, weighing 99 lbs., and loaded with I76 lbs. of
ballast, was caused to glide under a cable 1,300 ft. long,
stretched between two bluffs. There was no deflection in the
cable when the aeroplane glided across at speed, but the deflec-
tion was about 26 ft. when the apparatus was stopped in the
middle.

lf then released (by tripping a hook) it would at first drop al-
most vertically : then after the first second it would glide for-
ward at increasing speed, while the rate of vertical fall dimin-
ished; but upon the slightest disturbance in the equilibrium,
consequent upon any divergence between the center of gravity
and the center of pressure. theinert ballast would aggravate the
oscillation, and the apparatus would plunge down to smash. It
seemed evident to me that if intelligence were applied to regtr
late the position of the center of gravity, steady progression
would result.

I then suspended the apparatus by along rope attached in
the middle of the cable, and substituted my own person for the
ballast. I found that with an intelligent live control the appa-
ratus would oscillate in the wind according to my pleasure. as
Ihave already indicated in a previous communication. The
supporting surface of 301 sq. ft. sufficed to sustain a man at a
comparatively slow rate of fall, and by a wind of 22 miles per
hour it lifted me up with two assistants, and sustained us in the
air during the entire period that we kept the holding-back line
taut, by maintaining a proper angle of incidence.

The last and more interesting experiment which I attempted
was based upon these previous results, and also upon the fact
160 FLYING MACHINES.

that soaring birds can rise into the air on a helical path, or else
maintain themselves a long while at the same altitude without
beating their wings, provided always that they possess sufficient
horizontal speed as regards the air. I therefore experimented
with an apparatus somewhat similar to the preceding, but round
in shape, suspended by a vertical rope 650 ft. long,* and caused
it to swing around in a circle, so that the suspending rope de-
scribed in its path the outer periphery of a cone. In this ex-
periment I could feel a notable reaction against my weight, but
it required a much longer suspending rope to allow so large an
apparatus to swing in a circle of sufficient diameter to permit
its gaining the necessary speed, and to manoeuvre freely. I
believe, however, from the feeling produced upon my mind by
the experiment, that I had really taken possession of space
within the limits of my somewhat irregular speed, and also,
from my observations of soaring birds advancing against the
wind on rigid wings, that man can succeed in reproducing sail-
ing flight.

If one had an unlimited height to fall in, affording plenty of
time to think and to act, he would probably succeed in guiding
himself at will. In calm air man does not possess sufficient
energy to sustain himself, but either in asufficient wind, or with
a proper horizontal speed of his own, he finds himself under
different circumstances, and derives from the air quite enough
supporting power. It is through the operation of this dynamic
equilibrium that he will eventually succeed in compassing prac-
tical flight.

I caused to be constructed, from manuscript notes furnished
by M. Biot, a very ingenious apparatus intended to comply with
the above conditions, and I experimented With it. This appa-
ratus consisted in two great wings supported on a light carriage,
which gained its initial speed by rolling down a long incline
covered with an asphalt floor. It rose into the air pretty well,
but always with the disadvantage that the experiment could not
be sufficiently prolonged to furnish decisive results ; each time
upon coming down the apparatus was injured.

It appears to me that a long, vertical rope, such as that pre-
viously described, swinging around so as to describe a cone of
extended base, must afford greater chances for careful experi-
ment and for eventual success.

The writer has been unable to find any further records
of experiments by M. De Sanderz/al. He seems to have
been baffled by the lack of means to maintain equilibrium,
but even had he possessed the appliances and the skill to
bring the center of gravity to coincide with the center of
pressure, as often and as fast as the angle of incidence
changed, it may be questioned whether he could have ac-
quired, without avery long apprenticeship, that instinctive
use of them which constitutes the science of the birds.

* Stated at zoo meters; may be a misprint.
AEROPLANES. 16 I

It is inferred from the description that M. De Smzderval
experimented with plane surfaces, although it is possible
that under the action of the wind they may have assumed
those concavo—convex shapes which we have seen to obtain
with the birds and to be more effective than flat planes.
In any case, he is to be commended for having made an
earnest. if unsuccessful effort 2‘0 [66277; Izow to soar in a
wind [2736 a éz’ra’, the possibility of which performance for
man Will be further discussed hereafter.

In 1848 M. Armour, the author of several papers which
will be found in the reports of the Aeronautical Society of
Great Britain, patented a flying machine, in which he pro-
posed the use of aeroplanes or wings, oscillating upon
springs transversely to the line of motion, these wings
being set behind each other as well as superposed. It is
not known whether any experiments were tried with this
curious device, which seems to be a combination of fixed
wings (or aeroplanes) with oscillating wings, but it seems
doubtful that it. can prove efficient.

There was a second aeronautical exhibition in 1885,
under the patronage of the Aeronautical Society of Great
Britain, but the total number of exhibits was only 16 as
against 78 in 1868.

Among these exhibits the model which attracted most
attention was that of M. C. Ring, of Denmark, which con—
sisted of an aeroplane with a pair of arched wings, some—
what similar in the front-edge view to the arched wings of
the gull and of the albatross. In plan, however, these
wings were rectangular instead of the approximately tri-
angular shape which obtains with the birds. These aero-
planes were to act as sustaining surfaces, the angle at
which they met the wind being determined bythe position
of a large flat tail, and the propulsion being furnished by
four wing—propellers oscillating beneath the aeroplane, and
driven in the model by twisted rubber.

The apparatus was supported by a string fastened verti—
cally above its center of gravity to the crosspiece of a light
framework. It prOpelled itself slowly, but was incapable
of free flight, probably in consequence of defective equilib-
rium.

M. [Bing also exhibited a model of a-gun-cotton engine
in which small charges were to be exploded between two
pistons, moving in opposite directions in a long cylinder;
but the model was not aworking one, and no attempt was
made to construct a full—sized engine.

Reference has already been made toa “ trunk steam—en-
gine," shown by M. 5. Holland: at this exhibition. He
gave a description of this and of two other types of light
steam—engines with which he had experimented, at subse-

II
162 FLYING MACHINES.

quent meetings of the Aeronautical Society of Great
Britain.

The first was a “ direct—acting" engine, rotating at high
speed twin vertical screw fans (right and left) in opposite
directions, and a model of this machine, developing 1% horse
power, was said to have weighed 6 oz. for the engine and
boiler, or at the rate of only 6 lbs. per horse power. It
was first intended to generate the steam by burning liquid
fuel, but M. Hollands subsequently concluded that hydro-
gen gas, carried highly compressed in a suitable reservoir,
and burned with an admixture of twice its volume of air,
would prove preferable for lightness and heating efficiency.
He estimated that the weight of this type of motor, includ—
ing not only the engine and boiler, but also the water
therein, the fuel-gas reservoir and the driver’s stand, would
be 11.5 lbs.~ per indicated horse power.

The other engine was “ geared” so as to rotate two right
and left fans on comem‘rz'c vertical shafts, one inside of the
other, through the intervention of toothed mitre gear. The
function of these two vertically superposed fans was to lift
only ; a smaller horizontal fan being carried on a prolonga-
tion of the crank—shaft, and its thrust aided by the reaction
of the exhaust steam ejected through a suitable nozzle.
The weight of this engine per horse power is not stated.

Both these arrangements, it will be observed, involved
discharging the exhaust steam into the air, and thus wast-
ing some 20 to 22 lbs. of water per horse power per hour,
M. Hal/ands not seeing his way to adding an aerial con—
denser (to recover the steam) in any form, within any ad—
missible limits of weight. He stated that the power neces-
sary was one indicated horse power for every 30 lbs. of the
whole weight, so that without a condenser the flight of
such an apparatus as he proposed would have been limit-
ed by the very small quantity of water which it could
lift.

M. Hollands. however, made some experiments on the
best form of lifting screw—blades, and stated that he had
found it advantageous to make the fan blade concave on
the driving or lifting side, and that the angle of maximum
efficiency was 15° with the plane of motion at the tin. and
30° at the root. The form which he found most efficient
was two—bladed; with the blades narrowest at the tips,
slightly concave on the lifting side, the tip slightly droop—
ing, each blade being approximately the shape of an elon-
gated shallow spoon or scoop, and with a pitch equal to
about two-thirds of the fan’s diameter. giving a mean
angle of blade of 22° 30’ with the plane of motion. These
blades were of thin sheet steel, and their forms will be
noted as confirming what has already been stated as to the
AEROPLANES. I63

advantages of the bird—like form of wing. M. Hollands
said further :

I find another advantage accrues also from the use of these
very thin, sharp edged hollow blades—viz., that there is no
appreciaél: resistance 2‘0 rotalion tlzat does not conlrz'lmte to lifting
eflect. A marked contrast to this desirable quality is presented
in the results given by flexiéle élaa’ea’ fans, constructed to vary
Meir pita/z automatically, being normally of coarse pitch (when
still), but decreasing their pitch when rotated. and further de-
creasing it with increase of speed. Some experiments I made
with fans of this description showed an unmistakable loss of
power, as compared with the other type above described, due

    

 

  

          
   

 

     

1'31“" 1» fix/::»+/
”>Jllm’ T," . ,

 

Fm. 63.——BEESON-—1888.

apparently to the energy absorbed in deflecting the elastic
blades ; which deflection, with a given speed. causes a constant
strain and resistance, with no compensating useful effect.

In 1888 W”. Beeson patented, in the United States, the
singular soaring device shown in fig. 63. He had already
patented, in 1881, a soaring apparatus consisting of two
or more sets of adjustable superposed sails stretched on
inverted A frames, which he expected to raise into the air
like a kite, and then sail upon the wind, but he apparently
164 FLYING MACHINES.

abandoned this device in favor of the simpler form shown
in fig. 63.

This consisted in a mainsailA and a tail or back—sail 15’,
both of which were supported on a plate or board C, rang-
ing fore and aft. This plate was convexed at its upper
edge so that the sail A might extend over, forward and
downward to a cross-bar forming the front edge, and thus
enclose a head pocket to catch the wind. A forked pendu-
lum—bar, I, was pivoted to the plate C, and it supported at
its lower end a trapeze arrangement to carry the operator,
who by means of three light cords extending to his hand
might alter the angle of incidence of the mainsail A, of the
tail B, or of the rudder R. The mainsail and tail being,
moreover, connected by an adjustable bar, which caused
the mainsail to act upon the tail automatically, so as to
maintain the equilibrium at all angles of incidence through
the compound lever thus formed.

M. Beeson states in his patentthat “ this machine is self-
supporting in a light wind, say, of 10 miles or more per
hour, and that when once raised by a kite or otherwise,
and cut loose, it will of itself perform the evolutions of a
soaring bird and rise to any altitude.”

The writer confesses that he has tried the experiment
with a small model and has failed; and so, in the hope
that some of his readers may be more fortunate, he has
given this account of what seems to be a remarkably sim-
ple device—if it will work.

At the Paris Exposition of 1889, Commandant Renard,
of the French Aeronautical Department, exhibited, in
connection with the dirigible war balloon ” La France,”
an apparatus which he had designed some years before
(1873) as embodying his conception of a flying machine,
and which he termed a “ dirigible parachute."

This is shown in fig. 64, and consists in an oviform
body, to which is pivoted a couple of standards carrying
a series of narrow and long superposed flat blades, in-
tended to sustain the machine when gliding downward
through the air.

The dotted lines in the side view indicate the maximum
angle of inclination which it was proposed to give to this
similitude of a Venetian blind, and it is evident that by
setting it at the proper angle, and dropping the apparatus
from a balloon, it can be made to travel back against the
wind a considerable distance, and also that it may be
steered laterally by the addition of a rudder. Beneath
the body a sort of skate will be noticed, probably intended
to glide over the ground in alighting, or in obtaining
initial velocity to rise should a motor be applied ; but the
French War Department is reticent concerning its ex-
AEROPLANES. 165

 

SIDE ELEVATION.

 

END ELEVATION.

FIG. 64.-~RENARD——1889.
166 FLYING MACHINES.

periments in aerial navigation, and the writer has been
unable to gather any information concerning the working
of this apparatus.

It will be noted that Commandant Renard proposed to
equip this machine with flat blades, thus conforming to
the predilection in favor of plane surfaces exhibited by
most of the experimenters with aeroplanes already noticed
except Captain Le Brz's and M. Gonpz’l, who took a differ-
ent View as to the best shapes to employ. In point of fact,
as already intimated, those who have succeeded in the
air, the true experts in gliding, the soaring birds, do not
perform their evolutions with plane surfaces. Their wings
are more or less convex on top and concave beneath, and
are warped surfaces of complicated outlines. It is true
that in many cases they do not differ greatly from planes,
and the mind of man so strongly tends to the simplifica-
tion of complicated shapes, that most inventors have as-
sumed that the effect on the air will be practically the
same.

Flight is possible with flat planes, as witness the butter-
fly, the dragon fly, and insects generally, but such crea-
tures are endowed with greater relative power, as already
explained; and, moreover, the elasticity of their wings
produces change of shape under action. In the case of
the birds, although the outer ends of the feathers are
elastic, yet the wing is stiffer as a whole, and the curved
surfaces may prove more efficient than planes in obtaining
su port from the air.

his view seems to have prevailed with Mr. H. F. Plzz'l-
lz'fls, for he patented, in 1884, a whole series of curved
shapes, intended to be used in conjunction with suitable
propelling apparatus for raising and supporting an aerial
machine in the air. These shapes were to be utilized in
a set of narrow blades arranged at suitable distances
apart; the idea being to defect upward the current of air
coming into contact with their forward edges when under
motion, so as to cause a partial vacuum over a portion of
the upper surface of the blade, and thus to increase the
supporting effect of the air pressure below the blade.

These shapes were the result of a series of experiments
tried by Mr. Phillips in artificial currents of air, produced
by induction from a steam jet in a wooden trunk or con—
duit, and described in London Engineering in its issue of
August 14, 1885.

A cross—section of the shapes patented will be found on
fig. 65, Nos. [—8. The following table gives the re-
sults observed, the last column having been added by
myself :
AERUPLANES. 167

PHILLIPS’S EXPERIMENTS ON SHAPES.

 

 

 

 

 

Speed
Description Of A” 1 Dimensions of Lift, Thrust, POM
of Form. (ailment. Forms—Inches. Ounces. Ounces. Pounds per
h eet per; Pound.
Second.‘
Plane .......... 39 16 X 5 l 9 2. 8.67
Shape 1. .. 6o 16 X 1.25 9 0.87 5.80
“ 2. .. 48 16 X 3 9 0.87 4.64
“ 3 ........ 44 l 16 X 3 9 0.87 4.25
“ 4 ........ 44 ‘ 16 X 5 9 0.87 4.25
“ 5. 39 ‘ 16X 5 9 0.87 3.77
“ 6 ........ 27 16 X 5 9 2.25 6.75
Rook’s \Ving.... 39 f 0.5 sq. ft. 8 1.00 4.87

 

 

 

The intent of these experiments seems to have been to
ascertain the speed ot current required to sustain various
forms and areas of surfaces, carrying the same weight in
a soaring attitude. For this purpose they were exposed
to the varying current with their long edges transversely
thereto, and they were loaded with a weight applied one-
third of the width back from the forward edge, which
point was thought to be the center of pressure. These
shapes were swung by two wires attached to their front
edges, and when they assumed a soaring attitude in the
velocity of current required to sustain the weight, the
“thrust” or drift was then measured.

The most efficient shape is, of course, that which re—
quires the least expenditure of power, or the smallest num—
ber of foot-pounds per pound of weight to keep it afloat,
and this is seen to be shape No, 5. which soared with 3.77
foot—pounds per pound, or at the rate of I46 lbs. sustained
per horse power, while the flat plane absorbed more than
twice as much power.

The comparison would have been more satisfactory if
the soaring angles of incidence had been stated. This is
given for the plane only as having been 15° by measure—
ment. This agrees fairly well with calculation ; for if the
“ thrust” is to the “ lift” as the tangent of the angle of
incidence, then we have % : 0.222 = tang. 12° 32’. But
all the results obtained were probably somewhat. vitiated
by assuming that the center of pressure was uniformly
one—third of the distance back from the front edge, and
therefore applying the load at that point.

We have already seen that this center of pressure varies
with the angle of incidence in accordance with Joéssel’s
law, and the load should have been attached accordingly.
168 FLYING MACHINES.

If, for instance, the possible soaring angle were 4°, we
should have for the position of the center of pressure. back
from the front edge, a distance of 0.2 + 0.3 ml. 4° = 0.22
per cent. So that it seems probable that if its load had
been applied at 22 per cent. instead of 33 per cent. back
from the front edge, the flat plane would have soared at
a flatter angle than 15°, and would have shown less
“ thrust," because the effect of placing the weight so far

Patenlgg I881;
1‘” ..b- ”A“
A H

M , ,4,

Arab.
K at ,.
.4”! 7 '

A’g 8 K

 

FIG. 65.——PHILLIPS——1884—1891.

back was to tilt the plane unduly, and thus to increase
both the angle of incidence and the thrust.

It is not known whether jo'e‘ssel's formula applies to
curved surfaces ; but be this as it may, it is reasonable to
believe that it would be but little modified, so that perhaps
the error in locating the center of pressure operated to the
disadvantage of the curved» forms nearly as much as to
that of the plane. We may. therefore, accept the general
AEROPLANES. 169

statement that greater weights per horse power can be
sustained in the air with concavo-convex surfaces than
w1th fiat planes ; but it seems very desirable that further
experiments should be made, for it is quite possible that,
in consequence of the loading of the blades at a point
differing from the center of pressure, the shapes patented
by Mr. Phi/1'1): are not absolutely the most efficient forms.

It will be interesting, in this connection, to note how
these various shapes behaved. It was found that in order
to get. the maximum efficiency from any given surface, the
greatest depth of hollow should be one—third of the total
width from the forward leading edge, and that the amount
of concavity of the lower surface and the convexity of the
upper surface should bear a relation to the speed of the
air current. Thus in shapes I and 2 the under surface
was nearly flat, and the upper curvature not great, while
speeds of current of 60 ft. and 48 ft. per second were re~
quired respectively to produce a soaring attitude. In
shape 3 the curvature was more marked, and the required
speed fell to 44 ft. per second. Shapes 4 and 5 were made
broader, with a moderate degree of curvature both above
and below, and the speeds of current to produce soaring
were 44 ft. and 39 ft. per second respectively. Shape 6
was an extreme case, in which the distinguishing features
of the experiments were purposely carried to excess ; for
when impinged upon by a current of air of 27 ft. per sec-
ond in the direction of the arrow do, it was seen (by a fine
attached ribbon) that there was an induced current flow-
ing outward in the direction a].

Shapes 7 and 8 were used to demonstrate that the im-
pinging air is deflected upward by the forward part of the
upper surface, and that a partial vacuum results in the
alter part ; they were not loaded with weights, and when
exposed to a current of air of sufficient. velocity, coming
in the direction of the arrow, they rose into the position
shown in the figure.

In 1890 Mr. I’M/[2253 patented an aerial vehicle in which
these curved surfaces were applied to an apparatus similar
to the “dirigible parachute” of Commandant Renard,
except that there were to be two (or more) series of curved
blades behind each other at suitable distances apart.
They were to be attached to an elongated body, which he
indicated might. be of fish shape, and, say, 30 ft. long.
The cross-blades, which he termed “ sustainers," might
be 15 ft. long, 6 in. wide, and 2 in. apart, so many being
superposed as to furnish the required supporting air sur—
face. Each set of “ sustainers" was to be held in place
by a number of vertical bars of angular form, so as to offer
the least resistance to the air.
I70 FLYING MACHINES.

The propelling power was not indicated specifically, save
the general statement that it should be “ suitable,” but a
rudder was located at the top of the front series of curved
blades, being affixed to a spindle bar terminating below
(at the body) with a lever arm. A shifting weight was
also provided, capable of being moved across the body,
transversely to its line of motion, in order, when moved
to either side, not only to depress it, but, by the resistance
of the air acting on the surface of that weight, to check
forward motion on that side, and thus cause the machine
to describe the curve required.

The patent drawings show the vertical standards carry-
ing the blades as being rigidly attached to the body instead
of being pivoted thereto, as in the case of Commandant
Renard's device, and hence the angle of incidence of the
machine could not be conveniently varied in order to rise
or to descend; but it is probable that Mr. P/zz'llz'fls has
long since remedied this defect, for he is understood to
have been continuously experimenting, although the re—
sults attained have not as yet been published.

He apparently concluded that he had not developed the
best shape in 1884, for he patented, in 1891, the form
shown at the bottom of fig. 65. In this, the upper side A
of the blade was made convex, as formerly, but. the after
portion of the lower side of the blade was made concave,
as shown at 8, while the curvature of the forward portion
of this lower side was in the form of a reverse curve con—
sisting of a convex curve, C, at the forward edge, followed
by a concave curve, 1). He states in his patent :

“ The particles of air struck by the convex upper sur-
face ‘4 at the point Eare deflected upward, as indicated
by the dotted lines, thereby causing a partial vacuum
over the greater portion of the upper surface. The par-
ticles of air under the point E follow the lower convex and
concave surface C D until they arrive at about the point G,
where they are brought to rest. From this point G the
particles of air are gradually put into motion in a down-
ward direction, the motion being an accelerating one
until the after edge Fof the blade is passed. In this way
a greater pressure than the atmospheric pressure is pro-
duced on the under surface of the blade."

Mr. P/zz'llz'ps indicates that such blades may be of wood,
12 ft. in length and 6 in. in width, from the leading edge
E to the rearward edge F, but further experiment led- him
to make these blades still narrower, and he finally con—
structed an experimental machine which was tested in the
early part of 1893, and has been described in various Eng-
lish journals, notably in Engineering of March 10 and
May 5, 1893, the latter issue containing four illustrations,
AEROPLANES- 171

which were reproduced in the AMERICAN ENGINEER for
June, 1893. From these various publications the follow-
ing description of the Phillips experimental machine is
compiled.

Instead of providing two series of curved blades, one
behind the other, there was but. one set, approximately as
shown in fig. 64. The apparatus looks like a huge Vene-
tian blind with the slats open. There are 50 of these slats
or " sustainers" 1% in. wide and 22 ft. long, fitted 2 in.
apart in a frame 22 ft. broad and 9% ft. high. The sus-
tainers have a combined area of 136 sq. ft. ; they are con-
vex on the upper surface and concave below, the hollow
being about r11: in. deep. The frame holding the sustain-
ers is set up on a light canoe-shaped carriage, composed
principally of two bent planks like the two top streaks of
a whale boat, and being 25 ft. long and 18 in. wide, mounted
on three wheels I ft. in diameter, one in front and two at the
rear. This vehicle carries a small boiler with compound en-
gine, which works a two—bladed aerial screw propeller re-
volving about 400 times per minute. The fuel used is Welsh
coal. There is said to have been no attempt to provide
exceptionally light machinery. The weights of the various
parts of the machine are, approximately: carriage and
wheels, 60 lbs. ; machinery with water in boiler and fire
on grate, 200 lbs. ; sustainers, 70 lbs. ; total weight, 330
lbs. The machine was run on acircular path of wood
with a circumference of 628 ft. (200 ft. diameter), and to
keep it in position (preventing erratic flight) wires were
carried from various parts of the machine to a central
pole, as in the Tali” experiments heretofore described.
Still further to control the flight, which there is no means
of guiding, as the machine is not of sufficient size to carry
a man, the forward wheel is so balanced that it never
leaves the track, and therefore serves as a guide, carrying
some 17 lbs. of the weight, the remainder being on the
hind wheels.

On the first run 72 lbs. dead weight were added, mak—
ing the total lift 402 lbs. As soon as speed was got up,
and when the machine faced the wind, the hind wheels rose
some 2 or 3 ft. clear of the track, thus showing that the
weight was carried by the air upon the Venetian blind sus—
tainers. A second trial was made with the dead weight
reduced to 16 lbs. and the circuit was made at a speed of
about 28 miles per hour (2,464 ft. per minute), and with the
wheels clear of the ground for about three-fourths of the
distance. That the machine can not only sustain itself, but
an added weight, was demonstrated beyond all doubt,
even under the disadvantages of proceeding in a circle,
with the wind blowing pretty stiffiy.
I72 FLYING MACHINES.

It is stated in the journal [7071 that the boiler is a cylin-
drical phosphor-bronze vessel 12 in. in diameter and 16 in.
long. The tire grate area is 70 sq. in., and the fuel Welsh
coal. The engine is compound, having cylinders I}{
in. X 3% in. X 6 in. stroke, fitted with ordinary slide
valves. The working pressure of steam is 180 lbs. per
square inch. The propeller is 6 ft. in diameter and 8 ft.
pitch, with a projected blade surface of 4 sq. ft. The ma-
chine was also moored by a stern rope in which a dyna—
mometer was inserted, and on the engine being run at full
speed the dead pull was 75 lbs.

If the latter figures be correct, then the power developed
was 75 X 2,464 + 33,000 = 5.6 horse power, and the
weight carried per horse power was 402 + 5.6, or 72 lbs.
per horse power, which is inferior to the 110 lbs. per horse
power carried by M. Talz'fl's apparatus, and probably due
to the increased resistance produced by the frame which
holds the sustainers.

Mr. P/zz'llz'ps’s experimental machine neglects any pro-
visions for maintaining equilibrium in full flight, or for
rising and alighting safely. Those he may add later ; but
whether he does or not, he is entitled to great credit for
having been among the first experimenters who have
tested concavo-convex surfacesinstead of adheringto plane
surfaces, and who have thus drawn attention to what may
prove to be a very important line of inquiry.

Almost all scientific experiments in air have hitherto
been tried with planes, and such few formulm as have
been proposed are based upon the effect on flat surfaces.
It is probable that such formulae—those of Smeaton,
Duchemin, Joe'ssel and others—will be found to need
modification, either in form or in constants, when applied
to curved surfaces. In such case the tables of “ lift” and
“ drift" heretofore given herein will either need recalcu—
lation for each specific curved shape, or require the appli—
cation of a variable coefficient, as exemplified in the cal-
culations of the power expended by the pigeon as hereto—
fore given. In any case it seems very desirable that
further scientific experiments be made on concavo-convex
surfaces of varying shapes, for it is not impossible that
the difference between success and failure of a proposed
flying machine will depend upon the sustaining effect
(with a given motor) between a plane surface and one
properly curved to get a maximum of " lift.”

Fig. 66 represents a kite—like aeroplane proposed by
M. de Grafifgny, a French aeronaut, and the author of
several works upon aerial navigation. This apparatus
was to consist of a kite 46 ft. across, with its fabric sur-
face capable of bag'ging to a certain extent, and attached
AEROPLANES. 173

to a longitudinal frame, as shown, which was to be trussed
both above and below. In front, a stiff triangular head
was to be affixed, and an adjustable horizontal tail was to
be placed in the rear. Between these, a boat-shaped body
containing the machinery and aviators was to be swung

 

 

SIDE VIEW.

FIG. 66,—‘GRAFFIGNY—d1890,

on trunnions and attached to the frame. In front of this
car a two—armed screw was to rotate, and behind the car
a vertical steering rudder was to be placed, above the sur-
face of the kite.

M. de Graflz‘gny estimated that the power required to
drive the apparatus was in the proportion of one horse
I 74 FLYING MACHINES.

power for every 110 lbs., and he proposed the use of
liquefied carbonic acid gas, which he states to weigh but
55 lbs. per horse power, including the motor, the recipient
and a supply for several hours. This, of course, was a
mere makeshift, a reservoir of power for experiment, and
not a prime mover ; inasmuch as the whole apparatus was
to weigh but 396 lbs. and to have sufficient sustaining
surface (some 1,300 sq. ft.) to come down like a parachute,
should the motor break down while in the air. The screw
was to be 6 it. in diameter and loft. pitch, and its shaft
was to remain constantly horizontal (this being the object
of hanging the car on trunnions), so that the position of
the propeller should be independent of the angle of inci-
dence of the sustaining surface, in accordance with the
theory of the designer.

M. de Grafigny states that he experimented with a
model of this apparatus in 1890. The screw was rotated
some 300 turns per minute by a skein of twisted rubber
threads weighing, in the aggregate, 1.1 lbs., and produc—
ing 1,085 foot-pounds in 212- minutes, or at the rate of 7.23
foot—pounds per second, which proved quite insufficient to
give to the apparatus (mounted on three wheels, the fore—
most of which was adjustable) the velocity necessary to
cause it to rise upon the air. The designer expresses
himself as unable to state what would be the result with
a full—sized apparatus.

It will be noted that this proposal resembles a number
of others which have already been described. It is proba-
ble enough that the best form for sustaining a given
weight and for propelling it with a minimum of surface
and of power, or for maintaining equilibrium, were not
selected; but M. de Grafigny, in the book’l< in which
this design is incidentally described, strongly advocates
the kite principle generally, as the one most likely to lead
to success in devising a flying machine, and in learning
how to manage it in the air.

This will have occurred to many readers, and it may be
interesting to them to inquire as to what has been pub-
lished upon past experiments with kites, a subject upon
which the writer has found distressingly little on record.

Among the first, if not the very first, to call attention
to the fact that the study of the kite as a means of obtain-
ing unlimited lifting and tractive power had been unduly
neglected was Mr. Wenham, who, in his celebrated paper
on “ Aerial Locomotion,” published in 1866, described
briefly some very interesting experiments with kites, and
who has kindly furnished the writer with some additional

* “ Traité d’Ae’Iostation.” H. defiGraffigny, 1891, p. 189.
AEROPLANES. I75

particulars. Mr. Wen/mm states that his principal sum-
mary ot facts was taken from a little book, styled the
“History of the Charvolant, or Kite Carriage,” by Mr.
George Puma/c, of Bristol, England, who also published a
small work on “ Aeroplastics,” both of them, unfortu-
nately, now having become very rare.

The experiments described took place more than half a
century ago, and the purpose of the inventor was not to
evolve a flying machine, but to provide a floating observa-
tory to serve in warfare, or to drag wheeled vehicles over
land.

The apparatus was, in fact, a huge kite, of suitable size
to carry the intended weight, with a chair swung just
below, and so rigged that by tightening or slackening the
different cords which held it, the wind would meet it at
any angle desired, and the apparatus would rise or fall,
or could be made to swing a considerable distance to one
side or the other. It was so arranged that in case the
cords broke, it would act like a parachute, and thus insure
safet .

Th1; following quotation. descriptive of the experiments,
was given by Mr. Wen/mm in his paper:

“ While on this subject we must not omit to observe that the
first person who soared aloft in the air by this invention was a
lady, whose courage would not be denied this test of its
strength. An arm-chair was brought on the ground; then,
lowering the cordage of the kite by slackening the lower brace,
the chair was firmly lashed to the main line, and the lady took
her seat. The main brace being hauled taut, the huge buoyant
sail rose aloft with its fair burden, continuing to ascend to the
height of 100 yards. On descending she expressed herself
much pleased with the easy motion of the kite and the delight-
ful prospect she had enjoyed. Soon after this another experi-
ment of a similar nature took place, when the inventor’s son
successfully carried out a design not less safe than bold—that
of scaling, by this powerful aerial machine, the brow of a cliff
200 ft. in perpendicular height. Here, after safely landing, he
again took his seat in a chair expressly prepared for the pur-
pose, and, detaching the swivel line, which kept it at its eleva-
tion, glided gently down the cordage to the hand of the direc-
tor. The buoyant sail employed on this occasion was 30 ft.
in height, with a proportional spread of canvas. The rise of
the machine was most majestic, and nothing could surpass the
steadiness with which it was manoeuvred ; the certainty with
which it answered the action of the braces, and the ease with
which its power was lessened or increased. . . . Subsequently
to this an experiment of a very bold and novel character was
made upon an extensive down, where a wagon with a consider-
able load was drawn along, while this huge machine, at the
same time, carried an observer aloft in the air, realizing almost
the romance of flying.
176 FLYING MACHINES.

“ It may be remarked (continues Mr. Wm/zam) that the
brace lines here referred to were conveyed down the main line
and managed below ; but it is evident that the same lines could
be managed with equal facility by the person seated in the car
above ; and if the main line were attached to a water-drag in-
stead of a. wheeled car, the adventurer could cross rivers, lakes,
or bays with considerable latitude for steering and selecting the
point of landing, by hauling on the port or starboard brace-
lines as required. And from the uniformity of the resistance
offered by the water—drag, this experiment could not be attended
With any greater amount of risk than a land flight by the same
means."

The reader may perhaps inquire whether there was not
some risk that the kite should run away with the wagon
when the wind freshened; but Mr. Wen/mm further ex—
plains that the kite attached to the “ charvolant” or chariot
was provided with a smaller" pilot,” or upper kite, which
was sufficient to support the “ draft,” or lower kite, when
it was relaxed or allowed to float edgewise, on the wind.
The “draft” kite had two cords, one attached well for-
ward, and the other attached well aft, running through
rings to keep the cords together. If the aft cord was
slacked off by the driver of the chariot, the “ draft” kite
floated edgewise on the Wind, and the wagon stopped;
but by pulling on the aft cord the kite could be made to
face the wind absolutely, and to produce the maximum of
draft.

Mr. Wen/mm also mentions in his paper Captain Dan-
sey's kite, for communicating with a lee shore, as de-
scribed in Vol. XLI. of the “ Transactions of the Society
of Arts.” This was made of a sheet of holland fabric
exactly 9 ft. square, and, as stretched by two spars placed
diagonally, spread a surface of 55 sq. ft., the remarkable
fact about its performance being that in the experiment
about to be quoted this surface of 55 sq. ft. sustained no
less than gzi lbs. The quotation is as follows :

“ The kite, in a strong breeze, extended 1,100 yards of line
g in. in circumference, and would have extended more had it
been at hand. It also extended 3,,0 yards of line 1% in. in cir-
cumference, weighing 60 lbs. The holland weighed 34; lbs.,
the spars, one of which was armed at the head with iron spikes
for the purpose of mooring it, weighed 6% lbs., and the tail was
five times its length, composed of 8 lbs. of rope and I4 lbs. of
elm plank, weighing together 22 lbs.”

This latter kite seems to have been provided with a tail
to steady it in the air, and in considering the bearing of
such experiments upon possible flying machines, it is
preferable to select those upon tailless kites, sailed with
one single line, for it is easy to maintain the stability if
AEROPLANES. I77

several restraining cords be used. Mr. Wen/2am has
kindly furnished to the writerthe particulars concerning
a tailless kite, or, rather, series of superposed kites, pat—
ented in Great Britain in I859, by E.f. Cordner, an Irish
Catholic priest, who designed the apparatus to save life in
shipwrecks, and who preferred to arrange hexagonal
disks of fabric (stretched upon three sticks), above each
other on the same line, so that they would all pull to-
gether. The operation was to be as tollows :

When a sailing-vessel had struck, which almost in every
case occurs by the ship being blown on a lee shore, a
common kite was to be elevated in the usual way from on
board the vessel. When enough cord had been paid out
to keep the kite well suspended, the end of the cord on
board was to be attached in a peculiar manner to the back
of another and larger kite (without tail), andithe second
kite was then to be suffered to ascend. The end of the
suspending rope was to be attached in a similar manner
to the back of another and still larger kite, and the process
to be repeated until enough elevating and tractive power
was obtained, when a light boat or basket with one occu-
pant was to be fastened to the kite line, the latter being
paid out until the occupant reached the shore and alighted,
when by means of a light running line, extending from
the ship to the person ashore, it was deemed easy to haul
the basket back and forth as many times as necessary to
rescue the passengers and crew.

It is not known whether this ingenious method of saving
life without extraneous aid was ever used in a case of
actual shipwreck, but it was tested by transporting a
number of persons purposely assembled on a rock off the
Irish coast, one at a time, through the air to the main
land, quite above the waves, and it was claimed that the
invention of thus superposing kites so as to obtain great
tractive power was applicable to various other purposes,
such as towing vessels, etc.

Many proposals have been made at various times and
in various countries to utilize kites in life saving, but none
seem to have come into practical use. Such attempts may
have suggested to Mr. Simmons (the English aeronaut)
the experiments which he is said to have tried, in 1876, of
gliding downward under such buoyant sails.

The only accounts which the writer has found of these
experiments are given in the Aéronaute for April, and for
November, 1876. The apparatus of Mr. Simmons is de—
scribed as consisting of a huge “ pilot" kite 49 ft. high
and 49 ft. wide, with another kite below, still larger. The
pilot kite was first to be raised, and to carry up the sec-
ond ; the two were to be adjusted to the breeze, and the

12
I78 FLYING MACHINES.

aeronaut was to be suspended in a car, and allowed to
ascend 200 or 300 yards. Then by adjusting his weight
by means of guy lines, so as to obtain a proper angle of
incidence, the apparatus was said to glide downward to
the ground, being slightly dirigible throughthe guy lines,
and to be arrested by the bystanders seizing a dragging
guide rope.

Mr. Szminom is said to have been fairly successful with
his experiments in England, but to have failed to repeat
the feat at Brussels, Belgium. 1n the latter case it was
claimed that there was not sufficient wind, but steadiness
of breeze would be more important. The surfaces oper-
ated with seem to have been very large—some two to three
square feet per pound in order to alight gently ; but such
extent of surface is so unmanageable in a gusty wind as
probably to have led to the abandonment of the experi—
ments.

The exploit is feasible, and would prove useful in experi-
menting with various shapes and extent of surfaces, but
such experiments should be tried with areas more nearly
corresponding to the proportions which exist in soaring
birds, and the operator should invariably alight in water
until he has learned how to manage his apparatus.

In July, 1880, M. Biol exhibited to the French Society
for Aerial Navigation an ingenious kite, invented by him-
self, which sailed without a tail and possessed great stabil-
ity under all conditions of wind.

At the top of a flat plane of elongated elliptical shape
two hollow cones were affixed, one on each side. The
base or large end of these cones faced the wind, and the
other end or point was slightly truncated, so as to leave
an opening through which the wind could blow, and, by
the action of the streams or columns of compressed air
thus created, counteract any tendency of the plane to tip
to one side or to the other. This provided for the lateral
stability on the same principle as in the well—known Jap-
anese kite, in which the side-pockets catch the wind and
maintain the equipoise.

The fore and aft equilibrium was provided for by affix-
ing a rotating screw at the lower end of'the plane, pivoted
on its central line. This screw had two vanes of coarse
pitch, and was free to rotate under the impulse received
from the wind. It spun around with great speed when
the kite was raised, and obviated any need of the usual tail
by performing the same steadying office. It prevented
any oscillations, without impeding the rising of the kite,
and maintained it perfectly steady in all winds.

It was not agreed between the French aviators whether
this effect was due to the action of the vanes, making an
AEROPLANES. I79

angle with the sustaining plane, as in the case of Péizaud’s
“ planophore.” or to “ gyroscopic” action, but when the
screw was omitted the kite swayed about, while when the
screw was rotating, its twirling and tremor could be felt
through half a mile of string, and the kite remained per-
fectly upright and steady.

M. Bz'ot carried on quite a series of experiments with
this apparatus. In the kite which he used the elliptical
plane was 15 in. high, the two cones at the side were each
8 in. in diameter at the base by a height; of 8 in., while
the screw was 12 in. in diameter, its two vanes being each
15;— in. broad.

The experiments were carried on in winds varying from

3 to 33 miles per hour, and the kite was found to be
steady under all conditions, the only difference being in
the height to which it would rise. When the wind blew
from 13 to 18 miles per hour, 4,900 ft. of cord were paid
out, the kite remaining at this distance during two hours.
On other occasions, with stronger wind, as much as 6,500
and 8,200 lineal feet of cord were paid out, and the kite
mounted so high that it passed through several strata or
currents of wind of varying direction, as was conclusively
proved by the fact that the restraining cord as:umed a
sinuous attitude when the full height was gained, and
instead of approximating to a straight line or a regular
curve, as usual, the line became serpentine in form, thus
indicating that different trends existed in the various strata
of air.

In one instance the kite, with 2,600 ft. of cord paid out,
advanced against the wind and mounted directly over the
head of the operator. This was attributed to an ascend-
ing trend in the wind, for the kite still tended to rise ver-
tically and to advance against the wind, although the
plane was horizontal, and the cord, now greatly bowed
by the wind, tended to drag the apparatus backward.
This attitude continued but a short time, when, the trend
of the wind having apparently changed, the kite settled
back to its original position, flying at an angle of 40° to
609 with the horizon.

M. [)‘z'm‘, who was an old experimenter with kites (having
as early as 1868 been lifted up from the ground by a large
apparatus of this kind), found the gyroscopic stability of
the arrangement which has just been described so satis—
factory, that he thereupon designed, in connection with
M. Dmm’rz'wx, a full—sized aeroplane on the same prin-
ciple, calculated to carry up a man. This design was
submitted early in 1881 to a special committee of the
French Society for Aerial Navigation, but this committee
seems to have hesitated in recommending its construction,
180 FLYING MACHINES.

and no record has been found by the writer of its having
been built or experimented with about that time.

When, however, the publication and discussion of M.
Maui/Zara”: “ L'Empire de l’Air" had directed iresh at-
tention to the soaring of birds on rigid wings, and given
grounds for the belief that man conid utilize the wind in
the same way, M. Bio! constructed in 1887 a soaring ap-
paratus in the shape of an artificial bird 27 ft. across, and
weighing 551bs., with which he hoped to reproduce the
manoeuvres of the sailing birds.

