AMERICAN GLIDING EXPERIMENTS
While Pilcher was carrying on Lilienthal's work in England, the great German had also a follower in America; one Octave Chanute, who, in one of the statements which he has left on the subject of his experiments acknowledges forty years' interest in the problem of flight, did more to develop the glider in America than with the possible exception of Montgomery any other man. Chanute had all the practicality of an American; he began his work, so far as actual gliding was concerned, with a full-sized glider of the Lilienthal type, just before Lilienthal was killed. In a rather rare monograph, entitled Experiments in Flying, Chanute states that he found the Lilienthal glider hazardous and decided to test the value of an idea of his own; in this, he followed the same general method, but reversed the principle upon which Lilienthal had depended for maintaining his equilibrium in the air. Lilienthal had shifted the weight of his body, under immovable wings, as fast and as far as the sustaining pressure varied under his surfaces; this shifting was mainly done by moving the feet, as the actions required were small except when alighting. Chanute's idea was to have the operator remain seated in the machine in the air, and to intervene only to steer or to alight; moving mechanism was provided to adjust the wings automatically in order to restore balance when necessary.
Chanute realized that experiments with models were of little use; in order to be fully instructive, these experiments should be made with a full-sized machine which carried its operator, for models seldom fly twice alike in the open air, and no relation can be gained from them of the divergent air currents which they have experienced. Chanute's idea was that any flying machine, which might be constructed, must be able to operate in a wind; hence, the necessity for an operator to report upon what occurred in flight, and to acquire practical experience of the work of the human factor in imitation of bird flight. From this point of view he conducted his own experiments; it must be noted that he was over sixty years of age when he began, and, being no longer sufficiently young and active to perform any but short and insignificant glides, the courage of the man becomes all the more noteworthy; he set to work to evolve the state required by the problem of stability, and without any expectation of advancing to the construction of a flying machine which might be of commercial value. His main idea was the testing of devices to secure equilibrium; for this purpose, he employed assistants to carry out the practical work, where he himself was unable to supply the necessary physical energy.
Together with his assistants, he found a suitable place for experiments among the sand hills on the shore of Lake Michigan, about thirty miles eastward from Chicago. Here a hill about ninety-five feet high was selected as a point from which Chanute's gliders could set off; in practice, it was found that the best observation was to be obtained from short glides at low speed, and, consequently, a hill which was only sixty-one feet above the shore of the lake was employed for the Experimental work done by the party.
In the years 1896 and 1897, with parties of from four to six persons, five full-sized gliders were tried out, and from these two distinct types were evolved: of these one was a machine consisting of five tiers of wings and a steering tail, and the other was of the biplane type; Chanute believed these to be safer than any other machine previously evolved, solving, as he states in his monograph, the problem of inherent equilibrium as fully as this could be done. Unfortunately, very few photographs were taken of the work in the first year, but one view of a multiple wing-glider survives, showing the machine in flight. In 1897, a series of photographs was taken exhibiting the consecutive phases of a single flight; this series of photographs represents the experience gained in a total of about one thousand glides, but the point of view was varied so as to exhibit the consecutive phases of one single flight.
The experience gained is best told in Chanute's own words. 'The first thing,' he says, 'which we discovered practically was that the wind flowing up a hillside is not a steadily flowing current like that of a river. It comes as a rolling mass, full of tumultuous whirls and eddies, like those issuing from a chimney; and they strike the apparatus with constantly varying force and direction, sometimes withdrawing support when most needed. It has long been known, through instrumental observations, that the wind is constantly changing in force and direction; but it needed the experience of an operator afloat on a gliding machine to realize that this all proceeded from cyclonic action; so that more was learned in this respect in a week than had previously been acquired by several years of experiments with models. There was a pair of eagles, living in the top of a dead tree about two miles from our tent, that came almost daily to show us how such wind effects are overcome and utilized. The birds swept in circles overhead on pulse less wings, and rose high up in the air. Occasionally there was a side-rocking motion, as of a ship rolling at sea, and then the birds rocked back to an even keel; but although we thought the action was clearly automatic, and were willing to learn, our teachers were too far off to show us just how it was done, and we had to experiment for ourselves.'
