The Wright Brothers

by Fred C. Kelly

As it would be impractical to keep so large a machine with them in the tent, as they had done with the smaller glider, the brothers built near Kill Devil Hill a rough frame shed, twenty-five feet long, sixteen feet wide, and seven feet high at the eaves. Both ends of the building except the gable parts were made into doors, hinged above. When open, the doors provided an awning at each end of the building. For living quarters they still used a tent. By driving a pipe ten or twelve feet into the sand they got a water supply.

Though the great stretch of sandy waste seemed too desolate for anyone to bother about owning, yet it was all under the ownership of one person or another and the Wrights took the precaution to obtain permission to erect their buildings.

This year they were to have company in camp. Octave Chanute, with whom they had been in correspondence for about a year, stopped in Dayton in June, 1901, at their invitation, to get better acquainted. When he learned that the Wrights had carried on their experiments in 1900 without the presence of a doctor in camp, and were intending to do so again, he told them he thought that was too risky, considering the kind of work and the isolation of the experiment ground. He said he knew a young man in Coatesville, Pennsylvania, George A. Spratt, “an amateur” in aeronautics, who had had some medical training. Spratt had never seen any gliding experiments, and Chanute thought he would be eager for the opportunity. If the Wrights would board him at camp, Chanute said, he would be glad to pay Spratt’s traveling expenses to Kitty Hawk and would consider himself “compensated by the pleasure given to him.” Chanute also proposed that they have in camp with them E. C. Huffaker, of Chuckey City, Tennessee, who was building a glider that Chanute was financing, and the Wrights consented. Thus there were four regularly in camp that season, and for a time Chanute himself was with them as a guest.

The new machine was completed and ready for trial on the afternoon of July 27. Since it was designed to be flown in a wind of seventeen miles, and there was but thirteen miles of wind on that day, the brothers took the machine to the big Kill Devil Hill for its first trial. After five or six short tuning-up flights they made a glide of 315 feet in nineteen seconds. Although several flights on this first day of experiments in 1901 exceeded the best made the year before, yet it was soon evident that in several respects the machine was not as good as the first one. It was found that the wings, with a camber of one to twelve—the camber recommended by Lilienthal, and used by Chanute and others—was not so good as the camber of one to twenty-two, used by the Wrights in 1900. (Camber of one to twenty-two means that the length of the chord, the straight-line distance between the front and rear edges of the wings, is twenty-two times the distance from the chord to the deepest part of the wing curve.) This was demonstrated by the fact that the 1901 machine could not glide on a slope as nearly level as had the earlier machine. The Wrights found, too, that a machine with wings of one to twelve camber was not so easily controlled fore and aft as when the wings were of one to twenty-two camber. They decided therefore to reduce the camber of the wings to make them more like those of the earlier machine. When they resumed their gliding, after the camber had been reduced (one to eighteen), the control of the machine appeared to be as good as it was the year before, and they then made flights in winds of twenty-two to twenty-seven miles an hour, without accident. Though in most of these flights the lateral control was highly effective, in a few others—under conditions seemingly the same—the wing warping appeared to have no effect at all.

The Wrights now made the discovery that in free flight, when the wing on one side of the machine was presented to the wind at a greater angle than that on the other side, the wing with the greater angle, instead of rising as it was expected to do, sometimes descended. The explanation was that the greater angle of the wing at one side gave more resistance to forward motion and thus reduced the speed on that side. This decrease in speed more than counter-balanced the effect of the larger angle of the wing in producing lift. (The Wrights had not discovered this when flying the glider as a kite, because, when held by ropes, the wings always maintained equal air speeds, even when their resistances were unbalanced.)

It was evident to the brothers that their present method of controlling equilibrium was not yet complete. Something was needed to maintain equal speeds at the two wing tips. The idea occurred to them that the addition of a vertical fin attached to the machine at some distance in the rear of the wings might be the solution of the problem. But the test of such a fin had to be left until another season.

The behavior of the glider in these various flights forced the Wrights to give thought to another scientific problem, that regarding the center of air pressure on curved surfaces. Contrary to the teachings of scientific books on the subject, it was becoming more and more evident that the travel of the center of pressure on a cambered surface is not always in the same direction as the travel on a plane surface. When the angle of attack on a plane surface is decreased, the center of pressure moves toward the front edge; but on a cambered surface this is true only when larger angles are being decreased. When the angle of attack on a cambered surface is decreased from, say, thirty degrees to twenty-five degrees, the center of pressure moves forward, as it does on a plane surface; but when a certain angle (between twelve and fifteen degrees) is reached, then the movement of the center of pressure is reversed. From there on, the center of pressure moves toward the rear so long as any further decrease is made in the angle of attack. The Wrights proved this by a series of experiments with a single surface from their plane. Knowledge of the phenomenon of this reversal of center of pressure was of great importance to them in their later work of designing aeroplanes.

Scientific problems were not the only ones to perplex the Wrights. A sore trial were the mosquitoes and sandfleas, particularly numerous and aggressive in that summer of 1901. As Orville Wright recalled in later years, there were times when he thought, while fighting mosquitoes through the night, that if he could just survive until morning he would pack up and return home. Those mosquitoes might have caused a long postponement of the conquest of the air.

By the time they left Kitty Hawk on August 20, the brothers had satisfied themselves that a glider of large surfaces could be controlled almost as easily as a smaller one, provided the control is by manipulation of the surfaces themselves instead of by movements of the operator’s body. So far as they knew, judging from figures previously published, they had broken all records for distance in gliding. Chanute, who had witnessed part of the 1901 experiments, insisted that the results were better than had ever been attained before. All that was encouraging. But, on the other hand, if most of the supposedly scientific information available was worthless, then their task was even more formidable than they had expected. With no dependable previous knowledge to guide them, who were they to determine how man should fly? Wilbur seemed much discouraged. Possibly he had entertained hopes of actually flying, though he had always disclaimed having such an idea. He was ready to drop the experiments altogether. On the way home, Wilbur declared his belief: Not within a thousand years would man ever fly!

Chanute urged the brothers not to drop their experiments, arguing that if they did it would be a long time before anyone else would come as near to understanding the problem or how to work toward its solution. Without knowing it, Chanute made a great contribution to aviation history, for the Wrights heeded his repeated admonitions against ceasing their efforts. Without the proddings of Chanute they might not have gone on.