THE LANGLEY AERODROME

Now, in all ordinary construction, as in building a steamboat or a house, engineers have what they call a factor of safety. An iron column, for instance, will be made strong enough to hold five or ten times the weight that this ever going to be put upon it, but if we try anything of the kind here the construction will be too heavy to fly. Everything in the work has got to be so light as to be on the edge of breaking down and disaster, and when the breakdown comes all we can do is to find what is the weakest part and make that part stronger; and in this way work went on, week by week and month by month, constantly altering the form of construction so as to strengthen the weakest parts, until, to abridge a story which extended over years, it was finally brought nearly to the shape it is now, where the completed mechanism, furnishing over a horse power, weights collectively something less than 7 pounds. This does not include water, the amount of which depends on how long we are to run; but the whole thing, as now constructed, boiler, fire grate, and all that is required to turn out an actual horse power and more, weighs something less than one one-hundredth part of what the horse himself does. I am here anticipating; but after these first three years something not greatly inferior to this was already reached, and so long ago as that, there had accordingly been secured mechanical power to fly, if that were all – but it is not all.

After that came years more of delay arising from other causes, and I can hardly repeat the long story of subsequent disappointment, which commenced with the first attempts at actual flight.

Mechanical power to fly was, as I say, obtained three years ago; the machine could lift itself if it ran along a railroad track, and it might seem as though, when it could lift itself, the problem was solved. I knew that it was far from solved, but felt that the point was reached where an attempt at actual free flight should be made, though the anticipated difficulties of this were of quite another order than those experienced in shop construction. It is enough to look up at the gulls or buzzards soaring overhead, and to watch the incessant rocking and balancing which accompanies their gliding motion, to apprehend that they find something more than mere strength of wing necessary, and that the machine would have need of something more than mechanical power, though what this something was was not clear. It looked as thought it might need a power like instinctive adaption to the varying needs of each moment, something that even an intelligent steersman on board could hardly supply, but to find what this was a trial had to be made. The first difficulty seemed to be to make the initial flight in such conditions that the machine would not wreck itself at the outset in its descent, and the first question was where to attempt to make the flight.

Hiram Maxim’s Flying Machine c. 1894, the tracked machine referenced by Langley above.

It became clear, without much thought, that since the machine was at first unprovided with any means to save it from breakage on striking against the ground, it would be well in the initial stage of the experiment not to have it light on the ground at all, but on water. As it was probable that while skill in launching was being gained, and until after practice had made perfect, failures would occur, and as it was not desired to make any public exhibition of these, a great many places were examined along the shores of the Potomac and on its high bluffs which were condemned partly for their publicity, but partly for another reason. In the course of my experiments I had found out, among the infinite things pertaining to this problem, that the machine must begin to fly in the face of the wind and just in the opposite way to a ship, which begins its voyage with the wind behind it.

If the reader has ever noticed a soaring bird get upon the wing he will see that it does so with the breeze against it, and thus whenever the aerodrome is cast into the air it must face a wind which may happen to blow from the north, south, east, or west, and we had better not make the launching station a place like the bank of a river, where it can go only one way. It was necessary, then, to send it from something which could be turned in any direction, and taking this need in connection with the desirability that at first the airship should light in the water, there came at last the idea (which seems obvious enough when it is stated) if getting some kind of a barge or boat and building a small structure upon it which could house the aerodrome when not in use, and from whose flat roof it could be launched in any direction. Means for this were limited, but a little “scow” was procured, and on it was built a primitive sort of a house, one story high, and on the house a platform about 10 feet higher, so that the top of the platform was about 20 feet from the water, and this was to be the place of the launch. This boat it was found necessary to take down the river as much as 30 miles from Washington, where I then was – since no suitable place could be found nearer – to an island having a stretch of quiet water between it and the main shore; and here the first experiments in attempted flight developed difficulties of a new kind – difficulties which were partly anticipated, but which nobody would probably have conjectured would be of their actually formidable character, which was such as for a long time to prevent any trial being made at all. They arose partly out of the fact that even such a flying machine as a soaring bird has to get up an artificial speed before it is on the wing. Some soaring birds do this by an initial run upon the ground, and even under the most urgent pressure can not fly without it.

We have not all had a chance to see this striking illustration of the necessity of getting up a preliminary speed before soaring, but many of us have disturbed wild ducks on the water and noticed them run along it, flapping their wings for some distance to get velocity before they can fly, and the necessity of the initial velocity is at least as great with our flying machine as it is with a bird.