Chanute provided his multiple gliders with a seat, but, since each glide only occupied between eight and twelve seconds, there was little possibility of the operator seating himself. With the multiple glider a pair of horizontal bars provided rest for the arms, and beyond these was a pair of vertical bars which the operator grasped with his hands; beyond this, the operator was in no way attached to the machine. He took, at the most, four running steps into the wind, which launched him in the air, and thereupon he sailed into the wind on a generally descending course. In the matter of descent, Chanute observed the sparrow and decided to imitate it. 'When the latter,' he says, 'approaches the street, he throws his body back, tilts his outspread wings nearly square to the course, and on the cushion of air thus encountered he stops his speed and drops lightly to the ground. So, do all birds. We tried it with misgivings, but found it perfectly effective. The soft sand was a great advantage, and even when the experts were racing there was not a single sprained ankle.'
With the multiple winged glider some two to three hundred glides were made without any accident either to the man or to the machine, and the action was found so effective, the principle so sound, that full plans were published for the benefit of any experimenters who might wish to improve on this apparatus. The American Aeronautical Annual for 1897 contains these plans; Chanute confessed that some movement on the part of the operator was still required to control the machine, but it was only a seventh or a sixth part of the movement required for control of the Lilienthal type.
Chanute waxed enthusiastic over the possibilities of gliding, concerning which he remarks that 'There is no more delightful sensation than that of gliding through the air. All the faculties are on the alert, and the motion is astonishingly smooth and elastic. The machine responds instantly to the slightest movement of the operator; the air rushes by one's ears; the trees and bushes flit away underneath, and the landing comes all too quickly. Skating, sliding, and bicycling are not to be compared for a moment to aerial conveyance, in which, perhaps, the spice of danger adds zest. For it must be distinctly understood that there is constant danger in such preliminary experiments. When this hazard has been eliminated by further evolution, gliding will become a most popular sport.'
Later experiments proved that the biplane type of glider gave better results than the rather cumbrous model consisting of five tiers of planes. Longer and more numerous glides, to the number of seven to eight hundred, were obtained, the rate of descent being about one in six. The longest distance traversed was about 120 yards, but Chanute had dreams of starting from a hill about 200 feet high, which would have given him gliding flights of 1,200 feet. He remarked that 'In consequence of the speed gained by running, the initial stage of the flight is nearly horizontal, and it is thrilling to see the operator pass from thirty to forty feet overhead, steering his machine, undulating his course, and struggling with the wind-gusts which whistle through the guy wires. The automatic mechanism restores the angle of advance when compromised by variations of the breeze; but when these come from one side and tilt the apparatus, the weight has to be shifted to right the machine... these gusts sometimes raise the machine from ten to twenty feet vertically, and sometimes they strike the apparatus from above, causing it to descend suddenly. When sailing near the ground, these vicissitudes can be counteracted by movements of the body from three to four inches; but this has to be done instantly, for neither wings nor gravity will wait on meditation. At a height of three hundred or four hundred feet, the regulating mechanism would probably take care of these wind-gusts, as it does, in fact, for their minor variations. The speed of the machine is generally about seventeen miles an hour over the ground, and from twenty-two to thirty miles an hour relative to the air.
Constant effort was directed to keep down the velocity, which was at times fifty-two miles an hour. This is the purpose of the starting and gliding against the wind, which thus furnishes an initial velocity without there being undue speed at the landing. The highest wind we dared to experiment in blew at thirty-one miles an hour; when the wind was stronger, we waited and watched the birds.'
Chanute details an amusing little incident, which occurred in the course of experiment with the biplane glider. He says that 'We had taken one of the machines to the top of the hill, and loaded its lower wings with sand to hold it while we e went to lunch. A gull came strolling inland, and flapped full-winged to inspect. He swept several circles above the machine, stretched his neck, gave a squawk, and went off. Presently he returned with eleven other gulls, and they seemed to hold a conclave about one hundred feet above the big new white bird, which they had discovered on the sand. They circled round after round, and once in a while, there was a series of loud peeps, like those of a rusty gate, as if in conference, with sudden fluttering, as if a terrifying suggestion had been made. The bolder birds occasionally swooped downwards to inspect the monster more closely; they twisted their heads around to bring first one eye and then the other to bear, and then they rose again. After some seven or eight minutes of this performance, they evidently concluded either that the stranger was too formidable to tackle, if alive, or that he was not good to eat, if dead, and they flew off to resume fishing, for the weak point about a bird is his stomach.'