It is known that a number of very interesting experi—
ments were tried with this apparatus, but the writer has
been quite unable to find in print, or to obtain from cor-
respondents, a description of the machine or a record of
its trials. He merely knows that these trials were many,
and that on one occasion M. Biol suffered a tumble which
was not encouraging to further experiment, but no ac—
count of them is to be found in the Aéronaute.

It is to be hoped that a full narrative may yet be given
to the public of the results ot experiments which must
have been most instructive for other aviators who con—
template imitating the birds.

In 1882 M./0bert exhibited before the French Society
for Aerial Navigation the model of a proposed apparatus
designed by himself, in order to test the possibility of
imitating the manoeuvres of the soaring birds, as described
by M. Maui/lard. This aeroplane was to be hinged and
jointed, so that it might be folded up like an umbrella for
convenience in transportation, or opened out and stiffened
by sliding bars in order to make the Wings rigid. With
this M. joéerz‘ proposed to experiment on various areas
of surfaces in proportion to the weight, and to test the
efficacy of both fixed and adjustable sustaining surfaces.
He does not seem to have met sufficient encouragement
to carry out his design, for the writer has been qune un-
able to learn that he ever completed a full-sized aeroplane
capable of sustaining a man.

Having begun where M. Biol terminated—z'e., with
the design for a soaring apparatus-M. foéerl next
turned his attention to kites, and proposed in 1887 the
apparatus shown in fig. 67, which he termed a “ rope-
bearing kite,” designed for establishing communication
with wrecked vessels. It consisted of a hollow truncated
cone C, under which was rigidly connected a kite P,
from which depended two light lines terminating in a
ring, the latter carrying a light cord steadied by the drag
D. The object of this arrangement was to ensure a rapid
and certain connection with the shipwrecked mariners,
who, by seizing the light cord, could at once haul down
AEROPLANES. 181

the kite and thus gain access to the main carrying rope,
with which to haul aboard the usual life—saving cable.
This carrying rope was fastened to a bridle attached to
the top cross-stick of the kite, and to the top of the cone
at V. which arrangement was claimed to produce perfect
stability, and to ensure that the apparatus should travel
straight back in the line of the wind without rising to any
great elevation. In order to regulate the height, the
angle of the plane could be varied by means of a light
string (not shown), extending from the lower cross-stick
to the carrying rope and fastened by a hook in one of a
series of loops.

The sustaining plane was, like the cone, formed of cali-
co, in which hems were turned at the top and at the two
sides, in order to form cases for the sticks of the frame,

 

 

 

 

 

 

 

FIG. 67.—_IOBE RT~—1887.

the lower edge of the kite being left uncased, in order to
produce bagging and consequent increase of lifting pow-
er. At the small end of the cone a couple of thin metal-
lic tongues were fastened, which, thrown into vibration
by the wind rushing through the cone, produced a howl—
ing sound which might notify the shipwrecked sailors of
the approach of the apparatus, and the whole arrange-
ment, as will readily be perceived, was quite cheap and
readily rigged up or folded away, no matter how large it
might be.

The writer does not know whether this apparatus ever
came into practical use. It has here been figured in
order to show how a cone can be applied to a kite in
order to impart stability to the latter, but the arrange—
182 FLYING MACHINES.

rnent would need to be greatly modified in order to admit
of its utilization in an aeroplane, so as not unduly to in-
crease the resistance to forward motion.

in 1886 and 1887 M. [VIM/[01, a French rope~maker,
tried quite a series of experiments with the kite repre—
sented in fig. 68. This was constructed of poles and can-
vas. in the shape of a regular octagon; it measured 775
sq. ft. in area, about 32 ft. across, and weighed 165 lbs.
It had neither balancing head nor tail, and was so poised
by the bridle of attachment that the center of pull corre-
sponded to a point only one-third of the distance back
from the front edge, or to a spot, therefore, decidedly for-
ward of the center of pressure, at the comparatively coarse
angle; (300 to 60°) usually assumed by kites. This angle
of incidence it Was intended to regulate by a cord, at-
tached to the rear edge and carried to the seat swung
beneath the kite for the operator, who might then, by
hauling in or paying out this cord. regulate the angle of
incidence and cause the kite to rise or to fall. This was
intended to furnish the longitudinal stability, while (there
being no provision for automatic lateral equilibrium) the
side oscillations caused by the varying intensity and direc-
tions of the wind were restrained by side ropes attached
to the kite and handled by men standing on the ground.

In the first experiments (May, 1886) M. [Wail/0! was dis-
suaded from ascending beneath the kite, and he therefore
substituted for his person a bag of ballast weighing 150
lbs., tied just below the seat. The kite was raised by
first securely anchoring the main rope, which was 800 ft.
long, and then lifting up the front edge so that the wind
might sweep under the surface; upon which the kite rose
to such height that the bag of ballast swung some 30 ft.
above the ground, where M. Mai/lot and two assistants
managed the two side ropes and the tail cord (not shown
in the figure), which latter regulated the angle of inci-
dence by depressing or raising the rear of the kite.

Allowing 33 lbs. for half the weight of the main rope,
it was estimated that the apparatus sustained, on this
occasion, an aggregate weight of 348 lbs., or in the pro-
portion of 2.23 sq. ft. per pound. The wind was vari-
ously estimated at 15 to 22 miles per hour; but as this
speed was not measured, nor the pull upon the various
ropes ascertained, while the angle of maximum incidence
was merely guessed at, as about 45°, no accurate compu-
tation can be made of the various reactions. The kite
was easily controlled by the three men, hauling or paying
out the two side ropes and the tail cord, but it plunged
about with the varying intensity of the wind, and in one
of the oscillations so produced the bag of ballast was
AEROPLANES. 183

whipped about and broke the rope by which it was sus-
pended.
M. Maillot repeatedly experimented with this and other

 

FIG. 68.——MAILLOT—1887.

kites (but smaller) on the same principle during the year
1887. He states that he succeeded in sustaining as much
as 594 lbs., but whether he ever went up himself beneath
I84 FLYING MACHINES.

the kite the writer has been unable to ascertain. There
would have been little or no risk in doing so, provided
the wind was steady and strong, for it is evident that. the
three lines carried to the ground would give almost com-
plete command over the apparatus, but then such a per-
formance would have taught very little toward the manage-
ment of an aeroplane free in the air. Changes were made
from time to time in the modes and points of attachment
of the various ropes, and the endeavor seems to have been
directed to the discovery of some arrangement by which
automatic equilibrium could be secured, under all condi-
tions and varying velocities of wind, without the use 01 a
tail. From the discontinuance of the experiments it is
inferred that they did not succeed, and the writer attrib—
utes this failure (it failure it was) to the employment of
a single rigid plane ; for it will be remembered that M.
Pénazm’ obtained a stable kite, on the principle of his
“ planophore,” by adding to the upper pair of planes a
second set, inclined at a slight angle to the first, the
effect of which was to regulate the incidence.

On the same principle, M. Barneti, whose proposed
aeroplane has already been noticed, obtained stability
with a tailless kite many years ago, by shaping the plane
like a laundry “ flat-iron,” cutting out a portion of this
from the rear or broad end, and adjusting the band so
obtained at an angle with the rest of the surface, so that
the kite would fly steadily.

M. Coflz'e, on the other hand, obtained partly the same
effect by inserting a hemispherical pocket in the body of
the kite, but this did not prove quite satisfactory until an
opening was cut in the apex, on the same principle as the
hole which is provided in the top of a parachute, after
which the wind, rushing through the pocket, produced
much the same effect as in the joéert regulating cone;
but the device is not one which can be profitably applied
to an aeroplane in forward motion.

Upon the whole, M. Mai/[M's kite was rather crude,
and decidedly inferior to Pococ/é's “ charvolant,” hereto-
fore described, in which the pilot kite might be used to
regulate the carrying kite. The stability of the Mai/[0t
arrangement. could probably have been improved, and the
side ropes dispensed with. by breaking up the surface
into two planes, forming a diedral angle with each other,
like the attitude of a bird gliding downward, or the same
effect might have been partially produced by providing the
plane with a keel.

Very good results with central keels have been obtained
by M. Bog/Mon with his various forms of " Fin” kites,
which are now sold in the shops. They consist of a
AEROPLANES. 185

plane, to which is affixed at right angles a “ fin” or keel
located in the lower part of the kite, and raised slightly
above its surface. They fly without a tail, with a steadi-
ness depending somewhat upon the form of the main
bearing surface, and seem to afford a good opportunity
for further experiment as to the shape of greatest stabil-
ity; for keels have been frequently proposed for aero-
planes, in which they will produce less resistance to for-
ward motion than obtains with other arrangements, but
few seem to have tested how such keels should be applied.

These remarks chiefly apply to plane rigid kites, and to
the various adjuncts and forms which have been tried in
order to confer stability upon a main plane surface sus-
taining the weight ; but still better results have been ob—
tained with fiex1ble surfaces, and it seems not improbable
that this is the arrangement which will give the greatest
amount of stability to a kite, by producing automatic ad-
justment to the Wind’s varying intensity.

As an example of such action may be mentioned the
“ Bi—Polar” kite of M. Basin, who experimented with it
in 1888. It consists of a main sustaining surface like a
boy's “ bow" kite, or practically the same in shape as the
kite surface in fig. 66. The frame is composed of two
sticks, one of them a flexible rod at the head, bent to a
bow, and the other a main central spine at right angles,
to which the bow-strings are fastened. The peculiarity
of the “ Bi-Polar" kite is that this central spine is also
made flexible, and that to its lower end (projecting some
distance below the supporting surface of the kite) three
triangular fins are attached, just like the tail of a dart,
omitting one fin. This arrangement obviates any neces-
sity for a tail and confers automatic stability, for the
lateral equilibrium is obtained through the elasticity side-
ways of the main surface or head, which is blown back by
the pressure to a convex surface with a diedral angle,
which angle varies in accordance to the violence of the
wind, while the longitudinal equipoise is likewise main-
tained by the balancmg pressures on the head and on the
fins, as the flexible spine yields more or less to the breeze.
The kite is thus made stable in both directions, and flies
steadily without a balancing tail. M. Basin sailed it
with two strings, one attached at the top and the other at
the bottom of the main sustaining surface; these strings
were both carried to the ground, and attached at each
end of a stick of equal length with the vertical distance
which they spanned at the kite, and with this stick in his
hand the operator could vary the angle of incidence.
This was intended to secure measurements of this angle
of incidence in connection with the pull, but the results
186 FLYING MACHINES.

thus obtained have not as yet, to the writer's knowledge,
been published.

Even better results can be attained with the “ Malay”
kite, which is in shape a lozenge, composed of two flexible
sticks crossing each other at right angles. The cross or
horizontal stick is the longest, being preferably 1.14 times
the length of the upright stick, and fastened to the latter
at a point 0.18 of its length below the top; a string is
then carried (in notches at the ends of the sticks) around
the periphery of the resulting lozenge, and this is covered
with paper or with muslin in the usual way. This sur-
face, when impinged upon by the wind and restrained by
the bridle, is bent back by the pressure and adjusts itself
to the varying irregularities of the breeze, the kite flying
without a tail with great steadiness and rising to great
elevations.

M. Eddy, of Bayonne, N. J., who has been constantly
experimenting with kites during the last few years, and
who is recognized as an expert in such matters, prefers
the “ Malay” kite to all others. He has improved it by
so fastening the cross-stick and tying its outer ends as to
produce a slight initial convexity, which is further in-
creased by the action of the wind, and which materially
adds to the steadiness of the flight. With this arrange-
ment M. Eddy has succeeded in causing a single kite to
ascend to a height of 2,400 ft. with 3000 ft. of line, and
then bringing it to the zenith directly over his head, or
even a little back of his hand, where its attitude strongly
suggested the advance of the soaring bird against the
wind. Upon a previous occasion he had succeeded in
attaining a height of 4,000 ft., with a string of five kites
flying in ” tandem"-——that is to say, each kite attached by
a string of its own to the string of the preceding kite al-
ready raised, so as to take up the slack or sagging of the
line, and thus enable the upper kite to rise to an altitude
otherwise unattainable. This performance seems to sug-
gest an easy way for the exploration of the upper air by
the Weather Bureau, for by affixing to the upper kite self—
registering instruments (thermometer, barometer, hygro~
meter, etc.), or, preferably, by connecting such_instru—
ments (and an anemometer besides) electrically with re—
cording instruments on the ground (through a series of
fine wires insulated in the kite string), observations of the
conditions prevailing aloft can be easily obtained. The
French have lately been making such observations by
means of “ free balloons” of medium size, and they are
said to be of material assistance in forecasting the
weather; the records obtained from the top of the Eiffel
Tower showing that even at that moderate height coming
AEROPLANES. 187

changes in wind and in temperature are indicated several
hours in advance of their prevalence at the ground.

The same principle of obtaining stability without a
tail, by means of an elastic frame, can be applied to other
forms than the "Malay” or the “ Bi-Polar” kites, but it
requires a good deal of delicate adjustment and balancing.
It has been done with the common hexagonal form of kite
by M. C. E. Myers, of Frankfort, N. Y., the aeronautical
engineer who furnished and operated the balloons and
kites by means of which the recent (1891) rain-compelling
experiments were tried in Texas.

It will be remembered that the explosions intended to
produce rain were in some cases produced by exploding
dynamite suspended below kites, and fired by electricity.
In providing for this, M. [IQ/em, who has for several
years been conducting systematic experiments with kites,
evolved some very interesting facts, and he has published
part of his experience in the Scientific American Supple-
men! (No. 835) for January 2, 1892, from which the fol-
lowing is extracted :

The originating cause of my interest in kite flying is aerial
navigation, and by successive steps I have adapted kites to fly
without tails, to fly with considerable weight attached, and,
finally, to fly without the restraint of the usual kite-string;
and, rising higher and higher, finally to disappear miles in
height and miles away on the verge of the distant horizon.

Theoretically, there should be no difficulty in attaining these
results. Practically, there is as much difficulty as with a child
learning to walk or a youth learning to manage a bicycle. In
a word, it is the art of balancing. . . .

Theoretically, the kite should be light or possess much sur-
face with little comparative weight. It should balance at the
flattest possible angle, nearly horizontal, and its surface should
be widespread, like the wings of a soaring bird. As a fact.
I have obtained the best results with this model, but had great
difficulty at first to induce it to fly at all, and was finally forced
to attach a compromise tail—vnot a kite tail, but a bird—like
tail, which, being flexible, vibrated or undulated with the verti-
cal oscillations of the kite, and thus acted as a propeller, so
that this kite actually moved against the wind. . . .

The most practical form of kite for general purposes seems,
however, to be the sixsided. Those created by me as part of
my apparatus for the Government rainfall expedition in Texas
were composed of an X, formed of two spruce sticks, each 6 ft.
long, tapering, with a top section of :41; in. X 9; in. and bottom
section of % in. X % in. tacked flatwise together with a very
small pinhail, and bound with hemp cord at the joining. Five
in. below this crossing (which was about 2 ft. from the top) was
a similar piece of timber, but I4 in. shorter, and tapering each
way, placed crosswise of the X, horizontally, so as to form a
188 FLYING MACHINES.

5-in. triangle, which stiffened the frame more than if all crossed
at one point. The outer end of each stick was creased with a
knife and notched around, so that a hemp cord passed first
through the crease and was “ half-hitched’ around each stick
to prevent splitting. The kites were covered with red calico,
pasted on tight, and bits of cloth were also pasted across the
sticks Where the kite-strings attached. These strings were at-
tached as long loops—one loop to the top sticks about 6 in.
from their tips, one loop to the two bottom sticks about 30 in.
from the bottom, and one loop to the cross-bar about a foot
from each end. All these loops Were then gathered together
and drawn through one hand as the kite lay on the ground,
held in place by one foot on its crossing, and being adjusted
carefully and equally to draw from apoinl wmewIzere midway
between 1116' cross-slick and top, best attained by trial, were then
tied together.

The kite was thus rather stiff and light at top, elaxtz'c and
heavier at the bottom,‘ and suspended at a point (ll/aw its center
of gravity and center of surface. To the loop at the bottom
was usually hung a narrow strip of cloth to afford greater
steadiness in supporting the kite’s burden of dynamite to be
exploded. I have been thus particular to describe minutely
this construction because many have written me for this infor-
mation.

The first trial kite flown at Midland, Tex., escaped. I had
built it all myself, as a model, and it had drawn up one ball of
hemp twine, and an assistant was holding the string prepara-
tory to running out another ball when the cord parted at a
flaw, and the kite flew into space. When last seen with a
glass, it was estimated to be about 3 miles high and 8 or 10
miles away, a fading red dot in the distance. . . .

In ordinary light winds this kite floats well, is steadier than
many other kinds I have tried, and would seem to be well
adapted for photography. If hung very near its top, it is prone
to advance upward and forward against the Wlnd, till over and
beyond the party holding the string, and literally floats on the
air as if propelled by its fluttering triangular section at or near
the bottom of the kite.

The accidental escape of this kite exhibited a very in—
terestmg example of partial “ aspiration,” and it is under-
stood from additional information, kindly furnished by
M. Myers, that he succeeded in reproducing this effect
on several occasions. The kites were hung, after con-
siderable experiment, so that they floated nearly flat on
the air, with as little tail as possible, and sometimes none
at all. They rose upon a light breeze, and drew away as
long as the string was let out. When checked or pulled,
they rose higher and higher until quite overhead, when
the string had to be released. If suitably balanced the
kite then rose still higher and drifted back, éut not as
fasl as file wind blew, its rearward flap vibrating more
AEROPLANES. 189

or less, and maéiflg z‘z‘s action a progressive one relaz’z've
to the wind, thus producing “ aspiration” with respect to
the breeze. A long string, or small weight at the end of
a shorter string, was sufficient to keep it balanced, so that
it might remain up for hours and go floating out of sight.

The possibility of this progressive action against the
wind without loss of height (or of “ aspiration") has been
strenuously denied, and yet it is easily explained if, in-
stead of assuming the Wind to blow horizontally, as we
generally do, we consider that it has at times a more or
less ascending trend, this being a not. unusual condition
over the sunbroiled plains of Texas. It is clear, from the
description of the mode of attachment of the string, that
its weight when released would tilt the kite forward, so
that the plane would point below instead of above the
horizon. In this position the direction in which the
“ drift" is exerted would be reversed—that is to say, the
horizontal component of the pressure, instead of pushing
backward, would be pulling forward, and thus éecome a
propelling forge against z‘lze wind, provided, of course,
that the latter still exerted its pressure on the under side
of the kite. Thus an upward trend in the breeze of but
3D or 5°, operating against a kite inclined forward 2°
below the horizon, would be sufficient to cause it to ad-
vance relatively to the wind, somewhat as a vessel “ close
hauled" advances against the breeze which furnishes its
motive power. In point of fact, therefore, that. which has
herein been termed the “drift” may act upon a plane
surface, as a force pushing backward or propelling for-
ward, according as that plmze is inclined to the front
[wave or éaluw [/ze fiarz’amz ; but in the latter case there
needs be an ascending trend in the wind in order to pro-
duce a sustaining pressure on the under side, for other-
wise the horizontal wind would strike the upper surface of
the flame and press it downward instead of upward.
The effect may be quite otherwise with concave-convex
surfaces.

Ascending trends of wind are by no means rare, as
abundantly proved by published observations since M.
Pizzazm’ called attention to the many causes which must
produce such trends. This was shown in a very able
paper on “ Sailing Flight," which was published in part
in the Aéronmzz’e for March and April, 1875, but. which,
unfortunately, was left unfinished. M. Pénaua’ demon-‘
strated that such winds must necessarily result from even
moderate undulations of the ground (and therefore a
fortz'orz' from mountains or deep valleys). from natural or
artificial objects acting as wind breaks, from the meeting
of air currents flowing in different directions, or even
190 FLYING MACHINES.

from the heating effect of the sun. He doubtless expected
to show, in the portion of the paper remaining unpub-
lished, that an upward trend of % t0 ,1, (from 60 to 100) in
the wind was quite sufficient to enable a sailing bird to
progress against the breeze by inclining his aeroplane so
that the horizontal component of the pressure would have
a forward direction, while the wind still acted on the
under side; for we have already seen in computing the
foot-pounds expended by a I-lb. pigeon in gliding, that
with a speed of 40 miles per hour and an angle of inci-
dence of 3° the “ drift" Will be 005647 lbs., while the
body resistance and that of the edges of the wings to—
gether will be 0.05555 lbs, and that at 50 (30 miles per
hour) the “ drift” will be 0.08892 lbs., and the resistance
of the body and edge of wings will be 0.03124 lbs., so
that in both these cases the “ drift" (calculated even with
the coefficients which have been obtained with planes,
and which are known to be inferior to those to be expect-
ed frOm concave-convex surfaces) is sufficient, if directed
forward. to overcome the resistances and to give to the
sailing bird a forward impulse ; this reversal in direction
of the “drift,” as previously explained, occurring when
the plane becomes inclined so as to point forward below
the horizon.

Since Pénazzd's day a great many observations have
confirmed the frequent prevalence of both ascending and
descending currents. Aeronauts, more particularly, have
noted that the atmospheric currents follow the undula—
tions of the ground, causing their balloons to subside upon
approaching a valley, or to rise when nearing a cliff or a
mountain. They have also inferred, from the fact that
they have found butterflies a mile or more above the earth
while sailing over table lands, that these trends are fre—
quent in such regions, although their effect upon the bal-
loon is less immediately noticeable than in mountainous
countries, where the angle of ascent often is 450 or more.
In such broken countries very curious observations have
been made as to the invariable prevalence of steeply as—
cending winds in certain well-defined localities when the
wind blows from a particular quarter; such, for instance,
as the observations of M. [Maui/lard in the Lybian chain
near Cairo, and those of M. Bretomzz‘ere in the vicinity of
Constantine, Algeria, where certain zones or gaps of as—
cending winds seem to exist, which the sailing birds util-
ize to gain elevation by circling. There they congregate
in crowds, forsaking the rest of the sky, and spirally
mount on rigid wings, until they have gained sufficient
altitude to carry them toward any point which they may
want to reach in descending.
AEROPLANES. 191

It is probably in sub-tropical regions that such phe-
nomena are most numerous and permanent ; but the read-
er, who is accustomed to thinking of the wind as blowing
horizontally, may be quickly edified by watching the
smoke issuing from a tall chimney even in northerly cli—
mates. This smoke will be seen at various hours, or on
various days, to trend either upward or downward or with
exact horizontality, as may depend upon the undulations
of the great atmospheric waves which are produced by
the impinging upon each other of the currents flowing and
crossing at various altitudes ; or if the observer have the
good fortune to be in the regions inhabited by the sailing
birds, he may satisfy himself as to the similar atmospheric
undulations which are constantly taking place, even in a

 

FIG. 69.—-SIMPLEST CHINESE KITE.

perfectly flat country, such as the plains of Texas or the
sea beaches of Florida, by liberating bits of down or
threads of smoke from the same spot at various times or
days. He will also-observe the local ascending currents
permanently produced by a mere wind break, such as a
belt of trees facing the infiowing sea breeze. He may
satisfy himself (by attaching light strips of bunting or
bright-colored threads to the tops of those trees) that the
breeze is deflected upward just over their upper branches,
and he will then understand why these spots constitute
the favorite haunts of the sailing birds when the breeze is
light. He will see the soarers for hours gliding back and
forth and back and forth on pulseless wings. just above
the top of the wind break formed by these belts of trees,
evidently utilizing the ascending current to patrol the ad-
joining beach while awaiting, with no labor, whatever
food may be brought by the incoming tide, or an oppor-
tunity of eating it undisturbed.

It is not intended here to convey the impression that
ascending trends of wind are absolutely necessary for
192 FLYING MACHINES.

sailing flight. The writer has seen the feat performed
many times, when every test seemed to prove that the
current was absolutely horizontal ; but it then seemed to
him that on such occasions the equilibrium was more
difficult to maintain, and that the bird had to bestow
greater attention upon the nice adjustments required to
preserve his balance and to produce “ aspiration” when
the wind varied in intensity and direction; just as an
acrobat experiences greater fatigue in walking a tight
rope, through the attention and care expended to avoid
falling. than in walking many times the same distance on
the ground, where no particular care is required to pre-
serve the balance. It is probably because of such relief
from all cerebral strain that the soaring birds seem to
sail with less care and with far greater steadiness when-

 

FIG. 7o.—CHINESE MUSICAL KITE.

ever they are utilizing an ascending current. They are
then easily and safely sustained, and so mechanical does
the performance seem that some obser'vers have expressed
the opinion that they then sleep on the wing. There is no
doubt, moreover, that ascending trends ot wind enable
the creatures to soar in lighter breezes than would other-
wise be possible, and when the faint morning wind first
begins to blow, many of the sailing birds will be seen
congregated just above wind breaks, while the other parts
of the sky are vacant.

But to return from this digression, occasioned by the
feat of “aspiration” performed by M. Myers 3 kites, it
will be discerned that the principle of flexibility alluded
to confers stability upon the well—known 7aflmzese Hie,
specimens of which are now to be found in almost all toy
shops. This kite flies without a tail, the frame being so
light and elastic that the surface adjusts itself constantly
to the irregularities of the breeze. The side pockets
catch the wind, and by springing back of the medial line
AEROPLANES- 193

form a diedral angle which confers lateral balance, while
the flexibility up and down confers longitudinal equilib-
rium. The same principle is exemplified in the upward
bending of the extremities of the feathers of birds in
flight, which doubtless adds much to their stability, and,
indeed, so universally is this principle illustrated by all
creatures which navigate fluids, that Dr. Amans, in a
work upon the locomotive organs of flshesfi'< lays it down
as an axiom derived from physiological considerations,
that an aeroplane of rigid form is com‘re nature, or in
direct antagonism with all the inferences to be drawn
from the observation of creation.

The Japanese are expert kite-flyers, and have produced
many shapes besides that which has been above alluded
to. They are said to use kites as weather vanes, and
to have hitching posts in their gardens to which the de-
vice is almost permanently afflxed. Indeed, it is said that
these kites sometimes remain 8 or 10 consecutive days up
in the air—an astonishing achievement to European and
American kite fanciers, who seldom succeed in keeping
their apparatus up more than a few hours. The explana—
tion is probably to be found in the greater regularity and
permanence of the air currents in the regions of trade
winds, and these too are the regions where the soaring
birds are most numerously found, probably because they
are there sure of a sustaining breeze every day, through
the use of which they may evade the fatigue of flapping
flight.

The various forms of the C/zz'nese laz'z‘es are even more
numerous than those of the Japanese, and most of the
tailless kind are said to depend upon the same principle
of flexibility for their equilibrium. It would not at all be
surprising to find, should a stable aeroplane be hereafter
produced, that it has its prototype in a Chinese kite ; but
the writer has discovered very little information in print
upon the subject; the following article, translated from
La Nalure by the Scz'em‘z'fic American and published in
its issue of March 24th, I888, being perhaps the best
available :

One of our correspondents in China, Mr. Huchet, at present
in Paris, has had the kindness to have made for our purposes,
by a skillful Chinese manufacturer, a series of models repre-
senting the different types of kites used everywhere in China,
Annam, and Tonkin, and which the same gentleman has been
obliging enough to bring to us in person.

Fig. 69 represents the simplest form of these kites. Its
frame is formed solely of a stiff bamboo stick, A B, and two

* Comparaison des organes de la locomotion aquatique, P. C. Amans.

13
I94 FLYING MACHINES.

slightly curved side rods, CD and EF. To this frame is
pastedasheet of paper, which is somewhat loose at the ex—
tremities CE and D F, where, under the action of the wind,
pockets are formed that keep the affair bellied and in an excel-
lent position of equilibrium. Our engraving shows the mode
of attaching the strings that serve to hold it. Kites of this kind
are usually about 3 ft. in width.

Fig. 70 shows the appearance of the musical kite, so called
because it is provided with a bamboo resonator, 1? containing
three apertures, one in the center, and one at each extremity.
When the kite is flying. the air, in rushing into the resonator,
produces a somewhat intense and plaintive sound, which can
be heard at a great distance. This kite is somewhat like the
preceding, but the transverse rods of its frame are connected
at the extremities and give the kite the aspect of two birds’
wings affixed to a central axis. This kite sometimes reaches
large dimensions—say IO ft. in width. There are often three

 

FIG. 7I.—CHINESE BIRD KITE.

or four resonators placed one above another over the kite, and
in this case a very pronounced grave sound is produced. Mr.
Huchet informs us that the musical kite is very common in
China and Tonkin. Hundreds of them are sometimes seen
hovering in the air in the vicinity of Hanoi. This kite is the
object of certain superstitious beliefs, and is thought to charm
evil spirits away. To this effect it is often, during the preva-
lence of winds, tied to the roofs of houses, where, during the
whole night, it emits plaintive murmurs after the manner of
[Eolian harps.

Among ingenious fancies of the Chinese is their bird kite,
fig. 71, the frame of which is made elastic. The thin paper at-
tached to the wings moves under the action of the wind and
simulates the flapping of the wings. This kite is sometimes 3
ft. in length.

The most curious style of Chinese kite is the dragon kite,
fig. 72. It consists of a series of small elliptic, very light disks
AEROPLANES. 195

formed of a bamboo frame covered with India paper. These
disks are connected by two cords which keep them equidistant.
A transverse bamboo rod is fixed in the long axis of the ellipse,
and extends a little beyond each disk. To each extremity of
this is fixed a sprig of grass which forms a balancing plume on
each side. The surface of the foremost disk is slightly convex,
and a fantastic face is drawn upon it, having two eyes made of
small mirrors. The disks gradually decrease in size from head
to tail, and are inclined about 45° in the wind. As a whole,
they assume an undulatory form, and give the kite the appear-
ance of a crawling serpent. The rear disk is provided with
two little streamers that form the tail of the kite. It requires
great skill to raise this device.

This last device resembles in arrangement the multiple
disk kites for life saving of the Rev. Mr. Cowman already
described, and suggests that the superposition of kites
affords a good field for experiment. There is a limit in

 

FIG. 7:..—CHINESE DRAGON KITE.

size beyond which the increasing leverage will so add to
the required strength and weight of the frame as to make
a kite unduly heavy as well as unwieldyfi’< and superposi-
tion naturally suggests itself for experiments intended to
test the efficacy and equilibrium of kite aeroplanes. There
will be many practical details to work out in devising the
best mode of attachment of such aeroplanes with each
other, so that all surfaces may pull together and yet coun—
teract the effects of wind gusts, so that experiments with
kites seem to offer the readiest, quickest, and least expen-
sive method of working out this part of the problem.

The attention of experimenters is specially called to
the form of kite shown in fig. 70. It resembles in shape

. * The largest kite. on. record is said to belong to a Japanese gentleman, and
is sodft. X 45 ft.,weigh1ng 1,700 lbs. Its frame is composed of 350 pieces of
woo .,
196 FLYING MACHINES.

and attitude those of the soaring birds, which, as already
remarked, perform their manmuvres with peculiarly
curved and warped surfaces, and it will be seen here-
after that. the nearest success in compassing gliding flight
hitherto obtained—that of M. Lz‘Zz’em‘lzaZ—has been
achieved with just such surfaces.

Inventors seem to have bestowed but little attention
upon kites, less than a score of such devices having thus
far been patented in the United States. These patents
chiefly cover various methods of making the frames to
fold, so that the kite may be more portable, while but few
inventors seem to have considered how the stability may
be increased. Among these latter may be mentioned Mr.
Clarke (No. 96,550), who proposes the insertion of a
spring on one of the three cords which compose the bridle.
By the yielding of this spring the angle of incidence of the
kite may vary somewhat with the varying velocities of the
wind, and thus diminish the perturbations.

Mr. Maddans (No. 121,056) proposes a kite with a con—
vex surface, this being obtained by providing a stick across
the top, which stick is sprung into a bow by attaching its
ends to each other ; but this bowing seems to have been
chiefly devised to attach a flapping tongue, rotating on
the bowstring, and so making a drumming noise, while
there is no doubt that the convexity of the kite must add
to its stability.

Mr. Thompson (No. 225,306) patents a reversible con-
vex or concave kite. with a frame, like that of an umbrella;
but nothing is said of the equilibrium or of dispensing
with a tail, the object being, apparently, to provide for
convenience in carrying.

Mr. Coléy (No. 354,098) provides for the stability by
inserting in the middle surface of a kite a wind bag rear—
wardly projecting, which is distended by the breeze and
prevents the kite from darting. This is virtually the same
device as that of Mr. Copie, already mentioned, which
was found to require a central opening to allow the escape
of the air when experimented in large dimensions. It is
evident. that such a device, if applied to a navigable aero-
plane, would largely increase the resistance to forward
motion; but. this might be minimized by making such
wind pockets very shallow, and inserting a large number
in the aeroplane. The experiment may be worth trying
by kite fanciers.

While several forms of folding frames for kites have
been patented by inventors, few seem to have been de-
signed to act as parachutes also. This has been accom-
plished recently by Mr. May in a very simple way (British
patent No. 1,916, A.D. 1892) by providing the folding frame
AEROPLANES. 197

with a central hub. to which a trapeze bar may be sus-
pended when such a kite is used for conveying passengers
or for exploration. By using two lines, the angle of inel—
dence may be controlled, and the kite be made either to
raise a weight or to descend slowly to the ground as a
parachute.

As already intimated, the writer has found singularly
little on record concerning kites, and that little bears but
slightly upon the important question of the stability of
aeroplanes. It may be for lack of more thorough search
that only fragmentary information has been gathered.
Kites are supposed to have been invented 400 years be-
fore the Christian era by Archytas, a resident of Smyrna
(where the flying of kites remains a national sport to this
day), and the Asiatics have always been and are now the
great kite experts of the world. It is, therefore, not im-
probable that search in books of travel or inquiries ad-
dressed to Orientals might elicit information bearing di-
rectly upon the flying machine problem ; and it is much
to be desired that some competent person shall undertake
to write a critical account of kite experiments as well as of
the kites of all nations, and of the influence of form as to
stability and sustaining power. There is a large collec-
tion of Chinese kites in the National Museum at VVashing-
ton, and it would certainly be interesting to have an ac-
count of the various principles exemplified and of the be—
havior of the various shapes in the air.

At the annual meeting of the American Association for
the Advancement of Science, held in Buffalo, N. Y., in
1886, a paper on The Soaring Birds was read by Mr. Lan-
caster, then of Chicago, which paper attracted great interest
and attention.

Mr. Lancasler, in the hope of surprising the secret of
the birds, had the pluck, in 1876, to exile himself to the
wilderness of Southwestern Florida, on the Gulf coast,
near the Everglades, and there to remain for five consecu—
tive years watching the sailing of the master soarers. He
published some of his observations and deductions in the
London Engineer, in the reports of the Aeronautical Sod
ciety of Great Britain, and in the American Naz‘ura/z'st;
but the subject was by no means exhausted, and his de-
scription of the phenomena observed was so interesting to
the members of the association, few of whom had ever
seen a soaring bird at close range, that they demanded to
hear more upon a subsequent day.

Unfortunately for Mr. Lancaster, upon the latter occa-
sion he attempted to give a mechanical and mathematical
explanation of the performances which he had previously
so well described, and his theory was so plainly erroneous
198 FLYING MACHINES.

that he was subjected to harsh ridicule and criticism.
He had witnessed some remarkable feats of “ Aspiration,”
he had attempted to reproduce them artificially, but he
was clearly wrong in his expounding of the mystery, and
his critics did not properly discriminate between the state—
ments of observed facts and the attempted explanation.

The principal issue, however, was made concerning
some attempts to imitate soaring action, which Mr. Lan-
casz‘er claimed to have successfully made in Florida, and
which he unwisely declined to exhibit at Buffalo. He had
described them in his paper as follows :

I constructed floating planes which, for lack of a better name,
I have termed “efligies,” and which are an example in point.
I have made scores of them. They would draw into the breeze
from the hand and simulate the soaring birds perfectly, moving
on horizontal lines or on an inclination to avertical. They
would float in the best winds with neither ledge, rough front
surface nor rear curve, if very nicely adjusted ; but one of this
construction I never induced to pass beyond the limits of
vision, as the equilibrium was so very delicate that a little in-
equality in the wind current would capsize it.

There is every probability that such an experiment
would invariably fail it tried in any but a perfectly steady
sea breeze, an inflowing curent of air with peculiar condi-
tions; but it does not follow that the action described is
impossible, for if we presume that current to have an up-
ward trend (and the writer knows, of his own knowledge,
that such upward trends are not rare in sea breezes), we
can readily see that an aeroplane, tipped forward so as to
point below the horizon, may be both sustained and “ as-
pirated," or possess a forward component of pressure, so
that it may advance against the wind, and rise at the
same time. like the kite of M. rMyers.

The equilibrium is, of course, excessively delicate, and
hence the requirement for a sea breeze ; for a local homo-
geneous mass of air flowing from the water over the land
to replace the rising quantity heated by the sun ; but it: is
erroneous to suppose that the experiment described by Mr.
Lancaster involves a mechanical impossibility. It is,
doubtless, difficult to repeat it successfully, because it
requires a combination of peculiar conditions; but the
soaring birds are daily performing the feat, and apparent-
ly in horizontal winds,

In order that those who are favorably circumstanced
may test the matter experimentally, the following descrip-
tion of the device is copied from a paper of Mr. Lancas-
ter, published in 1882.

Take a stick of wood I in. square and 18 in. long, and point
AEROPLANES. 199

one end. Slit the other end 3 or 4 in., and insert a piece of
stiff cardboard o in. wide and I ft. long. This will represent
the body and tail of the bird. Fasten on both sides near the
pointed end a tapering stick 2 ft. long, with the outer ends
slightly elevated, and fasten to these and the body a piece of
cardboard IO in. wide and 2 ft. long. Have the tail vertical
instead of horizontal, as in the bird. Round off the outer rear
corners of the wings for 3 or 4 in. The imitation of the natu-
ral bird is now complete. There is no need of exactness, as
the air you are to try it in will be an unknown quantity, and it
may just suit the shape you make. An indispensable part is
now to be added, which is to preserve the equilibrium and is
not used by the natural bird. A tapering stick, say 1—}; in.
wide, 43 in. thick at the top, {a in. square at the other end, and
18 in. long is used. This piece is to be securely fastened by a
small bolt through the upper end of the body piece, about 5 in.
from the front end. Itmust be capable of adjustment by allow-
ing the lower end to swing front and back through say 40°. To
the lower end is fastened a muslin bag which will hold 2 lbs. of
shot. Expose the effigy to a breeze of from 3 to 20 miles an
hour, from as high a situation as it is possible for you to obtain,
by holding it by the pendant stick near the body. Adjust the
Weighted stick forward or back, and add or subtract shot until
the etfigy has a tendency to spring from your hand against the
current of air, when it may be released at a moment of great-
est steadiness of breeze

I have made hundreds of these toys, with all kinds of suc-
cess, but have never yet succeeded in getting one to travel be-
yond the limits of vision. They have proceeded directly
against the breeze for 500 yards, and obliquely, up or down,
or to right or left, within those limits, when they would lose
their balance and come down. Sometimes almost any kind of
one that was presented to the air would float creditably, while
at others none would succeed. The pendant weight for main-
taining equilibrium, though the best I have ever devised, is far
too sluggish for perfect work. The momentum of this weight
prevents the best results, for, if a succession of puffs of wind
upon the same wing should occur quickly together, the weight
would swing far enough, in obedience to the impulse given, to
capsize the effigy. Such a succession of puffs is sure to occur,
sooner or later, at each trial. These toys operate long enough,
however, to prove the purely mechanical character of flight,
and serve to materially strengthen the theory.

The writer may confess that he has tried this experi—
ment several times under special instructions furnished by
Mr. Lancasz’er, but that he has never succeeded in floating
one of these“ effigies" so that they would advance against
the wind. Others have, to his knowledge, tested the matter,
and had no better success, yet. it is not rational to say that
the feat is impossible, for it is very clear that if the wind
have an ascending trend, and the “ effigy” be slightly
tipped toward the front, the horizontal component of air
200 FLYING MACHINES.

pressure will drag it forward, while the vertical com—
ponent will sustain or elevate it, as already explained. It
is probably because of the uncertain prevalence of ascend-
ing trends that Mr. Lancasz‘er complains that sometimes
almost all these toys would succeed in simulating soaring,
and sometimes none at all.

In 1888 Mr. Lancaster moved to Colorado, where he
has been experimenting with a view to the solution of the
problem of soaring flight ; and in the Amem'can Nalural-
is! for September, 1891, he gave an account of some of
his experiments, with the conclusions which he deduced
therefrom. The following extract contains an account of
a remarkable occurrence. He says :

I can produce true soaring flight in natural wind, with a
plane exceeding 2 lbs. to a square foot of surface, whenever I
wish to do so and can obtain wind strong enough for the pur-
pose. During the past three years I have made about 50
planes [aeroplanes ?] of various shapes and sizes, and from 25
lbs. to 400 lbs. in weight. These planes are not set free in
wind, but used in the experimental caSes above described, but
with rigid rods in place of the parallel wires. These rods run
in large rings and have a cross~head at their outer ends allow-
ing the plane to run to the front until its edge rests against the
rings. In the best trial the parallel [with the plane ?] com-
ponent is neutralized at 10° from horizontal, far exceeding my
expectations derived from observations of the birds, their angle
of obliquity being rarely over 5°.