To get up this preliminary speed many plans were proposed, one of which was to put the aerodrome on the deck of a steamboat, and go faster and faster until the head wind lifted it off the deck. This sounds reasonable, but is absolutely impracticable, for when the aerodrome is set up anywhere in the open air we find that the very slightest wind will turn it over, unless it is firmly held. The whole must be in motion, but in motion from something to which it is held till that critical instant when it is set free as it springs into the air.

The house boat was fitted with an apparatus for launching the aerodrome with a certain initial velocity, and was (in 1893) taken down the river and moored in the stretch of quiet water I have mentioned; and it was here that the first trials at launching were made, under the difficulties to which I have alluded.

Perhaps the reader will take patience to hear an abstract of a part of the diary of these trials, which commenced with a small aerodrome which had finally been built to weight only about 10 pounds, which had an engine of not quite one-half horse power, and which could lift much more than was theoretically necessary to enable it to fly. The exact construction of this early aerodrome is unimportant, as it was replaced later by an improved one, of which a drawing is given, but it was the first outcome of the series of experiments which had occupied three years, though the disposition of its supporting surfaces, which should cause it to be properly balanced in the air and neither fly up nor down, had yet to be ascertained by trial.

What must still precede this trial was the provision of the apparatus for launching it into the air. It is a difficult thing to launch a ship, although gravity keeps it down upon the ways, but the problem here is that of launching a kind of ship which is as ready to go up into the air like a balloon as to go off sideways, and readier to do either than to go straight forward, as it is wanted to do, for though there is no gas in the flying machine, its great extent of wing surface renders it something like an albatross on a ship’s deck – the most unmanageable and helpless of creatures until it is in its proper element.

If there were an absolute calm, which never really happens, it would still be impracticable to launch it as a ship is launched, because the wind made by running it along would get under the wings and turn it over.  But there is always more or less wind, and even the gentlest breeze was afterward found to make the air ship unmanageable unless it was absolutely clamped down to whatever served to launch it, and when it was thus firmly clamped, as it must be at several distinct points, it was necessary that it should be released simultaneously at all these at the one critical instant that it was leaping into the air.  This is another difficult condition, but that it is an indispensable one may be inferred from what has been said.  In the first form of launching piece this initial velocity was sought to be obtained by a spring, which threw forward the supporting frame on which the aerodrome rested; but at this time the extreme susceptibility of the whole construction to injury from the wing and the need of protecting it from even the gentlest breeze had not been appreciated by experience.  On November 18, 1893, the aerodrome had been taken down the river, and the whole day was spent in waiting for a calm, as the machine could not be held in position for launching for two seconds in the lightest breeze.  The party returned to Washington and came down again on the 20th, and although it seemed that there was scarcely any movement in the air, what little remained was enough to make it impossible to maintain the aerodrome in position.  It was let go, notwithstanding, and a portion struck against the edge of the launching piece, and all fell into the water before it had an opportunity to fly. 

On the 24th another trip was made and another day spent ineffectively on account of the wind.  On the 27th there was a similar experience, and here four days and four (round-trip journeys of 60 miles each had been spent without a single result.  This may seem to be a trial of patience, but it was repeated in December, when five fruitless trips were made, and thus nine such trips were made in these two months and but once was the aerodrome even attempted to be launched, and this attempt was attended with disaster.  The principal cause lay, as I have said, in the unrecognized amount of difficulty introduced even by the very smallest wind, as a breeze of 3 or 4 miles an hour, hardly perceptible to the face, was enough to keep the airship from resting in place for the critical seconds preceding the launching. 

Has the reader enough of this tale of disaster?  If so, he may be spared the account of what went on in the same way.  Launch after launch was successively made.  The wings were finally, and after infinite practice and labor, made at once light enough and strong enough to do the work, and for now in the long struggle the way had been fought up to the face of the final difficulty, which in nearly a year more passed, for the all-important difficulty of balancing the aerodrome was now reached, where it could be discriminated from other preliminary ones, which have been alluded to, and which at first obscured it.  If the reader will look at the hawk or any soaring bird, he will see that as it sails through the air without flapping the wing, there are hardly two consecutive seconds of its flight in which it is not swaying a little from side to side, lifting one wing or the other, or turning in a way that suggests an acrobat on a tight rope, only that the bird uses its widely outstretched wings in place of the pole. 

There is something, then, which is difficult even for the bird in this act of balancing.  In fact, he is sailing so close to the wind in order to fly at all that if he dips his head but the least he will catch the wing on the top of his wing and fall, as I have seen gulls do, when they have literally tumbled toward the water before they could recover themselves. 