The gliders were found so stable, more especially the biplane form, that in the end Chanute permitted amateurs to make trials under guidance, and throughout the whole series of experiments not a single accident occurred. Chanute came to the conclusion that any young, quick, and handy man could master a gliding machine almost as soon as he could get the hang of a bicycle, although the penalty for any mistake would be much more severe.
At the conclusion of his experiments, he decided that neither the multiple planes nor the biplane type of glider was sufficiently perfected for the application of motive power. In spite of the amount of automatic stability that he had obtained he considered that there was yet more to be done, and he therefore advised that every possible method of securing stability and safety should be tested, first with models, and then with full-sized machines; designers, he said, should make a point of practice in order to make sure of the action, to proportion and adjust the parts of their machine, and to eliminate hidden defects. Experimental flight, he suggested, should be tried over water, in order to break any accidental fall; when a series of experiments had proved the stability of a glider, it would then be time to apply motive power. He admitted that such a process would be both costly and slow, but, he said, that 'it greatly diminished the chance of those accidents which bring a whole line of investigation into contempt.' He saw the flying machine as what it has, in fact, been; a child of evolution, carried on step by step by one investigator after another, through the stages of doubt and perplexity which lie behind the realm of possibility, beyond which is the present day stage of actual performance and promise of ultimate success and triumph over the earlier, more cumbrous, and slower forms of the transport that we know.
Chanute's monograph, from which the foregoing notes have been comprised, was written soon after the conclusion of his series of experiments. He does not appear to have gone in for further practical work, but to have studied the subject from a theoretical viewpoint and with great attention to the work done by others. In a paper contributed in 1900 to the American Independent, he remarks that 'Flying machines promise better results as to speed, but yet will be of limited commercial application. They may carry mails and reach other inaccessible places, but they cannot compete with railroads as carriers of passengers or freight. They will not fill the heavens with commerce, abolish customhouses, or revolutionize the world, for they will be expensive for the loads, which they can carry, and subject to too many weather contingencies. Success is, however, probable. Each experimenter has added something to previous knowledge, which his successors can avail of. It now seems likely that two forms of flying machines, a sporting type and an exploration type, will be gradually evolved within one or two generations, but the evolution will be costly and slow, and must be carried on by well-equipped and thoroughly informed scientific men; for the casual inventor, who relies upon one or two happy inspirations, will have no chance of success whatever.'
Follows Professor John J. Montgomery, who, in the true American spirit, describes his own experiments so well that nobody can possibly do it better. His account of his work was given first of all in the American Journal, Aeronautics, in January, 1909, and thence transcribed in the English paper of the same name in May, 1910, and that account is here copied word for word. It may, however, be noted first that as far back as 1860, when Montgomery was only a boy, he was attracted to the study of aeronautical problems, and in 1883 he built his first machine, which was of the flapping-wing ornithopter type, and which showed its designer, with only one experiment, that he must design some other form of machine if he wished to attain to a successful flight. Chanute details how, in 1884 and 1885, Montgomery built three gliders, demonstrating the value of curved surfaces. With the first of these gliders, Montgomery copied the wing of a seagull; with the second, he proved that a flat surface was virtually useless, and with the third he pivoted his wings as in the Antoinette type of power-propelled aeroplane, proving to his own satisfaction that success lay in this direction. His own account of the gliding flights carried out under his direction is here set forth, being the best description of his work that can be obtained:--
'When I commenced practical demonstration in my work with aeroplanes I had before me three points; first, equilibrium; second, complete control; and third, long continued or soaring flight. In starting I constructed and tested three sets of models, each in advance of the other in regard to the continuance of their soaring powers, but all equally perfect as to equilibrium and control. These models were tested by dropping them from a cable stretched between two mountaintops, with various loads, adjustments, and positions. And it made no difference whether the models were dropped upside down or any other conceivable position, they always found their equilibrium immediately and glided safely to earth.
'Then I constructed a large machine patterned after the first model, and with the assistance of three cowboy friends personally made a number of flights in the steep mountains near San Juan (a hundred miles distant). In making these flights, I simply took the aeroplane and made a running jump. These tests were discontinued after I put my foot into a squirrel hole in landing and hurt my leg.