On a few occasions these planes accidentally escaped me in
time of highest wind, and were ruined at once for all purposes
excepting firewood, in each case being a loss of two or three
months’ work. and playing havoc with my finances. One that
I valued particularly plunged to the front in a violent blast of
wind with force sufficient to tear out the rings. It rose into the
air. gradually higher and higher, until an elevation of at least
3,000 ft. was attained, when some part of the device giving
away, it lost equilibr um and plunged through the air, striking
the earth about 2% miles from the starting-point, and 1,000 it.
higher than that locality. Another mile would have carried it
to the summit of the Flat Top Mountains. It was in the air
about three hours, and I walked beneath it during its flight.
Its course was directly against the highest wind I have experi-
enced during my residence here. At times it did not progress,
but went higher. It weighed IIO lbs., and had been well bal-
anced for experimenting on surface manipulation. There was
no lesson taught in this flight, the birds having been doing the
same thing for a long time. It was an interesting spectacle to’
look at: so is a large bird in the same act. Ipresume Mr.
Darwin’s provisional solution would apply to this plane as well
as to the condors; but I am trying to explain the actual me-
chanical activity of both.

The best effects produced were with a plane of 400 lbs.
AEROPLANES. 201

Weight and 80 sq. ft. of surface. In a wind that would he
rightly termed a gale, arising about midnight, this plane was
thrown about 7° from horizontal. It ran to the front against
the rings at 10°, where the entire parallel component was neu-
tralized, and at 7° it hugged the rings with a force that required
a backward pull of 15 lbs. to detach it.

This plane would make a splendid navigator, and I would
have no hesitation in trusting myself to it, when steering.
equilibrium and alighting or stopping items had been worked
out. Imean to say that it would navigate wind. I am now
just entering on a course of experiments in calm air.

This very interesting case of ” aspiration" may have
been produced by the same cause as in the case of M.
.Myers's kite—z’.e., an ascending trend of wind ; but cer—
tainty concerning this depends upon the shape of the sur-
face. Mr. Lancasz‘er writes of it as a “ plane ;” but as
he mentions also the “ front ledge" and the “ rear curve,”
the surface operated upon by the wind was probably a
more or less compound surface, for which there is no
specific name, but which may be described as an aero-
plane. If it was shaped like those of the soaring birds,
then “ aspiration” might occur with a horizontal wind,
but the equilibrium would be very unstable, and, as Mr.
Lmzmsz‘er points out, the steering, alighting, and stop-
ping would be the important points to work out.

Among the most systematic and carefully conducted
series of experiments that have ever been made in the
direction of artificial flight are those of Herr Otto Lilian-
l/zal, of Berlin, Germany, a mechanical engineer and con-
structor, and a prominent member of the German Society
for the Advancement of Aerial Navigation.

The general position that he maintains, and in pursu-
ance of which he has made his more recent experiments.
is that bird flight should be made the basis of artificial
flight. Dexterity alone, as he maintains, invests with supe-
riority the native denizens of the air, and, therefore, man,
if he possessed sufficient skill, might participate in flight.
He evidently believes, like M. Mouz’llam’, that for the soar-
ing birds ascension is the result of the skillful use of the
power of the wind, and that no other force is required;
and, therefore, that to imitate them no engines or other
external sources of power are needed, but that all the
necessary apparatus consists of properly constructed sus-
taining surfaces skillfully operated.

Herr Lz'Zz'mt/zal, instead of first flying at conclusions,
began by a systematic analysis of the problem, verified by
experiments, which latter were carried on by himself and
his brother, G. Lilz'em‘lzal, during a period covering
nearly 25 years, and he published in 1889 a book on
202 FLYING MACHINES.

“ Bird-Flight as the Basis of the Flying Art," * in which
he gave the result of his investigations.

From a review of this remarkable book in the Aéronaule
for January, 1892, the following account of its contents
has been prepared.

Herr Lz'lz'em‘lzal seems to have begun by observing the
sailing of various sea birds following vessels at sea, and
of the stork, an expert soarer, which inhabits Germany ;
he drew the conclusion that fl/ane surfaces present undue
resistance, and that success in artificial flight is only to be
expected from concavo-convex sustaining surfaces ; a be-
lief which, as we have already seen, was also entertained
by Le Brz's, [fa/25071, Goupz'l, P/zz'ZZz'ps, and others.

He declares that the laws of air resistances and reac—
tions which, unfortunately, are as yet but imperfectly
known, form the whole basis for the “ technique" or
actual performance of flight, and that the shapes and
methods of birds so completely utilize these laws and offer
such appropriate mechanical movements that failure must
follow if they be discarded.

Herr Li/z'mtlml’s experiments were in great part directed
toward an investigation of the resistances and reactions
of air, and the power necessary for flight. One of these
consisted in suspending himself from a spar projecting
from a house and operating a set of six wings opening and
closinglike concave Venetian blinds, through which he
measured the lifting effects of wing strokes performed
with the muscles of the legs, so that the step of each foot
would produce a double stroke of the wing. The weight
of the operator and wings combined was I761bs., and they
were counterweighted with 88 lbs. suspended to a rope
passing over two pulleys. With some practice he was
enabled, by operating the wings with the pedals, to lift
himself 30 ft. from the earth, thus proving that he ob~
tained, through his mechanism, wing power sufficient to
lift the remaining 88 lbs.—a very excellent performance,
and much in excess of most of those hitherto described in
this review of Progress in Flying Machines.

This and other experiments, together with a considera-
tion of the power to be obtained from the wind, convinced
him that artificial flight was accessible to man, aided by
considerably weaker motors than have generally been
thought indispensable, and, indeed, under favorable cir-
cumstances of wind, with no motor at all.

Herr Lz'lz'enZ/zal, therefore, carefully analyzed the shapes
and methods of the living birds and the exact proportions

* “ Der Vogelflug als Grundlage der Fliegekunst,” Von Otto Lilienthal,
Berlin, 1889.
AEROPLANES. 203

of their concavo-convex surfaces. He went into this in
detail, and finally formulated in his book the following
conclusions :

I. The construction of machines for practical operation in
nowise depends upon the discovery of light and powerful
motors.

2. Hovering or stationary flight without forward motion can-
not be compassed by man’s unaided strength. This mode of
flight would require him to develop, under the most favorable
circumstances, at least 1.5 horse power.

3. With an ordinary wind man’s strength is suflicient to work
efliciently an appropriate flying apparatus.

4. With a wind of more than 22 miles per hour, man can
perform soaring or sailing flight by means of adequate and ap—
propriate sustaining surfaces.

5. A flying apparatus, in order to operate with the greatest
possible economv, must be based, both in shape and propor-
tion, upon the wings of the large, high-flying birds.

6 The sustaining wing surface may be from 0.49 to 0.61 sq.
ft. per pound of weight.

7. Sufliciently strong apparatus can be built of Willow frame
and stretched fabric, so as to provide a sustaining surface of
107 sq. ft., with a weight of about 33 lbs.

8. A man provided with such an apparatus would have an
aggregate weight of 198 lbs., and would then have 0 55 sq. ft.
of sustaining surface per pound, or about the proportions of
large birds.

9. Experiment must determine whether the most advantageous
shape be that of birds of prey and of waders, with broad wings
and spread out primary feathers, or that of sea birds, with nar—
row wings tapering to a point.

10. If the broad wing be adopted, the wings of an apparatus
with 107 sq. ft. of sustaining surface would needs be of 26.25
ft. spread, with a maximum width of 5.25 ft.

II. If the narrow wing be adopted, a surface of 107 sq. ft.
would need a spread of 36 ft. with a maximum width of 4.60 ft.

I2. The application of an additional bearing surface, as a
tail, is of minor importance.

13. The wings must be curved in transverse section so as to
be concave on the under side.

14. The depth of flexure should be one-twelfth of the width,
in order to correspond with that of birds’ wings.

I5. Experiment must determine whether greater or lesser
flexure will prove preferable for larger wing surfaces.

16. The framing and spars of the wings should be at the front
edge so far as possible.

17. A sharp cutting edge should terminate this framed front
edge if possible.

I8. The flexure should be parabolic, the greater curvature
being to the front and flatter to the rear.

19. The be! shape of flexure for large surfaces must be de-
termined by experiment; also what preference is to be given
204 FLYING MACHINES.

to those shapes which produce the least resistance to forward
motion at flat angles of incidence.

20. Construction must be such as to admit of the rotation of
the wing upon its longitudinal axis, which rotation will best be
obtained, in whole or in part, by the pressure of impinging air.

2I. In flapping flight the inner wide portion of the wing
should oscillate as little as possible, and serve exclusively in
sustaining weight.

22. Thepropulsion to maintain speed should be obtained by
.up-and-down beats of the wing tips or of the primary feathers,
the forward edge being depressed.

23. In flapping flight the widest portion of the wing must also
co-operate in the up stroke in order to sustain weight.

24. The wing tips should encounter as little resistance as pos-
sible on the up stroke.

 

FIG. 73,- -LILIENTHAL—1891.

25. The down stroke should be in duration at It ast six—tenths
of the time occupied by the double stroke.

26. The wing-tips alone need oscillate; that portion of the
wing which merely sustains may remain rigid, as in soaring
flight.

27. If only the wing-tips oscillate they should not be articu-
lated. as this would dislocate them; moreover, 'the transition
to the up stroke should be as gentle as possible.

28. In order to beat a pair of wings, man must employ his
extensor muscles, and this not simultaneously, but alternating
each side, so that each stroke of the foot shall produce a double
stroke of the wings.

29. The up stroke may be produced by the pressure of the
air under the wings.

30. The energy of the air pressure under the wings may be
partly stored in a spring so as to restore the power on the down
stroke, and thus produce economy in work done.

Such are the principal considerations which must be observed
in the application of the theories herein expounded. . . .

Governed by these considerations, equipped with much
preliminary experiment and analysis, Herr Lz'lz'ml/zal put
AEROPLANES. 205

his theories and conclusions to practical test, in the sum-
mer of 1891, by undertaking a series of experiments with
a pair of curved wings designed for soaring alone—that is,
to serve as sustaining surfaces and not for flapping or pro-
pulsion.

The following account of these experiments has been
furnished by Mr. George E. Curiz's, of Washington, D. C..
who has also obtained from Dr. C. Kassner, of the Mete-
orological Institute at Berlin, the very graphic photographs
from which the engravings have been made.

The Lz'lz'mt/m/ apparatus is shown in fig. 73, and con-
sists of a pair of extended bird-like wings, incurvated from
front to back on parabolic lines, and sinuous in the direc—
tion of their lengths. The area of sustaining surface, as
at. first constructed, was 107 sq. ft., but. it was diminished
in the course of numerous changes and remodellings to 86
sq. ft. There was, as will be observed, a horizontal tail
and a vertlcal rudder or keel. The framework was made
of willow, and covered with sheeting fabric. The weight
of the whole apparatus, without the operator, was 39.6
lbs.

In order to become accustomed to the management of
these artificial wings, Herr Lz‘lz'ml/zal first practised in his
garden. Here he had a spring-board, toward which he
ran for a distance of about 26 ft. ; and with the velocity
thus acquired, together with the reaction of the spring-
board, he launched himself iuto the air, where he could
learn to operate and to manage the wings.

After these preliminary experiments had given him dex—
terity and facility in the management of the apparatus, he
betook himself to a hilly region in the suburbs of Berlin,
and there practised soaring flight in natural winds of
moderate velocities. The plan, of course, consisted in
first runningragainst the wind, and thus deriving there-
from the necessary sustaining air pressure.

Having selected a hill whose downward inclination
faced the prevailing wind, he ran along the summit straight
toward the wind, until a sufficient velocity was attained
at the brow, where he was carried into the air and landed
safely at the foot of the hill, having sailed a distance of 65
t6 82 ft.

When the wind velocity became greater than II to 13
miles per hour. the management of the apparatus became
exceedingly difficult, and Herr Lz'lz'enl/za/ advises an ex-
perimenter not to venture to leave the ground under such
circumstances, unless he has attained, through long prac—
tice, a considerable degree of dexterity in manoeuvre.

The results attained in the practice of the season of
1891 were sufficiently encouraging to warrant the further
206 FLYING MACHINES.

prosecution of these experiments in the following year;
but they disclosed a number of points to which additional
attention needed to be given in order to overcomethe prac-
tical difficulties in imitating the birds. These points re-
lated to a better adjustment of the center of gravity, to
methods for obtaining greater stability, and to the mode
of management of the apparatus when the wind blew
more rapidly than II to 13 miles per hour.

 

Fm. 74.—LILIENTHAL——1892.

In the issue of the Zez'z‘sckrz’fz‘ fz‘2r Lzzf/sc/zzflhfirl for
November, 1892, Herr Lilian/m! published an article on
“ Soaring and its Imitation,” in which he gives a brief ac-
count ot his experiments in the summer of 1892, from
which the following abstract has been prepared :

Many theories have been proposed to explain soaring. My
own explanation is based upon the advantageous relations of
air resistances incident to the use of slightly curved wing sur—
faces (as I have demonstrated) and upon the gently rising trend
of air current which I have found to prevail.

A flying apparatus which has the same proportions as those
of a good soaring bird and is of sufficient size to carryfa man,
can scarcely be held fast by three or four men together when
exposed to a brisk wind. When we look at the safe and quiet
sailing of the birds, it almost seems as if some undiscovered
mechanical principle were at work, some feature in the elastic
AEROPLANES. 207

properties of air or in the elastic curvature of the feathers
which accounts for the mystery of sailing flight; but my ex-
periments have taught me that there is no mystery, and that
the same mechanical science which has explained the theory of
the steam engine and followed the orbits of the planets is ade-
quate to explaining the operations of soaring flight.

Dexterity alone, in my opinion. invests the native inhab-
itants of the air with superiority over man in that element. . . .
Inasmuch as continuous soaring with large wings in high winds
can terminate in scarcely anything but the destruction of the
foolhardy fellow who may first attempt the experiment without
previous practice, I,first undertook last year to gain some ex-
pertness with a smaller apparatus and in moderate winds. In
spite of my caution the wind several times played the mischief
With me. Even with only 86 sq. ft. of sustaining surface,I
was several times tossed up into the air by unexpected gusts of
wind, and but for the circumstance that I was able to release
myself quickly from my apparatus, I might have had a broken
neck instead of the sprains in feet or arms which always healed
in a few weeks.

Almost every Sunday, and sometimes on week days, I went
out to practise on the hill between Grosskreutz and Werder. A
mechanic, Herr Hugo Eulitz, the maker of my apparatus, went
with me, and each practised alternately while the other rested.
Thus we obtained dexterity in gliding down on the air and in
landing at the foot of the hill without mishap.

Herr Kassner, of the Meteorological Institute, was so kind
as to photograph me in the air, and has thus enabled me to ex-
hibit to the members of the society how I sailed right over the
head of the miller of Derwitz (in whose barn I stored my ap-
paratus) and of his esteemed poodle dog.

Equipped with the experience gained in I89I, I this year at-
tempted to soar with wings measuring I72 sq. ft. in surface.
My apparatus weighed 53 lbs., and my own weight is I761bs.,
so that the whole was 229 lbs. Each square foot of surface,
therefore, sustained 229 -:— I72 2 L33 lbs.

The up-thrust of the wind (the lift) upon the wing surface is
perhaps half as much as the pressure of the same wind upon
the same surface if turned perpendicular thereto.* Now, as
the apparatus therefore needs to sustain it a wind producing a
pressure of 1.33 X 2 : 2.66 lbs. per square foot, we see that
(by ordinary tables of wind pressures) it must blow at a velocity
of about 23 miles per hour.

I have, however, beenivery cautious about exposing myself
to such a Wind with this largeapparatus; and in such high
winds have used smaller surfaces for my sailing practice.

This year I selected a locality between Stegiitz and Si'rdende.
It had, however, the disadvantage that only westerly starts
were possible. Herr Kassner has again taken instantaneous
photographs of my apparatus, which have been laid before

* Lilienthal, “Der Vogelflug als Grundlage der Fliegekunst,” Tafel VII.
208 FLYING MACHINES.

the society (fig. 74). The strongest winds in which I practised
had a velocity which I estimated at between 15 and 16 miles
per hour. By running I obtained an additional velocity of 7
miles an hour, making the total relative velocity 23 miles an
hour, which was required for soaring. Under these circum-
stances the first part of my‘flight was almost horizontal, and
the alighting was always a gentle one. . . . Each apparatus
had a vertical and horizontal tail, without which it is imprac-
ticable to practice in the wind. In conclusion, I will remark
that sailing flight near the earth’s surface must be much more
difficult than at greater heights, where the wind blows more
regularly. while every irregularity of the ground at lower levels
starts whirls in the air.

In the opinion of the writer of these lines Herr [.z'lz'mt/zal
has attacked the most difficult, and perhaps the most im-
portant, of the many problems which must besolved before
success can be hoped for in navigating the air with flying
machines. He has engaged in the effort to work out the
maintenance of equilibrium in flight, and to learn the
science of the bird. He has made a good beginning, and
seems to be in a fair way to accomplish some success in
riding on the wind.

we have already seen that this has been tried before, and
that (to say nothing of ancient myths) 7. B. Danie, Paul
Gm’doz‘tz', Francisco Orujo, and Captain Le Brz's, all met
with partial success in soaring. Singularly enough all four
met also with the same accident—4.6)., a broken leg, in con-
sequence of the loss of equipoise. Herr Lz‘lz'enl/zal has
greater chances of success, not only because he seems to
have set about his experiments only after thorough investi-
gation and consideration, but also because mechanical
knowledge as well as constructive methods and workman-
ship have greatly improved since even [.6 Brz's’s time. Be-
sides this, we have the gliding explmt of M. Mouz'llard,
whose experiment has already been related, and that of
M. Adar. which is yet to be mentioned.

Most of the capable inventors who have undertaken to
solve the problem of flight have first concerned themselves
with the question of motive power, and we shall see here-
after that very great progress has been achieved in this
direction since 1890; but no amount of motive power will
avail unless the apparatus to which it is applied is stable in
the air—unless it.can rise, sail, and come down again with-
out danger of losing its equipoise. As has already been
said, safety is the first requisite, and until this is assured,
all the other elements of success will be unavailable.

Herr Lz'lz'em‘kal has eliminated for the present. the ques-
tion of motive power, by undertaking to utilize ascending
trends of wind, like asailing bird; and if he succeeds in
AEROPLANES. 209

gliding up as well as down, and to the right or left, and
m matntaining at all times the coincidence of the center
of gravity with the center of pressure at all angles of incr-
dence, he may not only apply an artificial power hereafter,
for use when great speed is required or when there is no
wind, but he will also probably have evolved a method of
gratuitous transportation through the air when the wind
blows under proper conditions ; for there seems to be no
good reason why a soaring apparatus for one man should
cost more than twice as much as a first-class bicycle, or
half as much as a city carriage; and when the wind is in
the right direction, a good many miles could be sailed
over in a day with no expenditure of force save for the
evolutions necessary to maintain the equilibrium, although
this can only be done under peculiar circumstances, and
the commercial use must be very much less than that of
bicycles.

That this expectation is not altogether absurd will ap-
pear from a brief consideration of the power of the wind ;
and to make the matter plain we will suppose it to have
an upward trend of 15° or 26 per cent. or a very moderate
inclination, which must be frequently exceeded. Under
that circumstance a horizontal aeroplane will, as pre-
viously explained, have the horizontal component of the
normal pressure directed to the front and acting as a for—
ward propelling force. We may now calculate what the
effect of this would be upon Herr [.z'lz'mz‘fzal’s aeroplane.

This was proportioned in the ratio of 0.75 sq. ft. of sur-
face to the pound of weight; but as the surfaces were
concave-convex, we may assume that the coefficient of
efficiency would be about the same as that which we have
assumed heretofore for the pigeon, or 1.3 per cent. of the
actual surface, and we may further simplify the calcula-
tions by assuming the equivalent [filam’ surface as egual
to I sq. ft. per pound to be sustained. Now if this be ex-
posed to a wind blowing at the rate of 25 miles per hour,
at which the rectangular pressure, as given by Smeaton's
table, is 3.125 lbs. per square foot, and if we suppose the
plane to be inclined forward, so as to point 5° below the
horizon, then the wind will make an angle of 10° with the
plane, at which the normal pressure, by our tables, will
be 0.337 of the rectangular pressure. As the effect upon
the plane is in the ratio of the angle which the latter
makes with the direction in which we desire to calculate
it—z'e.. the horizon, and this angle is 5°, the sine of which
is 0.087, then we have for the propelling force for each
square foot of sustaining surface :

Drift: I. X 3.125 x 0.337 X 0087 : 00916 lbs per
square foot.

14
210 FLYING MACHINES.

But as the speed is 2,200 ft. per minute, we have for the
power :

Power = 0.0916 X 2200 + 33000 = 0.00611 horse power
per square foot,

which for an apparatus with 172 sq. ft. of sustaining sur-
face furnishes a motive power of

0.00611 X 172 = 1.05 horse power,

which is the power at. the disposal of Herr Lz'lz'ml/ml
when the wind blows 25 miles per hour, with an upward
trend of 15°.

This, of course, varies with the trend and the strength
of the wind ; but it will be noticed that with the data as—
sumed it will amount to some 6 horse power for an aero-
plane with 1,000 sq. ft. of sustaining surface—an amount
which will probably be surprisingly great to those who
have not considered the subject.

It will doubtless be objected that these calculations are
all based upon the assumption that the wind has an as-
cending trend, and that this condition does not uniformly
obtain, particularly at sailing heights above the earth,
where the wind may be horizontal at the very time that
experiment shows an ascending trend near the surface.
This is granted; it is acknowleged that the calculations
of power to be obtained from the wind are predicated
upon an assumption which may be untrue part of the
time; but the answer to the main objection is that Z/ze
birds soar at all limes when there is wind enough (not
too much), and that while we cannot yet explain how they
do it, man ought to be able to avail himself of the same
circumstances as the birds, if only he can maintain his
equilibrium.

This is what Herr Lz'lz'mMaZ has undertaken ; he has
done so with great prudence and good sense, and so far
as the results of his experiments have been published they
teach several valuable lessons, which may be summed up
as follows :

1. The upright position for the body of the aviator is the
most favorable, as being most natural to man.

2. Safety while learning the management of an appa-
ratus is promoted by beginning with comparatively small
surfaces, because wind gusts are liable to destroy the
balance. It is best to glide downward in initial experi-
ments until practice has conferred the skill requisite to
maintain the equilibrium, in case the apparatus is tossed up
in the air by the wind. This is a lesson which was not
obvious, and it should be heeded by experimenters, some
of whom have assumed that safety was best promoted by
large surfaces.
AEROPLANES. 2 I I

3. The aviator must be so affixed to his apparatus that
he can detach himself instantly should the machine take a
sheer.

4. It is not safe to experiment in winds blowing more
than 23 miles per hour until sk1ll has been acquired in the
management of the apparatus, or until the latter has been
so improved as to minimize the danger.

5. It seems now reasonably possible for designers of
soaring machines (and the writer knows several) to ex-
periment with their apparatus without further search for
some hidden secret, for Herr Lz'lz'ml/zal says that his ex—
periments have taught him that there 15 no mystery about
sailing flight; that the wind is sufficient to account for it.
Inventors need not look for some new mysterious force,
some “negative gravity,"* like that in Mr. Stockton's
tale, to take them up into the air; nor need they be afraid
that if they propose to experiment with soaring machines
they will be considered lunatics. The main question for
them to consider is that of the equilibrium.

Of course, even if this be worked out, the practical use—
fulness of a soaring machine would be very limited. It
could only be availed of when the wind blew with about
the favorable velocity (neither too slow nor too fast), and
its field of daily use would probably be limited to the
trade wind latitudes, or, in other words, to those regions
inhabited by the sailing birds; but if the equipoise be
worked out, if man succeeds in devising an adequate soar-
ing apparatus and in learning how to use it, unhampered
by the necessity for looking after a motor at the same
time, it will not probably be long before some motor is
added to confer upon him command of space at all times.

In June, 1891, the quidnuncs 1n Paris were interested in
the rumored success of some experiments with a flying
machine carried on near Paris, in the private park of Mr.
E. Pereire, the banker, by M. Clemem‘ Adar, who was

* One theorist expounds his ideas as follows : “One point I have studied
and that is, How can a twenty pound wild goose carry itself so easily ?
\Veigh every feather you can pick off from a wild goose and they will not
weigh one pound. Now if the feathers be picked off from the goose he can
come no nearer flying than we can.

“ So there we have it clearly demonstrated that one pound of goose feathers
can pickup nineteen pounds of goose and carry this nineteen pounds and its
on?2 pound of feathers through space at about half a mile a minute if in a
a urry.

Now my theory 1s this and it applies to all birds. Notice any bird when
he suddenly starts to fly and you will notice a lightning-like quiver of his
feathers I believe that this quiver causes the production ofa negative force
of magnetism, or some kind of force which pushes the bird from the earth—-
just the reverse of the loadstone. He then has only to use his wings to propel
the body, for the magnetic negative earth- force does the lifting and that IS
all produced by the feathers. If it were not, then the bird ought to fly when
divested of his feathers. ’1 his is the force which should be looked for; who-
ever discovers it will make a fortune.”
212 FLYING MACHINES

said to have succeeded in rising to a height of about 60 ft.,
and in flying a distance variously e5timated at 100 to
400 yds.

M. Adar is a well-known French electrician, the inven—
tor of a telephone, and has long been interested in the
flying—machine problem. In 1872 he constructed an arti—
ficial bird 26 ft. across and weighing some 53 lbs., with
beating wings actuated by the muscular force of the oper-
ator's legs, aided by elastic auxiliary pectorals. In high
winds, and restrained by ropes in order to guard against
accidents, it would lift up a man, but it was found, as
many times before, that man has not the requisite energy
to sustain his weight in calm air. Subsequently the same
apparatus, or a modification of it (for the accounts are
not quite clear), was set up under a shed at Passy, and
visited by M. (2’6 [a Landelle,* who states that the operator
was stretched horizontally (a bad position) between the
wings. and worked with his feet and hands the organism
of transmission to the parts that acted upon the air. A
certain lifting effect was produced, but not enough to sus-
tain the whole weight. This apparatus was never photo-
graphed, but its inventor now contemplates unboxmg it
and setting it up again as a curiosity.

In 1891, as already mentioned, M. Adar built another
artificial bird 54 ft. across, with which he experimented in
the open air with such close privacy as he could secure ;
but the details are being kept secret, as the inventor states
that he believes that it is destined to play an important
part in the national defense of his country. He merely
mentions the fact that the motor and the man who works
it are placed in the interior of the machine, which is shaped
like a huge bat; that the motor is actuated by a “ mixture
of a combination of vapors," and that the instrument of
propulsion is a screw (of which he tried some eight pat-
terns) placed at the head ; that the whole apparatus rests
upon skates or upon wheels, and that he needs a long
smooth, flat space to gather headway by sliding or rolling
some 20 or 30 yds. or more. He stated that he had
already expended some $120,000 in his aerial experiments
during the 15 years that he had been working at the prob-
lem, and that he contemplated exhibiting his machine in
the air, if he could secure the use of the great machinery
hall built for the Paris Exposition of 1889.

The above data are extracted from an account of an in-
terview with M. Adar, published in the Paris Tam/)3 of
July 9, I891, in which he gave an interesting account of
tie preliminary studies that led to his last conception, the

* Dans les airs, G. de la Landelle, pp. 236, 237.
AEROPLANES. 2 13

result, as he says, of a private theory of the resistances of
air, which he proposes to publish some day.

Moved, probably, by the accounts of the sailing of large
birds published by M. Maui/lard as witnessed by him in
Africa, M. Adar first obtained from the‘zoéilogical gardens
some eagles and some large bats, and observed their flight
in his workshop. Judging this to be insufficient, he next
went to Algeria, but could find none of the large vultures
near Constantine; so, disguising himself as an Arab, he
went into the interior with two Arab guides, and by en—
ticing the birds with pieces of meat left in secluded places,
he succeeded in obtaining ample observations.

M. Adar states that he became fully convinced that
these vultures, some of them measuring IO ft. across, do
not beat their wings when rising on the air; that they
flap them at most two or three times when first rising
from the ground, and then hold them rigidly spread out
to the cuirent of wind upon which they ride, and upon
which they rise in great circling sweeps by merely adjust-
ing their aeroplane to the varying conditions of incidence
and force of wind.

Starting from his theory and observations, M. Adar next
built the machine which he has been experimenting with
near Paris, in the presence, it is said, of only three or four
persons, and with many precautions to aVOid divulging
his secret. He has even announced that he intends, from
patriotic motives, to take no patents in foreign countries,
so as not to divulge the design of his apparatus, and that
all he can say at present is that the problem is an exceed-
ingly difficult one, involving enormous mechanical diffi—
culties, which increase rapidly with the size of the appa-
ratus.

Naturally this reticence excited curiosity, and the French
paper L‘fllustraz‘z'on, in its issue of june 20, 189t, pub-
lished a picture from which fig. 75 is reproduced, and it
also made the following comments :

 

FIG. 75.——ADER-—189t.
2 r4 FLYING MACHINES.

Nobody has seen anything, nobody knows anything, but
L’l/[ustratz'on has its friends everywhere. One of them was
hunting lately in the environs of Paris, when he caught a
glimpse through the leaves of a strange object resembling an
enormous birJ of bluish hue. It was impossible to approach
close to it; an enclosure surrounded the private park shut in
by the forest in which the aforesaid machine was situated.
Assuredly it could only be a flying machine. Our friend is
something of a limner as well as an engineer, and he communi-
cates to us the sketch which he made from a distance, and
which is as correct as it was practicable to make it. Upon
making due inquiry it turns out to be the invention of M. Adar,
the electrician, well known for his telephone apparatus, and it
seems that the machine has really flown several hundred yards,
rising some 50 to 65 ft., and holding a course through
Spice. . .

The name of the inventor of this machine should be a guar~
antee of its possible success; still we have our doubts. It is
said to have glided a certain distance in the air—100 or 200, or,
say, 400 yds But can it continue to do so for several hours,
Without hiving recourse to some fixed supply of power to re-
charge the motor actuating it? For this is the vital point:
what is the motor? As the inventor is an eminent electrician,
thoroughly understanding this new science, he must have
selected his favorite motor, the dynamo.

But electric accumulators are impracticable on account of
their weight, while primary batteries act for only a short time,
and they, too, are heavy.

Therefore, for the present, and until we have witnessed a
convincing experiment, at which we shall have seen with our
own eyes the generator of the power employed, we shall re-
main skeptics, and we shall believe (and this only because of
the high scientific standing of the inventor) that if the machine
sketched by our friend can really fly, it is only for a very brief
period of time.

In point of fact, it is surmised by the writer of these
lines that M. Adar has really been experimenting with a
soaring machine, using a motor only to get under way,
and (if the sketch of the apparatus is correct) that the
principal difficulty he has met with has been to maintain
the equilibrium. He may have had a few good flights
under favorable circumstances, but he must have had
many mishaps.

It is probable that one of his errors lies in adopting too
large a sustaining surface, under the mistaken belief that
this would promote safety. It would probably do just the
reverse, by enabling little wind gusts and ground currents
to upset the equipoise. The machine is 54 ft. across, and
must spread to the breeze twice the surface employed by
Herr Lz'lz'eizl/zal, which we have already seen is found by
the latter to be dangerous in winds of more than 23 miles

per hour.
AEROPLANES. 2 15

In August, 1891, M. Tram/é, whose mechanical bird
with flapping wmgs actuated by explosions within a Bour—
don tube, and whose hovering screw machine, worked by
a dynamo connected by a wire to a source of electrical
energy remaining on the ground, have already been no-
ticed, deposited with the French Academy of Sciences a
sealed letter, containing descriptions and drawings of an
aeroplane, which he believes to be, destined to solve suc-
cessfully the problem of aerial navigation.

This method of depositing sealed descriptions of in-
choate inventions with the Academy of Sciences is a favor—
ite one in France, and answers generally much as the filing
of a caveat does in the United States.

Nothing is known. of course, concerning the designs for
this aeroplane, but. M. Tram/é says that. he has made great
strides toward developing his aerial apparatus since 1870,
and especially since 1884 ; that his laboratory experiments
have convinced him that while his explosion motor is sat-
isfactory as to the power exerted in proportion to weight,
wings are less efficient than screws as instruments of pro-
pulsion. He has therefore designed an aeroplane pro-
pelled by two screws, rotating in contrary directions,
which he believes to be superior to the former arrange-
ment of beating wings.

The arrangement of this aeroplane is said to be such
that the surface may always be proportioned to the weight
to he carried, no matter what that weight may be.

The method of obtaining initial velocity is ingenious and
effective. The apparatus is to be placed upon a railway
car, and this is to be towed by a locomotive upon an ordi-
nary railway, until the speed is sufficient to furnish the
required reactive support from the air; when, the machine
rises, and is thenceforth supported by its sustaining sur-
faces, driven by the two screws moved by the explosion
motor.

M. Tram/é believes that success is now a simple ques-
tion of money expenditure, and that the daring man,
favored by fortune, who first navigates the air will reap
the glory of that success with less title thereto than his
predecessors, who have pointed out the way.

In 189t Gustav KOC/Z, an aeronaut of Munich, published
a pamphlet entitled “ Free Human Flying, as the Pre—
liminary Condition of Dynamic Aeronautics,” * which
contains the plan and description of an apparatus designed
by him, in order to endeavor to imitate the soaring of
the birds, and which also gives an account of the experi-
ments which he had tried with models. This design has

* Der freie Menschliche Flug, als Vorbedingung dynamischer Luftschif—
fahrt. Miinchen, 1891.
216 FLYING MACHINES.

been thought worthy of trial, and the Bavarian Ministers
of the interior and of Education in May, 1893, granted
1,600 marks ($400) to Herr Kat/z to enable him to make
experiments. This he is about to do (with an assistant)
over the lake of Constance near Lindau, and while the
results may not prove satisfactory, they cannot but prove
interesting.

The aeroplane designed by Herr Koc/z consists in a pair
of rigid wings, approximately shaped like those of the
dragon fly, each about 27 ft. long and 6 ft. broad, back of
which there is a triangular tail, some 7 ft. long and about
8 ft. wide at the rear end. The wings are to be constructed
of bamboo, covered with unbleached silk slightly oiled,
and pivoted to the back of the operator. The latter is to
lie horizontally, face downward, in a sort of hammock
suspended from a frame which attaches to the wings, and
the latter can thus be swung forward or back within small
limits, so as to change their position with respect to the
center of gravity, but they have no flapping aetion what-
ever. The operator is to swing the wings and to elevate
or depress the tall by means of pedals on which his feet
rest, and of lines leading to his hands.

It will thus be seen that the action of the apparatus,
which is some 57 ft. across, consists in altering the posi-
tion of the center of pressure, with respect to the center
of gravity, by swinging the wings forward or back, and
thus changing the angle of inc1dence which the apparatus
makes with the course, while still further changes can be
produced by the action of the tail.

The weight of the aeroplane. including the mechanism
which works it, is estimated at 99 lbs., and that of the
operator at 176 lbs., making a total of 275 lbs., to be sus-
tained by about 325 sq. ft. of surface.

Herr Kat/z proposes to test the apparatus by taking it
up beneath a balloon and cutting it loose when about
3,000 ft. in the air. The first experiments, of course, are
to be tried with a dummy instead of a man, and if these
indicate sufficient strength and stability, the operator is to
take the place of the dummy. He expects the machine to
descend like a stone for the first second or two, and then,
when air pressure has gathered under the wings, to grad—
ually right itself, and to glide downward upon an easy
slope, which would bring it down to the water in about
8 minutes and a distance of some 2% miles. thus being a
dirigible parachute. Meanwhile, however, the operator
is expected to bring the apparatus under control; b
swinging the wings forward he expects to tilt the planes
so as to glide upward again, by virtue of the acquired
momentum, and by movements of the tail and of his own
AEROPLANES. 2 17

body, which has a certain latitude of motion in the ham-
mock, he expects to tack and to sail upon the wind like a
soaring bird, sweeping in circles or making a series of
zigzag glances, during which elevation might be gained
by utilizing the force of the wind.

Such is the scheme; it is not wholly devoid of merit.
because the soaring birds perform those very manoeuvres,
and they do it much in the way which Herr [for]; has indi—
cated, but it may be questioned whether his apparatus is
properly designed to accomplish the results desired. In
the first place, the sustaining surface and the spread
across are too great, and will terribly strain the strength
of materials. It would be better to shorten the wings and
to make them broader in order to reduce the length of
leverage. In the second place, the horizontal position
selected for the operator, probably to reduce horizontal
resistance, is decidedly bad, because it is unnatural to
man, and gives him inadequate control over the appa—
ratus. The man should be placed vertically, and instead
of manoevring, as planned, to cause the back part of the
tail to strike the ground first and roll along, while the
aeroplane settles forward slowly, the operator should
alight on his feet and stop his impetus while running it he
alights on land. In the third place, the mode of experi—
menting proposed is exceedingly dangerous. Herr [(06];
says, quite properly, that the first step toward success in
artificial flight consists in acquiring the skill to manage
an apparatus, but until that skill has been acquired it will
evidently be little short of suicide to cut himself loose high
in air, even if over a bed of water.

Perhaps, however, these various elements of failure have
already been eliminated. The design was published in
1259!, and may by this time have been so remodelled as to
lead, not to an absolute success, for this is not to be ex-
pected, but to such partial control over the apparatus as
to warrant further experiments.

In the Cosmopolitan Magazine for November, 1892,
and in Carrier’s Magazine for February, 1893, appeared
two analytic articles by M. f P. Holland, in which he
takes the ground that mechanical flight has already been
proved to be attainable, that what remains to be done is
merely to combine things already tried and proved by
other experimenters; and in which articles he advances
three proposals or designs for flying machines.

In the Cosmopolitan article M. Holland proposes to
place two aerial screws, superposed and rotating in con-
trary directions, above a spindle-shaped body containing
the machinery, with a pair of wings or aeroplanes at—
tached. This may be termed his first design, as indicated
2 r8 FLYING MACHINES.

by his figs. 2, 3 and 4. In his second design the spindle
and the superposed screws are retained, but the support-
ing surface consists of 10 narrow, superposed, concavo-
convex aeroplanes, somewhat like a Venetian blind, and
they as well as the screws are mounted upon a frame
pivoted to the spindle-shaped body, so that the screws
may first be used to raise the apparatus from the ground,
and then to drive it forward when the frame is raised to
the vertical; support being then derived from the aero-
planes. This is indicated in M. Holland's figs. 5, 6 and 7.

In the Cassier’s Magazine article the design is further
modified by placing the aerial screws side by side in the
frame instead of superposing them. The superposed aero-
planes are retained, but the number is increased to 16,
and the mode of operation is much the same.

The design is somewhat similar to that which Mr. P/zz'l—
lips experimented in England, which was illustrated in
Engineering of May 5, 1893, but is an improvement upon
the latter design in the provision for pivoting the Vene-
tian-blind aeroplanes to the body, and in the employment
of two screws instead of one for the propelling instrument.

If there be one man, more than another, who deserves
to succeed in flying through the air, that man is Mr.
Laurence Hargra'z/e, of Sydney, New South Wales. He
has now constructed with his own hands no less than 18
flying machines of increasing size, all of which fly, and as
a result of his many experiments (of which ,an account is
about to be given) he now says, in a private letter to the
writer, that: “ I know that success is dead sure to come.”

M. Hargrave takes out no patents for any of his aerial
inventions, and he publishes from time to time full ac-
counts of them, in order that a mutual interchange of
ideas may take place with other inventors working in the
same field, so as to expedite joint progress. He says:
“ Workers must root out the idea that by keeping the re-
sults of their labors to themselves a fortune will be assured
to them. Patent fees are so much wasted money. The
flying machine of the future will not be born fully fledged
and capable of a flight for 1.000 miles or so. Like every-
thing else it must be evolved gradually. The first diffi-
culty is to get a thing that will fly at all. When this is
made, a full description should be published as an aid to
others. Excellence of design and workmanship will
always defy competition.”

M. Hargrave is probably correct in his reasoning ; for
the history of all new methods of transportation teaches
that the original inventor seldom receives pecuniary re-
ward for the contrivance which is the first to succeed, but
nevertheless be is certainly broadly liberal in giving to
AEROPLANES. 2 19

the world gratuitously the results of his constant studies
and labors. He uses exceeding care in determining the
diflerent elements which compose the flight of his models.
He has carefully registered the stzes of all the parts, the
power consumed in each performance, and the length of
the flight, together With its trajectory. He states that. he
has always kept his work in such shape that it could be
taken up and continued by any person at any time; so
that a stranger, if an expert, could come into his shop,
study his notes and drawings, pick up his tools and
continue his work, and thus no portion of it would be
lost.

M. Hargra'Z/e reports regularly the progress of his work
to the Royal Society of New South Wales, of which he is
a member. Thus far 13 such papers have been published,
the latest having been read June 7, 1893.

He first devoted his attention to the motions performed
by the propelling surfaces of birds and fishes, the waves
which these created in the fluids on which they acted, and
the counteraction of these waves upon the forms of the
propelling surfaces themselves. The first paper, there—
fore, presented in August, 1884, was on the Troc/zoz‘dea’
plane, which M. Hargrave defines as “ a flat surface, the
center of which moves at a uniform speed in a circle, the
plane being kept normal to the surface of a trochoidal
wave, having a period equal to the time occupied by the
center of the plane in completing one revolution." This
was illustrated by working models, and the motions of
wings and of fishes in swimming were artificially repro-
duced.