All this has to be provided for in our mechanical bird, which has neither intelligence nor instinct, without which, although there be all the power of the engines requisite, all the rigidity of wing, all the requisite initial velocity, it still can not fly.  This is what is meant by balancing, or the disposal of the parts, so that the air ship will have a position of equilibrium into which it tends to fall when it is disturbed, and which will enable it to move of its own volition, as it were, in a horizontal course. 

Now the reader may be prepared to look at the apparatus which finally has flown.  In the completed form we see two pairs of wings, each slightly curved, each attached to a long steel rod which supports them both, and from which depends the body of the machine, in which are the boilers, the engines, the machinery, and the propeller wheels, these latter being not in the position of those of an ocean steamer, but more nearly amidships.  They are made sometimes of wood, sometimes of steel and canvas, and are between 3 and 4 feet in diameter.

The hull itself is formed of steel tubing.  The front portion is closed by a sheathing of metal which hides from view the fire grate and apparatus for heating, but allows us to see a little of the coils of the boiler and all of the relatively large smokestack in which it ends.  The conical vessel in front is an empty float, whose use is to keep the whole from sinking if it should fall in the water. 

This boiler supplies steam for an engine of between 1 and 1-1/2 horse power, and, with its fire grate, weighs a little over 5 pounds.  This weight is exclusive of that of the engine, which weighs, with all its moving parts, but 26 ounces.  Its duty is to drive the propeller wheels, which it does at rates varying from 800 to 1,200, or even more, turns a minute, the highest number being reached when the whole is speeding freely ahead. 

The rudder, it will be noticed, is of a shape very unlike that of a ship, for it is adapted both for vertical and horizontal steering.  It is impossible within the limits of such an article as this, however, to give an intelligible account of the manner in which it performs its automatic function.  Sufficient it is to say that it does perform it. 

The width of the wings from tip to tip is between 12 and 13 feet, and the length of the whole about 16 feet.  The weight is nearly thirty pounds, of which about one-fourth is contained in the machinery.  The engine and boilers are constructed with an almost single eye to economy of weight, not of force, and are very wasteful of steam, of which they spend their own weight in five minutes.  This steam might all be recondensed and the water re-used by proper condensing apparatus, but this can not be easily introduced in so small a scale of construction.  With it the time of flight might be hours instead of minutes, but without it the flight (of the present aerodrome) is limited to about five minutes, though in that time, as will be seen presently, it can go some miles; but owing to the danger of its leaving the surface of the water for that of the land, and wrecking itself on shore, the time of flight is limited designedly to less than two minutes. 

I have spared the reader an account of numberless delays, from continuous accidents and from failures in attempted flights, which prevented a single entirely satisfactory one during nearly three years after a machine with power to fly had been attained.  It is true that the aerodrome maintained itself in the air at many times, but some disaster had so often intervened to prevent a complete flight that the most persistent hope must at some time have yielded.  On the 6th of May, of last year I had journeyed, perhaps for the twentieth time to the distant river station and recommend the weary routine of another launch, with very moderate expectation indeed; and when on that, to me, memorable afternoon the signal was given and the aerodrome sprang into the air I watched it from the shore with hardly a hope that the long series of accidents had come to a close.  And yet, it had, and for the first time the aerodrome swept continuously through the air like a living thing, and as second after second passed on the face of the stop watch until a minute had gone by and it still flew on, and as I heard the cheering of the few spectators, I felt that something had been accomplished at last, for never in any part of the world or in any period had any machine of man’s construction sustained itself in the air before or even half of this brief time.  Still the aerodrome went on in a rising course until, at the end of a minute and a half (for which time only it was provided with fuel and water), it had accomplished a little over half a minute, and now it settled rather than fell into the river with a gentle descent.  It was immediately taken out and flown again with equal success, nor was there anything to indicate that it might not have flown indefinitely except for the limit put upon it. 

I was accompanied by my friend, Mr. Alexander Graham Bell, who not only witnessed the flight, but took the instantaneous photograph of it which had been given.  He spoke of it in a communication to the Institute of France and in a similar communication to Nature.

On November 28 I obtained, with another aerodrome of somewhat similar construction, a rather longer flight, in which it traversed about three-quarters of a mile, and descended with equal safety.  In this the speed was greater, or about 30 miles an hour.  The course of this date is indicated by the dotted line in the diagram.  We may live to see airships a common sight but habit has not dulled the edge of wonder, and I wish that the reader could have witnessed the actual spectacle.  “It looked like a miracle,” said one who saw it, and the photograph, though taken from the original, conveys but imperfectly the impression given by the flight itself.