'The following year I commenced the work on a larger scale, by engaging aeronauts to ride my aeroplane dropped from balloons. During this work I used five hot-air balloons and one gas balloon, five or six aeroplanes, three riders Maloney, Wilkie, and Defolco and had sixteen applicants on my list, and had a training station to prepare any when I needed them.
'Exhibitions were given in Santa Cruz, San Jose, Santa Clara, Oaklands, and Sacramento. The flights that were made, instead of being haphazard affairs, were in the order of safety and development. In the first flight of an aeronaut the aeroplane was so arranged that the rider had little liberty of action, consequently he could make only a limited flight. In some of the first flights, the aeroplane did little more than settles in the air. But as the rider gained experience in each successive flight I changed the adjustments, giving him more liberty of action, so he could obtain longer flights and more varied movements in the flights. But in none of the flights did I have the adjustments so that the riders had full liberty, as I did not consider that they had the requisite knowledge and experience necessary for their safety; and hence, none of my aeroplanes were launched so arranged that the rider could make adjustments necessary for a full flight.
'This line of action caused a good deal of trouble with aeronauts or riders, who had unbounded confidence and wanted to make long flights after the first few trials; but I found it necessary, as they seemed slow in comprehending the important elements and were willing to take risks. To give them the full knowledge in these matters I was formulating plans for a large starting station on the Mount Hamilton Range from which I could launch an aeroplane capable of carrying two, one of my aeronauts and myself, so I could teach him by demonstration. But the disasters consequent on the great earthquake completely stopped all my work on these lines. The flights that were given were only the first of the series with aeroplanes patterned after the first model. There were no aeroplanes constructed according to the two other models, as I had not given the full demonstration of the workings of the first, though some remarkable and startling work was done. On one occasion, Maloney, in trying to make a very short turn in rapid flight, pressed very hard on the stirrup, which gives a screw-shape to the wings, and made a side somersault. The course of the machine was very much like one turn of a corkscrew. After this movement, the machine continued on its regular course. And afterwards Wilkie, not to be outdone by Maloney, told his friends he would do the same, and in a subsequent flight made two side somersaults, one in one direction and the other in an opposite, then made a deep dive and a long glide, and, when about three hundred feet in the air, brought the aeroplane to a sudden stop and settled to the earth. After these antics, I decreased the extent of the possible change in the form of wing-surface, so as to allow only straight sailing or only long curves in turning.
'During my work I had a few carping critics that I silenced by this standing offer: If they would deposit a thousand dollars I would cover it on this proposition. I would fasten a 150-pound sack of sand in the rider's seat, make the necessary adjustments, and send up an aeroplane upside down with a balloon, the aeroplane to be liberated by a time fuse. If the aeroplane did not immediately right itself, make a flight, and come safely to the ground, the money was theirs.
'Now a word in regard to the fatal accident. The circumstances are these: The ascension was given to entertain a military company in which were many of Maloney's friends, and he had told them he would give the most sensational flight they ever heard of. As the balloon was rising with the aeroplane, a guy rope dropping switched around the right wing and broke the tower that braced the two rear wings and which also gave control over the tail. We shouted Maloney that the machine was broken, but he probably did not hear us, as he was at the same time saying, "Hurrah for Montgomery's airship”, and as the break was behind him, he may not have detected it. Now did he know of the breakage or not, and if he knew of it did he take a risk so as not to disappoint his friends? At all events, when the machine started on its flight the rear wings commenced to flap (thus indicating they were loose), the machine turned on its back, and settled a little faster than a parachute. When we reached Maloney he was unconscious and lived only thirty minutes. The only mark of any kind on him was a scratch from a wire on the side of his neck. The six attending physicians were puzzled at the cause of his death. This is remarkable for a vertical descent of over 2,000 feet.'
The flights were brought to an end by the San Francisco earthquake in April, 1906, which, Montgomery states, 'Wrought such a disaster that I had to turn my attention to other subjects and let the aeroplane rest for a time.’ Montgomery resumed experiments in 1911 in California, and in October of that year, an accident brought his work to an end. The report in the American Aeronautics says that 'a little whirlwind caught the machine and dashed it head on to the ground; Professor Montgomery landed on his head and right hip. He did not believe himself seriously hurt, and talked with his year-old bride in the tent. He complained of pains in his back, and continued to grow worse until he died.'