Starting from these data, M. Hargrave next experi—
mented with nearly 50 models intended to reproduce hori-
zontal flight, and in exhibiting some of these and reading
his second paper. June, 1885, he said: ” If the motion is
not that used by birds, it is at all events very like it, and
its acceptance or rejection as a scientific truth is of no
further interest, as it only remains for practical mechanics
to step in and adjust the details to suit the material and
the motive power which they may think best for the pur-
pose they have in View ; or, in other words, that the solu-
tion of the problem of just how a bird flies is of very trifling
importance from a practical standpomt. as compared with
the judicious variations of the parts of the machine that.
will have to be made before any return can he expected
for money invested in such undertakings."

Some of these models seem to have been driven by
clock-work, and the motions were those of the “ trochoided
planes." as applied to flapping wings; then selecting the
best of these models, and making their mean dimensions
220 FLYING MACHINES.

a standard from which to take a fresh departure, M. Har-
grave next built a series of experimental flying machines,
actuated by india~rubber in tension.

The French experimenters, as we have seen, have pre-
ferred to use rubber in torsion in order to diminish the
strains upon the central spine or backbone of the model,
but they thus obtained less energy per pound of weight
than if they had used it in tension. M. Hargrave stretched
the rubber so that its elongation was multiplied by pulley-
tackle, and that, as the rubber contracted, its center of
gravity moved forward, thus advancing the center of
gravity of the entire machine, and consequently diminish—
ing the angle of flight as the force of the rubber decreased.

No less than 10 different flying machines of various types
were thus built and experimented with, all moved by rub—
ber in tension. In the first models the cord proceeding
from the rubber was wound around a cylindrical drum on
the crank-shaft, but owing to the variable resistance nat-
ural to a crank-shaft, it was found better to replace the
cylindrical drum by a flat winder, so adjusted on the shalt
that the moment of the cord varied with the resistance of
the crank, and thus communicated a more uniform move-
ment to the wings.

Seven of these machines seem to have been propelled
by flapping wings—z’.e., “ trochoided planes”—but in
order that a comparison might be made, three varieties of
models were made with screw propulsion—namely, with
double and with single screws in the bow, and with a
single screw in the stern, which latter was concluded to
be the most practicable and serviceable form.

From these experiments M. Hargrave concluded that
the screw and the flapping wings are about equally effec-
tive as instruments of propulsion, although he rather pre-
fers the latter, as the wings possess several marked advan-
tages. Any currents, he says, initiated during the up-
stroke are utilized in giving increased efficiency to the
down-stroke, if the machine has not progressed far enough
to be acting upon entirely undisturbed air. Moreover,
when steam-engines come to be used, there will be only
one cylinder needed for both wings, there will be no con-
version of reciprocating into rotary motion, and no vari-
able listing moment to be counteracted, while. finally,
there is less liability that wings shall be damaged in
alighting than screw blades.

Fig. 76 shows the last one (1889‘) of the india-rubber
driven machines described by M. Hzzrgrave. He calls it
the “ 48 band-screw." The screw is at the stern, and the
machine weighs exactly 2 lbs. Its sustaining area is x4.51
sq. ft. (7.26 sq. ft. per pound), and it flew 120 lineal feet
AEROPLANES. 221

with the expenditure of 196 foot—pounds of energy, while
the preceding machine, weighing 2.09 lbs., with flapping
wings, had flown 270 ft. with 470 loot-pounds, thus show-
ing respectively 0.61 and 0.57 lineal feet flown per foot-
pounds of power.

The framework of these machines was of pine, the larger
piece (main spine) being a hollow box-girder, to secure
strength and lightness. The sustaining surfaces were of
paper, pasted on, and after the gum was dry rendered as
tight as a drum by blowing a light spray of water over the
paper and allowing it to dry. Thus with small, light,
simple, and inexpensive models many experiments were
made. and great advance realized in the distance flown
over any previous experiments of others.

 

Fm. 76.~HARGRAVE~1889.

Having progressed thus far with india-rubber as a mo-
tive power, and gathered most valuable data and experi-
ence : as to the best arrangement and proportion of parts,
the equipoise and the power required, M. Hczrgraz’e next
undertook the construction of a flying machine actuated
by compressed air, and, in 1890, he produced the machine
illustrated by fig. 77, Which he calls his “ No. 10, 4045 02.
compressed air,” and which marked a very considerable
advance in design by a great simplification of the propel-
ling arrangement.

In presenting it to the Royal Society, June 4, 1890, M.
Hargrave said :

The principle embodied in this experiment is that of Borelli,
222 FLYING MACHINES.

published in I680, and it doubtless has had many stanch advo-
cates in later times; but the writer maintains that this is the
first practical demonstration that a machine can and does fly by
the simple (vertical) flapping of wings ; the feathering, tilting,
twisting, trochoiding, or whatever it may be called, being solely
effected by torsional stress on the wing arms.

The combination of Borelli’s views with the results of work
recorded in your proceedings (Royal Society) has swept away
such a mass of tackle from the machine that its construction
becomes a ridiculously simple matter. The engine of the
model, of course, retains its precedence as the most important
part, and by continuous effort the number of pieces and the
difficulties of construction have been so reduced that it is pos-
sible to make them by the gross at a cost that cannot exceed
five shillings each ($I.25). For instance, the cylinder, usually
the most expensive portion of an engine, can be produced with
the ease and celerity of a tin can. . .

It might be said that this flying machine is not on the principle
enunciated by Borelli, because the wings are not continuous
from their tip to the body. But this arrangement is only a de-
vice to enable the wing tips to act on the required quantity of
air with less spread ; it may possibly be one of those variations
which make all the difference between success and failure.
These wings are also distinctly double-acting, and it is not
quite clear that birds’ wings thrust during the up-stroke; but,
as previously stated, the question as to the exact movement of
a bird’s wing is merely straw-splitting, when Wt: have a mech-
anism that actually flies and is manifestly imperfect in its pres-
ent mechanical details.

This machine flew 368 ft., with the expenditure (as cor-
rected by M. Hargmve) of 870 foot-pounds of energy. It
weighed 2.53 lbs., and the sustaining body plane measured
14.78 sq. ft., while the two wings measured 1.50 sq. ft. in
area, making a total of 16.28 sq. ft., or, say, 6 43 sq. ft.
per pound.

London Engineering, in its issue of December 26, 1890,
gives the following description of the machine:

The compressed air is stored in a tube which forms the back-
bone of the whole construction. This tube is 2 in. in diameter,
48$ in. long, and has a capacity of 144.6 cub. in. Its weight is
19.5 02., and the working pressure is 230 lbs. per square inch.
The engine cylinder has a diameter of 1% in. and a stroke of
1:1- in.. while the total weight of the engine is only 6% oz. The
piston‘rod is made fast to the end of the backbone, and the
cylinder moves up and down over the piston. Two links con-
nect the cylinder to the Canadian red pine rods which carry the
wings. The air is admitted to the cylinder and exhausted by
means of a valve worked by tappets. The period of admission
continues through the entire stroke. The cylinder and receiver
ends are pressed, and the piston is made of vulcanite, with a
leather cup ring for packing.
AEROPLANES. 2 2 3

The wings are made of paper, and have no canting or leather-
ing motion other than that due to the springing of the material
of which they are made. The weight of the wings is 3 02. To
find how much the wings deflected. one was held by the butt
and a weight of 7% oz. was put on the membrane 24 in. from
the fixed point, and 1% in. abaft the wing arm. The deflection
produced, due to torsional stress, was 31?. By moving the
weight half way across the wing it was twisted 8%). The area
of the body is 2.I28 sq in.; the area of the wings 216 sq. in.,
and the total area 2.344 sq. in.

When first made, the machine had its center of gravity so
placed that the percentage of area in advance of it was 30 per
cent. of the whole area, but continued disaster caused its reduc-
tion to 23.3 per cent. In a dead calm the machine flew 368 ft.
horizontally.

It will be noted that the engine is a marvel of simplicity
and lightness. Its cylinder is made like a common tin can,
the cylinder covers are cut from sheet tin and pressed into

 

 

FIG, 77.——HARGRAVE, No. 10—1890.

shape in a vice, the piston and junk-ring are made of vul-
canlte, and the cup leather packing does away with the
necessity for the cylinder being either round or parallel.

Beside the engine. a marked advance consisted in secur-
ing the torsion of the wings through no special mechan—
ism, as formerly, but simply by the elasticity of the mate-
rial composing them. This throws a new light upon the
part performed in the flight of birds by the elasticity of
their feathers, and promises great simplicity and efficiency
in the future designing of artificial wings.

By looking at the figure, a bowsprit will be noticed.
This was a so-called safety stick, which was added to
break the fall of the machine when alighting, and it has
proved quite successful in accomplishing that object.

A noticeable feature of this and subsequent machines
exhibited by M. Hargra'z/e consists in the extraordinary
length of its supporting body plane. The same surface
224 FLYING MACHINES.

would carry a far greater load if it were driven broadside
instead of lengthwxse ; but M. Hargrat/e explains that the
plane was purposely so designed in order to insure longi-
tudinal stability. This quality might also be secured by
placing a tail far in the rear ot a narrow supporting plane,
as practiced by Pénaua’ and others. He states, moreover,
that the plane is rendered more effective per unit of sur—
face by being cut away in the middle portion, or by being
formed in two parts, separated by a gap.

As regards the lateral equilibrium, he seems to have
met with but little difficulty; a slight diedral angle of the
two halves of the body plane with each other providing
the necessary stability, and preventing any swerving, so
long as the center of gravity was at all below the center
of effort; but he had great trouble in working out the
longitudinal stability. This he did upon the “ cut and try”
principle~a method doubtless the most thorough, the
surest, and the‘most convincing, but also the most tedious.
He found that the direction up or down of the machines
in flight was entirely due to the distance of the center of
gravrty from the forward edge of the body plane. and
therefore to the coincidence or otherwise of the center of
gravity with the center of pressure. He measured the
percentage of area in advance of the center of gravity in
his three most successful machines, and found it respec-
tively 19.3, 20 and 23 3 per cent. of the length of the plane,
while subsequently he came to the general conclusion that
the true p051tion for the center of gravity for a continuous
rectangular surface is situated between 0.25 and 0.2 of the
length from the forward end, these positions being arrived
at " by experience gained by repeated wrecks when grop-
ing in comparative darkness."

This independent working out of a complex question
well illustrates the perseverance and ingenuity of this ex-
perimenter. At this juncture, however, he would have
been saved much groping. time, and annoyance had he
been aware of the formula of Joesse‘l for determining the
center of pressure :

C = (0.2 + 0.3 sin. a) L,

in which Cis the distance from the forward edge of a rec-
tangular plane to its center of pressure, when inclined at
the angle of incidence a with the course, and L is the
length of the plane along the line of motion.

In the same year (1890) M. Hargra'z/e built another fly-
ing machine, actuated by compressed air and propelled
by beating wings. This is shown by fig. 78. It was of
the increased weight of 4.63 lbs., with sustaining body
plane of different shape, measuring 2963 sq. ft., or in the
AEROPLANES. _ 225

proportion of 640 sq ft. per pound. It flew 343 ft., with
an expenditure of 789 foot-pounds of energy, and there-
fore showed better results than the preVious machine
(N0. 10), inasmuch as more pounds were transported on
the air approximately the satne distance, with a somewhat
smaller expend ture of energy.

Having apparently found some advantage by shortening
the body plane,M. Hargrave next built his flying machine
N0. 13, which 5 shown in fig. 79, with a body plane still
shorter, and he provided it with a two—bladed aerial screw,
set in the bow and actuated by a three-cylinder com-
pressed-air engine of the Brotherhood type. This drox'e
it 128 ft. in eight seconds, with an expenditure of I43 foot-
pounds of energy. The apparatus weighed 46.86 oz. (293
lbs), and exposed 2,952 sq. in. or 20.5 ft. of floating sur-
face, being in the ratio of 7.00 sq. ft. per pound.

 

FIG. 78.—HARGRAVE, No. 12~1890.

This is the first time (paper 10, July I, 1891) that M.
Hargrar/e gives us the time of flight of his machines, so
that we may calculate the number of pounds of weight
transported in ratio to the horse power. He says :

The time of flight is taken with a sandglass which has a locp
of string at each end of it. The loop at the sand end is pLt
round the right wrist, and the other loop is held between the
right thumb and the receiver, so that the glass is turned the
moment that the machine is let go. On the machine taking
the ground the glass is put horizontal, and the sand which has
fallen is timed at leisure. This seems an obvious enough
method of finding the speed, but a practical way to do it was
not devised previously.

This showed for No. I3 machine a speed of 10.34 miles
per hour, which is about what we should have expected
from the large proportional surface, it being about in the
ratio of the slowest flying birds. This low speed M. Har-

I5
226 FLYING MACHINES.

grave adopts on purpose, the better to observe the mo“
tions of the machines and to save breakage. and he adds
quaintly that he sees no objection to this course, so long
as the atmosphere is not crowded with flying machines.
As No. 13 machine (fig. 79) is reported as having expended
I43 foot-pounds in eight seconds, we have :

Power = 143 + 8 = 18 foot-pounds per second,

nearly, and, as it weighed (as reported) 2.93 lbs., we have
for the weight sustained per horse power :

2.93 X 550 + 18 = 89.53 lbs. per horse power;

while it will be recollected that M. Talz'n sustained 110
lbs. per horse power and that M. Phillips in his recent
(1893) experiments floated 72 lbs. per horse power. We
Will see by the analysis of subsequent performances that
M. Hargrave did not obtain quite as good results with
subsequent flying machines.

He next built his No. 14 flying machine. with much the
same shape of body surface, but propelled by beating
wings instead of a screw. It weighed 369 lbs. and ex-
posed 22.84 sq. ft. of surface, being in the proportion of
619 sq. ft. per pound. It flew 312 ft. in 19 seconds, with
an expenditure of 509 foot-pounds, and thus we have :

Power = 509 —:- 19 = 26.79 foot- pounds per second,
and for the weight floated per horse power :
3.69 x 550 + 26.79 = 75.75 lbs. per horse power.

This apparatus (No. 14) M. Hargrave has generously
offered to present to some American institution which will
take proper care of it, believing it to be one in which “ the
increased skill in construction acquired by practice is
thought to have resulted in an apparatus that, for its
weight, it will be hard to excel.” He says in his paper to
the Royal Society :

It may be said that it is a waste of time to make machines
of such small capabilities, and that no practical good can come
of them. But we must not try too much at first ; we must re-
member that all our inventions are but developments of crude
ideas; that a commercially successful result in a practically
unexplored field cannot possibly be got without an enormous
amount of unremunerative work. It is the piled-up and re
corded experience of many busy-brains that has produced the
luxurious travelling conveniences of to-day, which in no way
astonish us, and there is no good reason for supposing that we
shall always be content to keep on the agitated surface of the
sea and air, when it is possible to travel in a superior plane,
unimpeded by frictional disturbances.
AEROPLANES. 227

No 16 was another compressed-air flying machine with
beating wings and somewhat differently shaped body
plane. It weighed 4.66 lbs., spread 26.06 sq. ft. of sur-
face, and flew 343 ft. in 23 seconds, with an expenditure
of 742 foot-pounds. The power was therefore :

Power = 742 -:— 23 = 32.26 foot-pounds per second,
and the weight floated per horse power:
4.66 x 550 —:— 32.26 = 79.45 lbs. per horse power.

Several forms of body plane seem to have been tested in
this machine and no less than 12 trials were recorded, trial
No. 10 being the successful one, from which the above
data have been taken.

Having now constructed to flying machines of different
types and proportions actuated by india-rubher in tension,
and six actuated by compressed air, of increasing size and
weight, M. Hargrar/e then turned his attention to produc-

 

 

FIG. 7g.—HARGRAVE, No. 13—1891.

ing a steam motor which should equal in lightness and
surpass in power the best compressed-air motors thus far
constructed by him, and which should furnish driving
power for a longer time.

But first he endeavored to work out an idea which he
seems to have entertained for some years, of testing an
explosion motor. His engine No. 15 consisted of a turbine
to be worked by the gases resulting from the explosion of
a mixture of nitrate of ammonia. charcoal, and sulphur ;
but a considerable expenditure of time only resulted in a
failure.

He also experimented upon a method of utilizing sea
228 FLYING MACHINES.

waves in propelling vessels, which he believes to be the
germ of the solution of the soaring problem, and he suc-
ceeded in securing such automatic action that a 12% lb.
mode advanced in the wind’s eye at tive-eighths ot a mile
per hour.

He also made some experiments upon pure aluminium,
but found that it presented no advantages for flying-
machine construction.

No. 17 flying machine of M. Hargrave is described in
his twelfth communication to the Royal Society of New
South Wales, read August 3, 1892. The total weight of
the apparatus is 64.5 02, or 4.03 lbs., including 12?; oz.
for the strut and body plane, so that the engine and boiler,
including 5 oz. for spirit fuel and water, weighs 3.25 lbs.,
and develops 0.169 horse power, or at the rate of I H. P.
per 19.2 lbs.—a very remarkable achievement.

The boiler is of the “ Serpollet" type, made of 12 lineal
feet of i in. copper tubing (sieel pipe could not be got in
Sydney), in the form of a double-stranded coil, encased in
asbestos, and placed just over the backbone of the appa-
ratus. The fuel is methylated spirits of Wine, drawn from
a tank placed above the bOiler, vaporized, mixed With air
and spurted into the furnace. As much as 6.9 cub. in. of
water have been evaporated by 1.7 cub. in. of spirit in 80
seconds, making 182 double vibrations of the propelling
wings, say, 235 per second, and developing 0.169 horse
power.

It was estimated that if the apparatus were loaded with
10 02. more of spirit and water, and thus made to weigh
the same as the compressed-air machine No. 12, which
flew 343 ft., then the steam apparatus No. 17 would pos-
sess a sufficient store of energy to fly 1,640 yds., or nearly
I mile.

But M. Hargrcwe has done still better, for in March,
1893, he prepared a paper, which was presented to the
Conference on Aerial Navigation at Chicago, August 2,
1893, in which he gave data concerning his N0. 18 flying
machine. This apparatus is also driven by a steam-engine
which weighs. with 21 oz. of fuel and water, an aggregate
of 7 lbs., and indicates 0.653 horse power, or at the rate
of 10.7 lbs. per horse power; so that, roughly speaking,
the weight of the motor has been doubled, and the power
has been increased fourfold.

Four boilers were constructed. The final one was
made of 21 lineal feet of i in. copper pipe, with an inter-
nal diameter of 0.18 in., and arranged in three concentric
vertical coils whose diameters were 1.6 in., 2.6 in., and
3.6 in. respectively. It weighed 37 02., but it is now
known “that a coil of equal capacity can be made weigh-
AEROPLANES. 229

ing only 8 02.. and still excessively strong." The cylinder
is 2 in. diameter, with a stroke of 2.52 in. The feed-pump
ram is 0.266 in. diameter, and the piston valves 0.3 in.
diameter. On one occasion this motor evaporated I4 7
cub. in. of water with 4.13 cub. in. of spirit in 40 seconds.
During a portion of the time it was working at a speed of
171 double vibrations per minute.

M. Hargrzz'z/e gives no data concerning the flight of his
last two (steam) machines. He states that 11 different
burners have been tried, and that the flame striking the
water boiler first has a tendency to vary the supply oi heat
to the spirit holder. From this it is inferred that he is

 

 

FIG. 80.—HARGRAVE—1893.

struggling with the same difficulties already encountered
by Strz'ngfe/Mw, by May. and by [Maxim in regulating
and keeping alight spirit burners when the apparatus gets
under forward head-way; but this difficulty. while a seri-
ous one, will doubtless be eventually overcome by persis-
tent experiment, and we may then expect flights of aston—
ishing lengths.

Seeing now his way to an adequate motor and to exten-
sive flights in the near future, M. Hargrave recently
turned his attention to experiments upon curved surfaces,
and to the seeking for a better disposition of the sustain-
ing surfaces or body planes. He had described the eccen—
tricities of a curved strip in the form of asegment of a
hollow cylinder, when exposed to the wind, in his paper
230 FLYING MACHINES.

No. 12 to the Royal Society of New South \Vales, read
August 3, 1892, and he describes some of his experiments
with “cellular kites,” in his paper read in the Aerial
Navigation at Chicago, August 2, 1893.

The “ cellular kites” constitute quite a new departure,
and practically consist of superposed aeroplanes con-
nected together in pairs. 8, in fig. 80, shows the simplest
form. This consisted of two hollow cylinders of alumin-
ium, each 13 in. diameter by 4% in. deep, mounted 30 in.
apart upon a connecting stick, and weighing 14341le. The
kite-string was attached II in. back from the forward sec-
tion, and as a consequence of the angle of incidence thus
produced, the apparatus mounted upon the wind. Its
particular behavior is not described in the paper. C, in
fig. 80, shows a kite with 16 cells, the length of each being
3 in., by a height of 3 in., and a breadth of 3 in. It was
made of cardboard, and the two sections were 22 in. apart,
the point of attachment of the kite-string being 61} in. dis-
tant from the forward section, while the weight was 10.5
lbs. This seems to indicate that this kite flew at a steeper
angle than the preceding. although we should expect the
reverse, in consequence of the greater proportion of sus-
taining surface. M. Hargrave says, “ These kites have
a fine angle of incidence, so that they correspond with the
flying machines they are meant to represent, and differ
from the kites of our youth, which we recollect floating at
an angle of about 45°, in which position the lift and the
drift are about equal. The fine angle makes the lift
largely exceed the drift, and brings the kite so that the
upper part of the string is nearly vertical."

Kites E and E fig. 81, are of exactly the same size and
weight, consisting of one cell, 4 in. long, 10.7 in. broad
by 6.25 in. high, constructed of wood and paper, and
weighing 3.25 lbs.; the two sections are 21.25 in. apart,
and the string is fastened 7.25 in. back of the forward sec-
tion. The only difference is that kite E has its horizontal
(top and bottom) surfaces curved to a radius of 4.5 in.,
while all the surfaces of kite Fare true planes. The re-
sult is that when kite E is flown with the convex sides up,
it pulls about twice as hard on the string as kite F, so
that, as M. Hargrave says : “ A flying machine with
curved surfaces would be better than one with a flat body
plane, if the form could be made with the same weight of
material.”

M. Hargraw, in this last paper, figures and describes
two other forms of cellular kites with which he has experi—
mented, and points out that the rectangular form of cell
is collapsible when one diagonal tie is disconnected. so as
to make it easy of transportation. He says : “ Theoreti-
AEROPLANES. 23 I

cally. if the kite is perfect in construction and the wind
steady, the string could be attached infinitely near the
center of the connecting stick, and the kite would fly very
near the zenith. It is obvious that any number of kites
may be strung together on the same line, and that there
is no limit to the weight that may be buoyed up in a breeze
by means of light and handy tackle. The next step is
clear enough—namely, that a flying machine with acres
of surface can be safely got under way, or anchored and
hauled to the ground by means of the string of kites."

He duly gives credit to M. Wen/2am for suggesting the
superposition of planes in 1866. and it is an interesting
circumstance to note that at the same Chicago Conference,

 

 

FIG. 8r.—HARGRAVE——1893.

a paper from M. Wen/2am was read suggesting a course
of experiments with kites, to determine the best arrange-
ment of superposed aeroplanes and the conditions of
equ1pmse.

Such are the labors of M. Hargra'z/e up to the present
time. He no longer troubles himself about. the general
problem of man‘s eventual success in nav1gating the air,
but he says: "The people of Sydney who can speak of
my work without a smile are very scarce ; it is doubtless
the same with American workers. I know that success is
dead sure to come. and therefore do not waste time and
words in trying to convince unbelievers.”
 

..r, _5 K

.52: 2:3: I.

Nw dim

 

 

 
AERUPLANES. 233

Instead of this, he constructs machines and reports the
results in detail, so that others may repeat his experiments.
He says that the record of unsuccessful experiments takes
up aconsxderable portion of his notes, and further, that
“there is no use in the mind’s conceivmg an idea, if the
hands are not ready to carry out the work skillfully, in the
absence of reliable assrstance, and if the design be found
faulty, the whole thing should be begun again without
trying to use up old machines. The question of intricate
workmanship and costliness is being continually battled
with ; my constant endeavors are directed to making the
machines simple and cheap. so that any one who doubts
can verify my work, prov1ded his hands are as skillful as
mine, and I am sure that the photographs show clearly
that the workmanship is anything but first-rate.”

He began with small, cheap models, and has gradually
enlarged their size, and obtained flights longer than any
heretofore accomplished. It is noticeable that the heavier
the model, and the smaller the sustaining area in propor-
tion to the weight, the more successful has been the flight.
He may not be the first man to ride at will upon the air,
but he deserves to succeed.

In November, 1890, M. Hiram S. fliaxz‘m, the celebrated
American inventor of a writing telegraph. of several sys-
tems of electric lighting, and of the ” Maxim automatic
machine gun," addressed a letter to the New York T277163,
in which he stated that, before sailing back to England,
he thought it would be well to state what he was doing
toward constructing a flying machine which had been
alluded to lately by the American press. Among other
things he said:

I would say that among the large number of societies to
which I belong in England, the Aeronautical Society is one,
and need I say that I am the most active member? At the
present moment experiments are being conducted by me at
Baldwin’s Park, Bexley, Kent. England, with a View of find-
ing out exactly what the supporting power of a plane is when
driven through the air at a slight angle from the horizontal.
For this purpose I constructed a very elaborate apparatus, pro-
vided with a great number of instruments, and arranged in
such a manner that I can ascertain accurately the efficiency of
a screw working in air, the amount of power rtquired to drive
a screw, the amount of push developed by a screw, the amount
of slip, and also the power required for propelling planes
through the air when placed at different angles, as well as to
ascertain the friction and all other phenomena connected with
the subject. I have been experimenting with motors and have
succeeded in making them so that they will develop I horse
pwwer for every 6 lbs. My experiments show that as much as
I33 lbs. may be sustained in the air by the expenditure of
234 FLYING MACHINES.

I horse power; of course. it is premature now to express any
opinion; still, if I am not very much mistaken, and if some
new phenomenon, which I do not understand, does not prevent
it, I think I stand a fair chance of solving the problem, and I
think I can assert that within a very few years some one—if
not mvself, somebody else—will have made a machine which
can be guided through the air, will travel with considerable
velocity, and will be sufficiently under control to be used for
military purposes. I have found in my experiments that it is
necessary to have a speed of at least 30 miles per hour, that 50
miles is still more favorable, and that 100 miles would seem to
be attainable. Everything seems to be in favor of high speed.

Whether I succeed or not, the results of my experiments will
be published, and as I am the only man who has ever tried the
experiments in a thorough manner with delicate and accurate
apparatus, the data which I shall be able to furnish will be of
much greater value to experimenters hereafter than all that has
ever been published before.

In May, 189t, M. Maxim again visited the United States,
and he gave to various newspaper reporters, notably to
one from the New York Sun, some particulars concerning
the flying machine, or “ first kite of war," which he was
building in England, and upon which he had spent up to
that time (including the preliminary experiments) some
$45,000.

He described the apparatus with which he had made his
preliminary experiments, to ascertain accurately the sup-
porting power and resistance of air to aeroplanes at small
angles of incidence, and then continued as follows:

My large apparatus is provided with a plane 110 ft. long and
40 ft. wide, made of a frame of steel tubes covered with silk.
Other smaller planes attached to this make up a surface of
5,500 sq. ft. There is one great central plane, and to this are
hinged various other planes, very much smaller, which are used
for keeping the equilibrium correct, and for keeping the flying
machine at a fixed angle in the air. The whole apparatus, in-
cluding the steering gear, is 145 ft. long. . . . A part of
the aeroplane, or actual kite. is made of very thin metal, and
serves as a very efficient condenser for the steam. .

It is ready and awaiting my return. It is now resting on a
track 8 ft. wide and half a mile long. in my park. The first
quarter of a mile of the track is double-that is to say, the
upper track is 3 in. above the lower. By that means I am able
to observe and measure the lift of the machine when it starts,
because the upper track will hold it down when it lifts off the
lower one. When ‘completed the machine will weigh, with
water tanks and fuel, somewhere between 5 000 lbs. and 6,000
lbs.. and the power at my disposal will be 300 horse power in
case I wish to use it; but it is expected that about 40 horse
power will suflice after the machine has once been started, and
that the consumption of fuel will be from 40 lbs. to 50 lbs. per
AERUPLANES. 235

hour. The machine is made with its present great length so
as to give a man time to think; its length makes it easier to
steer and to change its angle in the air. Its quantity of power
is so enormously great in proportion to its weight that it will
quickly getits speed. It will rise in the air like a sea—gull if
the engine be run at full speed while the machine is held fast
to the track. and if it is then suddenlv loosened and let go.

M. Maxim very judiciously refrained from furnishing
drawings or detailed descriptions of an apparatus which
was still in process of evolution, and which he might want
to modify as he proceeded in erection and trial. Indeed,
it is probable that. he has varied considerably from the
various arrangements which he has patented from time to
time,* so that drawmgs and descriptions made from these
might be wide of the mark.

The important, the vital feature, however, he recog-
nized to be the motor, and to perfecting this he gave his
first attention. In steam motors he seems to have accom-
plished wonderful results, hitherto quite unreached, and
in an article published in the sz‘ury Magazine for Octo-
ber, i891, after describing and illustrating the experimen-
tal whirling machine with which he had gathered his pre-
liminary data, he gives the following account of what he
had accomplished up to that time with the motor :

Ihave come to the conclusion that the greatest amount of
force with the minimum amount of weight can be ottained
from a high-pressure compound steam engine, using steam at
a pressure of from 200 lbs. to 350 lbs. to the square inch, and
lately I have constructed two such engines, each weighing 300
lbs. These engines, when working under a pressure of 200
lbs. to the square inch, and with a piston speed of only 400 it.
per minute, develop in useful effect in push of screws over 100
horse power, the push of the screws collectively being over
1,000 lbs. By increasing the number of turns, and also the
steam pressure. I believe it will be possible to obtain from 200
horse power to 300 horse power from the same engines, and
with a piston speed no greater than 850 ft. per minute.’r These
engines are made throughout of tempered steel, and are of
great strength and lightness. The new feature about my
motors. however, is the manner of generating steam. The
steam generator itself, without the casing about it, weighs only
3501bs.; the engine, generator, casing, pumps, cranks, screw-
shaft, anl screws weigh 1,8001bs., and the rest of the machine
as much more. With a supply of fuel, water, and three men,
the weight will not be far from 5,000 lbs. As the foregoing
experiments have shown that the load may be 14 times the
push of the screw, it would appear that this machine ought to
carry a burden, including its own weight, of 14,000 lbs., thus
leaving a margin of 9,000 lbs, provided that the steam

* British patents Nos. 10359 and 16,883, A.D._I889; No. rg.228. A.D.'189t.
1' The piston speed of an express locomotive is about 1,000 ft. per minute.
236 FLYING MACHINES.

pressure is maintained at 200 105. to the square inch. The
steam generator is self-regulating, has 48,000 brazed joints,
and is heated by 45,000 gas jets, gas being made by a Simple
process lrom petroleum. When the machine is fin shed the
exhaust steam will be condensed by an atmospheric condenser,
made of a great number of very thin metallic tubes, arranged
in such a manner that they form a considerable portion of the
lifting surface of the aeroplane. The greater part of the ma-
chine is ronstructed from thin steel tubes. I found that these
were much more suitable for the purpose than the much-talked-
of aluminium; still I believe that if I should succeed in con-
structing a successful machine, it would lead to such improve-
ments in the manufacture of aluminium products that it will be
possible to reduce greatly the weight of the machine.

The quzstion of keeping the machine on an “ even keel,” of
steering, and of landing, hcS been duly considered and pro-
vided for, but a description of these would be premature before
the machine has actually been tried.

When it is remembered that locomotives weigh some
200 lbs. per horse power, that the lightest marine (launch)
engines in 1889 weighed about 60 lbs. per horse p0wer,
and that the largest steam-engines previously built for
aerial navigation purposes were those of szmzra’ and of
M’oy, each of 3 horse power and weighing (with their
boilers) Ito lbs. and 27 lbs. per horse power respectively,
then the importance of M. [Maxim's achievement, as
above set forth, may be partially realized; particularly
when it is considered that the relative weight tends to in-
crease with the size, and that M. zl/axz'm’s expectations of
obtaining 300 horse power from the same engines have
been fully confirmed, as will be seen hereafter.

Moreover, as exhausting the steam into the air would
involve carrying a supply of water amounting to some 20
or 25 lbs. per horse power per hour, and this would have
been simply prohibitory. M. Maxim’s plans included a
surface aero-condenser. in order that the same water
might be used over and over again. This was a wholly
unsolved problem, such tentative experiments as had been
tried prevrously by others having indicated weights of 50
lbs. to 150 lbs: per horse power, as necessary for efficient
aero-condensers, and this would also have been prohibi-
tOI‘ .

lei. [Maxim proposes to solve this problem by making
all the lrames of his apparatus of hollow tubes, and con—
necting therewith a condenser consisting of a large num-
ber of wide, flat, or film tubes-that is to say. of tubes of
thin metal having a flat bore, through which the steam
will pass in thin films of considerable width; these film
tubes being so arranged that in the forward motion of the
machine the air will impinge upon them, thus effectually
AEROPLANES. 237

cooling them and condensing the steam therein. This
aero-condenser is util12cd as a part or the whole of the
sustaining surlace, or there may be substituted therefor a
large tleXible bag or chamber, connected at the forward
part with the exhaust steam-pipe, and at the rear end with
the hot well, or directly with the suction-pipe of the feed-
pump. He relies, of course, upon the increased condensa—
tion produced by air currents due to the forward motion
of the machine, and the extent of the condenser is there-
fore a matter for experiment, so that its exact weight can-
not be settled in advance.

The horizontal angle of incidence in flight. is to be main-
tained by a " Gyrostat,” which consists in a gyroscopic
wheel rotating rapidly, suspended by universal jomts and
connected With two horiZtintal rudders, one at the front
and the other at the back of the apparatus, so as to act
upon them instantly (through the well-known property of
the gyroscope to continue rotating in the same plane), in
case any tendency occurs to deviate from the angle of inci—
dence with the horizon.

The whole of the apparatus is to be thoroughly stayed
by diagonal wire ties, so as to make every part rigid and
prevent deformations under varying wind pressures.

Fig. 82, engraved from a photograph kindly furnished
by M. Maxim, exhibits the main features of the apparatus.
It does not show the front or back rudders, which have
been removed, nor the side wings, set at a diedral angle,
to preserve the transverse stability, nor sundry possible
keel—cloths or auxtliary planes intended to promote the
same object. It exhibits the .central or principal aero-
plane, with the forward end facing the observer. This
main aerOplaiie is understood to be 50 ft. wide, about 58
ft. long, and slightly concave in the direction of its length.
while it is tru5sed and stiffened in every direction by Wire
stays. The condenser is indicated by the dark shading at
the front oi the main plane, and, as will readily be seen.
can be largely increased in surface, but, however, at the
expense of added weight. The driving screws are placed
at the rear, and are understood to be 17 ft. 10 in. in diam-
eter, the speed of rctation varying, of course, with the
power exerted.

The whole apparatus is mounted upon wheels, running
over a railway track, so as to acquire sufficient speed to
rise upon the air. and the three men who are grouped
about the front may enable the reader to gather by com-
parison some general conception of the colossal dimen-
sions of this flying machine.

Having thus designed and built his apparatus, the next
point for M. Maxim to consider was how to get it up into
238 FLYING MACHINES.

the air, how to control it while sailing. and how to alight
with it safely. To this he has eVidently given much
thought, and in an article published by him in the Cosmo-
;fiolz'lcm Magazine for june, 1892, he thus describes what
course he would pursue it a sum of $100000 were placed
at his disposal, for constructing and experimenting a suc-
cessful flying machine; which course seems to he so care-
fully planned that we may fairly assume that it is the one
determined upon by M. Maxim for experiments with his
own actual machine.

“The machine should he run around the one-mile track
at all speeds, trom 20 miles per hour to 100 miles per
hour, and the power actually required should be carefully
noted. These runs would enable us to ascertain how our
pumps worked at high speed, and how much our screws
pushed, and if we put a brake to the wheels we should
find out the slip of the screws. We could also ascertain
the efficiency of our condenser at various speeds, and the
temperature of the water could be taken. In order to run
on a railway track, the machine, of course, must be pro—
vided with wheels, and two sets of these would be neces-
sary; one set should be of great weight, so as to hold the
machine down when running on the track. and the other
set should be light, for actual flying. Springs should be
interposed between the axletrees and the machine, after
the manner of railway carriages, and there should be at-
tached above each wheel some sort of an index or indica-
tor to show the exact load resting on each wheel. When
all the parts of the machine had been made to operate
smoothly and satisfactorily, the silk could be placed on the
aeroplanes, and then our serious experiments might be
said to commence.

” We should first begin by running slowly —say at the rate
of 20 miles per hour—and carefully note the lift on the in-
dexes over each wheel. If we found that with a speed of
20 miles an hour, three fourths of the load was lifted off
the forward axletree, and only one-fourth off the hind one,
then we should change the center of weight further for—
ward, so as to bring it as near; as possible under the cen-
ter of effort or lift. We should then make another trial,
and if we found that the lift was equal both fore and aft,
we should increase the speed very carefully, gradually ob-
serving the lift at the four corners of the machine, until
the whole weight of the machine was supported by the
aeroplane, and the whole weight of the wheels (about one
ton) by the railway track. Then, when there was neither
lift nor load on either wheel, we might consider that we
had arrived at a stage in our experiments'where we could
turn our attention to the subject of steering.
AEROPLANES. 239

“A boat has to be steered in only one direction—namely,
a horizontal direction, to the right or to the left. A loco-
motive torpedo or a flying machine must be steered in two
directions—right or left, or up or down. We should ex-
periment with the more difficult one at first—namely, the
up and down or vertical direction. We should attach two
long arms to our aeroplane in such a manner that they
would project a considerable distance in the rear of the
machine. To these arms we should pivot a very large
and light silk-covered rudder and connect it with ropes,
so that it could be turned up or down by a small Windlass
from the machine. We should then take a run on the
track and see if the changing the angle of this rudder
would increase or diminish the load on the forward or
hind wheels. If we found that it would do this, but not
sufficiently so, we should attach another rudder in exactly
the same manner to the forward end of the machine. Sup-
pose that, at a speed of 35 miles per hour, with both rud-
ders set at the same angle as the aeroplane, we should
find that the whole weight of the machine was carried by
the aeroplane and the whole weight of the wheels (2,000
lbs.) by the track, we could then consider that the adjust-
ment of our load was correct, and that the center of weight
was directly under the center of effort for a speed of 35
miles an hour. We should then elevate the front edge of
the forward rudder and depress the front edge of the rear
rudder; this would cause the machine to lift on the for-
ward axletree and the rear end of the machine to press on
the hind axletree. If we found by changing the angle of
the rudders that the load could be increased or diminished
on either axletree to the extent of 15 per cent. of our whole
load we could consider that this phase of the problem was
solved.

“ For horizontal steering we should try first the effect of
the screws. There should be a three-way valve in the
steam pipe connected with a lever, so that we should be
able to partly close off the steam from the engine of one
screw, and turn more steam on to the other. This would
probably be all that would be found necessary ; if not, we
should try rudders.

“ To prevent the machine from swaying in the air, the
aeroplane should so be constructed that no matter in
which direction it tilted it would diminish the lifting power
of the lifted part and increase the lifting power of the de—
pressed part. This (diedral side wings) would be simple
and automatic; moreover, the stability of the machine
could be still further increased by having the center of
gravity much below the center of lift.

“Having all things in readiness, the heavy wheels should
240 FLYING MACHINES.

be removed and the light ones put on; and taking one
man with us to attend to the two horizontal rudders and
to keep the machine on an even keel,* we should take our
first fly, running the engines and doing the right and left
steering ourselves. A day should be selected when there
wasafresh breeze of about 10 miles per hour. We should
first travel slowly around the circular railway until we
came near that part of the track in which we should face
the wind. The speed should then be increased until it
attained a velocrty of 38 or 40 miles an hour. This would
lift the machine off the track and probably would slightly
change the center of effort. This, however, would be
quickly corrected by the man at the wheel. While the
machine was still in the air careful experiments should be
tried in regard to the action of the rudders; it should be
ascertained to what degree they had to be tilted in order
to produce the desired effect on the machine. The ma-
chine should also be run at a speed less than 35 miles per
hour in order to allow it to approach the earth gradually ;
then the speed should be increased again to more than
35 miles an hour in order to rise, at the same time trying
the effect of running one propeller faster than the other,
to ascertain to what extent this would have to be done in
order to cause the machine to turn to the right or to the
left. If the machine should be constructed so that each
particular foot of its surface carried a load of 1 lb. 2 02.,
and if we should stop the engine dead and allow the ma-
chine to fall, it would approach the earth at a speed of 15
miles an hour. or one mile in four minutes. This evi—
dently would cause a considerable shock, and unless there
Was a good deal of elasticity to the parts and a good deal
of traVel between the axletrees and the machine, the shock
would probably be sufiicient to distort or injure some part
of the light structure. But it is not necessary to approach
the earth directly. Professor Lang/5y found in his experi-
ments that when a horizontal plane was travelling rapidly
through the air, it approached the earth as though it were
‘settling through jelly.’

