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PROFESSOR LANGLEY'S AERODROME IN FLIGHT: A VIEW FROM ABOVE.

MCCLURE'S MAGAZINE.

JUNE, 1897.

No. 2.

VOL. IX.

I

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With illustrations made directly from Professor Langley's machine and approved by him.

HAVE been asked to prepare an account of some experiments I have conducted with flying-machines, built chiefly of steel, driven by steam-engines,

PROFESSOR S. P. LANGLEY.

and which have actually flown for considerable distances. There is in preparation a description of this work for the professional reader; but in view of the great gen

eral interest in it, and of the numerous unauthorized statements about it, it has seemed well to write provisionally the informal and popular account which is now given. The work has occupied so much of my life that I have presented what I have to say at present in narrative form.

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By flying-machine" is here meant something much heavier than the air, and entirely different in principle from the balloon, which floats only on account of its lightness, as a ship in water. Nature has made her flying-machine in the bird, which is nearly a thousand times as heavy as the air its bulk displaces, and only those who have tried to rival it know how inimitable her work is, for the "way of a bird in the air" remains as wonderful to us as it was to Solomon, and the sight of the bird has constantly held this wonder before men's eyes and in some men's minds, and kept the flame of hope from utter extinction, in spite of long disappointment. I well remember how, as a child, when lying in a New England pasture, I watched a hawk soaring far up in the blue, and sailing for a long time without any motion of its

From the painting by Robert Gordon Hardie, 1893.
Copyright, 1897, by the S. S. MCCLURE Co. All rights reserved.

wings, as though it needed no work to sustain it, but was kept up there by some miracle. But, however sustained, I saw it sweep, in a few seconds of its leisurely flight, over a distance that to me was encumbered with every sort of obstacle, which did not exist for it. The wall over which I had climbed when I left the road, the ravine I had crossed, the patch of undergrowth through which I had pushed my way-all these were nothing to the bird, and while the road had only taken me in one direction, the bird's level highway led everywhere, and opened the way into every nook and corner of the landscape. How wonderfully easy, too, was its flight! There was not a flutter of its pinions as it swept over the field, in a motion which seemed as effortless as that of its shadow.

After many years and in mature life, I was brought to think of these things again, and to ask myself whether the problem of artificial flight was as hopeless and as absurd as it was then thought to be. Nature had solved it, and why not man? Perhaps it was because he had begun at the wrong end, and attempted to construct machines to fly before knowing the principles on which flight rested. I turned for these principles to my books,

and got no help. Sir Isaac Newton had indicated a rule for finding the resistance to advance through the air, which seemed, if correct, to call for enormous mechanical power, and a distinguished French mathematician had given a formula showing how rapidly the power must increase with the velocity of flight, and according to which a swallow, to attain a speed it is now known to reach, must be possessed of the strength of a man.

Remembering the effortless flight of the soaring bird, it seemed that the first thing to do was to discard rules which led to such results, and to commence new experiments, not to build a flying-machine at once, but to find the principles upon which one should be built; to find, for instance, with certainty by direct trial how much horse-power was needed to sustain a surface of given weight by means of its motion through the air.

Having decided to look for myself at these questions, and at first hand, the apparatus for this preliminary investigation was installed at Allegheny, Pennsylvania, about ten years ago. It consisted of a "whirling table" of unprecedented size, mounted in the open air, and driven round by a steam-engine, so that the end of its revolving arm swept through a circumfer

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ence of two hundred feet, at all speeds up
At the end of
to seventy miles an hour.
this arm was placed the apparatus to be
tested, and, among other things, this in-
cluded surfaces disposed like wings, which
were hung from the end of the arm and

same time, took less strain than in the first
case. A plate of brass weighing one pound,
for instance, was hung from the end of the
arm by a spring, which was drawn out till
it registered that pound weight when the
arm was still. When the arm was in mo-
tion, with the spring
pulling the plate af-
ter it, it might natu-
rally be supposed
that, as it was drawn
faster, the pull would
be greater, but the
contrary was ob-
under
served, for
these circumstances
the spring contracted,
till it registered less.
than an ounce.
When the speed in-
creased to that of a
bird, the brass plate
seemed to float on
the air; and not only
this, but taking into
both
consideration
the strain and the
velocity, it was
found that abso-
lutely less power was
spent to make the
plate move fast than
slow, a result which
seemed very extraor-
dinary, since in all
methods of land and
water transport
high speed costs

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much more

a

power

than a slow one for the same distance.

These experiments were continued for three years, with the general conclusion that by simply moving any given weight of this form fast enough in a horizontal path it was possible to sustain it with less than one-twentieth of the power that Newton's rule called for. In particular it was proved that if we could insure horizontal flight without friction, about two hundred pounds of such plates could be

THE AERODROME IN FLIGHT, MAY 6, 1896. TWO VIEWS FROM moved through the air at the speed of an

INSTANTANEOUS

PHOTOGRAPHS

BELL, ESQ. SEE PAGE 659.

TAKEN BY A. GRAHAM

dragged through the air, till its resistance supported them as a kite is supported by the wind. One of the first things observed was that if it took a certain strain to sustain a properly disposed weight while it was stationary in the air, then not only to suspend it but to advance it rapidly at the

express train and sustained upon it, with the expenditure of one horse-power-sustained, that is, without any gas to lighten the weight, or by other means of flotation than the air over which it is made to run, as a swift skater runs safely over thin ice, or a skipping stone goes over water withalone out sinking, till its speed is exhausted. This was saying that, so far as power

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