“ A large field as near our railway as possible should be
selected for alighting, and having approached the field so
as to be facing the wind, we should gradually descend by
slowing up the engines, and finally alight while the ma-
chine was still advancing at the rate of 20 miles an hour.
If the wind should be blowing at the rate of 10 miles an
hour the machine would approach the earth very grad-
ually indeed. so that all shock would be avoided. It would
only require a few yards of comparatively smooth ground

* M. Maxim has since added the gyrostat.
AEROPLANES. 241

to run on after alighting, in order that there should be no
disagreeable shock or danger.

“ The cost of these experiments would be from $50,000 to
$100,000, and the time required would be two years.”

It will be noted how complicated and delicate these
various adjustments must necessarily be, and how many
different parts must be made to do their work perfectly
before it can be safe to venture into the air. The aero-
plane surfaces must be prevented from altering their
shapes at varying speeds, the rudders must be made to
maintain the course automatically, the engine must be
governed as to speed. the boiler and gas—jet flames must
be regulated by the consumption of steam, and the con-
denser must be efficient at all temperatures of the air, as
well as at all speeds. Moreover, and most important. no
plrt must break under varying strains, and the equilibrium
must be maintained.

These are formidable and yet indispensable requirements,
well calculated to appall the boldest inventor; for while
with an experimental model an accident is of little conse-
quence and is easily repaired, with an actual flying ma-
chine an accident will probably prove disastrous, even if
the inventor does not lose his life.

M flhxim, therefore, has acted most wisely in taking
plenty of time and in testing his apparatus in every way
before venturing to leave the ground with it. Having
completed it so that it was ready for the hazard of actual
trial, he next experimented with it under conditions of
comparative safety, and opened up the chapter of accidents.

The first difficulty he met with occurred through the
breaking of some of the wire stays. These had been made
of steel high in carbon in order to secure great tensile
strength, and they proved brittle. From a private letter
from M. fl/axz'm, dated October 6, 1892. the writer is per—
mitted to give the following extract, which gives also a
most interesting and hitherto unpublished description of
the steam-engine and boiler, which constitute thus far the
great achievement of M. Maxim .'

The steam generator is constructed somewhat on the Thor-
neycroft principle, except that the tubes are much lighter and
thinner and have a greater number of sinuosities in them. In
the Thorneycroft boiler the distributing water tubes at the bot-
tom are of considerable size and of great weight. In my en-
gine they are only 21} in. in diameter and 11} mm. in thickness.
The downtake for the water is onlv 3 in. in diameter, and in-
stead of having two, as with the Thorneycroft boiler, there is
one, which branches off like the inverted letter Y. In the
Thorneycrott boiler the difference in gravity of the water in

16
242 FLYING MACHINES.

the hot interior tubes and in the two external ones, which are
not heated, is the only means of keeping up the circulation;
but as all the passage-ways for water are very large, this is
SJflicient.

Suppose that in my system I am using steam at 300 lbs.
pressure to the square inch ; I have my water at a pressure of
335 lbs. to tie squire inch, and the water escapes through a
species of automatic injector, and in falling 35 lbs. in pressure
does a certain amount of work on the surrounding water.
The cold water going in from the pump is therefore made to
combine with the hot water in the downtake. This increases
the graVin of the water and at the same time causes a very
rapid forced circulation. No matter to what extent the fire
may be forced, the water has to go through in any event. All
the water that is coming in from the pump, as well as all of
the water that it takes along with it from the top separating
drum, from which the steam is taken, is forced through the hot
tubes. The nozzle through which the incoming water escapes
from the higher to the lower pressure is provided with a spring,
which always keeps a difference in pressure of about 35 lb:.;
Whether the qu intllV of water pressing in is large or small, the
difference is always the same. A very convenient apparatus
is attached to the feed water pipe, by which it is possible to see
at a glance exactly how many pounds of water per hour are
entering the boiler. Directly over the boiler proper there is
another series of very snail copper tubes through which the
water passes before entering the boiler proper, therefore prod-
uClS of combustion, after passing between the tubes of the
boiler, are brought in contact with the incoming water before
escaping. This so reduces the temperature of the escaping
products of combustion that Brunswick black or linseed-oil are
not burned off the smoke-stack.

For a fuel I employ naphtha of 72° Beaumé. This naphtha
is pumped into a small vertical boiler heated with a part of its
own contents.

The vapors from the boiler are led directly to an air injector,
where they escape under a pressure of 35 lbs. to the square
inch. The mixture of air and gas is then burned through rather
more than 6,000 gas jets under the boiler. Steam might be
also mixed if required. The distributing of the flame is very
even, and it is possible to fill the whole fire-box with a purple
flame. The regulating of the supply of naphtha is controlled
by the weight of the gas generator; if the weight of the gener-
ator is too great, it operates upon a ratchet, which shortens the
stroke of the pump; if it is too light, a spring raises the gener-
ator and its contents, when the ratchet operates in a contrary
direction and increases the stroke of the pump. In this way
the quantity of naphtha in the boiler is kept constant. The
fire is regulated not only by the pressure in the boiler, but by
a thermostatic regulator also. The feed-water pump is also
regulated by changing the length of the stroke.

The engines are compound, and have a peculiar arrangement
placed in a connection between the high and low-pressure cyl-
AEROPLANES. 243

inders in such a manner that if the pressure in the boiler rises
above 300 lbs. to the square inch the steam is shunted past the
high-pressure cylinder and enters the low-pressure cylinder,
and it is arranged in such a manner that the pressure ,of steam
falling from 300 lbs. to I00 lbs. does a certain amount of work
on the exhaust steam that is passing through the high-pressure
cylinder after the manner of an injector—that is to say, the
escaping force of the steam reduces the back pressure on the
high-pressure cyl nder and increases the pressure on the low-
pressure piston.

With two screws, each 17 ft. 10 in. in diameter, and with 300
lbs. pressure to the square inch, the machine has been made to
pull on a dynamometer 1,960 lbs. If we multiply this pull by
the number of turns per minute that the engine makes, and by
the pitch of the screws, we find that the engines develop 300
horse power.

The complete weight of engines, boilers, pumps, generators,
condensers, and the Weight of water in the complete circulation,
amounts to 8 lbs to the horse power, and this of itself I con-
sider quite an achievement.

The spread of the wings of the machine is 107 ft., and the
total length from the point of the forward rudder to the rear
end of the after rudder is about 200 ft. Beneath the main
aeroplane there is a considerable number of narrow planes
superposed, which extend outward to nearly the full width of
the machine. So far, trials have only commenced with the
main aeroplane, which is 50 ft. wide and 45 ft. long in the
direction of the length of the machine.

The whole machine is mounted on steel wheels 8-ft. gauge,
and springs are interposed between the machine and the axle-
trees , both forward and back axletrees are attached to a dyna-
graph, which makes a diagram of the lift of the machine as it
advances upon the track. The drum which holds the paper
turns once round in 1,800 ft., and whatever the machine lifts
either forward or back is recorded upon the paper drum. One
of the drums is also provided with a pencil, which makes a
diagram of the speed at which the machine is traveling.

I am very much hampered, however, for room ; there is very
little clear space betWeen the trees. and to obtain adjoining
premises without trees costs a prohibitive sum. What I should
have is a circular or oval track, which would be a mile long.
When the experiments are tried with a side wind blowing five
miles an hour, a lift of one ton has been recorded on one side
of the machine, while the other side would not lift over 100 lbs.

The whole machine, when loaded, will weigh about 7,000
lbs., so you will see if the machine will lift anything like as
much, per pound of push, as I succeeded in lifting with my
first apparatus, it will be sure to go.

However, I find that a great number of steel stays are neces-
sary in order to hold the machine in shape, and while these do
not weigh much, they appear to offer a considerable resistance
to the passage of the machine through the air. If I were to
build another machine I should aim more at getting less atmos-
244 FLYING MACHINES.

pheric resistance, because I can see now that everything else is
assured except this single factor. If the machine does not go
it will simply be because too much force is expended in driving
the framework through the air.

Work has been greatly delayed, in the first place, because
I was absent from England a great deal, and, in the second
place, we have had several serious accidents. The high-class
steel wires—plow rope—which are used for stays are not always
reliable. On two occasions these wires have broken, and,
becoming entangled in the wheels, have made a complete wreck
of the wheels and everything about them. The last break-
down will take about a month to repair, and I shall put in a
lower class of steel in all the stays that are near the wheels.

This damage was duly repaired, and the experiments
were resumed early in 1893. In one of these, with a
spread of somewhat more than half of the sustaining sur-
face which the apparatus is designed to carry in full flight,
M. Maxim succeeded in obtaining, at a speed of 25 miles
per hour and with a thrust of the screws of I,ooo lbs , a
lift over the front wheels of 2,3001bs., and over the hind
wheels of 1,900 lbs., as recorded by the dynagraphs. On
a subsequent run, after making some alterations, he suc-
ceeded in obtaining, at a speed of 27 miles per hour and
with a thrust of screws of only 700 lbs., a lift over the
front wheels of 2,5001bs., or quite all the weight resting
on them, and of 2,800 lbs. over the hind wheels; thus
showing a total lift of 7 57 lbs. per pound of thrust, as
against 4.20 lbs. lifted per pound of thrust on the former
occasron.

M. Maxim published the diagrams illustrating both
these runs (and still another subsequently made) in the
London Engineer for March 17, 1893, and gave a descrip-
tion in which he stated that the principal lift was obtained
from the large aeroplane of 2,894 sq. ft. in area.

The run last above described was made on February 16,
1893, and on the same day two more runs were made un-
til stopped by an accident.

First, an additional pair of wheels was attached under
the front end of the machine, connected in such a manner
that the small and lighter wheels could lift 3 in. from the
track. Three men were also placed over the forward
axletree. and a run was then made with 900 lbs. pull on
the dynamometer. After the machine had run about 400
ft. the light wheels lifted clear of the track, and when the
engines were stopped they came back to the track all-
right. The machine was then run again with 1.000 lbs.
pull on the dynamometer, with the following result, de-
scribed in a letter to the writer from M. Alarm)”, dated
February 21, I893:
AEROPLANES. 245

I have had another accident with my apparatus.

My main aeroplane is 50 ft. wide and 47 ft. long in the direc-
tion in which the machine travels. I had another aeroplane
directly in front of the engine, which was abottt 18 ft. long and
4 ft. wide. On the first runs which I had been making I found
a great deal of atmospheric resistance which I could not account
for except that it resulted from the bagging of the main aero-
plane and the resistance oflered by the numerous struts and
wires which I used in my attempts to keep it approximately
flat. With the engines running at a sufficient speed to give a
push of 1,325 lbs., it was found that the lift on the aeroplane
did not much exceed the push of the screws.

I then made a radical change in the manner of holding the
plane flat, and tried my first experiments after this with a push
of 800 lbs., when it was found that the lift was a great deal
more than it was with the 1.325 lbs. in the previous experi'
ments-; in fact, the lift on the front pair of wheels was equal to
the weight resting on these wheels, and the machine was only
kept from leaving the track by the weight of three men whom
I carried directly over the front axletree. This I regarded as
dangerous. I then attached two very large cast-iron wheels in
sucha manner that the light wheels could lift some inches from
the track before the heavy wheels were lifted at all, the weight
of the heavy wheels and their axletree being about 1,400 lbs.
Three men were also added to this load.

in making the. run the gas was Carefully turned on until the
engines gave a push of 1,000 lbs I had noticed that as the
machine advanced and the engme ran faster, the boiler pressure
was diminished. I therefore, upon starting, turned on a little
more gas, so that the pressure, instead of falling, increased
slightly during the run. When about 400 ft. had been covered,
the two front wheels lifted off the track, leaving the heavy
wheels still on the track; but just before stopping the heavy
iron wherls also lifted from the track, and when the engines
were stopped one of the wheels got into the soft earth, sinking
down and tilting the machine over to one side. A gust of wind
then tipped the machine on its side; but the breaking. which
was confined almost entirely to the framework for holding the
cloth. was caused by the impetuosity of a lot of men who
tugged away at my ropes, and putting a strain downward in-
stead of upward on the ropes, succeeded in completely destroy-
ing the framework.

The speed was 27 miles an hour, and the pressure of steam
about 200 lbs. The lift recorded was nearly 6,000 lbs., as
shown by the diagrams taken from the dynographs. The in-
cline of the main aeroplane was, however, very steep, being
about I in 9.

The lift was more than I expected. 1 did not think that a
plane so very large, especially in the direction in which it was
traveling, would be so eflicient. I thought Ishould have to
depend more on the narrow planes which extend beyond the
main plane. This more than expected lift. however, may have
been due to the wind, during the last end of the run, being
246 FLYING MACHINES.

contrary to the direction in which the machine was travel-
mg.

I think that these experiments demonstrate that an aeroplane
may be made to carry a considerable load.

It will take some time to repair the damage. None of the
expensive machinery was damaged in the least. Ishall take
greater care in the future not to experiment when there is a
liability to squalls, and shall have a fender, so that if the ma.—
chine gets off the lracx it will not topple over.

It is understood that at the time this run was made
about half of all the sails were in position—namely, 3,160
sq. ft. The power which the engines developed was about
half of their full power, so that it will be realized that
there will be ample lifting power when free flight is at-
tempted.

Since then the apparatus has been repaired, and in an
article which has been extensively published in American
newspapers, a correspondent, writing under date of Lon-
don, September 12, 1893, gives an account of a ride which
he took on the machine. After describing it and the
house in which it is sheltered, he says :

I mounted the platform, made of light matched boards so
thin that they seemed scarcely able to bear a man’s weight.
Prior to the start a rope running to a dynamometer and p05t
was attached behind, to measure the forward impulse or push
of the screws. . . . The action of the screws caused very
little shaking through the whole machine, and this was a sur-
prise to rue, comparing the tremendous force with the delicate
framework. Behind the ship, IO ft. away, two men were
shouting from the dynamometer and indicating the degree of
push on a large board for the engineer to read. The index
quickly marked in succession 400. 500, 600. 700, and finally
1,200 lbs. of push, and then the commander yelled, “ Let go l”
A rope was pulled, and then the machine shot forward like a
railway locomotive, and with the big wheels whirling, the
steam hissing, and the waste pipes puffing and gurgling, flew
over the 1,800 ft. of track. It was stopped by a couple of ropes
stretched across the track working on capstans fitted with re-
verse fans. The stoppage was quite gentle. The ship was
then pushed back over the track by the men, it not being
built, any more than a bird, to fly backward.

M. Maxim is quoted by the correspondent as saying,
among other things, concerning his apparatus :

Propulsion and lifting are solved problems; the rest is a
mere matter of time. . . . Haste in such a venture is the
worst of policies. Weak points must be thoroughly sought
for, and everything made completely safe before the public is
invited to consider the air-ship as a practical means of transit.
1 am looking for a location with more room for me to experi-
AEROPLANES. 247

mint in thanI can find in England. I am cramped here for
want of space.

Such is the present status (1893) of this bold and costly
attempt to solve the problem 0t aviation with an aero—
plane. M. Maxim, as he says himself, may not. achieve
final success; but he has, in the opinion of the writer,
very greatly advanced the chances of eventual success.
He has constructed, it may be said invented, a steam-
engine with its adjuncts developing 300 horse power, and
weighing only 8 lbs. to the horse power—an achievement
hitherto unparalleled, and probably the most important
problem to solve before man can hope to succeed in navi-
gating the air at will.

There doubtless remain other problems to be worked
out practically, notably that of effectually controlling a
flying machine while in the air, both in the vertical and the
horizontal direction; that of maintaining the equilibrium
under all Circumstances of speed and angles of incidence,
and also those of devising methods of starting up and of
alighting safely anywhere; for in practical operation,
even for war purposes, M. Maxims machine cannot
always be brought back to get a start upon its initial rail-
wav track.

There probably also remain some questions to be settled
as to the best forms, extent and texture of the supporting
surfaces ; and it is not impossible thathis experiments will
eventually lead M. Maxim to a complete remodeling of
his aeroplanes; but, as has been pomted out in discussmg
“ screws to lift and prepel,” it is already within his power,
by reason of his marvelously light steam-engine, to go up
into the air with an aerial screw, and to perform therein
various evolutions.

In any event, the name of M. Maxim must ever remain
as that of one of the men who have hitherto done most to
advance the solution of the problem of aviation.

The Conference on Aerial Navigation in Chicago in
August, 1893, brought out a number of experimenters
whose ventures had theretot'ore been unpublished.

One of these, Mr. E. C. Huflaéer, of Tennessee, had
been experimenting with a model somewhat resembling
the “effigy” of Mr. Lancasz‘er. It consisted in 3. rec-
tangular surface of fabric made concavo-convex by a rigid
front spar with curved ribs at right angles thereto, so as
to resemble the cross-section of a soaring bird‘s wing.
A cross stick attached thereto carried a balancing hori-
zontal tail, the center of gravity being determined at the
front by loading with lead. The area of sustaining sur-
face was 2 sq. ft., and when held by the cross stick at
arm’s length overhead, vibrating between two fingers and
248 FLYING MACHINES.

facing a wind of 35 miles per hour (6 lbs. pressure at right
angles), the weight sustained (or lift) was estimated at
2 lbs. to the square foot, or that corresponding to an angle
of 10° upon a flat plane, while in point of fact the model
seemed to be horizontal, and the force required to hold it
in the wind was very small.

When the model was let go in a steady breeze it would
rise to a height of 12 or 15 ft., slowly retreating from the
wind, but always facing it ; then, tipping slightly forward,
it would descend into the face of the wind ; all these
effects being easily explained in a horizontal current.

When projected forward by hand, the model would sail
away in steady flight with a velocity of about 17 miles per
hour, and then descend on a gradient of about I in 15. If
thrust rapidly forward it would rise some 8 or loft, and
then, hanging suspended for a moment, it sailed forward
to the ground.

These experiments are interesting as confirming what
has hitherto been said concerning the greater lift apper—
taining to concavo-convex surfaces, and it is to be hoped
.that they will be continued.

The other experimenter was Mr.f./. Montgomery, of
California. He had, some years prevxously, constructed
a soaring apparatus, consisting of two wings, each 10 ft.
long by an average width of 4?; ft., united together by a
framework to which a seat was suspended, and provided
with a horizontal tail which could be elevated or depressed
by pulleys. The wings were arched beneath, like those
of a gull, and afforded a sustaining area of about 90 sq. ft.
The weight of the apparatus was 40 lbs., and that of the
experimenter some 130 lbs. more.

Mr. Monlgomery took this apparatus to the top of a hill
nearly a mile long, which gradually sloped at an angle of
about 10°, and placing himself within the central frame-
work, the rods of which he grasped with each hand, ready
to Sit down, he faced a sea breeze steadily blowing from
8 to 12 miles an hour, and gave a jump into the air with-
out previous running.

He found himself at once launched upon the wind, and
glided gently forward, almost horizontally at first, and
then descended to the ground, finding that he could mean-
while direct his course by leaning to one side or the other.
The total distance glided was about 100 ft., and the sen-
sation was that of firm yet yielding and soft support, being
quite similar to the experience of M. Mouz'llard, as already
described, except that there was no apprehension of dis-
aster.

Mr. Montgomery carried his machine back to the top
of the hill and prepared to repeat the experiment, but as
AEROPLANES. 249

soon as he got into position the apparatus began to sway
and to twist about in the wind; one side dipped down-
ward, caught on a small shrub, and, as quick as a flash,
the operator was tossed some 8 or 10 ft. into the air, over-
turned, and thrown down headlong. He fortunately fell
without. serious injury, and found, as soon as he recovered
himself, that one side of his machine was smashed past
mending.

This experience led him to design and build a second
soaring apparatus, in which he endeavored to relieve un-
due pressure upon either side by providing a diagonal
hinge in each wing, along which the rear triangle might
fold back (it was restrained by a spring) and yield to a
wind gust. This apparatus measured some 132 sq. ft. of
sustaining surface. and weighed 45 lbs. It was not suc-
cessful; several trials were made. but no effective lift
could be obtained with it. This was attributed to the fact
that the wings had been made true planes (flat) instead of
being arched underneath as in the first machine.

So a third apparatus was designed and built. The
wings were each 12 ft. long by an average width of 6 ft.,
and were given the cross-section and front sinuosity of
those of a soaring vulture. They were so built and braced
as to allow rotation in a socket at the front of the frame
which supported the seat. A hinged tail was added, as in
the two prev10us trials, and the machine weighed 50 lbs.

This last apparatus proved an entire failure, as no lift-
ing effect. could be obtained from the wind sufficient to
carry the 180 lbs. it was designed to bear. Mr. Mom‘-
gomery then turned his attention to other matters, but he
has since made a more careful and complete study ot the
principles involved, and he expects to resume his experi-
ments.

 

The foregoing pages comprise all the experiments, the
result of which has been published, which the writerhas
been able to collate, and which he has considered of suffi-
cient importance to be described in this account of “ Prog-
ress in Flying Machines.” Other important experiments
are pending or in partial progress; but the designers of
these have as yet given out no information for publication,
and indeed could scarcelv do so concerning tentative plans,
subject to constant modifications.

The writer has gathered from the newspapers, accounts
of some other experiments, but these seem to be so erro—
neously or vaguely described that no instruction could be
obtained by republishing them. It has been the aim of
the writer throughout to gather all the information possi-
250 FLYING MACHINES.

ble, but only to publish that which was reliable and in-
structive.

CONCLUSION.

Having thus passed in review the-various attempts which
have hitherto been made to compass artificial flight, there
remains the task of pointing out as briefly as possible
whether and how the information gathered may be made
to conduce to a possible solution of the problem of avia-
tion.

It was thought more effective to bring out the various
theories of flight, and my own views, while describing the
experiments, rather than to present them in a series of
abstract statements and propositions. the immediate bear-
ing of which might not be so evident. The reader has
probably reached deductions of his own ; but he may also
wish to know my own general conclusions, and in what
manner if any the many failures which I have described
can be made to subserve eventual Success.

These failures have resulted from so many different
causes that it is evident that many conditions must be
observed. These conditions virtually each constitute a
separate problem, which can probably be solved in more
ways than one, and these various solutions must then be
harmoniously combined in a design which shall deal with
the general problem as a whole. These various condi-
tions, or problems, as I prefer to call them, may be enu-
merated as follows :

I. The resistance and supporting power of air.

. The motor, its character and its energy.

, The instrument for obtaining propulsion.
. The form and kind of the apparatus.

. The extent of the sustaining surfaces.

. The material and texture of the apparatus.
The maintenance of the equilibrium.

. The guidance in any desired direction.

. The starting up under all conditions.

10 The alighting safely anywhere.

Analyzed and viewed in this way. the reader may realize
how complicated is the question and how formidable are
the various diflflculties which are to be surmounted. And
yet the scrutiny which has been made of the various ex-
periments attempted and of the progress accomplished in
flying machines enables us to perceive that many of these
problems have been approximately solved, more particu-
larlv since 1889, and that a better understanding of the
difficulties to be overcome has been obtained concerning
several others.

I. The first problem to be considered is that pertaining

\o 00>: O‘iknvhwm
CONCLUSION. 251

to the resistance and supporting power of air. By the
use of currently accepted formulae it could not be figured
out a few years ago how birds were supported in flight.
Now that Professor Lang/ey’s experiments have confirmed
many of those previously tried, we are enabled to say that
the empirical formula of Dar/13min (from which the table
of “ lift” and “ drilt" herein given was calculated) is ap—
proximately correct, and to figure out the support and the
resistance with some confidence of not going far wrong.

These calculations seem to indicate that artificial flight
is possible, even with planes ; that very flat angles of inci-
dence, from 2° to 5°, hitherto considered inadmissxble,
will be the most advantageous, and that Within certain
limits of hull resistance high speeds will require less
power than low speeds, because they admit of obtaining
support from the air at a flatter angle.

We have seen that the " drift" diminishes as the angle
of incidence becomes less, that the “ hull resistance" (in-
cluding car, framing, braces, etc.) increases as the square
of the speed, and that the skin friction is so small that it
may for the present be disregarded, and we are enabled
to calculate, approximately at least, the power required to
obtain support in flight With planes, and to overcome the
resistance, although we are not yet aware what limit will
be imposed upon the size of artificial apparatus by the law
that the weight will increase as the cube, while the sus-
taining surfaces will grow only as the square of the sim—
ilar dimensions.

Moreover, the formulae which give this promise of suc-
cess were derived from experiments with plane surfaces,
and we already know that concavo-convex surfaces will
be still more effective, although the most favorable shapes
are not yet ascertained. This statement indicates the
direction in which scientific investigation and experiment
shOuld now proceed, and holds out the hope that this first
problem is in a fair way of being solved.

2. The second problem—that concerning the motor to
be employed—has justly been considered to be the most
important and difficult of solution. It seemed hopeless to
rival, with an artificial motor. the output of energy apper-
taining to the motor muscles of birds in proportion to their
weight, which, as we have seen, there is good reason to
believe develop work in ordinary flight at the rate of
I H.P. to 20 lbs. of weight, and can for a brief period, in
rising, give out energy at such rate as to represent an en-
gine of only 5 or 6 lbs. of weight developing I HP.

The writer has, on a former occasion,* passed in review

* Aerial Navigation. A lecture to the students of Sibley College, 1890.
252 FLYING MACHINES.

the comparative weights of various classes of engines.
He found that the lightest engines in use in I890. includ-
ing the generator of power, weighed 60 lbs. per HP. for
steam, 88 lbs. per -H.P. for gas engines, and 130 lbs. per
HP. for electric motors. He intended to discuss the sub-
ject further in this account of “ Progress in Flying Ma-
chines," but recent achievements with steam-engines seem
to make this unnecessary. Marine (yacht) engines have
been reduced more than one half in weight; Mr. Har-
grm/e has produced a steam-engine weighing 10.7 lbs.
per H.P.; M. Maxim has created one weighing but 8 lbs.
per H.P., including a condenser, and other experimenters
are approximating closely to the same weights,

Steam-engines. therefore, seem to have been so much
reduced in weight as to admit of their being employed as
motors for flying machines. This may not be a final solu-
tion. for it may be that some form of gas or petroleum
engine will prove to be still better adapted to aerial pur-
poses, as indeed has been already hinted by M. Maxim ;
but in any event, his steam-engine seems to be light enough
to make a beginning of artificial flight, if the other prob-
lems pertaining thereto can also be solved.

But it is possible to utilize a still lighter power, for we
have seen that the wind may be availed of under favorable
circumstances, and that it will furnish an extraneous motor
which costs nothing and imposes no weight upon the
apparatus.

Just how much .power can be thus utilized cannot well
be told in advance of experiment; but we have calculated
that under certain supposed conditions it may be as much
as some 6 H P. for an aeroplane with 1,000 sq. ft. of sus—
taining surface; and we have also seen that while but
few experimenters have resorted to the wind as a motor,
those few have accomplished remarkable results.

3. As regards the selection of the instrument through
which propulsion is to be obtained, we have seen that ex—
periment has shown that reaction jets, whether obtained
from explosives, steam, or blasts of air; that wave action ;
that valvular, folding or feathering paddles or vanes have
all proved inferior in practical application to screw pro-
pellers orto propelling wings, and that the two latter (if we
are to judge from Mr. Hargrave’s experiments) are about
equally effective. It being understood, however, that this
statement refers to wings only as propelling instruments
and not as sustaining surfaces. We may conclude, there-
fore, that the third problem may now be solved either with
screws or with waving wings, as best conforms to the rest
of the design.

4. This brings us, therefore, to consider the solution of
CONCLUSION. 253

the fourth and important problem of what kind or form of
apparatus should be selected for sustaining the weight-—
whether flapping wings, screws, or aeroplanes. The best
measure oi comparison will be the weights or number of
pounds which experiment shows may be sustained per
H.P. with each form, considered in connection with the
weight of the construction required to make that form
abundantly strong against the resulting strains. The dif-
ference between the two weights will indicate the propor—
tion of the whole which may be devoted to the motor. It
is desirable, therefore, to consider each form or kind of
apparatus separately.

We do not yet know accurately how many pounds per
H.P. can be sustained in horizontal flight with a bird-like
apparatus of flapping wings. The toy birds which have
been described support only from 6 to 20 lbs. per H.P.,
but this inefficiency is largely due to the undue friction of
the working parts and to the abnormal head resistance of
the framing in such imperfect models. The writer has
estimated that in the case of a flying pigeon about 77 lbs.
are sustained per H.P., but as this is partly based on con-
jecture, it may be an underestimate.*

Upon the whole, the writer is inclined to admit that
about 100 lbs. per H.P. may be sustained with flapping
wings, this including the power required both to support
the weight and to overcome the head resistance. He
believes, moreover, that in an artificial machine of suffi-
cient size to sustain one man, the strength required to re-
sist the constant reversals of strains due to the alternating
motion of the wings will involve such dimensions that the
weight of the apparatus and man will amount to at least
three-fourths of the whole. thus leaving but one—fourth of
the total weight which can be devoted to the motor and
its adjuncts, including the fuel and supplies for the jour-
ney.

Concerning aerial screws we have abundant experimen-
tal data. Nadar, Wmfiam and Frem'nges each obtained
a sustaining effect of 33 lbs. per H.P.; Dz'ezzaz'a’e realized
26.4 lbs, and Dal/1151mm and Lolzmmz secured 37.6 and
55 lbs. per H.P., while Renard obtained from 17 to 48 lbs.
thrust by screws rotating at various speeds, and May re-
corded 40 lbs. per H.P. sustained from a wind wheel with
vanes of variable pitch.

These performances, however, included a certain
amount of ascension, which absorbed part of the power,
so that probably we shall be quite safe in assuming that

* M. Lz'lz'ent/ml raised 93 lbs, per H.P. in his experiments. but this was
counterbalanced weight, and there was no head resistance of forward flight
to be overCOme.
254 FLYING MACHINES.

in mere horizontal flight some 45 lbs. per H.P. can be sus-
tained with screws.

As the strains in a rotating apparatus will be less de-
structive than those involving reversals of motion, it seems
probable that screws may be constructed with a less weight
of materials than flapping wings of the same sustaining
power. It is judged that an apparatus can be constructed
to sustain the weight of one man with rotating screws, in
which only about two—thirds of the weight shall be ab-
sorbed by the framing, screws, car and man, thus leaving
one-third of the whole weight for the motor and its various
adjuncts. The practical result of this estimate will be
elicited further on.

We have also a number of experimental data concern-
ing aeroplanes. Professor Langley sustained a maximum
of 209 lbs. per H.P. with planes at an angle of incidence
of 2°, and M. Maxim sustained i33 lbs. per H.P. at an
inclination of I in I4. These data apply to the plane
only. Neither of these performances included the head
resistance due to the framing and car which are indis-
pensable in an actual machine, so that we must derive
our premises from complete models. With one of the
latter Tali” sustained 110 lbs.; Phillips, 72 lbs., and
Hzzrgrave, 89 lbs, 76 lbs., and 79 lbs. per H.P. in hori-
zontal flight. We may safely conclude, therefore, that
100 lbs. per H.P. can be sustained in horizontal Flight with
an aeroplane.

As the latter consists of fixed surfaces receiving no
strains save the sustaining pressure of the air, it is be-
lieved that such class of apparatus can be constructed of
sufficient size to sustain one man, so that about one-half
of the whole weight shall be devoted to the apparatus and
man, and the other half to the motor and its adjuncts.

These estimates of the proportion of the sustained total
weight which can be spared for the motor, are necessarily
mere estimates made in advance of actual testing, and
(for reasons to be stated hereafter) upon the smallest size
of apparatus practicable for actual man flight, yet they
enable a comparison to be made between the various forms
of apparatus which have been herein described. The re-
sult is as follows :

COMPARATIVE EFFICIENCY or VARIOUS Forms.

 

 

Proportion Resultinry pos-
- Pounds sus- . . .6
Kind of Apparatus. tained per HP. available for Slble weight of
motor. motor per H.P.
Screws .................... 45 l 3‘; 15 lbs
Wings. ............... 100 l .1,- 25 “
Aeroplanes ............... 100 1 4} 50 “

 
CONCLUSION. 255

The above table, based as it is upon experimental data
of weights actually sustained, indicates that aeroplanes
are probably the best forms to experiment with, because
they admit of a larger proportion of the whole weight
being appropriated to the motor. It. also indlcates the
pOSsibility of success in artificial flight, with motors weigh—
ing to or 15 lbs. per HP” provided that the remaining
problems be also solved; but it must not be overlooked
that more power will be required in rising from the ground
than in horizontal flight. and that the actual proportion of
the total weight available for the motor, although con-
servatively estimated from the best. data available,* is still
a matter to be proved by experiment.

The common basis which has been here selected for
comparison is that size of apparatus sufficient to support
the weight of one man. This is the smallest which can
be adopted, and it is theoretically the most favorable, for
inasmuch as the weight of the framing will presumably
increase as the cube of the dimensions, while the sustain-
ing surfaces will increase as the square of these same
dimensions, it is seen that the ratio of the total weight
sustained which can be spared for the motor will not be
constant, but that the larger the apparatus the more it
will weigh in proportion to its surface and the less there
will remain for the engine and its adjuncts. Flying ma-
chines, therefore, should preferably be designed as small
as practicable, and experimenters will place themselves
at a disadvantage if they construct large machines.

5. As regards the fifth problem—the amount of the sus-
taining surface required—it depends on the speed, and it
is probable that, within certain limits, no particular extent
(in ratio to the weight) can be said to be absolutely the
best, because a large part of the resistance will consrst in
the “ drift," and the latter is independent of the area of
the sustaining surface; a small area at high speed being
able to sustain as much weight as a larger area at a cor-
responding lesser speed, as 1ndeed is indicated by the
formula already given for the drift: R : chmg. @, 1n
which the element of surface disappears.

Practically, however, the weight of the necessary fram—
ing and the hull resistance will determine the ratio of sur-
face to weight which will be most advantageous. We
have seen that encouraging experiments have been made
with surfaces varying from 075 sq. ft. per pound in the
case of Herr Lz‘lz'enl/zalto 7 sq. ft. per pound in the case
of M. Hargrave. It seems probable that the latter is in
excess, and that it would be preferable to confine the

* r’llax/‘m's aeroplane and the soaring devices of Le Brz’r. [Maui/lard, Lili-
enI/ml, and [I’Iom‘gomeryJ
256 FLYING MACHINES.

dimensions of artificial machines within the proportions
which obtain with fast flying birds, as shown in the table
heretofore given, this being from\3.62 sq. ft. per pound in
the case of the swallow, to 0.44 sq. ft. per pound in the
case of the male duck, with which areas, if we consider
their wings as planes, and the angle of incidence to be 3°,
the swallow requires a speed of 23.1 miles per hour and
the duck a veloc1ty of 66.2 miles per hour to sustain their
weight.

To come down safely, at the speed of the parachute, re-
quires about the ratio of the swallow, while the propor-
tions of the duck are more favorable to high speed. As
the drift will increase only if the angle of incidence be
increased, it would seem preferable to maintain this angle
as uniform as possible, and to provide variable supporting
surfaces to be folded or unfolded with variations of speed,
if such a construction can be devised in connection with
the concavo-convex surfaces which have already been
mentioned as likely to give the most satisfactory results.

6. The sixth problem cannot be said to be solved, for
there is considerable uncertainty concerning the best
materials to be employed for the framing and for the
moving parts; or what should be the texture of the sus-
taining surfaces in an actual flying machine. Hitherto
the main question has been to construct a model which
would fly at all; and experiments with models have not
thrown much light on the question of materials. If a
partial success be realized, this problem will assume
greater importance.

It involves considering materials from a somewhat new
point of View, or investigating their strength and stiffness
per unit of weight, so as to secure a maximum of resist-
ance with a minimum of weight. The quill of a bird’s
feather is stronger and more elastic than an equal weight
of steel, and the texture of its barb is peculiar.

It now seems probable that bamboo, the lighter of the
stiff woods, and some varieties of steel, will be found to
be the preferable materials for the framing. Contrary to
popular belief, aluminium is inferior to steel per unit of
weight, particularly in compression, but it does not cor-
rode and may be preferable on that account. It may be
utilized for the sustaining surfaces, either as thin sheets
or as wire gauze made smooth by some coating; but tex-
tile fabrics will probably be the first to be employed for
full-sized apparatus. One important requirement, how—
ever, is that the surfaces shall not unduly change their
shape under varying air pressures. They must be rigid,
and, perhaps, elastic, and the fluttering of textile fabrics
is likely to give trouble to experimenters. It may be,
CONCLUSION. 257

therefore, that thin wood, parchment, or pasteboard may
prove preferable, the latter being corrugated lengthwise
of the direction of motion in order to gain stiffness.

The barb of a feather is smooth in one direction and
asperous in the other; and it is possible that a similar
texture of surface may prove of advantage in flying ma-
chines, but this probably will not be determined until par-
tial success has been achieved with an apparatus of suffi-
cient size to sustain the weight of a man.

7. The problem of the maintenance of the equilibrium is
now, in my judgment, the most important and diflicult of
those remaining to be solved. It has been seen, from this
review of “Progress in Flying Machines," that almost
every failure in practical experiments has resulted from
lack of equilibrium. This is the first requisite thing to
secure, for, as has already been said, safety is the most
important element of success—safety in starting up, in
sailing, and in coming down.

If a flying machine were only required to sail at one un-
varying angle of incidence in calm air, the problem would
be much easier of solution. The center of gravity would
be so adjusted as to coincide with the center of pressure
at the particular angle of flight desired, and the speed
would be kept as regular as possible ; but the flying ma-
chine, like the bird, must rise and must fall, and it must
encounter whirls, eddies, and gusts from the wind. The
bird meets these by constantly changing his center of
gravity; he is an acrobat, and balances himself by in-
stinct ; but the problem is very much more difficult for an
inanimate machine, and it requires an equipoise—auto-
matic if possible—which shall be more stable than that of
the bird.

We have seen from the experiments described that the
transverse stability can be procured in two ways : (I) by
placing the two halves of the sustaining surfaces at a
diedral angle to each other, and (2) by adding a longi-
tudinal keel to the apparatus, as in the case of Mr. Boy”-
ton’s fin kites. The mode of action is practically the
same for both, and consists in producing increased air
pressure upon the side which tends to dip downward.
The two may be employed conjointly. but the keel will
produce less head resistance to forward motion than the
diedral angle, which resistance, however, may be dimin-
ished by turning upward only the outer ends of the sus-
taining surfaces in a manner similar to the upbending
primary feathers of the soaring birds.

Longitudinal stability may be promoted in three ways :
(I) By additional surfaces at a slight angle to the main
sustaining surface, (2) by placing several surfaces behind

I7
258 FLYING MACHINES.

each other, (3) by causing the center of gravity always to
coincide with the center of pressure. The first way cor-
responds to the method which has been mentioned as pro-
curing transverse stability by means of surfaces at a
diedral angle ; it is illustrated by M. Maxim’s aeroplane,
in which two such surfaces are affixed, front and rear;
and by M. Pémzud's aeroplane, in which but one is affixed
in the rear. The second way is illustrated by M. Brown's
bi-planes and by M. Hargrave‘: cellular kites; and the
third is the method universally employed by the birds.

For an artificial machine this last method is as yet an
unsolved problem. Several inventors have proposed
methods of shifting weights to change the position of the
center of gravity as the apparatus changes its angle of
incidence, but none of these are automatic, and none have
been tested practically.

8. The guidance in a vertical direction—2' 49., up or down,
depends in a great degree upon success in the changin
the center of gravity which has just been alluded to. It
may be partly effected by changes in the speed or by hori—
zontal rudders, but in such case the equilibrium Will be dis-
turbed. Guidance in a horizontal direction has been
secured, as we have seen in several experiments, by verti-
cal rudders; but there are probably other methods still
more effective, although their merits cannot be tested until
a practical apparatus is experimented with. Upon the
whole, this problem may give trouble, but it does not seem
unsolvable.

9. A really adequate practical flying machine will hardly
be said to have come into existence until it possesses the
power of starting up into the air under all conditions.
This problem is as yet unsolved, and may not be until the
other problems have been worked out to a success. It is
clear that in rising upward more power will be required
than in horizontal flight; for to the force required to ob-
tain horizontal support must be added that required to
ascend, and the latter will vary with the rapidity of the
upward motion. Three principal methods have been ex-
perimented with : (I) By acquiring speed and momentum
on the ground; (2) by the reaction of rotating screws;
(3) by utilizing the force of the wind. The first we have
seen to require the use of Special appliances, such as rail-
way tracks, so that its application-must be limited, and
the third necessitates that the wind shall blow, and with
sufficient force; either or both may be utilized with the
earlier types of practical machines should one or more be
hereafter developed ; but the writer believes that the sec-
ond method —that of rising through the reaction of a screw
—-will eventually supersede the two others. It will in-
CONCLUSION. 259

volve the difficult design of a simple form of sustaining
surfaces which can be alternately rotated as a screw or
held as a fixed aeroplane when sailing, the change being
effected while under motion in the air.

The writer does not believe that a bird-like machine
can rise into the air, under all conditions, by flapping its
artificial wings. It would need to be already up some
distance to permit such action. Birds spring up three or
four times their own height, or run against the wind to
acquire speed, and with vigorous flaps of wing they rise
at an angle seldom greater than 45°, but their initial action
would be quite impracticable to a machine of suflicient
size to sustain the weight of a man.

10. The alighting safely anywhere is also an unsolved
problem, and one, as will readily be perceived without
argument, of vital consequence. It has been slurred over
by most of the designers of flying machines, and the best
method which has been thus far proposed involves the
selection of a smooth, soft piece of ground and the alight-
ing thereon at an acute angle. When it is considered that
the speed required for support will be somewhere from
20 to 40 miles an hour, it will be realized that the per—
formance will be somewhat dangerous, and that it would
be preferable, if the design of the apparatus will admit of
it, to imitate the manoeuvre of the bird who stops his
headway by opening his wings wide, tilting back his body,
and obtaining the utmost possible pressure and retarda-
tion from the air before alighting upon the ground. This
would require for an artific1al machine a rapid change of
the center of gravity so as to tilt the apparatus backward
to the angle of maximum lift (about 36° by the table) and,
immediately thereafter, a counter change of the center of
gravity, so as to bring the apparatus back upon an even
keel in order to alight at the diminished velocity.

This manoeuvre is not as difficult and dangerous as may
at first sight appear ; but it must be acknowledged that it
would be preferable to utilize the reaction of a rotating
screw to diminish the forward motion and to hover over
the ground before alighting. This involves the same diffi-
cult design which has been alluded to as desirable for use
in rising, for it does not seem practicable, within the req-
uisite limits of weight, to provide two sets of sustaining
surfaces, one set to be used in rising and in alighting, and
the other to serve in horizontal flight. These last two
problems—the rising and the alighting safely, without
special preparation of the ground—seem very difficult of
solution, and are probably the last which will be worked
out.

The general problem having been thus decomposed into
260 FLYING MACHINES.

its several elements, and each element considered as a
separate problem, it will be seen that the mechanical diffi-
culties are very great; but it will be discerned also that
none of them can now be said to be insuperable, and that
material progress has recently been achieved toward their
solution.

The resistance and supporting power of air are approxi-
mately known, the motor and the propelling instrument
are probably sufficiently worked out to make a beginning ;
we know in a general way the kind of apparatus to adopt,
its approximate extent and required texture of sustaining
surfaces, and there remain to solve the problems of the
maintenance of the equilibrium, the guidance, the starting
up, and the alighting, as well as the final combination of
these several solutions into one homogeneous design.

In spite, therefore, of the continued failures herein re-
corded, it is my own judgment, as the result of this inves-
tigation into the “ progress in flying machines,” more
particularly the progress of late years, and into the recent
studies of the principles and problems which are involved,
that, once the problem of equilibrium is solved, man may
hope to navigate the air, and that this will probably be
accomplished (perhaps at no very distant day), with some
form of aeroplane provided with fixed concavo-convex sur-
faces, which will at first utilize the wind as a motive
power, and eventually be provided with an artificial motor.

The conclusion that important progress may be achieved
without an artificial motor was little expected when this
investigation was begun ; but the study of the various ex-
periments which have been passed in review, the percep-
tion of the partial successes which have been accomplished
with soaring devices, and the general consideration of the
subject, have led to the conclusion that the first problem
which it is needful to solve is that of the equilibrium, and
that in working this out the wind may furnish an adequate
motive power.

Preliminary experiments will, of course, be tried upon
a small scale, but no experiment with a model can be
deemed quite conclusive until the same principles have
been extended to a full-sized apparatus capable of sus—
taining a man, and until this has been exposed to all the
vicissitudes of actual flight. It will readily be discerned
that a less achievement than this would not prove an ade-
quate performance, and that no matter how well a model
might behave in still air, there would still remain the
questions as to how it would behave in a wind, and how
it was to solve the problems of starting up and of alighting.

It would seem, therefore, that the first problem to solve
is that of the maintenance of the equilibrium at all the
CONCLUSION. 26:

angles of incidence required ; in rising, in sailing, in en-
countering wind eddies, and in alighting.

For this purpose, it is now my opinion, based upon the
performance of the soaring birds and upon the partial (suc-
cess of some soaring devices, that the problem of equilib-
rium can best be solved with an apparatus which shall
utilize the wind as a motive power-11¢, with some form
of aeroplane of sufficient size to sustain a man, with which
the operator shall endeavor to perform the various manoeu-
vres required to meet the varying conditions of actual
flight, and to preserve at all times his balance in the air.
In other words, a flying machine to be successful must be
at all times under intelligent control, and the skill to ob—
tain that control may be acquired by utilizing the impulse
of the wind. thus eliminating, for a time at least, the
further complications incident to a motor.

But whether a soaring device be first experimented with,
or whether the initial apparatus be provided with a motor,
the next question pertains to the conditions under which
a machine carrying a man can be experimented with most
safel .

Vaii’ious methods have been suggested, and a few have
been tried. The most obvious is to suspend the apparatus
from a cable stretched between two tall masts or between
two steep hills. This has been proposed many times, but
we have seen by the experience of M. Sanderz/al that it
does not afford sufficient length of suspending rope to per-
mit. of unimpeded manoeuvres, and that experience gained
in that way would scarcely be available in free flight. A
preferable plan has been proposed by M. Duryea (and
probably by others), which consists in suspending the ap-
paratus to be experimented with from a captive balloon,
anchored by several divergent ropes so as to remain a half
mile or thereabouts from the ground, as shown in fig. 83.
By means of a rope passing through a pulley block at-
tached to the balloon, and thence to a Windlass on the
ground, the machine to .be experimented with may be
drawn into the air to a sufficient height to clear the gusty
air conditions found at or near the ground, and there, in
comparative safety, the sky-cycler might manipulate his
devices, ascertain the effect of various manoeuvres, and
gradually gain control, skill. and confidence preparatory
to trusting himself to actual flight.

This method is understood to have been employed by
M. C. E. Myers, the aeronautical engineer, in experi-
menting with parachutes, and to have given promise of
satisfactory results within certain limits. It is well worth
testing as a preliminary trial of a flying apparatus, but it
should be remembered that a machine suspended from a
262 FLYING MACHINES.

rope, however long, will not be under quite the same cir-
cumstances as in free flight. Even if it rises upon the
wind and is wholly supported thereon it will still be ham-
pered by the rope, and perhaps restrained from some
action which it is important to understand in order to
maintain the equilibrium, so that the operator will never
be quite certain that he has gained complete control over
his apparatus.

Other methods have been proposed by various writers.

 

Fm. 83.—DURYEA’S PROPOSAL—x893.

M. 0;. Way/tar, for instance, in the Aéronauz‘e for July,
1884, suggested the construction of a circular railway of
600 to 1,000 ft. diameter, upon which a large platform car,
covered with a soft mattress, should carry the apparatus
to be tested, attached with restraining ropes about breast
high. This car to be towed at varying speeds by a loco-
motive, so as to afford a sustaining effect and to encounter
the wind at various angles, until the Operator shall master
the necessary manoeuvres.

M. A. Goupz'l, on the other hand, proposes a circular
CONCLUSION. 263

elevated railway consisting of a single central girder sus-
pended by wire ropes between two rows of posts, and
serving to carry a truck to which the apparatus to be ex-
perimented with may be suspended. In this case the
machine might be provided with its own motive power, or
towed by a wire rope, or driven by an electric motor, but
in either case there would still remain the restraint of the
safety suspending rope, which, as previously suggested,
might vitiate the various air reactions which it is impor-
tant for the operator to experience practically.

These, and other devices which may be suggested, may
doubtless prove useful in making the preliminary trials
with various forms of apparatus, thus testing their be-
havior when restrained, but there will always come a
time when such apparatus, if apparently adequate, must
be tried at full liberty and encounter all the contingencies
of free flight. It seems clear that after the preliminary
trials with models have been made, time may be saved in
ascertaining the full merits of a device and in improving
it, if experiments with the full-size apparatus be made at
entire liberty instead of under restraint, provided adequate
precautions be taken to avoid serious injury in alighting.

Referring to the various experiments which have been
made with full—sized apparatus, more particularly those of
Dante, Le Brz's, Maui/lard, Lz’lz’enZ/zal, and Montgomery,
it is seen that Dante adopted the more rational plan of all
by experimenting over a sheet of water, although the ex-
act method he pursued is not known.

Upon the whole, the best mode of procedure is prob-
ably that proposed by Le Brz‘s, which want of means pre—
vented him from adopting—that is to say, to start from
the deck of a steam vessel under way, so as to obtain
initial velocity. as well as to face the wind from whatever
direction it may blow, and to be quickly picked up after
alighting. If the machine be provided with a light buoy
and line, and the operator be encased in a cork 1acket or
life-preserver, he may thus quickly put to the test the
merits and the deficiencies of his apparatus with but little
danger to himself, and ascertain whether it can be brought
under control. The machine may experience breakages,
the operator will doubtless suffer many duckings, he may
even be stunned at times, but he is not likely to lose his life
or to break a limb, as he might do were he to experiment
over land.

It is believed that salt water is preferable to fresh water,
over which to carry on such experiments, not only because
of the greater buoyant power of the water, but especially
because sea breezes are more regular and less gusty than
land breezes. It is evident that it would be preferable to
264 FLYING MACHINES.

operate over a genial or a tepid sea, in trade-wind regions
if possible, and in locations where steady sea breezes of
no great intensity may be relied upon to blow almost
daily. It would be desirable to select the vicinity of some
projecting tongue of land or of some isthmus, where cap-
tive preliminary tests may be made, and also that there
should be a cliff in the neighborhood whence models and
perhaps the apparatus itsell might be floated off. There
are many such spots to be found within proximity of ma-
chine shops, in the Mediterranean, in the Gulf of Mextco,
and on the coast of Southern California, and the attention
of designers of flying machines, who may want to test the
merits of their deVices upon a really adequate scale, is
particularly directed to the vicinity of San Diego, Cal.,
where all the Circumstances which have been alluded to
are to be found combined, even to a local railroad along
the beach, on which the tests proposed by M. Wey/zer
might be carried on.

All this presupposes that the preliminary experiments
with small models have resulted satisfactorily, and that
the designer wishes further to test. the merits of his appa-
ratus upon a practical working scale. with a machine
capable of carrying a man and provided with the requisite
devices to bring it under control while in the air, and thus
to work out the problem of equilibrium. The expense
will doubtless be considerable, and the mishaps not. infre-
quent, but there seems to be no surer way of ascertaining
whether a full-sized apparatus will preserve its balance in
the air, while the risk of serious injury will be small. If
such experiments finally succeed in solving the equilibrium
problem. in securing safety in rising, in sailing, and in
coming down, with a machine carrying its operator, an
immense step forward will have been taken toward solvmg
the other problems mentioned, and toward finally develop-
ing a safe flying machine, provided with a motor of its
own and capable of being operated anywhere; for once
safety has been secured under the various actual condi-
tions of out-door performance, it ought to be a compara-
tively easy and short task to work out the other questions.
save perhaps those pertaining to the starting up from and
alighting upon the ground.

Assuming all this to be possible—and while the mechan-
ical difficulties are doubtless great, they do not seem to
be insuperable—the final working out of the general prob-
lem is likely to take place through a process of evolution.
The first apparatus to achieve a notable success will neces-
sarily be somewhat crude and imperfect. It will probably
need to be modified, reconstructed. and readventured
many times before it is developed into practical shape.
CONCLUSION. 265

The inventor will doubtless have to construct the first
models and perhaps the first full-sized machine at his
own expense, in order to demonstrate the soundness of
his conception and the comparative safety of its operation ;
but after this much is accomplished further remodelling
and experiment will still probably be required to develop
the apparatus into commercial value.

This phase of the evolution is likely to require the aid
of capital, because the expense may be quite considerable ;
and inasmuch as a financial venture to develop such a
difficult and novel contrivance must be gone into as a
hazard, with the acceptance of the possibility of total loss
as an offset for the hope of drawing a prize, the parties
advancing the capital will probably require that the in-
vention (if invention there be) shall be fully protected by
patents.

In view of this probable requirement, it may be ques-
tioned whether M. Hargrave IS quite prudent in taking
out no patents for his various devices, for he hints in his
last paper that he is hampered in his experiments by hav-
ing to perform them in public. The difficulty arises from
the fact that the experiments, to be of practical value,
have to be performed out. of doors, and the writer knows
of some designers who, unable, on the one hand, to Secure
a patent—in the United States at least—until they can
demonstrate the practical performance which they hope
for, and apprehensive, on the other hand, of being an—
noyed by spectators, have retired into a wilderness to
make their experiments, thus placing themselves at serious
disadvantage in case a mishap of any kind occurs.

Most of the patents heretofore granted for flying ma-
chines are quite impracticable, yet the claims cover, here
and there, some feature which may eventually contribute
to success. It will be judicious, therefore, for designers
of projected flying machines to study prior patents, and
an attempt has been made in these pages to indicate some
of those which contain valuable suggestions. The nov-
elty (if any) in future patents will probably largely consist
in new combinations of features already patented.

There are probably a good many arrangements of sus-
taining surfaces which will prove available for aeroplanes ;
some will prove more effective and steadier than others,
and this must be ascertained by experiment; but in any
event success would be hastened by a working association
of experimenters in this inchoate research, for the prob—
lems, as has been seen, are many, and no inventor is
likely to be in possession of all the miscellaneous knowl-
edge and variety of talent required to perfect so novel an
undertaking.
266 FLYING MACHINES.

To the possible inquiry as to the probable character of
a successful flying machine, the writer would answer that
in his judgment two types of such machines may event-
ually be evolved : one, which may be termed the soaring
type, and which will carry but a single operator, and an-
other, likely to be developed somewhat later, which may
be termed the journeying type, to carry several passengers,
and to be provided with a motor.

The soaring type may or may not be provided with a
motor of its own. If it has one this must be a very simple
machine, probably capable of exerting power for a short
time only, in order to meet emergencies, particularly in
starting up and. in alighting. For most of the time this
type Will have to rely upon the power of the wind, just as
the soaring birds do, and whoever has observed such birds
will appreciate how continuously they can remain in the
air with no visible exertion. The utility of artificial ma-
chines availing of the same mechanical principles as the
soaring birds will principally be confined to those regions
in which the wind blows with such regularity, such force,
and such frequency as to allow of almost daily use. These
are the sub-tropical and the trade—wind regions, and the
best conditions are generally found in the vicinity of
mountains or of the sea.

This is the type of machine which experimenters with
soaring devices heretofore mentioned have been endeavor-
ing to work out. If unprovided with a motor, an appa-
ratus for one man need not weigh more than 40 or 50 lbs.,
nor cost more than twice as much as a first-class bicycle.
Such machines therefore are likely to serve for sport and
for reaching otherwise inaccessible places, rather than as
a means of regular travel, although it is not impossible
that in trade-wind latitudes extended journeys and explora-
tions may be accomplished with them; but if we are to
judge by the performance of the soaring birds, the aver-
age speeds are not likely to be more than 20 to 30 miles
per hour.

The other, or journeying type of flying machines, must
invariably be provided with a powerful and light motor,
but they will also utilize the wind at times. They will
probably be as small as the character of the intended
journey will admit of, for inasmuch as the weights will
increase as the cube of the dimensions, while the sustain-
ing power only grows as the square of those dimensions,
the larger the machine the greater the difficulties of light
construction and of safe operation. It seems probable,
therefore, that such machines will seldom be built. to carry
more than from three to to passengers, and will never
compete for heavy freights, for the useful weights, those
CONCLUSION. 267

carried in addition to the weight of the machine itself,
will be very small in proportion to the power required.
Thus M. Maxim provides his colossal aeroplane (5,500
sq. ft. of surface) with 300 horse power, and he hopes
that it will sustain an aggregate of 7 tons, about one-half
of which consists in its own dead weight, while the same
horse power, applied to existing modes of transportation,
would easily impel—at lesser speed, it is true—from 350
to 700 tons of weight either by rail or by water.

Although it by no means follows that. the aggregate cost
of transportation through the air will be in proportion to
the power required, the latter being but a portion of the
expense, it does not now seem probable that flying ma-
chines will ever compete economically with existing modes
of transportation. It is premature, in advance of any
positive success, to speculate upon the possible commer-
cial uses and value of such a novel mode of transit, but
we can already discern that its utility will spring from its
possible high speeds, and from its giving access to other-
wise unreachable points.

It seems to the writer quite certain that flying machines
can never carry even light and valuable freights at any-
thing like the present rates of water or land transporta-
tion, so that those who may apprehend that such machines
will, when successful, abolish frontiers and tariffs are
probably mistaken. Neither are passengers likely to be
carried with the cheapness and regularity of railways, for
although the wind may be utilized at times and thus re-
duce the cost, it will introduce uncertainty in the time re-
quired for a journey. If the wind be favorable, a trip
may be made very quickly ; but if it be adverse, the jour-
ney may be slow or even impracticable.

The actual speeds through the air will probably be
great. It seems not unreasonable to expect that they will
be 40 to 60 miles per hour soon after success is accom-
plished with machines provided with motors, and event-
ually perhaps from 100 to 150 miles per hour. Almost
every element of the problem seems to favor high speeds,
and, as repeatedly pointed out, high speeds will be (within
certain limits) more economical than moderate speeds.
This will eventually afford an extended range of journey
--not at first probably, because of the limited amount of
specially prepared fuel which can be carried. but later on
if the weight of motors is still further reduced. Of course
in civilized regions the supply of fuel can easily be replen-
ished. but in crossing seas or in explorations there will be
no such resource.

It seems difficult, therefore, to forecast in advance the
commercial results of a successful evolution of a flying
268 FLYING MACHINES.

machine. Nor is this necessary; for we may be sure
that such an untrammelled mode of transit will develop a
usefulness of its own, differing from and supplementing
the eXisting modes of transportation. It certainly must
advance civilization in many ways, through the resulting
access to all portions of the earth, and through the rapid
communications which it will afford.

It has been suggested that the first practical application
of a successful flying machine would be to the art of war,
and this is possibly true ; but the results may be far differ-
ent from those which are generally conjectured. In the
opinion of the writer such machines are not likely to prove
efficient in attacks upon hostile ships and fortifications.
They cannot be relied upon to drop explosives with any
accuracy, because the speed will be too great for effective
aim when the exact distance and height from the object
to be hit cannot be accurately known. Any one who may
have attempted to shoot at a mark from a rapidly moving
railway train will probably appreciate how uncertain the
shot must be.

For reconnoitring the enemy’s positions and for quickly
conveying information such machines will undoubtedly
be of great use, but they will be very vulnerable when
attacked with similar machines, and when injured they
may quickly crash down to disaster. There is little ques-
tion, however, that they may add greatly to the horrors
of battle by the promiscuous dropping of explosives from
overhead, although their limited capacity to carry weight
will not enable them to take up a large quantity, nor to
employ any heavy guns with which to secure better aim.

Upon the whole, the writer is glad to believe that when
man succeeds in flying through the air the ultimate effect
will be to diminish greatly the frequency of wars and to
substitute some more rational methods of settling inter-
national misunderstandings. This may come to pass not
only because of the additional horrors which will result
in battle, but because no part of the field will be safe, no
matter how distant from the actual scene of conflict. The
effect must be to produce great uncertainty as to the re-
sults of manoeuvres or of superior forces, by the removal
of that comparative immunity from danger which is neces-
sary to enable the commanding officers to carry out their
plans, for a chance explosive dropped from a flying ma-
chine may destroy the chiefs, disorganize the plans, and
bring confusion to the stronger or more skillfully led side.
This uncertainty as to results must render nations and
authorities still more unwilling to enter into contests than
they are now, and perhaps in time make wars of extremely
rare occurrence.
CONCLUSION. 269

So may it be ; let us hope that the advent of a success-
ful flying machine, now only dimly foreseen and neverthe-
less thought to be possible, will bring nothing but good
into the world; that it shall abridge distance, make all
parts of the globe accessible, bring men into closer rela-
tion with each other, advance civilization, and hasten the
promised era in which there shall be nothing but peace
and good-will among all men.

/’
I

vam‘: K e g

®§ «1 \\\
N

 

THE END.
 
APPENDIX.

THE FLIGHT OF THE ALBATROSS.

 

PAPER READ BEFORE THE BALLOON SOCIETY, OCTOBER 3, I884.

 

BY THOMAS MOY.

 

BEFOREI describe the mechanical portion of my subject it
may be useful if I make a few remarks on matters which,
although personal to myself, have now become historical.

In October, 1859, I published in the Mec/zam’t’: [Magazine a
description of a cigar-shaped vessel to contain gas for support,
and propellers placed in the same plane as the resistance, not
yardsbelow, as our French friends persist in placing the power.
I subsequently concluded that the bird principle proffered
greater chances of success.

Then on May 20, 1869. I described the flight of the albatross.
which I now intend to treat upon. Bear in mind that this sub-
ject is more than 15 years old. The only result arising there-
from was a word or two at the meeting, in opposition, in the dis-
cussion that followed.

Well, in 1875 I built a flying machine for experiment. I
made a steam-engine which gave an actual 3 H.P., and which
weighed altogether, engine and boiler combined, 80 lbs., and
I applied its power in two separate experiments, the records of
which will be found in the Reports of the Aeronautical Society,
and also in the Encyclopedia Britannica. These experiments
cost me many hundreds of pounds, and one of the experiments
was witnessed by the Duke of Argyll. the Duke of Sutherland,
Lord Dufferin, and others ; to whom I explained that a 30-H.P.
engine would do IO times the work of a 3-H.P. engine, but
would not weigh more than five times 80 lbs. When this
3 H.P. engine lifted 120 lbs. before their eyes, I thought that
the results warranted raising funds for further experiments,
but I did not have the money myself, and I was unable to
secure the assistance requisite to construct the larger machine.

On March 18, 1879. I constructed a model which, by its own
power. traveled forward on the ground and rose a short dis-
tance from the ground. You will find this experiment recorded
in the Report of the Aeronautical Society for that year, and
I shall probably exhibit this model next year at one of the
exhibitions.
272 APPENDIX.

I have sometimes been called sanguine, but I think this des-
ignation is a. great mistake. I do not expect my countrymen
to wake up to the importance of this subject during my life—
time. Fifteen years have passed since I gave the lesson of the
albatross, and I expect it will take another 15 years before it is
made use of.

Aerial navigation happens to be one of the subjects which
I have studied, and it is a mistake to suppose that I am more
anxious to effect that object than I am to effect improvements
in marine propulsion and steam boilers and engines and other
kindred subjects. Having quietly and patiently studied all
these subjects, I now propose to give you a very simple and
practical lesson on the flight of the albatross and its possible
imitation by man.

You know, of course, that the albatross is the king of the
sea, whose paradoxmal soaring on motionless wings amazes
travelers in southern seas. There are several varieties, but
the great albatross is seldom found north of the 35th parallel
of south latitude, and Mr. Wenham, in his celebrated paper on
aerial locomotion, alluded to the bird as follows :

“ One of the most perfect natural examples of easy and long-
sustained flight is the wandering albatross"—-a bird for en-
durance of flight probably unrivalled. Found over all parts of
the Southern Ocean, it seldom rests on the water. During
storms, even the most terrific, it is seen now dashing through
the whirling clouds, and now serenely floating, without the
least observable motion of its outstretched pinions. “The
wings of this bird extend 14 or 15 ft. from end to end, and
measure only 84,; in. across the broadest part. This conforma-
tion gives the bird such an extraordinary sustaining power,
that it is said to sleep on the wing during stormy weather, when
rest on the ocean is impossible. Rising high in the air. it
skims slowly down, with absolutely motionless wings, till a
near approach to the waves awakens it, when it rises again for
another rest."

These are the observed facts, concerning which there is no
dispute. The bird can remain indefinitely afloat upon the
wind, with no muscular exertion save the infinitesimal effort
required for steering and balancing himself, and the question
arises as to how he utilizes the wind.

Those who understand how to handle a sailing-vessel are
aware that by “ tacking" you can work a vessel to windward.
The operation is effected by what is called “ close hauling ;"
and any well-built fore-and-aft rigged vessel can sail within
four points of the wind. If the line A B in diagram Fig. 84,
indicates the direction of the wind, and the line C D the angle
of the sail, then the line E F represents the actual force pro-
pelling the vessel forward. I presume that there is no one
who will question the correctness of this. The wind may be
blowing southeast. and the vessel can travel due east.

Now we come to the bird. I shall not go into the subject of
the anatomy of the bird, or its food, etc., but would hope that
there is no one here who holds that exploded theory that a bird
APPENDIX. 273

 

Fig. 84.

fills its quills with a few cubic inches of gas and thereby be-
comes lighter than the air. Those bipeds, who shoot sea-gulls
or other flying creatures, know full well that when the birds
are maimed they fall with a thud : and under no circumstances
can a bird materially diminish his own weight.

The albatross, when sailing over a very calm sea, is obliged
to flap its wings in order to keep up its speed. But when a
strong wind is blowing it obtains the very impulse that it needs
without the necessity of using its wings as propellers; the
waves are produced by the pressure of the wind upon the
water, and the weather face of the wave throws the wind up-
ward, and gives the bird an upward thrust and impulse, of
which it takes advantage, and thus saves itself the exertion of
propulsion by flapping. The vertical direction of the wind
above the wave-tops enables the bird to “close haul” and
thereby obtain gratuitous propulsion, which supplies his need
until he reaches the next opportunity.

Now to prove the existence of this upward current. You
have seen the spray thrown up from the tops of the waves, you
have perhaps had a dash of it in your face while standing by
the weather gunwale. A dash of spray over the bows of a
cutter yacht has made you feel rather damp. These effects,
and others I might name, all prove the existence of this impulse
which serves the bird’s wants, like the impulse imparted to a
pendulum at the commencement of its oscillation.

Now if you look at my second diagram, Fig. 85, you will
see what I mean. The line A .8 represents here the upward

18
274 APPENDIX.

 

Fig. 85. \ A

direction of the current, caused by the shape of the weather
side of the wave, and you will at once perceive the similarity
of the forces, but you must bear in mind that one is horizontal
and the other vertical.

It is quite immaterial which way the bird travels, except that
its speed is much greater when it sails with the wind, or even
“ on a wind"—that is, with a beam wind. It can go dead to
windward, but it can also go in any other direction, just as a
vessel can, not only go to windward, but also with the wind
free. There are, however, several advantages possessed by
the bird over the ship which time will not permit of noticing.

You will therefore understand that the bird literally lies on
the upward current: takes a propulsive thrust by depressing
its head and sails to the next wave apex.

I must, however, warn you that this is only one kind of
flight, and it is this one kind of flight which I shall now show
you offers great facilities for man’s imitation ; and I now pro~
pose it as a first step toward conquering the air, not with cum-
brous gas-bags and feeble screws rotated by leaky accumulators
and a table-cloth for a rudder, but by following nature’s perfect
examples.

The method of flying which I have been attempting to de-
scribe to you is one which may be mastered by any intelligent
man in a short time, and it is one which may be learned, in
my judgment, with quite as much ease as bicycle riding.

His equipment Will be a Boynton dress, a pair of stiff, im-
movable wings or aeroplanes, a light sea-anchor with a length
of rope attached, and an accompanying boat. The frame of
the planes will be extended behind so as to carry a horizontal
rudder.

The Boynton dress and the aeroplanes will be firmly at-
APPENDIX. 275

tached together. Each plane might be 18 ft. X 3 ft., and made
stiff enough to bear three times the pressure that the total
weight would impose upon them. If the total weight of man
and equipment amounted to 250 lbs., I should test the strength
of the planes by resting the center on its back and spreading
upon the wings bags of sand to the amount of 750 lbs. If it
sustained this weight fairly, then it would be sale for an ex-
periment.

The albatross sometimes gets its initial velocity by starting
from the‘apex of a wave while floating. In like manner the
man could get his start by floating on the wave-top and using
his sea-anchor, composed of several small hoops covered with
canvas and open at one end. Holding on to the anchor and
slacking out slowly, with his head to the wind, he would watch
his opportunity, and pull the rope at the momentthat he arrived
at the top of a wave, when the wind would lift him just as a
boy’s kite is raised, and he could then go forward and pick up
his anchor, emptying out the water as he did 50. Every time
he approached the apex of a wave (say from to to 20 ft. above
it) he would depress the rudder, the effect of which would be
to place his body momentarily in the position shown in dia-
gram Fig. 85. This,'with the impulse of the wind, would give
him a high velocity which would not be very much lessened
before he received another impulse.

Suppose a wind of 40 miles an hour were blowing, this line
E F would represent a propulsive force of about 501bs.; but
the forward movement would probably reduce th s to 301bs.,
and this would be an ample propelling force for the purpose.

If the initial velocity were obtained by the same means that
birds obtain it, from a moderate elevation. it would be quite
easy to skim over the water at 10 or 20 ft. above the waves.

The first experiment would, of course, be in company with
a boat to render assistance in obtaining the first rise from the
water, and in any other emergency. After a few experiments
a mile or two would be easily covered, and after some practice
the speed would far exceed that of the bird, because the weight
is so much greater.

With a well—inflated Boynton dress and a good sea-boat in
attendance there would be no danger to life.

If you ask of what use is this? I say business, pleasure,
healthful exercise, and the accomplishment of the initial step
toward actual flight.

If a man thus equipped can go in the teeth of agale and
carry a rope to a wreck, that is business.

If a man thus equipped can travel at from 20 to 40 miles an
hour over the waves. that is pleasure and healthful exercise.

But it will also teach him the enormous sustaining power to
be derived from swift motion, and it will also explode many
of the silly, unmechanical notions which are now held upon
the subject.

We have had 100 years of balloons, and it is quite time that
some advance should be made, leaving drifting bladders be-
hind.
THE FLYING MAN.

THE CARRYING CAPACITY OF ARCHED SURFACES IN SAILING
FLIGHT.*

BY OTTO LILIENTHAL.

[After the foregoing pages were all in type. the index printed
and ready to go to the binder, a paper was received from Herr
Lilienthal describing his I893 experiments, which so fully sus-
tains the views set forth in this book, and holds out such prom-
ise of success in the near future, that it has been decided, at
some inconvenience, to include a translation of this paper in
an extra appendix.]

I PRESENT herewith an account of my personal experience in
soaring flight during the past year, this being the third annual
report published by me in this journal. I have now reached
the close of a series of experiments during which Ihad set
myself a definite task. This was to construct an apparatus
with curved carrying surfaces which should enable me to sail
through the air, starting from high points and gliding as far as
possible—that is to say, at the least obtainable inclination;
and to do this with stability and safety even in winds of medium
strength.

I may be permitted, in giving this account of experiments in
which artificial arched Wings were used, perhaps for the first
time. in a certain form of flight, to refer again to the introduc-
tion of this important element in the tea/mic: of flight.

Four years ago I completed a series of experiments on the
carrying capacity of arched wings, which I had carried on with
my brother for many years, and I published the results in my
book, “ The Flight of Birds as the Basis of the Art of Flying.”
In this work a new theory of flying, fairly explaining all the
phenomena of bird-flight, was for the first time completely
made known. The novel data involved in our calculations.
and the remarkable results arrived at in our experiments, were
my motives for not coming sooner before the public, until by
numerous and repeated trials every chance of error appeared
to be eliminated.

NowI have been accused in No. 6 of last year’s issues of
thisjournal* with having done wrong in keeping back these dis-
coveries so long. I am told that Ishould have come before
the public with them immediately after my first discovery of
the new laws of air resistance more than 20 years ago. That
while I was censuring the balloon for a delay of many decades,
I was myself postponing the solution of the question of aerial
navigation for two decades more by my silence.

* Translated from Zez'trc/zrzfz‘ fir Luftsclt zfla/zrt 24nd Physic dz Afmas-
p/zare for November, 1893.
APPENDIX. 277

Flattering as it is for me to see so great an influence on the
solution of the proolem of flying attributed to the new discov-
eries presented by me, yet I will not forbear to point out that
by these researches the theory of flight was merely put upon a
somewhat sounder basis, but that for the full solution of the
problem other very important questions will have to be settled.

The mere discovery that with arched wings supporting forces
are evolved which permit soaring to be performed with little
effort is far from being the final invention of flying. The suc-
cessful practical utilization of this important phenomenon in
air resistance is going to demand a considerable amount of in-
genuity. To get the upper hand over the wind with flying ma-
chines and to bring about a beneficial utilization of those favor-
able supporting forces—for such a task many a technical man

 

FIG. I.——LILIENTHAL’S “JUMPING-OFF” PLACE.

will have a chance to throw his talent into the scale; for the
field of work lying before us is no small one.

The great delav in publishing discoveries of myself and
brother on aviation was only the natural result of the circum-
stances under which they were made. Even when we were
devoting every hour of our leisure to the question of aviation,
and were already on the track of the laws which were to evolve
this problem, people in Germany still considered every man
who occupied himself with this unprofitable art as little better
than a lunatic. This was suflicient cause for our not attracting
unnecessary attention to such studies. The principal professor
of mathematics at the Berlin Gewerbe Academie in the sixties
heard from one of my fellow-students—they had given me
278 APPENDIX.

even then an appropriate nickname—that I was occupied with
investigations in aeronautics. The professor sent word to me
that there was no harm in my amusing myself with such calcu-
lations, but that I “ should, for Heaven's sake, not spend any
money for such things.” The professor, it is true, did not
know that this last advice was (for cause) quite unnecessary.
At that time a special learned commission appointed by the
State had just officially declared, once for all, that man would
never be able to fly; by which declaration naturally public
opinion, in favor of experiments on this problem, was not ex-
actly stimulated. Even later on the interest in aViation was
much less than it is to-day. German societies for the advance-
ment of aerial navigation were not yet in existence ; and when

/%
/, . ’
/ g/y \\

 

FIG. 2.-—-LILIENTHAL’S “JUMPING-OFF" PLACE.

they were formed the balloon, which I have always considered
an obstacle in the development of free flight, monopolized their
entire attention. For this reason Idid not at that time think
it advisable to join any one of the societies. When, however,
Ihad done so, and aviation had other representatives in the
society, I soon took advantage of the opportunity by communi-
cating our experimental results in a series of lectures, which
were followed shortly by the publication of my book.

To-day, with clear and comprehensive diagrams before us,
the explanation of the flight of birds seems very simple and
natural, while formerly every crow that flew by assigned us
the puzzle of its slowly moving,r wings to solve. To-day, too,
it is easy. in investigations on air resistance, to take surfaces
curved like the wings of a bird instead of flat plates, and to
APPENDIX. *279

develop in succession those wonderful effects, the first discov-
ery of which was, after all, not quite so simple and self-evident
as some may be inclined to assume now. The thoughtful
reader will readily understand that it took much time and study
to arrive at the conclusion that the slight curvature of the wing
was the real secret of flying. This was a conclusion which we
reached purely as a logical deduction from the flight of birds,
and which some noted investigators are not willing to admit
even at this late day. Besides this. being young men entirely
without resources, we were compelled to procure the means for
carrying on our experiments by the most petty economies, and
at times to suspend entirely our work in aeronautics by reason
of the struggle for existence. We should not at that time in
any event have been able to publish our results in proper form.
Even at the lastI had the very greatest difficulty in finding a
publisher for my book.

Although. then, the delay in publishing my work was simply
the result of circumstances, the position assumed toward it, in
the sequel, by certain investigators. proved to me that my satis-
faction in my work would have been much diminished if it had
been published before the entire data were on hand in a com-
plete form.

I must confess, however, that to us who abandoned flat wings
fully two decades ago, it seemed almost inconceivable that ex-
perimenters should cling so tenaciously to the aeroplane and
to hopeless calculations on the resistances of plane surfaces. as
practically all of them did during this whole period. Even to
the present hour the majority of aviators expend much painful
effort in attempting the hopeless task of trying to fly with flat
Wings.

Our expectation that the publication of our experiments,
showing the prob'em of flight in an entirely new light, would
be followed bv practical tests as to the correctness of the new
laws indicated by us was not at once realized. Our results
stood alone and unsupported until very latelv, and have but
recentlv been corroborated by the work of Wellner and Phil-
lips. Even now the flat wing does not show any signs of dis—
appearing from the field very soon.

When it became known that the French Government* had
granted funds for experiments on air resistance, I sought to in-
duce the president of the commission in charge of them to in-
clude curved surfaces as well as flat plates within the field of
his experiments. At the same time I sent him acopy of my
work, and by means of my diagrams pointed out to him the
favorable results in air resistance obtained with curved wings.

M. Hureau de Villeneuve thanked me for the book, pro
nounced it to be very interesting. but declined to grant my
request as to the consideration of hollow surfaces in his re-
searches.

His reasons for this course literally translated were the fol-
lowing :

* He means the French Society for the Advancement of Science—Eu.
280

APPENDIX

 

FIG. 3.—LILIENTHAL’S FLIGHTJ _]
APPENDIX.

 

FIG. 4.——LILIENTHAL’S FLIGHT.
282 APPENDIX.

“ I consider wings, pre-eminently, as moving organs for pro-
pelling at great'speed, and when this speed has been reached
the force necessary for supporting may be neglected. I have
shown this by constructing mechanical birds with flat wings,
which fly very fast and keep themselves up very well when
flying in the air. I try to make the wings true planes as far as
I can, for the flatter they are the greater is the speed attained.”

After this expression of opinion there is, 1 think, for the
present little prospects that experiments to be made in aeronau-
tic‘s with the aid of the French Government will be of any con-
siderable benefit to the technics of flight. It is also to be
greatly regretted that the extended experiments of Professor
Langley, carried out with so much care and expense, were lim-
ited to the resrstance of plane surfaces, as for such surfaces
data have long been on record sufficient for computing all cases
occurring in practice.

German and Austrian aviators, it is true, since the publica-
tion of my book have largely put aside flat wing and sail sur-
faces and introduced arched wings. However, this was done
mainly on paper. in proj’cts, and in aeronautical papers and
discussions. I therefore felt impelled all the more to carrv out
myself my theory in pracrice, and to utilize the results of my
preliminary small scale experiments. Through my long famil-
iarity with air and wind I had come to the conclusion that a
particular class of difficu'ties was next to be overcome. In
trials with movable Wings. in the building of steam air ships,
in experiments with mechanical birds of all kinds, 1 had found
out how hard it is to maintain astable equilibrium in the air
and to counteract the “ whims” of the wind.

For this reason 1 gave up for the time being motor mechan-
isms altogether, and limited myself to the simplest form of
flight—namely, gliding downward in an inclined direction.
The object of this was to ascertain practically whether rid/116
sailing and equilibrium through the air was possible ; whether
by practice we could learn to overcome the wind, that arch-
enemv of all wing builders, and, above all, whether with large
“human” wings the favorable carrying capacities of arched
wings would be maintained, which our experiments in small
wings (not over 7} sq. m. in area) had shown.

It was further my purpose to extend my former experience
in practical wing construction, and to build safer and lighter
sailing apparatus which should permit soaring safely at consid-
erable heights. As a final result we would also ascertain at
what angles of inclination sailing flight can be maintained with
and without the wind. and what conclusions can be drawn from
this as to the “ work" or power required for flying in general.

In addition to the details given in my communications of
I89! and 1892, I will mention briefly that this spring I erected
a special flying station on the “ Mai" hill, near Steglitz. The
owner of the property, Mr. Seldis, allowed me in the kindest
way to arrange a little earthmound at this spot for experiments
in soaring. By building a shed in the shape of a town, from
the roof of which I sailed, I obtained a “ jumping off" place
APPENDIX. 283

IO m. (33 ft.) high. The shed serves also for storing my ap-
paratus. The earth slope around the shed falls off toward the
southwest, the west, and the northwest. The roof is covered
with sod to give a firm footing in taking a run, and slopes in
the above—mentioned directions. In the assumption that I had
thus provided sufficiently for the frequent changes in the direc-
tion of the wind I was entirely mistaken. During the first half
of this summer the wind varied almost entirely between the
east and the north, and my flying tower remained unused for
nearly three months. The wind, be it understood once for all,
cannot be depended upon. A hill well suited for trials in sail-
ing flight should consist of a cone sloping on all sides, so that
the start may be made against the wind in any direction.

The two figures (figs. I and 2) show the “ jumping-off ’ place
from this tower, from in front as well as from the side. The
second figure shows also the attachment of the apparatus to the
body, already described in the past, which consists in simply
grasping it with both hands.

A novelty that I introduced this year in my apparatus is the
possibility of folding it up. The wings are formed of ribs
arranged radially and can be closed up, somewhat like the
wings cf a bat. In this way it became more portable and can
be stored anywhere.

I have gradually given up the great “ spread” of my former
apparatus. The unequal strength and direction of the wind,
under the right or the left wing, frequently produce a consider-
able displacement of the center of action of the air pressure,
which becomes worse the greater the “ spread” of the wings.
This spread I now never make greater than 7 m. (23 ft.), and
I am thus always able to restore equilibrium by a simple change
in my center of gravity.

The breadth of the wings has also its limits. It must be pos-
sible, in an instant, to transfer the center of gravity so far from
front to back as the point of action of the supporting air resist-
ance can move. The furthest backward limit of this motion is
the center of gravity of the wing surface. When you fall verti-
cally with this apparatus in calm air it acts entirely as a para-
chute. The air strikes vertically from below and presses uni-
formly on all parts of the surface. It is possible to get into
this position in flying if the aviator uses up, in gliding upward,
all the air-viva acquired in flying forward and downward,
whence the velocity will decrease very rapidly on the upward
turn. I have often been obliged thus to pass over some obsta-
cles—a tree, a crowd of people, or the photographer who was
getting a view of me from the front. It is easy to rise in this
way, but the apparatus comes to a stand at the summit, and if
it cannot be properly and promptly slanted down behind, it
will be tilted toward the front in falling, and the front edge will
be broken when it touches the ground.

The center of the supporting air pressure reaches its limit
toward tire front, when the machine is struck by a stronger
wind gust in flying. It is then necessary for the aviator to
throw himself as far forward as possible and also to stretch his
284 APPENDIX.

legs forward, otherwise velocity is lost. and the machine will
be driven back by the wind. The figure (No. 3) shows such a
critical position. I had started in a wind estimated by me at
from 6 to 7 m. velocity per second (I3 to 16 miles per hour),
and while I was in motion the velocity of the air rose to prob-
ably about IO m. (22 miles), for I was suddenly raised with so
much force that I became suspended in the air at a higher level
than my point of starting. Then I remained fixed at this point
for several seconds until the wind decreased, when I again
sailed forward and moved downward slowly. In order to be
able to conveniently equalize this fore-and—aft motion of air
pressure, by a change in the center of gravity, it is advisable
to make the breadth of wing not greater than 21} m. (8.2 ft.).
From these conditions we arrived at a pretty definite relation
in the shape and the size of the wings. With a spread of 7 m.
(23 ft.) and a breadth of 2% m. (8.2 ft.) we get, allowing for the
rounding of the ends, an area of 14 sq. m. (151 sq. ft), which
is sufficient to carry the mean weight of a man. Such wings
weigh about 20 kilograms (44 lbs.). My own weight is 80 kilo-
grams (176 lbs.), giving a total weight of exactly 100 kilograms
(220 lbs).

I have now moved my main practice ground to the Rhinow
Hills, which I referred to in my last year’s communication.
The topography is here as if made especially for experiments
in flying. Out of the surrounding flat fields a range of hills,
covered only with grass and heather, rises to a height of 60 m.
(200 ft.) with inclined slopes on all sides. The inclinations of
the slopes vary from 10° to 20°, so that one can select a place
for sailing along in any direction. When, this year, I unfolded
my flying outfit for the first time on these slopes, a somewhat
anxious feeling came over me, when I said to myself, “ From
up here you are now to sail down into the land spread out deep
before you.” But the first few careful leaps soon gave me
back a feeling of security, as the soaring flight began here far
more gently than from my flying tower. The wind did not
“ rear up” here as it did in front of the tower, where I always
felt a sudden upward blast from the wind in passing the edge,
which often threatened to be dangerous.

You run down hill against the wind with lowered wings, at
the proper moment you raise the carrying surface up a little,
so that it is approximately level ; and then, springing forward,
you try, by a proper position of the center of gravity of the ap-
paratus, to give it such an inclination that it will glide along
rapidly and drop as little as possible. Beginners will do well
to select for' this a gentle slope, over which they may glide
along a low elevation. The first rule is to keep yourlegs well
extended toward the front, and in landing to throw the upper
part of the body backward, so that the front edge raises itself
and thus checks the motion, as may be seen whenever a crow
alights. The starting and landing must be done exactly. square
against the wind. The fixed vertical rudder will keep the ap-
paratus exactly in the wind when in a state of rest. The hori-
zontal rudder keeps the apparatus from tipping over forWard,
APPENDIX. 285

a thing that arched surfaces are inclined to do. In landing,
however, the horizontal rudder must not hinder a rapid tipping
up of the machine; hence it must turn freely on its forward
edge when the air presses upward, and its motion must be lim-
ited at the bottom only.

The following mistake is to be particularly avoided. The
experimenter is soaring in the air and feels himself suddenly
raised by the wind, but unequally, as is usually the case—for
instance, the left wing more than the right. The inclined
position forces him toward the right. The beginner involun-
tarily stretches his legs to the right, because he foresees that
he will strike the earth on the right hand. The result is that
the right wing, which is already lower, is loaded still more,
and flight tends more and more downward and to the right,
until the tips of the right wing strike the earth and are broken.
For life and limb there is less danger, as the apparatus forms
an efficient guard in every direction, which checks the force of
the blow. The correct thing to do is always to extend one’s
legs toward the wind that is rising, and thus to press it down
again. In the beginning this requires some force of will, but
this useful movement soon becomes an unconscious one, after
we see how surely the wings can be guided this way and be
protected from damage.

Beginners are also easily tempted to utilize the momentum
which the easy downward glide gives them for a bold upward
flight. They are likely to forget, however, that at the summit
of the rising curve their apparatus becomes a mere parachute.
They do not lean back far enough and incur damages requiring
considerable repairs to the machine. It is better to postpone
such tricks until the regulating of the center of gravity has
become a second nature, like balancing on the bicycle, and
rather to lay most stress on gliding ahead at an inclination
which shall be uniform and as slight as possible, and particu-
larly to endeavor to make an elegant landing. Of course we
do not have time enough when in the air to consider carefully
whether the position of the Wings at any particular time is the
correct one. This is entirely a matter of practice and experi«
ence. After a few trials one begins to have a feeling of mas-
tery over the situation. A consciousness of safety crowds out
the first feeling of anxiety. Finally we become perfectly at
ease, even when soaring high in the air, while the indescrib-
ably beautiful and gentle gliding over the long sunny slope re-
kindles our ardor anew at every trial. It does not take very
long before it is quite a matter of indifference whether we are
gliding along 2 m. or 20 m. (6 ft. or 65 ft.) above the ground;
we feel how safely the air is carrying us, even though we see
diminutive men looking up at us with astonishment. Soon we
pass over ravines as high as houses, and sail for several hun-
dred meters through the air without any danger, parrying the
force of the wind at every movement.

After we have reached a feeling of safety in direct flight
against the wind, we involuntarily try, first a very little and
then more and more, to direct the course of our flight to the
286 APPENDIX.

right and to the left. A slight change in the center of gravity
to one side produces at once a small inclination of the carrying
surface, so that the supporting air pressure also moves to this
side and changes the direction of flight. There is nothing
simpler than steering flying machines It is important not to
forget in this connection that the landing must always be made
dead against the wind.

On the occasion shown by fig. 4. which represents a very
long and high flight, I had carried the deviation from straight
flight so far that at times I was flying almost in an opposite
direction. Coming from the hill at the right hand, I had almost
turned my back to the plain at the moment the picture was
taken.

For the present it does not appear to me to be advisable to
endeavor to bring the body into a horizontal position. because
the legs must always be ready for action in running, jumping,
steering and landing. Later on it will, perhaps, be possible to
make this change, after some other important improvements
have been made in the apparatus. Of course this would be
very important for producing easier passage through the air
and the consequent saving of energy in flying.

In the annexed figure (5) several lines of flight are illustrated.
The dotted line d: shows the path traversed in a calm. At the
top of the hill, at the point a, a running start is taken with as
high speed as possible and with wings lowered. The steeper
the hill the better. Then at é you raise your wings a very little
in front and try to glide along as close to the ground as possi—
ble, with your legs extended to the front. The diagram at C
shows how the air resistance L has at the same time a support-
ing and propelling force or component. Soon our velocity has
increased so much that at a’ we can change to a flatter inclina-
tion. Thus at an angle of 9° to 10° we approach the valley and
do not raise our wings in front till the very end at e, when we
apply a strong force by throwing the upper part of our body
back. Then the pressure of the air, acting suddenly at the
front, checks the motion, and we drop on to our feet quite
gently. just as if we had jumped, without wings, from the
height of a chair.

When there is any Wind the motion is still more gentle.
Flight against the wind, in reference to the earth, is in all cases
slower, as, of course, the relative motion of the air and the ap-
paratus governs the speed. The relative velocity attained is
felt by the strength of the breeze striking the face while flying.
A convenient device would be a little indicator pressure gauge
in the front of the apparatus, on which we could constantly
read the relative speed of the air. This would not involve any
appreciable increase in the resistance.

Although the wind compels us to resort to various extraor-
dinary manoeuvres, it also furnishes us an opportunity for test-
ing the real value and scope of sailing flight. By our calcula-
tions, based on experiments with arched surfaces on a small
scale during windy weather, extended and prolonged sailing
flight can be explained without further trouble. _With wings of
 

30. u.lFHZMM Om, HLHLZwZ‘HwbPCM fiPMQEH.
288 APPENDIX.

a proper form and position, the wind needs only to reach the
necessary strength in order to keep the experimenter from fall~
ing. Even with light winds of 4—5 m, velocity per second (9 to
11 miles per hour), we can with some little practice glide along
at the slight angle of 6° to 8°, as is shown in the line 12/.

The greatest velocity of the wind at which Idared to start
was about 7--8 m. per second (I5 to I8 miles per hour). In these
flightsI often had a very interesting though not dangerous
struggle with the wind, in which I sometimes came to a state
of absolute rest, and was suspended in the air at one point for
several seconds, almost exactly as the falcons of the Rhinow
Mountains are. Sometimes I was suddenly lifted from such a
position of rest many meters in a vertical direction, so that
I became alarmed lest the wind should carry me off altogether.
As, however, I never ventured out except when such gusts
were exceptional, I was always able to continue my flight and
to land safely. The line (5 g shows a wavy course, brought
about by gusts, during which I rose to the height of my point
of starting.

I want to emphasize particularly that the results obtained in
actual sailing agree well with my small-scale experiments on
the supporting power of arched surfaces. During a calm it is
quite feasible, with proper practice in placing the wings, to
sail downward at an angle of 9°. ObServation shows that the
wings are then approximately level. According to my dia-
grams on Plate VII* the supporting force of the air would then
be 80 per cent. of the resistance of the surfaces normally acted
upon. In a calm the velocity of flight as measured was about
9 m. per second, with a surface of 14 sq. m.; the uplifting force
would be : 0.8 X 0.13 x I4 X 99 r: 118 kilograms, while 100
kilograms would sutfice.

According to the diagram on Plate VI, if a curved surface is
struck at an angle of 9°, itsprersure will act toward the front
at an angle of 3° with the normal to the chord of the surface.
The propelling effect of the air pressure will therefore be :

100 X .rz'n. 3° = 5 kilograms.

This force is used up in propelling through the air the cross-
sections of the body and of the framework at a velocity of g m.
per second. This would correspond to a projected area F, to
be deduced from the equation :

5 kgm. = 0.13 x F X 9?,
which gives F: 0.5 sq. m., a result agreeing well with the
actual fact.

In a medium wind a practised “ sailer” can pass over con—
siderable space at an angle of 6°, as I have proved from experi-
ence ; the velocity of motion in this case is about 5 m. per sec-
ond. It is a fair assumption that the wind as it strikes the
mountains has a greater ascending trend, but I succeeded in
maintaining the same angle of descent on somewhat narrow

* Lilienthal: “ Der Vogelfiug als Grundlage der Fliegekunst.”
APPENDIX. 289

hill-sides, where the wind could escape easily to either side,
and also at a considerable distance away from the mountains.
For this reason I think it likely that the same results could be
obtained upon extended flights.

There can be no doubt, in my opinion, that by perfecting our
present apparatus, and by acquiring greater skill in using it,
we shall achieve still more favorable results with it, and finally
succeed in taking long sails even in rather strong winds. Even
without considering the chances of such continued sailing with—
out effort, the results already obtained provide us with data as
to the energy to be expended if horizontal flight is to be pro-
longed by mechanical means.

'I he wind seldom has a velocity exceeding 4—5 m. per second.
Sailing against the wind there will be a drop per second of :

5 sin. 6° : 0.5 m. = 1.64 ft.

If we disregard minor details the “ work” of my apparatus
will, therefore, be: 100 X 0.5 = 50 kilogrammeters per sec-
ond, or a. H.P. This is for the purely ideal case, when the
wings move downward uniformly in the line of flight, and are
raised without appreciable loss of time ; but the weight of the
motor, and the decrease in carrying force during the upward
stroke of the wings, will, of course, increase the total work
necessary. I have already completed a steam-engine which
I intend to use for moving wings in some experiments to be
made in the near future. It develops 2 H.P., will work half
an hour, and weighs 20 kilograms (44 lbs.), including all its
accessories. In this way the “work” required will be in-
creased to 60 kilogrammeters per second. When the separate
surfaces at the tip of the wings, corresponding to the primary
feathers, move up and down, Ist, the surfaces will move at a
more favorable angle of incidence, and, 2d, a further increase
in lifting power is produced by the beating action of the wings,
both of which facts decrease the necessary expenditure of power.
It thus appears possible that we may succeed in maintaining
horizontal flight with the above-mentioned motor, though the
upright position of the body is unfavorable to flying.

Of course it will be a matter of practice to learn how to guide
such a flying machine, with beating wings, as surely as a simple
sailing apparatus. For this reason I shall first use my new
machine with rigid wings as a simple sailing apparatus. Later
on, when I have again acquired perfect confidence, I shall allow
the tips of the wings to make very small beats, and shall in-
crease these very gradually to their full stroke.

In this way, passing by small gradations from sailing flight
to rowing flight with wings, the length and duration of flight
may be considerably increased, so that we may venture at last
to fly wit/z the wind for a time and then try flying in circles.

In my trials with such large carrying surfaces in flying
Ihave found that the concavity of the wings should be less
than results from my experiments in small models. While
with small surfaces, of less area than I sq. m., a depth of one-
twelfth of the breadth of the wing gave the best results, on the

19
290 APPENDIX.

large wings of 14 sq. m., a depth of one-eighteenth to one-
twentieth of the breadth proved to be the best. 1 have made
frequent changes in the profile of the wings to make certain of
this fact. My apparatus was specially arranged to permit this.

Of late much stress has been laid on the parabolic cross-sec-
tion of the bird's wings. It is evident that the “ projectile
curve” would be the natural form for diverting the air current
under the wing. Apparently the various profiles actually rep
resented have been drawn rather arbitrarily. If we compare
the circle with the half vertex of the parabola, which is the part
generally shown, the difierence is found to be so slight as to be
hardly worth considering. On the other hand, in the sketches
so presented by others, the front of the arch shows decidedly
more curvature than the back; this was probably done to ex-
plain the greater inclination of the air pressure in front. Of
course, it is quite feasible to give up the ordinary parabola of
the second degree, and use instead a parabola of a higher order,
which rises at first more steeply and runs out more gradually.
During three years of practical experiments I have repeatedly
tried such profiles in sailing, but I can only advise strongly
against making the surface too steep in front, as there is a risk
of getting a dangerous upward pressure. My advice is to stick
to the ordinary parabola even when it almost coincides with a
circle.

In closing. I would express the wish that the publication of
my results may incite others to take up the problem of flight
practically. I represent merely but one certain line of thought,
which has led me so strongly to the imitation of the flying
birds, that I have even been accused of “ aping ’ Ihem. Such
accusations cannot, however, divert me from the path Ihave
chosen. I do not imitate the flight of the birds because it hap-
pens to be convenient to copy, but because it combines logical
correctness with so many practical advantages which no other
principle of flying could furnish me.

The only method which, in my opinion, might to a certain
degree offer the advantages of moving wings is that of rotating
air propellers, which lift and propel at the same time. I have
already expressed my opinion in the past that possibly good
results may be obtained with such devices if skilfully worked
out. Actual trial alone can decide this question. as we must
let the air and the wind have their say in the matter. For this
reason it would be desirable to have some such ideas carried
out in practice, so that there will be an end to fruitless discus-
srons.
GENERAL INDEX.

Academy of Sciences, French, 32, 69, 215.

Accumulators, 214, 274.

Acrobat, 20.

Adam, Mr., 18.

Adelaide Gallery, 84.

Ader, M. Clement, 208, 211, 212, 213, 214.

Ader’s Apparatus, 213.

Adjustable Superposed Sails, 163; Tail, 143.

“ Advanced against the Wind,” 109, 189, 198, 200.

“Aerial, Automotion, Manifesto upon,” 52; Car, 33; Chariot, 88, 89; Condenser,
92, 162, 234, 236, 237, 238, 24!, 24.3 : Equilibrium, 73 ; Locomotion, 174, 272 ;
Locomotive, 24 ; Machine, Brearey’s, 146; Navigation, 10, 56, 66, 119, 128,
140, 187, 251,272; Navigation, Conference on, 228, 230, 247; Navigation,
French Society of, 118, 119, 178, 179, 180; Navigation, German Society for
the Advancement of, 201 ; Navigation, Problem of. 156, 215; Propeller, 66,
72. 125 ; Screw Machine. 54. 63: ScreWS. 38, 48. 49. 51, 52, 53. 54. 57, 60.61.
637 64‘ 651 661 67‘ 681 69. 7°: 711 729 1251 217: 2181 225, 2271 247s 253 i Steamer!
124 ; Steamer, Moy & Shill’s, 126 ; Steam Machine, 25 ; Vehicle, 144, 169;
Vessel, 33, 64; Wheels, 127.

“ Aero-bi-plane," 123, 258.

Acre-Condensers, 236, 237.

Aerodynamics, 68 ; Experiments in, 7.

[Eolian Harps, 194.

AeronaUte, 561 581 59‘ 947 95! 1°43 1179 1197 1221 I39! I47! 1589 I771 180! 1893 2021

2 2.

Aeronautical, Congress, International, 48; Department, French, 164; Exhibi-
tion, London, 16, 25, 26, 50, 54, 113, 147, 161 ; Society, French, 29, 56 ; Soci-
ety of Great Britain, 5, 16, 24, 25, 26, 33, 35, 100, 112, 113, 118, 123, 124, 128,
130, 131. 143, 145, 147, 161, 162, 197, 233, 271 ; Society of Great Britain, Re-
port of, 57, 58, 59, 271 ; War Establishment, French, 70.

“ Aeronautics, Dynamic,” 215 ; Wise’s “ History, and Practice of,” 81.

Aeroplane, Resistance of Pigeon’s, 43 ; Resistancepf Goupil’s, 157 ; Resistance
of Tatin‘s, 141.

Aeroplanes, as Steam Condensers, 92 ; Bird-like, 157 ; Concave-convex, 161,
218 ; Definition of, 72 ; Experiments with, Failures, 73 ; Fixed, 73 ; Living,
2; Soaring of, 153 ; Stability of, 73,123 ; Superposed, 99, 113, 218, 230, 231 ;
Sustaining, 127 ; Sustaining Power of, 246, 254 ; “ Wave Action,” 143.

" Aeroplastics,” 175.

“ Aeroscaphe,” 94, 95.

Air, Action of on Aeroplanes, 94 ; Blasts, Lifting Power of, 65; Deflection of,
166 ; Friction of, 10 ; Injector, 242; Pressure, Energy of, 204 ; Pressure of
Current of, 3 ; Pressure of, Table, 4, 5 ; Pressure under Swallow’s wing,
39 ; Propeller, Experiments on, 67 ; Resistance and Reaction, 1, 7, 10, 43,
94, 2oz, 206, 213, 263 ; Resistance and Supporting Power of, 250 251 ; Re-
sistances, Experiments on, 3, 5, 119 ; Ship, 66, 246 ; Strata of, 179, 186, 189.

Albatross, 105, 106, 108, 148, 272, 273, 275 ; Artificial, 105, 107 ; Flight of, 271,
272; Sailing of, 130; Wings, 161 ; Wandering, 272.

Alcohol Flame, 63.

Alexander, Mr., 39.

Algeria, 150, 213.

Alighting, 87, 103, 172, 201, 208, 240, 247, 250, 259, 260, 266.

Allard, 12.

Alternating Surfaces, 73.

Aluminium, 70, 228, 230, 236, 256.

Amans, Dr., 193.
292 GENERAL INDEX.

Amécourt, M. de Ponton d’, 52, 54, 55.

American, Association, for Ad. f Science, 197; Institution, 226 ; Naturalist,
197, 200.

Ammonia, 227.

Anemometer, 186.

Angle, Law of, 6; of Flight, 43.

“ Animal Locomotion," 15.

Animals, Energy of, 23; Flying, Division of, 46; Flying, Wing Area of, 45.

Antennae, 142.

“Anthropomis,” 32, 96.

Arab, 213.

Arched Wings, 161.

Archimedean Screw, 49.

Archytas, 197.

Area, Sustaining, 113.

Areas, Supporting, of Birds, Table of, 46, 47.

Argyle, Duke of, 271. m

Armour’s, M., Flying Machine, 161.

Arrows, Paper, 112.

Artificial. Albatross, 105, 107; Bird, 28, 29, 3o, 31, 36, 104, 105, 115, 117, 119,
212; Flight, 11, 137, 202, 255.

Artingstall, F. D., 24.

Asbestos, 228.

Ascending, Currents, 191 ; Currents of Wind, 119, 189, 190, 192, 208, 210, 273,
274; Resistance, 87.

Ascension, How Produced, 151, 152.

Asiatics, 197.

“ Aspiration,” 9, 81, 110, 188, 189, 192, 198, 201 ; Experiments on, 105.

“ Aspired Forward into the Breeze,” 108.

Atmospheric Condenser, 236; Resistance, 244.

Aubaud, Mr., 52, 87.

Australian Crane, Wing Area of, 45.

Automatic Equilibrium, 117, 118, 184; Kite, 134; Stability of, 185; Stability,
115,122, 130, 132, 187.

Aviation, 55, 82, 98, 140, 211 ; Problem of, 247.

Back—sail, I64.

Bacon, Roger. 81.

Bacqueville, Marquis de, 13, 14.

Balancing Tail, 185.

Baldwin, M. H., 33.

Baldwin’s Park, 233.

Balloon, 53, 81, 190, 216; Ascent, 119; Elongated, 130; Fish-shaped, 92;
Model, Marriott’s, 130; Society, 130, 271 ; War, 71, 164.

Balloons, Course of, 119; Free, 186.

Bamboo, 195, 256 ; Resonator, 194.

Barnett, Mr., 132, 133, 134, 184.

Barometer, 119, 186.

Bartholomew, Alviano, 82.

Basté, 99.

Bat, 29, 33, 38, 102, 212, 213.

Batteries, Primary, 92, 214.

Battlefield, 70, 268.

Bavarian Ministers, 216.

Bayonne, 186.

Bazin, M., 185.

Bazin's “ Bi-polar” Kite, 185.

Bearing Surface, 203.

Beating Wings, 115, 137, 212, 215, 224, 226, 227.

Beats of Wing Tips, 204.

Beeson’s Soaring Device, 163.

Beeson, W., 163, 202; Patent of, 163, 164.

Beetle, Stag, 16.

Béléguic, Captain, 110.

Bennett, James Gordon, 64.

Bennett, Mr., 118.

Berlin, 201, 205.

Bescherelle, “ Histoire des Ballons,” 76, 78, 80; Note, 81.

Besieged City, 70.
GENERAL INDEX. 293

Besnier, 12, 13.

Bienvenu, M., 49.

Biot, M., 160, 178, 179, 180.

Bi-planes, 123, 258.

“ Bi-polar” Kite, 185, 187.

Bird, Artificial, 28, 29, 3o, 31, 36, 104, 105, 115, 117, 119, 212; Equilibrium of,
192; Flight of, 6, 44, 147, 201 ; " Flight as the Basis of the Flying Art,” 202';
Flight, Phases of, 2, 3; Form of Wing, Advantages of, 163 ; Gliding, 78 ;
Kite, 194; Machines, 35; Mechanical, 27, 29, 3o, 36, 37, 137, 215 ; Principle,
_271 ; Science of, 76, 81, 83, 153, 208.

Blrds‘ 11‘ I" 133 161 22’ 30v 399 403 4Ii 45$ 53! 751 78’ 80$ 829 849 89‘ 1°33 108! 109,
142, 149, 200, 274; Energy of, 23; Fast Flying, 256; Flapping, 72 ; Flight
and Manoeuvres of, 148 ; High-flying, 203; Homing. 45; How Supported in
Flight, 251 ; Imitation of, 206 ; Large, 2, 6, 203; of Prey, 96, 203 ; Pectoral
Muscles of, 40; Power Developed by, 38 ; Power Expended by, 41 ; Pro,—
pelling Surfaces of, 219 ; Sailing, 153, 190, 206, 208, 211 ; Sailing Flight of,
153; Sea, 202, 203; Shapes and Methods of, 202 ; Small, Strength of, 2,;
Soaring, 7’, 76, 77, 83, 84, 111, 116, 148, 153, 164, 178, 180, 186, 192, 193, 195,
197, 198, 201, 206,210; Soaring, Form of, 153; Soaring, Helical Path of,
160 ; Soaring, Paper on, 197 ; Speed of, 48; Supporting Area of, Table of,
46, 47 ; Supporting Surfaces of, 45 ; Surfaces and Weight of, 44, 45 ; Sur-
faces of, 203 ; Steam, 29 ; Waders, 203 ; Weights, Surfaces, and Dimen-
sions of, 148 ; Wings, 89, 203 ; Wings, Tips of, 33 ; Wing, Pressure under,
41, 44 ; Theory of Flight of, 39 ; Weight of, 6.

Blades, Flexible, 163 ; Narrow, 166; of Screw, Best Form of, 162, 163 ;
Superposed, 164.

Bladud. King, 76.

Blanchard, 14.

Blasts of Air, 252.

Boat, Steering of, 239.

Body, of Soaring Birds, Form of, 153 ; Plane, 223, 227 ; Plane, Sustaining,
224 ; Upright Position of, 210.

Boiler, Maxim’s, 241, 242, 243 ; Self-generating, 63 ; Serpollet Type, 228 ;
Weight of, 27.

Boilers, Hargrave’s, 228.

Borelli, 221, 222.

“ Boring Through Air,” 68.

Bossut, Formula of, 5.

Bourcart, 15.

Bourdon Tube, 36, 37.

Bourne, Mr., 51.

“ Bow" Kite, 185.

Boynton, Dress, 130, 274, 275,

Boynton, M., 184, 257.

Bréant, 21.

Brearey, Mr. F. W., 84, 85, 143, 144, 145, 146, 147.

Brearey’s Device, 142.

Brest, 108, 109.

Bretonniere, M., 190.

Bright, Mr., 52.

Britain, Chronicles of, 76.

British Association, 66.

Brown’s, D. 5., Experiments, 88, 112, 123, 124, 258.

Buffalo, N. Y., 197, 198.

Bunting, 191.

Burners, 229.

Butler & Edwards, 112.

Butterfly, 56, 142, 143, 166, 190. _

Buzzard, 39 ; Beating his Wings, 2 ; Soaring, 74.

Cable, Life Saving, 181.

Cairo, 151, 190.

California, 247, 263 ; Flying Machine, 130.

Canoe, 105, 106, 107, 110.

Canvas Wings, 116.

Car, 113, 1.20 ; Aerial, 33, 52 ; Cylindrical, 111.
Carbonic Acid Exhaled by Bird, 41 ; Acid Gas, 174.
Carlingford Screw, 89 ; Viscount, 88, 96.

“ Carriage, Kite, History of," 175.

Carrier Pigeon, 45.
294 GENERAL INDEX.

Cartridges, 38 ; Explosion of, 37.

Cassz'er’s Magazine, 217, 218.

Castél, M., 61, 62.

Cavley, Sir George, 5, 17, 50, 55, 56, 95, 122.

Cells, India Rubber, 111, 112.

Cellular Kites, 230, 258.

Center, of Eflort, 224 ; of Gravity, 28, go, 92, 113, 118, 120, 121, 122, 216, 220,
223, 224. 258; of Gravity, Adjustment of, 94 ; of Pressure, 28, 122, 216, 224.

Central Keels, 184 ; Spine, 143.

Century Ma azz'ne, 71, 133, 235.

Chalais, 7o ; endon, 138.

Charcoal, 50, 227.

Chard, 84, 85, 114, 130.

Chariot, 176 ; Aerial, 88, 89 ; Flying, 14.

Chart of Air Pressur’e, 5.

“ Charvolant,” 176; “ History of," 175 ; Pocock’s, 184.

Chicago, 197, 228, 247 ; Conference, 231.

China, 193.

Chligiese, 194 ; Kites, 191, 193, 194, 197 ; Manufacturer of Kites, 193 ; Musical

lte, 1 2.

Chroniclegs of Britain, 76.

Cigar-shaped Vessel, 271.

City, Besieged, 7o.

Clarke. Mr., 196.

Claudel, M., 99.

Clock Springs, 27, 56.

Clockwork, 35, 219.

“ Close Hauling," 272, 273.

Cocking, 20, 122.

Coefficient of Efficiency, 209.

Colby, Mr., 196.

Commission, rench, 32.

Compressed Air, 87, 137, 221, 222, 224, 222 ; Air Engine, 60 ; Air Machine,
228 ; Air Motor, 227.

Concave, Bird-like Surfaces, 156; Screw, 58.

Concavo-convex, Aeroplanes, 218; Planes, 161; Surfaces, 156, 157, 169, 171,
189, 209, 247, 251, 260; Surfaces of Birds, 203 ; Sustaining Surfaces, 202.

Concertina, 112.

Conclusion, 250.

Condensation, 237.

Condenser, 234: Aerial, 162 ; Atmospheric, 236 ; Efficiency of, 238 ; Steam, 92,
93; Surface Air, 236, 237.

Condors, 200.

Cone, Inverted, 122.

Conference in Aerial Navigation, 228, 230, 247.

Congress, International Aeronautical, 48; Scientific at Toulouse, 69.

Constance, Lake of, 216.

Constantine, Algeria, 190, 213.

Constantinople, 8o.

Convex Wings, 166.

Copenhagen, 66, 115 ; Dock Yards in, 66.

Copie, M., 184, 196.

Copper Tubing, 228.

Cordner, Rev. Mr. E. J., 177, 195.

Cork Jacket, 263.

Cos-moflolitan Magazine, 217, 238.

Cossus, Mr., 51.

Counterweight. Movable, 109, 258.

Courier of Andalusia, 82.

Couturier, M., 147.

Coventry, 38.

Crane, Australian, Wing Area of, 45.

Cremorne Gardens, 18, 19, 86.

“ Cropper,” 155.

Crow, 5.

Crowel , 111.

Crystal Palace, 16, 38, 114, 125, 126.

Current, Horizontal, 192; of Air, Deflection of, 166 ; of Air, Pressure of, 3 ;
Upward, 273, 274.
GENERAL INDEX. 295

Currents, Ascending, 191 ; Ascending, in the Wind, 119 ; Ground, 85, 103.

Curtis, Mr. George E., 205.

Curved, Shapes, Patented, 166, 169, 170; Surfaces, 196, 230: Wings, 205;
Wing Surfaces, 206.

Cylinder, Engine, 222.

Cylindrical Car, 111.

Dahlstrom, 253; Dahlstrom & Lohlnan, 67.

Dandrieux, Apparatus, 142; M., 15, 56, 142, 179; Toy, 146.

Danger of Experiments, 211.

Danjard, M., 116, 117.

Dansey, Captain, 176.

" Dans les Airs,” 104, 115, 212.

Dante, 81, 82, 108, 208, 263.

Dart, 56, 112.

Darwin, 99.

lid-11.34 im, 223.

Dedalus, 78.

Deflection of Current of Air, 166.

Degen, J., 17, 18, 50.

De Groof, 19, 20.

De Louvrie, 96; Experiments of, 5.

De Lucy, Mr., 45, 46.

Demons, 77.

Denmark, 161.

Derval, note, 104.

Derwitz, 207.

Desforges, Abbé, 14.

D’Esterno, Count, 81, 96, 97, 98, 99, 106, 110.

Dexterity of Birds, 207.

Diedral Angle, 74, 75, 90, 95, 96, 112, 117, 120, 122, 132, 137. 145, 184, 185, 193,
224. 237, 257 ; Side Wings, 239.

Dienaide, E., 10, 55, 59, 88, 253.

Dimensions of Birds, 148.

Dines, D. W., Experiments of, 5.

Direct-acting Engine, 162.

Dirigible Parachute, 144, 146, 147, 161, 169, 216.

Dock Yards in Copenhagen, 66.

Dorsal Surfaces, 33.

Douarnenez, 105, 106, 109.

Double—acting Wings, 222 ; Bladed Screws, 62 ; Vaned Screw, 117 ; Screw, 56,

o, 1

“ Draft-Kite,” I76.

Dragon-fly, 27, 166; Kite, 195.

"Drift,” 7, 9, 10, 43, 44, 87, 95, 98, 114, 126, 127, 136, 140, 156, 157, 167, 172,
189, 190, 230, 251, 255, 256.

Driving Screws, 111.

Drzewiecki, S., 2, 44, 46, 48, 148.

Dubochet, 50.

Duchemin, 95, 251 ; Formula of, 3, 5, 8, 172.

Duchesnay, M., 115.

Duck, 13, 256.

Duck’s Foot, 25.

Dudgeon, Mr., 64.

Dufferin, Lord, 271.

Dummy, 216.

Durvea, M., 261.

Du Temple, 96.

Dynograph. 244. 243,245-

" Dynamic Aeronautics,” 215.

Dynamite, 188 ; Explosion of, 187.

Dynamo, 70, 214, 215.

Dynamometer, 39, 172, 246; Pull on, 243.

Eagles, 76, 77, 148, 151, 213.

Eddy, M., 186.

Edison, Mr., 55. 64.

Edwards & Butler, 112.

Efficiency, Coefficient of, 209 ; of Screws, 66, 71, 233.
296 GENERAL INDEX.

“Efi'izies,” 198. 199, 247.

Eiffel Tower, 186.

Elastic Blades of Fan, 163.

Elasticity of Wings, 166.

Electric Launches, 69; Motor, 38, 64, 69, 7o; Sparks, 112.

Electrical Motor, 92.

Electrician, 212, 214.

Electricity, 135 ; as a Motor, 92.

Elevator Muscle, 146.

Elmerus de Malemaria, 78.

Emperor, 80.

Encyclopaedia Britannica, 271.

Energy. of Air-pressure, 204 ; of Animals, 23 ; of Birds, 23.

Engine, Compressed Air, 60; Cylinder, 222; Direct-acting, 162; Explosion,
16, 119 ; Gunpowder, 23; Gun-cotton, 161 ; High-pressure Compound
Steam, 235; Lightest, 115 ; Maxim’s, 141, 235 ; Oscillating, 138 ; Phillip’s,
172 ; Power of, 138 ; Simple, 223.

Engineering, 68, 166, 170, 218, 222.

Engineer, London, 16, 197, 244.

Engines, Marine, Weight of, 252 ; Metallic, 112 ; Weight of, 27, 113, 115, 126,
252, 271.

England. 233, 234.

Equilibrium, 24, 28, 73, 88. 96, 108, 114, 123, 164, 172, 209, 210; Aerial, 73 ;
Automatic, 109, 117, 118 ; Automatic of Kite, 184; Defective, 161; Difficulty
of Maintaining, 16o; Fore and Aft, 111, 120, I78; Goupil’s Investigations,
154 ; in Flight, 208; Lateral, 224; Lateral. of Kite, 185 ; Longitudinal, 110,
122, 193; Maintenance of, 81, 153, 214, 250; of Bird, 192; of Flying Ma-
chine, 247 ; of Kite, 152, 193, 194, 196, 198, 199 ; of Kite Aeroplanes, 195 ; of
Ngaxim's Machine, 234 ; Problem of, 124, 257, 260, 261 ; Stable, 85, 103; Test
0 , 134.

Equipoise, 211, 231.

Eulitz, Herr Hugo, 207.

“ Even Keel,” 236, 240.

Everglades, 197.

Exhaust Steam, Reaction of, 162.

Exhibition, Aeronautical, 50 ; of Aeronautical Society of Great Britain, 161.

Experiment, Ader’s, 214.

Experimental Machine, Phillip’s, 172.

Experiments, Aerial, 212 ; Aerial, Account of, 104 ; Aerial, Failures in, 76; at
Sea, 110; Danger of, 211 ; in Aerodynamics, 7 ; in Floating, 82 ; in Flying,
210 ; of French War Department, 164 ; of Hargrave, 218 ; of Le Bris, 104—108 ;
ofLilienthal, 201, 202, 205, 206, 211 ; of Maxim, 233, 234, 244 ; of M. de San—
derval, 159 ; of M. Maillot, 182; of Montgomery, 248; of Mr. Simmons,
177; of Stringfellow, 113; of Tatin, 139; in Aerial Screws, 71 2, in Air Re-
sistances, 119 ; in “ Aspiration," 105 ; in Shapes, 167 ; Phillip’s, 171 ;
Pocock’s, 175 ; Rain-compelling, 187 ; with Aeroplanes, Failures, 73 ; with
Kites, 195, 197, 231.

Explosion Engine, 16, 119; Motor, 215, 227 ', oi Cartridges, 37 ; of Gases, 111,
227.

Explosions of Dynamite, 187.

Explosive Mixtures, 112.

Explosives, 252, 268.

Exposition Aéronautique, 99 ; Paris, 164, 212.

Extensor Muscles, 204.

Failures, 10, 73, 75, 76 ; Causes of, 250.

Falcon, 88

Fan-blade, Best Form of, 162 ; Blower, 65 ; Two-winged, 64.

Fans, Flexible Bladed, 163 ; Revolving, 50 ; Superposed, 162 ; Turn Vertical
Screw. 162.

Fast-flying Birds, 256.

Feathering Movement. 16.

Feathers, Elastic Curvature of, 207; Note, 211; of Birds, 193; Primary,

204.
Feathering Vanes, 33.
Pm, 185 ; Kites, 184.
Fire Annihilator, 5o.
Fishes, Locomotive Organs of, 193 ; Propelling Surfaces of, 219.
Fish-shaped Balloon, 92.
GENERAL INDEX. 297

Flapping, 106 ; Birds, 72, 153 ; Flight, 96, 97. 193, 204 ; Propulsion by, 273 ;
Wings, 11, 23, 28, 29, 48, 73, 81, 147, 148, 219, 220, 222, 253.

Flat-iron, 184 ; Top Mountains, 200.

Flexibility of Kites, 192.

Flexible Bladed Fans, 163 ; Surfaces, 185 ; Wings, 105.

Flexure of Wings, 203 ; Parabolic, 203.

Flight, 115, 118; Angle of, 43; Artificial, 11, 137, 145, 201, 202, 217, 255 ;
Bird,as the Basis of the Flying Art, 202 ; Equilibrium m, 208 ; “First
Steps to,” 124 ; Flapping, 96, 193, 204 ; Flapping and Soaring, 96 ; Free,
263 ; horizontal, 41 ; Hovering or Stationary, 203 ; Investigation of, 119 ;
Mechanical, 8, 217 ; Mechanical Character of, 199 ; Modes of, 148 ; Mys-
tery of, 105 ; of Birds, 2, 3, 44, 145, 148, 201 ; of Birds, Power Absorbed by,
43, 44 ; of Birds, Resistance to, 43, 44; of Eagles and Bats, 213 ; of Soar-
ing Birds, 147; of Tatin’s Machine, 138, 139; “ of the Albatross,” 271, 272;
of Vultures, 213 ; Ornithology Relating to, 147 ; Possibility of, 166 ; Power
Expended in, 41 ; Power Necessary for, 202; Problem of, 103, I44, 147.
250 ; Resistance of, 42 ; Sailing, 108, 208 ; Soaring, 200, 207 ; Soaring and
Sailing, 130, 203, 204 ; “ Technique” of, 202 ; Theories of, 115, 250 ; Time
of, 225 ; Without Flapping. 150.

Floating, Observatory, 175 ; Planes, 198.

Florida, 197, 198 ; Sea Beaches of, 191.

Fluid Reactions, Law of, 3.

Flying, Animals, Division of, 46 ; Animals, Wing Area of, 45, 46; Apparatus,
203, 206 ; Apparatus, Shape of, 203 ; “ Baronet,” 56 ; Birds, 22 ; Chariot,
14 ; “ Free Human,” 215 ; Machines, 1, 2, 10, 38, 50, 67, 72, 81, 164, 214,218,
221, 226 ; Ader’s, 213 ; Armour’s, 161 ; Aubaud’s, 87 ; Beeson’s, 163 ; Bes-
nier’s, 12 ; Bréant‘s, 21 ; Breary’s, 143; Bright’s, 52 ; Butler & Edwards’,
112 ; California, 130 ; Carlingiord’s, 89 ; Castel’s, 61 ; Claudel’s, 99 ; Con-
trol of, 246 ; Cossus’, 51 ; Dandrieux‘s, 142 : Danjard’s, 116 ; D’Amé-
court’s, 54 ; Degen‘s, 18; De Groof’s, 20; Dela Landell’s, 55; De Louvrie’s,
32, 94; D’Esterno's, 97; Dieuaide's, 59 ; Du Temple’s, 91 ; Forlanini’s,
63 ; Frost’s, 34 ; Gérard's, 24 ; Goupil’s, 155 ; Grafligny’s, 173 ; Har-
grave’s, 218, 219, 220, 221, 222, 223, 225, 227; Henson’s, 83; Hureau de
Villeneuve’s 29; Jobert’s, 28, 3o ; Kaufman’s, 26; Krueger’s, 154; Lau-
noy& Bienvenu’s, 49; Le Bris’, 22, 105 ; Leonardo da Vinci’s, 11 ; Le-
tur's, 19 ; Lilienthal’s. 204, 206 ; Loup’s, 88; Maxim's, 232, 233, 234, 235,
236, 237, 238 ; Mélikoff’s. 60 ; Mouillard’s, 149 ; Moy’s, 125, 129, 271 ; Pé-
naud’s, 28, 55, 117 ; Pénaud & Gauchot’s, 121 ; Pichancourt’s, 31 ; Pomé’s,
135 ; Pomés & De la Pauze’s, 57; Power Required by, 42 : Problem, 197 ;
Prignet’s, 27; Renard’s, 165; Smyth’s, 111 ; Steering of, 239; String-
fellow’s, 113 ; Struve & Telescheff’s, 25 ; Tatin’s, 138 ; Trouvé’s, 36, 69 ',
Wenham’s, 100, 101 ; Model, 128 ; of a Steam-engine, 86, 87 ; Screw, 55,
56, 57, 66, 117, 119.

Force of Wind, 209, 210, 258.

Forlanini, Professor, 62, 63 .

Form of Screws, 58 ; of Soaring Bird, 153 ; of Supporting Surfaces, 247.

Foster, Mr., 66.

Fortifications, 268.

Fowls, Domestic, 17.

Free Balloons, 186 ; Flight, 263; “ Human Flying,” 215.

French Academy of Sciences, 32, 36, 38, 49, 50, 69, 94, 158, 215 ; Aeronautical
Department, 164; Aeronautical Society, 29, 99 ; Aeronautical War Estab-
lishment, 70; Commission, 32; Experimenters, 71, 220; Society 57, 58;
Society for Aerial Navigation. 178, 179. 180 ; Society of Encouragement of
Aviation, 02 ; Society of Physics, 71 ; War Department, 164.

Freninges. Mr., 66, 67, 253.

Friction of Air, 10 ; of Air on Birds’ Wings, 43 ; Skin, 10, 251.

Frigate Bird, 148.

Frost, E. P., 34, 35.

Fulminates, 38.

Fuel for Flying Machines, 267 ; Gas Reservoir, 162 ; Liquid, 126.

Fusée, 92.

Gas, 245, 271. 273 ; Bags, 274; Engines, 38; Generator, 242 ; Jets, 236;
Motor, 61 ; Turbine, 6o

Gases, Explosion of, 111, 227.

Gauchot, M., 119, 132.

Géant, 53.

Generator, Gas, 242 ; Steam, Maxim’s, 241, 242, 243.
298 GENERAL INDEX.

Gérard, 23.

German Society for the Advancement of Aerial Navigation, 201.
Gibson, W., 16.

Giffard, 236 ; Experiments of. 60.

Gliding, 72, 209 ; Bird, 78 ; Experts in, 166.

Gnat, Wing Area of, 45.

Goose, 114 ; Wild (Note), 211.

Goupil, Aeroplane, Resistance of, 157.

Goupil, M., 9, 40, 154, 155, 156, 157, 158, 166, 202, 262.
Goupil’s Apparatus, 155 ; Experiments, 155, 158.

Grafiigny La Navigation Aérieniie, 77, 80 ; M. de, 77, 172, 173, 174.
Grafligny’s Apparatus, 173.

Greenough, Mr., 66.

Green, Thomas, 33.

Grosskreutz, 207.

Ground Currents, 85, 103. 158.

Guidance, 96, 250, 258, 260.

Guide Rope Brake, 119.

Guidotti, Paul, 82, 208.

Gulf of Mexico, 263.

Gull. 77, 81, 148; Flight of, 41 ; Photographs of, 41 ; Sea. 235.
Gull’s Wings, 161.

Gun-cotton Engine, 161.

Gun, Maxim’s, Machine, 233.

Gunpowder, 94 ; Engine, 23 ; Motor, 57, 135.

Gusty Wind, 75, 110.

Guy Lines, 178.

Cy}: Fair/us, 149.

Gypsum, 50.

Gyroscopic Action, 179 ; Stability of Kite, 179; Wheel, 237.
“ Gyrostat,” 237, 240.

Hammock, 216, 217.

Hancock, 112.

Hanoi, 194.

Hargrave, Lawrence, 218, 219, 220, 221, 222, 223, 224, 225, 226, 228, 230, 252,
254. 255, 258. 265- , ,

Hargrave’s Apparatus, 221, 223, 225, 227 ; Flying Machines, 218, 219, 220, 221
Kites, 229.

Hartings, Tables of Birds, 45, 46.

Hawk, Sparrow, 77, 78, 79, 86, 98.

“ Header,” 155.

Head Resistance, 10, 254.

Headway. Initial, 97.

Helical Path of Soaring Birds, 160.

“ Hélicoptére,” 55.

Henson’s Apparatus, 83 ; Machine, 113 ; Model, 86 ; Patent, 83.

Herald, N. Y., 68.

Hero of Alexandria, 50.

Hero’s Aeolipile, 113.

“ Histoire des Ballons,” 81.

“ History of the Charvolant,” 175 ; “of the Kite Carriage,” 175.

Holland, John P., 68, 217, 218.

Holland’s, M. 5., Engine, 147, 161, 162, 163.

Hollow Sphere, 9, 63 ; Tubes, 236.

Homing Birds, 45.

Horizontal Current, 192 ; Flight, 41, 254 ; Flight, Power Expended in, 41 ;
Flight, Resistance to, 42 ; Rudder, 118, 121, 125 ; Stability, 13o ; Wings,
115.

Horse-power, 31, 119, 120, 210; of Birds, 40; of Engine, 115, 126, 236, 271 z of
Holland's Engine, 162; of Man, 40 ;-of Steam-engines, 8 ; Sustaining Efl'ect
of, 73 ; Weight of Engine per, 53 ; Weight per, 226, 227, 228.

Hot-air Engine, 95.

Hovering, 41 ; Flight, 203 ; Screw—machine, 215.

Huchet, Mr., 193, 194.

Huffaker, E. C., 247.

Hull Resistance, 10, 128, 141, 251 ; of Birds, 44.

Hulls of Ships, Experiments With, 42.
GENERAL INDEX. 299

Humming Bird, Hovering of, 2.

Hureau de Villeneuve M., 29., 114, 122.

Hutton, Experiments of, 5.

Hydrocarbonous Matter, 16.

Hydrogen and Air, 112; Gas, 38 ; Gas, for Fuel, 162.
Hygrometer, 186.

Icarus, 80.

Impulse of Wind, 209, 210, 258, 275.

Impulsion, 96.

Inclined Plane, 131 ; Planes, Pressure on, 8 ; Plane, Sustaining Power of, 82.

India-rubber, 134, 137. 220, 227 ; Bag, 112, 123 ; Cells, 111, 112 ; Rope, 124 ;
Springs, 129 ; Strings, 128; Tension of, 28; Torsion of, 144‘; Twisted,'117,

134.
Initial Headway, 97 ; Velocity, 215.
Injector, Air, 242.
Insects, 143, 166.
Instantaneous Photography, 119.
Instinct of Bird, 98.
International Aeronautical Congress, 48 ; Exposition, 7o.
Inverted Cone, 122.

“ Iron,” 172.

japanese as Kite-Flyers, 193 ; Kites, 178, 192, 193.

Jay, R. C., 26.

jets of Steam, 113 ; Reaction, 252.

Jobert, M., 27, 3o, 99, 180.

&obert's Apparatus, 181 ; Regulating Cone, 184.
oéssel’s Formulae, 172; Law, 8, 75, 133, 167, 168.

jullien, 92.

Kassner, Dr. C., 205, 207.

Kaufman, I. M., 25.

Keel, 184, 185 ; Cloths, 237; “ Even,” 236, 240 ; Longltudinal, 257.

Keith, A. P., 33.

Keokuk, 1a., 132.

Kite, Aeroplanes, Equilibrium of, 195; Automatic, 134; Automatic Equilib-
rium of, 184; Barnett’s, 134; “ Bi-polar,” 185, 187; Bird, 194; “ Bow,”
185; Boy’s, 152, 275; “ Carnage, History of,” 175 ; Chinese, 191 ; Bird, 194;
Dragon, 19; ; Musical, 192; Circular, 96; Copie's, 184; Dragon, 195 ; Ex-
periments, 197; Fanciers, 193; Flat, 133 ; Flyers, Japanese, 193 ; Flying,
187;]obe1t’s, 181; Lateral Equilibrium of, 185; Like Aeroplane, 172 ; Mail-
lot’s, 183, 184; “Malay," 186, 187; Military, 128 ; of M. Myers, 198. 201 ;
Multiple Disk, 195; Musical, 194 ; “ of War,” 234 ; “' Pilot," 177 ; “Pilot"
and “ Draft," 176 ; Principle, 174; Reversible Convex or Concave, 196;
Rope-bearing, 18o; Sail, 95; Stable, 184 ; String, 187, 230; Tailless, 176,
177, 178, 184, 193 ; Triangular, 132, 133 ; Without a Tail, 119.

Kites, 148, 164, 172, 175, 176, 179, 180, 181, 182, 183, 184,188, 189, 196, 197,
234; as Weather Vanes, 193 ; Boynton's, 257 ; Cellular, 230, 258 ; Chinese,
191, 193. 194, 197 ; Equilibrium of, 193, 196, 198, 199 ' Experiments on, 174,
195, 231 ; Fin, 184 ; Flexibility of, 1'92 ; Hargrave s, 229, 230 ; Japanese,
178, 192, 193 ; Myer’s Experiments with, 187 ; of all Nations, 197 ; Patents
on, 196; Plane Rigid, 185 ; Stability and Sustaining Power, 197 ; Super-
posed, 177 ; Superposition of, 195 ; Stability of, 187, 196 ; Tandem, 186;
Without Tails, 187.

Knee-pans, 106.

Koch, Gustav, 215, 216, 217.

Krarup-Hansen, 115.

Krueger, Mr., 154..

Labouret, Captain de, 41.

L’Aéronaute. 77; Note. 56. 58. 59. 94. 95, 104, ”7.119. 122. 139, I47. 158. 177,
180, 189, 202, 262.

La France, 71, 164.

“ La Locomotion Aérienne,” 156.

Lamboley, F. X., 33.

La Nature, 193.

“ La Navigation Aérienne,” IO ; Note, 81.
300 GENERAL INDEX.

Lancaster, Mr. ., 197, 198 199. 200, 201, 247.

Landelle, M. de la, 52, 55, 82, 105, 108,109, 115,147, 212.

Landing, 236.

LangICY1 PrOfessora 37 5161 7‘ 8191 I01731 1°49 II97 1261 1341 240 251, 2541 255 1
Experiments of, 5.

Lateral Stability; 117, 122.

Launoy & Bienvenu, 50, 55.

Launoy, M.,49

“ Law of the 4Angle,” 6, 8.

Learning how to Soar, 161

Le Bris, Captain, 21, 52, 81,104, 105,106, 107, 108, 109, 110, 121, 166, 202, 208,
255. 263

Lee Shore, 177.

Legends, Early, 72, 76, 78, 8o, 81, 82.

Leg, Muscles of, 202.

Leipsic, 26.

“ L’Empire delAir,”46,147, 149, 150,151, 180.

Leonardo da Vinci, 11, 12, 49.

Les [Monday 94.

Le: Grandes Amours, 104.

Letur, 18.

“ Le (/01 ran: Battlements, ’ 149.

L1fe-b0at,13o , Preserver, 263; Saving Cable, 181.

“Lift.” 7.9. 43. 44. 95. 126 127. 130. 236 I40. 153. 157. I72. 230. 237. 243. 244.
245, 248, 25

Lift of Maxim’ 5 Machine. 234.

Lifting, 246; Effect, 212' , Force of Goupil Aeroplane, 157: Power of Concave
Surfaces, 156, Power of Screws, 64' , Screw Blades Best Form of, 162
Screws, 66, 111, 116.

Light Motor, 147.

Lilienthal, G. 201.

Lilienthal, Herr Otto, 196,201,202, 204, 205, 206, 208. 209, 210, 211, 214, 263.

Lilienthal: M. (Note), 253, 255.

Lilienthal’s Apparatus, 204, 205, 206 ,Experiments, 202, 211.

L’IZZustraz‘zWan 213, 214.

Lindau, 216.

Linfield, Mr. ., 135, 136,137.

Liquid Fuel, 126, 162.

Loadstone (Note), 211.

Locomotive, 215, 262 ; Aerial, 24, 174 ; Organs of Fishes, 193 ; Torpedo, 239.

Locomotives, Weight of, 236.

Lohman, 253.

Longitudinal, Equilibrium, 110, 122 ; Stability, 117, 120, 122, 127, 138, 257.

Loup, Michel, 88.

Louvrié, M. de, 32, 94, 95.

Lybian Chain, 190.

Machine Gun, Maxim’ s, 233.

Machines for Flight, 203.

Maddans, Mr. , 196.

Magnetism, Negative Force of (Note), 211.

Maillot, M. ., 182.

Maillot’s Experiments, 182 ; Kite, 181, 184.

Mainsail, 164.

Malaga Newspaper, 82.

“Malay” Kite, 186, 187.

Man, Horse Power of, 40; Position of, 210 ; Power, 116.

“Manifesto upon Aerial Austlomotion,” 52.

Manoeuvres of Birds, 149,1

Man 5 Muscular Power, InsuIfficiency of, 82.

Manuel Comnenus, 80.

Marcy. Professor, 2. 35. 39. 4!. 4s. 46. U9. I37

Marine Engines, We1ght of, 252 ; Navigation.I 66; Screws 69, 72.

Marriott, Mr., 130, 131.

Material of Apparatus, 250, 256.

Materials, 256.

Maxim. Hiram S» 38. 53. 68. 71. 73. 7s. 84. II4. 119. 133. 141, 154. 229. 233.
234, 235, 23.6, 237, 238, 241, 242, 243, 244, 245, 246. 252, 254, 258, 267.

Maxim Machme Gun, 233.
GENERAL INDEX. 301

Maxim’s, Engine, Weight of, 141 ; Experiments, 233, 234, 244, 245 ; Machine,
232: 234’ 735-

Mayer, Mr., 56.

Means, Mr. james, 68.

Mechanical Bird, :7, 29, 30, 36, 37, 137, 215; Flight, 8, 217.

Mechanic's Magaxz‘ne, 271.

Mediterranean, 263.

Meerwein, 2o.

Mélikoff, M., 60, 61.

Membrane, 223.

Men, Relative \Veakness of, 23.

Meteorological Institute at Berlin, 205, 207.

Methylated Spirits, 114, 127, 228.

Middleton, H., 35.

Midland, Texas, 188.

Military, Establishment, French, 138 ; Kite, 118.

Mitidja, 150,

Models of Chinese Kites, 193; of Flying Machines, 233.

Montgomery, J. J., 247, 263 ; (Note), 255.

Moore, Major, 38.

Motive-power, 38, 75, 113, 117, 208, 210 ; Light, 132 ; of Flying Machine, 50;
of Wind, 147.

Motor, 35, 75, 87, 111, 211, 212, 214, 251, 266; Compressed Air, 227; Efli-
ciency of, 70; Electric, 38, 64 ; Explosion, 215, 227; for Aerial Naviga-
tion, 38 ; for Screw, 53; Gunpowder, 57, 135 ; its Character and Energy,
250; Light, 69, 147; Maxim’s, 235 ; Muscles of Birds, 251 ; of Flying Ma-
chine, 45 ; Petroleum, 32, 62; Steam, 227; Weight of, 31, 38, 131, 162,
228. 229. 233. 255-

Motors, Artificial, 23 ; Inadequacy of, 91 ; Light and Powerful, 203.

Mouillard, Mr., 46, 48, 77, 81, 99, 147, 148, 149, 150, 151, 152, 180, 190, 201,
2081 2137 2487 2551 263'

Mouillard, L’Em/u're 2': PA fr, 77.

Mouillard’s, Experiments, 150, 151 ; Soaring Apparatus, 149.

Moy & Shill, Aerial Steamer, 126.

Moy, Mr. ThOmas, 27, 59, 123, 124, 126, 127, 128, 130, 196, 229, 236, 253, 271.

Moy’s Machine, 129.

Miillenhoff, 46.

Multiple Disk Kite, 177, 195.

Multiplying Wheels. 89.

Munich, 215.

Murrell, M. H., 33.

Muscle, Elevator, 146.

Muscles, Contractile Strength of, 39; Extensor, 204 ; of Birds, 22, 23, 62,
251 ; of the Leg, 202 ; of Man, 12 : Pectoral, 27 ; Pectoral, of Birds, 40.
Muscular Exertion of Bird, 145 ; Power, 21 ; Power, Insufficiency of Man’s,

82.

Museum, National, Washington, 197.

Musical Kite, 192, 194.

Myers, C. E., 187, 188, 192, 198, 201.

Myths, 11, 76, 80.

Nadar. Ma 52. 53. 54. 55. 253-

Naphtha Fuel, 242.

National Museum, Smithsonian Institute, 114, 197.
Navier, 39, 94.

Navigating the Air, 208, 231, 701.

Navigation, Aerial and Marine, 66.

Negative Force of Magnetism (Note), 211 ; “ Gravity," 211.
Newsletter, San Francisco, 130.

Newton, 3.

New York Sun, 234 ; Times, 233.

Nicholson’s journal, 17, 50, 56, 122.

Nitre, 50.

Oblique Surfaces, Action of Air on, 3, 4, 5, 6, 7, 8, 94.
Observatory, Floating, 175.

Oliver of Malmesbury, 78.

Orientals, 197.

Ornithology, Relating to Flight, 147.
302 GENERAL INDEX.

Orthogonal Theory, 2, 39.

Orujo, Francisco, 82, 208.

Oscillating, Engine, 138 ; Wings, 12, 26, 161.
Osc1113tions of Kite, 178, 182.

Ostrich, 22.

Ovid, 78.

Paddles, 252.

Paddle-wheels, 33.

Palmer, 1., 25.

Paper Arrows. 112 ; Planes, 73, 141.

Parabolic Flexure, 203.

Parachute, Dirigible, 144, 146, 147, 164, 216 ; Flat, 96; Parachute-like Sails,
116 ; Progressive, 123 ; Screw, 60.

Parachutes, 11, 18, 19, 2o, 29, 86, 108, 122, 184, 196, 197, 256, 261 ; and Wings,
148 ; Experiments with, 42.

Paris, 116, 193 ; Exposition, 164, 212.

Passy, 212.

Pasteboard, 74, 257.

Patent, Henson’s, 83.

Patents, British (Note), 235 ; on Flying Machine, 32 ; on Kites, 196.

Paucton, 49.

Pauze, M. de la, 135.

Peacock, Power of, 40.

Peal, 99.

“ Pectoral, Cord,” 144, 145, 146, 147 ; Muscles, 27 ; Muscle of Bird, 40, 145.

Pectorals, Elastic Auxiliary, 212.

Pelicans, 100.

Pénaud, M. A., 28, 40, 45, 55, 56, 99, 117, 118, 119, 120, 121, 122, 123, 124, 132,
138, 184, 189, 190, 224, 258.

Pénaud & Gauchot, 121.

Pénaud’s Planophore, 130, 179.

Pendent Weight, 26, 164, 199.

“ Pendule,” 26, 75.

Pendulum Bar, 164.

Pereire, Mr. E., 211.

Perugia, 82.

Petroleum, 234 ; Motor, 32, 62.

Pettigrew. Professor, 15, 33.

Phillips, H. F., 50, 62, 157, 166, 202, 218, 226, 254.

Phillips’ Engine, 172; Experimental Machine, 172; Experiments, 167, 169,

171.

Photography, from Kites, 188 -, Instantaneous, 119.

Pigeon, 27, 39, 4o, 44, 140, 172, 190, 209, 253 ; Carrier, 45 ; Dimensions of, 42 ;
Power of, 40.

Pillet, M., 58.

“ Pilot-kite,” 176, 177.

Piston Speed of Locomotives (Note), 235.

Pitch, of Aerial Screws, 59, 69, 71 ; of Fan Blades, 163.

Plane, Body Sustaining, 224 ; Rigid Kites, 185 ; Supporting Power of, 233,
234 ; Surfaces, 202, 251 ; Table, 119.

Planes, Auxiliary, 237 ; Floating, 198; in Pairs, 117; Paper, 141 ; Pressure
on, 7, 8 ; Propelling, Power Required, 233 ; Superposed, 99, 113, 114, 115 ;
Supporting, 87, 88 ; Sustaining, 112.

“Planophore,” 117, 120, 122, 123, 130, 184 ; Pénaud’s, 179.

Pockets of Kites, 194, 196.

Pocock, George, 175.

Pocock’s “ Charvolant,” 184 ; Experiments, 175.

Pomés & De la Pauze, 57.

Pomés, M., 135.

Popular Science Review, 84.

Power, Absorbed in Flight of Birds, 43; Developed by Birds, 38, 39, 42, 43, 44,
45; Expended by Birds, 41; Lifting of Screws, 64 ; of Engine, 139 ; ofWind,
201, 210.

Pressure of Air, Table of, 4, 5 ; of Air Under Swallow’s Wing, 39 ; of Air
Under Wings of Birds, 3, 41, 44.

Prigent, 26, 27.

Primary Batteries, 92, 214 ; Feathers, 204.

Problem of Flight, 103, 144.
GENERAL INDEX. 303

Projectiles, Velocity of, 7.

Propeller, Aerial, 66 ; Phillips”, 172 ; to Kite, 187; Water, 66.

Propellers, 2, 26, 48, 85, 102, 111, 112, 120, 132, 133, 138, 139, 140, 240; Di-
ameter of, 140; Efficiency of, 65; Elevating, 111; Horizontal, 111;
Most Efficient, 64; Screw, 113, 129, 252, 253 ; Thrust of, 66; Wing, 161.

Propelling, Aerial Wheels, 125; Apparatus, 50, 122; Effect, 66; Force,
209, 275 : Planes, Power Required, 233 ; Power, 170 ; Screws, 153 ; Sur-
faces, of Birds and Fishes, 219 ; Wings, 228, 252.

Propulsion, 204, 246 ; by Flapping, 273 ; Instrument for, 250; Screw, 22o.

Propulsive Force of Wind, 209, 210, 258, 275.

“ Propulsors,” 58.

“ Pterophore,” 49.

Pull on Dynamometer, 243.

Push of Screw, 233, 235, 245, 246.

Quills, 273.

Quarry, 107, 108.
Quartermain, W., 16, 17.
Quimby, W. F., 32, 65.

Railway, Circular, 262, 263.

Rain-compelling Experiments, 187.

Reaction jets, 252 ; of Exhaust Steam, 162.

Reactions of Air, 10, 43, 94, 202.

Rectprocating Wings, 53.

Regulator, Thermostatic, 242.

Renard, Com., 7o, 71, 164, 166, 169, 170, 253.

Renard‘s Apparatus, 164, 165.

Renoir, M., 57, 58.

Reservoir for Hydrogen Gas, 162.

Reservoirs of Energy, 27. ,

Resistance, and Supporting Power of Air, 250 ; Ascending, 87 ; Atmospheric,
244 ; Head, 10, 254; Hull, 10, 128, 141, 251 ; of Air, 202 ; ofGoupil Aero—
plane, 157; of Moy &Shill’s Machine, 126; of Surfaces, 103 ; of Tatin
Aeroplane, 141 ; of Wheels, etc., 141 ; to Birds’ Flight, 43, 44; to Forward
Motion, 204 ; to Horizontal Flight, 42; to Rotation, 163.

Resistances, Air, Experiments in, 119 ; of Air, 206, 213, 251.

Resonator, Bamboo, 194.

Reversible Convex or Concave Kite, 196.

Revolving Blades, 33 ; Fan, 50.

Revue (it L’Ae’ranautz’que, 7o, 95.

Revue Scz‘enttfique, 41.

Richet, C., 41.

Rigid Wings, 216.

Ring-Doves, 4o.

Ring’s, M. C., Model, 161.

Rising from Ground, 255.

Rocket, 23 ; Composition, 16.

Roger Bacon, 81.

Rope-bearing Kite, 180.

Rotating Screws, 48, 72, 81, 178, 251, 258 ; Surfaces, 73 ; Wings, 88, 204.

Rotation, Resistance to, 163.

Rotules, 106.

Royal Society of N. S. Wales, 221, 222, 226, 228, 230.

Rubber, Band, 92 ; Spring, 29; Strings, 55 ; Threads, 142 ; Twisted, 28, 29,
3o, 31, 56. 134, 137, I61. I74-

Rudder, Max1m's, 243.

Rudders, 57, 88, 116, 122, 164, 170, 237, 239, 240, 241, 275 ; Horizontal, 118,
120, 123, 125, 258 ; Vertical, 120, 258.

Running-gear, 138, 140.

Russian Lamps, 126, 127.

Sabot, 105.

Safety, 103, 147, 208, 210, 257 ; Stick, 223.

Sailing, 96 ; Birds, 153, 190, 191, 208, 211 ; by the Force of the Wind, 99 ;
Effect. 66 ; Flight, 95. 96, 98, 108, 130, 189, 203, 208 ; Flight, Mystery of,
119 ; Flight, n0 Mystery about, 211 ; Flight of Birds, 153 ; “ Flight, The-
ory of,” 95 ; of Birds, 2, 206 ; in the Wind, 76, 78 ; Vessel, 177.

Sail, Main, Tail, Back, 164.
304 GENERAL INDEX.

Sails, 246; Adjustable Superposed, 163; Screw~like, 65; Parachute-like,

11 .

“ Sainted Screw,” 53.

St. Peter, 77,7

Sanderval, M. 7de, 158, 261 ; Experiments by, 159, I60, 161.
Sand- glass, 225.

San Diego, 263.

San Francisco, 130; Newsletter, 130.

Saracen, 80, 81.

Sarti, 50

Science of the Bird, 76,81, 83, 153, 208.

Scgeutzflc, Amerz',ca7z 193; A merzum Supplement, 187; Congress at Toulouse,

9

Screw, Apparatus, 73 , Archimedean, 49; Axis of, 114; Best, 65, 71: Blades,
220 , Blades, Best Form of, 112; Carlingford, 89; Concave, 58; Double, 56,
6o 61 ; Double-vaned,117‘, Efficiency of, 71 ; l‘lying, 55, 56, 57, 66,117,
119' , Screw-like Sails, 65', Machine, 64; Machine, Hovering, 215', Parachute,
6o , Pitch of, 59' , Propellers, 65, 113, 129, 131, 252, 253', Propulsion, 22o ;
Push of, 233, 235 , Sustaining, 58; T hrust of, 71, 244, h245, 246; Two- blad-
ed, 71 ; Vanes, 125 , Water, 67;“ With Variable Pitch , 59.

Screws, 11.35, 62 2151 239; Aerlal 38. 491 51. 52. 53. 54. 57, 60 64. 69, 70 89.
125, 225, 247, 253' , Aerial, Action of, 68; Aerial, Best PllL‘h of, 69: Aerial,
Experiments 1n, 71 ; Aerial Know Little About Them, 72', Aerial, True
Function of, 72, Double- bladed, 62; Efficiency of, 65, 66,71, 233', Fee-
ble, 274' , Lifting, 66, 116, Lifting and Driving, 111 ; Lifting Power of,

64 , Marine, 69, 72 ; Propelling, 153 , Rotating, 72, 87, 178 254, 258; Slip
of, 233, 238 Spinning, 56 Superposed, 28, 49,137; Superposed Aerial,
217, 218, Tests of, 71 ; to Lift and Propel 48, 142; Vertical, 5o, 66.

Sea, 110; Anchor,275 , Birds, 148,202, 203 , Gulls 235, 273 , Pie, Power of,
40' , Waves, 227.

Secretary of French Aeronautical Society, 59.

Seguin, M. Marc, 116.

Seine, 13.

Self- -generating Steam Boiler, 63.

Sénécal, M ., 131, 132.

“ Serpollet” Boiler, 228.

Shape, Most Efficient, 167: of Wings of Birds, 157.

Shapes, Experiments 1n,167, 168.

Shill. Mr. ., 126.

Ships, 268.

Shipwreck, 177.

Shipwrecked Mariners, 176, 177, 180.

Shoe, Wooden, 105.

Simmons, Mr , 19, 177, 178.

Simon the Magician, 76, 78.

Skate-fish, 144.

Skates, 164, 212.

Skin Friction, 10, 251.

Skye, Experiments of 5.

Sleep on the Wing, 192, 27,2.

“ Slip,” 67: of Screw, 233 238 , of Screw Propeller, 65.

Smeaton s Formulae, 43. 172; T able, 126, 209.

Smithsonian History, Natural Museum of, 114.

Smyrna, 197.

Smyth, Dr. W.. 39, 111, 112.

Smythies, Mr., 92.

Soar, Learning how to, 161.

Soarers, 191, 197, 202.

Soaring, 72,96,208; Action, 198; Albatross, 106 ‘and its Imitation, " 206;
Angles of Incidence, 167, 168, Apparatus, 151,180, 211, 246, 249', Appara-
tus, Cost of, 209 , Attitude, 167, 169, B1rds, 16,72, 75, 76, 77, 78,111, 130,
147, 148,151, 153,164, 166, 178, 180, 186, 192,193, 195, 197, 198, 201, 206,
215, 217, 257, 266; B1rds, Form of,153; Birds, Helical Path of, 160 ; Birds,
Paper on ,;197 Buzzard, 74, Dev1ce, of Beeson, 163; Devices, 260, Flight,
95, 96,98,130, 149, 200, 203, 204, 205, 207 , Flight, Problem of, 200; Ma-
chine, 82, 214', Machines, Designers of, 211 ; Machines, Exoeriinents with,
211' , Machines, Usefulness of, 211 , of Aeroplane, 153; of Birds, 210 ; Par-
tial Success in 208; Problem, 228, Simulation of, 200; Theories of, 206;
Vulture, 249.
GENERAL INDEX. 305

Société de Physique, 69.

Society, French, for Aerial Navigation, 178, 179, 180 ; German, for the Ad-
vancement of Aerial Navigation, 201 ; of Aerial Navigation, French, 54
118, 119 ; of Arts, Transactions of, 176 ; Royal of N. S. Wales, 228, 230.

Southern Ocean, 272.

Sparrow, Hawk. 77, 78, 86, 98 ; Hawks' Excursion, 79 ; Power of Sparrow, 4o.

Sparrows, 2, 23, 118.

Speed, 234 ; of Birds, 48 ; of Flying Machines, 267 ; of Moy & Shill’s:Ma-
chine, 126 ; of Translation, 72, 140.

Spencer, Charles, 16.

Sphere, Hollow, 9.

Spine, Central, 143.

Spinelli, M. Crocé, 58.

Spinning Screws, 56.

Spirit Holder, 229.

Spirits, Methylated, 114, 127 ; of Wine, Methylated, 228.

Spring-board, 205.

Springs, 27; Steel, 35.

Stability, 89, 90, 103, 117, 124, 187, 206; Automatic, 115, 122, 130, 185; Auto-
matic of Kite, 185 ; Gyroscopic, of Kite, 179 ; Horizontal, 13o: Lateral, 117,
120, 122. 132; Longitudinal, 117, 120, 122, 130, 138, 224, 257 ; of Aeroplancs,
73 ; of Flying Machine, 239; of Kites, 181, 184, 185, 187, 196, 197; of Plane,
75 ; lieadjustment of, 122 ; Transverse, 130, 257; Transveise and Longitu-
dina , 127. '

Stable Equilibrium, 85, 96, 123; Kite, 184.

Stag Beetle, 16.

Starting, 250, 258, 260, 266.

Stationary Flight, 203.

Steadiness, 122.

Steam, Bird, 29; Bird Machine, 35 ; Boiler, Self-generating, 63 ;’ Condensers,

92) 3-

Steamg-Engine, Data of, 156; Flying of, 86, 87; High Pressure Compared,
235; Maxim’s, 141, 241, 242, 243, 246; Trunk, 161.

Steam-Engines, 29, 7o, 113, 126, 154, 220 ; H. P. of, 8 ; Weight of, 27, 53, 63.
228, 229, 252.

Steam Generator, 127; Maxim’s, 241, 242, 243; Jets of, 113, 166; Machine,
Aerial, 25; Motors, 235 ; Pressure, 235, 236, 243 ; Vessel, 110, 263.

Steel, 256 ; Pipe, 228; Springs, 35.

Steerage, 122.

Steering, 201, 236, 238, 239; Plane, 125.

Steglitz, 207,

Stork, 202.

Strata of Air, 179.

Stringfellow, Mr., 27, 84, 86, 87, 113, 114, 115, 126, 130, 229.

String, Kite, 23o.

Stockton’s Tale, 211.

Struvé, 24.

Sub-tropical Regions, 191.

Siidende, 207.

Sulphur, 227.

Sultan of Turkey, 80.

Sun, New York, 234.

Superposed, Adjustable Sails, 163; Aeroplanes, 218, 230, 231; Blades, 164;
Fans, 162; Kites, 177; Planes, 99, 104, 113, 114, 115, 131, 134; Screws, 28,
49, 137, 217, 218; Wings, 161.

Superposition of Kites, 195.

Supporting, Areas of Birds, Table of, 46, 47 ; Plane, 87, 88 ; Power, 111 ; Power
of Air, 250, 251 ; Power of Concave Surfaces, 157 ; Powerof Plane, 233, 234 ;
Surfaces, 106, 130; Surfaces, Areas of, 10; Surfaces, Form of, 247; Surfaces
of Birds. 45.

Surface, Bearing, 203.

Surfaces, Alternating, 73; and Weight of Birds, 44, 45; Concave Bird-like,
156; Concavo~convex, 156, 157, 169, 172, 209; Form of Supporting, 247;
of Birds, 148, 203 ; Plane, 161; Rotating, 73; Supporting, 106; Supporting,
Areas of, 10; Sustaining, 23o; Sustaining, Concavo—convex, 202 ; Sustain-
ing, Extent of, 250 ; Sustaining Wing, 203; Wing, 203 ; Wing, Curved, 206.

” Sustainers,” 169, 171, 172.

Sustaining, Aeroplanes, 116, 127 ; Area, 113 ; Body-plane, 224; Planes. 35, 85,
112 ; Power, 254, 272 ; Power of Air, 72; Power of Inclined Plane, 82 ; Power

20
306 GENERAL INDEX.

of Kites, 197 ; Power of Superposed Planes, 104 ; Screw, 58; Surfaces, 86,
88, 114, 120, 126, 138, 140, 161, 214, 221, 230, 265; Surfaces, Amount Re-
quired, 255; Surfaces, Concavo-convex, 202; Surfaces, Extent of, 250;
Wing Surface, 203.

Sutherland, Duke of, 271.

Sutton, H., 33.

Sydney, 218, 231.

Swallow, 32, 39, 256.

“ Tableau (21’ Aviation,” Note, 10.

“ Tacking,” 272.

Tail, Adjustable, 132, :43; Balancing, 185 ; Movements of, 148 ; of Kite, 195 ;
of Soaring Birds, Form of, 153; Sail, 164 ; Triangular, 216 ; Vertical and
Horizontal, 208.

TailleSs Kite, 176, 177, 178, 184, 193.

Tandem Kites, 186.

Tatin Aeroplane, Resistance of, 141.

Tatm, M. V., 30, 41, 137, 139, 140, 141, 226, 254.

Tatin’s Apparatus, 172 ; Experiments, 171 ; Machine, 138.

Tawny Vulture, 148.

“ Technique” of Flight, 202.

Telegraph Wire, 139.

Temple, Felix du, 90.

Temple, M. Louis du, 91, 92.

Templer, Capt., 146.

Temfls, Paris, 212.

Telescheff, 24.

Texas, 187, 189; Plains of, 191.

Theories of Flight, 250.

Theory of Flight, Essay upon, 115-. “ of Sailing Flight," 95.

Thermometer, 186.

Thermostatic Regulator, 242.

Thibault, 61, 103; Experiments of, 5.

Thompson, Mr., 196.

Thorneycroft Boiler, 241.

“ Thrust," 167, 168 ; of Air Propeller, 68 ; of Screw, 71, 244, 245, 246.

Times, New York, 233.

Tips of Birds’ Wings, 33.

Tissandier, M. Gaston, 10, 54, 88, 92 ; Note, 81.

Tonkin, 193. 194.

Torsion of Wings, 223.

Touche, M., 119.

Towmg Vessels, 177.

Toysg 343. I99-

Traditions, 11, 73, 76, 78, 80, 81, 82.

“ Traite d’Aérostation" (Note), 174.

Transactions of the Society of Arts, 176.

Translation, Speed of, 72, 140.

Transportation Through the Air, 267.

Transverse Stability, 127, 130.

Trapeze Arrangement, 164 ; Bar, 33.

Trasimene, Lake of, 81.

Trefeuntec, 106.

Trend of Wind, 179, 189, 190, 191, 192, 208, 210.

Triangular Kite, 132, 133.

Trinovar'ite, 76.

Trochoidal Wave, 219.

“ Trochoided Plane,” 219.220.

Trouvé. M. G-. 36. 37. 38. 69. 79. 7s. 89. ms.

Trunk Engine, 147, 161.

Tubes, Hollow, 236.

Tubing, Copper, 228.

Tuileries, 13, 118.

Turbine, 227 ; Gas, 60.

Twin Vertical Screw Fans, 162.

Twisted India-rubber, 117, 134.

Two bladed Screw, 71.

Two-winged Fan, 64.
GENERAL INDEX. 307

Umbrella-like Surfaces, 17, 18.

United States, 196, 215, 234.

Upright Position of Body, 210.

Up-thrust of Wind. 207.

Upward Current, 189, 190, 191, 192, 273, 274.

Vanes, 111, 252; Feathering. 33.

Vapors, Combination of, 212.

Velocity of Screws, 71.

Venetian Blind, 24, 33, 100, 164, 171, 202, 218.
Vertical Screws, 50, .

Vessel, Aerial, 33, 64; Sailing, 177.

Vessels, Towing, 177; Wrecked, 18o.

Vibrating, Wing Arms, 143, 144; Wings, 87, 116.
Villeneuve, M. Hureau de, 29, 114, 122.

Vince, Experiments of, 5.

Vogelflug als Grundlage der Fliegekunst, 207.
Vogt, H. C., 66, 68.

Vol-a-voile, 108.

Vulcanite, 222.

Vulture, Tawny, 148.

Vultures, 148, 151, 152, 213; Flight of, 213; Soaring, 249.

Waders, 203.

Wales, N. 5., Royal Society of, 221, 222, 226, 228, 230.

Walker, Mr., 65.

War, 268; Balloon, 71, 164 ; Department, French, 164; Establishment, Franch
Aeronautical, 7o; “Kite of," 234.

Ward, Mr., 64.

Warped Surfaces, 166, 196.

Washington, D. C., 205; National Museum, 197.

Watch Spring, 51.

Water, Drag, 176; Screw, 67; Tubes, 93.

“Wave Action,” 146, 147, 252; “Action," Aeroplane's, 144; Aerial Machine
Brearey’s, 146.

Waves, 273; Sea, 227.

Waving Wings, 252.

Weather Bureau, 186.

Weight and Surfaces of Birds, 44, 45; of Engine per Horse-power, 126 ; of
Hargrave's Apparatus, 228; of Steam Engines, 8, 63; Pendant, 199.

Weights of Birds, 148; Shifting, 258.

\Venham, .Mr. F. H., 56, 59, 67, 99, 100, 103, 113, 174, 175, 176, 177, 231, 253,
272.

Werder, 207.

Weyher, Mr. Charles, 77, 262, 264.

Wheeler, 1. M., 33.

Wheel, Wind, 253.

Wheels, 89, 212; Aerial, 127; Propelling Aerial, 125.

Whirling Machine, 235.

Wild Goose (Note), 211.

Willis, Professor, 9.

Wind, 81, 96, 98, 110, 186, 273 ; Advancing Against, 199 ; as a Motor, 252 ;
Ascending and Descending Currents of, 190; Ascending Currents of, 119 ;
Ascending Trends of, 179, 189, 190, 191, 192, 208, 210; Bag, 196, 275; Beam.
274 ; Breaks, 192; Currents of, 191 ; Force of, 258 ; Gusts, Danger 1 f, 210;
Gusty, 75, 110 ; Impulse of, 275 ; Mills, 9; Motive Power of, 147; Power of,
152, 201, 202, 203, 207, 210 2 Power of, in Ascension, 153; Trend of, 179, 208,
210; Upthrust of, 207; Wheel, 125, 253.

Wing-action, 145; Areas, of Flying Animals, 45; Arms, 145; Arms, Vi-
brating, 143, 144; Beats of Birds, 2, 41 : Bird Form, Advantages of, 163 ;
of Bird, Pressure Under, 41, 44; Power, 202; Propellers, 161; Spread,
35 ; Strokes, 202 ; Surface, 203; Surfaces, Curved, 206; Sustaining Sur-
face, 203 ; Tips, 204.

Wmgs, 11, 12,13. 14. Is, 16, 17, 231241251271281291301339351381429 567 62.
72’ 73v 781 8°, 821 88! 899 93! 96‘ 97s 991.1059 1069 IO71 108: 1177 1611 223‘ 274 i
and Parachutes, 137, 148 ; Arched, 161 ; Artificial, 81, 82; Artificial, Ex-
periments 0n, 158 ; Beating, 38, 115, 137, 212, 2:5, 224, 226 ; Birds, 203;
Broad and Narrow, 203 ; Canvas, 116; onvex and Concave, 166; Curved,
203; Diedral Side, 239; Elasticity of, 166; Flapping, 23, 31, 32,48, 81,

7
308 GENERAL INDEX.

147, 148, 215, 220, 222, 253; Flexure of, 203 ; for Man, 20; Horizontal, 115 ;
ovements of, I48 ; of Albatross, 105, 106, 16: ; of Birds, 6 ; of Birds,

Proportions, Shape, Concavity. and Convexity of, 158 ; of Birds, Shape of,
I57 ; of Gull, 161 ; of Maxim’s Machine, 243 ; of Soaring Birds, Form of,
153; Oscillating, 12, 26, 161 ; Propelling, 252 ; Propellin , 220 ; Recipro—
cating, 53; Rigid, 216; Rotating, 88, 204; Superposed, x61 ; Vibrating,
87, 116; Waving, 252.

Wire, Telegraph, x39.

Wise’s “ History and Practice of Aeronautics,” 81.

Wooden Shoe, 105.

Woolwich Arsenal, 147.

Wooton, Mn, 96.

Wrapping Paper, 73.

Wrecked Vessels, 180.

Young, Dr. Thomas, 9.

Zez'trcltrzftfflr Luftsclzzfahrt, 206.
“ Zenith,” 58.