Before returning to Dayton, the brothers were determined to try gliding on the side of a hill with a man on board. Four miles south of their camp was a magnificent sand dune about 100 feet high, covering 26 acres, called Kill Devil Hill. They carried their glider to this hill where they made about a dozen free flights down its side.
To take-off from the hillside, one brother and an assistant holding the ends of the glider ran forward against the wind, while the brother who was to operate it ran with them until the machine began to “take hold” of the air, or was airborne. Then the operator jumped aboard and glided free down the hill for 300 or 400 feet, usually gliding only 3 or 4 feet above the soft, sandy ground. The Wrights repeatedly made landings on sledlike skids while moving at a speed of more than 20 miles an hour. The glider was not damaged, nor did the brothers receive any injury. “The machine seemed a rather docile thing,” Orville wrote to his sister, from Kitty Hawk, “and we taught it to behave fairly well.”
Wilbur and Orville had misread the weather charts they had studied when choosing Kitty Hawk as the location for their experiments. The charts had listed monthly averages, while the day-by-day weather proved to be less than ideal. On some days tests could not be made because of a dead calm; other days the wind blew too strong—up to 45 miles an hour. Orville wrote about the strong winds that blew:
A little excitement once in a while is not undesirable, but every night, especially when you are so sleepy, it becomes a little monotonous.... About two or three nights a week we have to crawl up at ten or eleven o’clock to hold the tent down.... We certainly can’t complain of the place. We came down here for wind and sand, and we have got them.
Fellow campers at Kill Devil Hills, August 1901. From left: E. C. Huffaker, Octave Chanute, Wilbur Wright, George Spratt.
Even though the Wrights had only brief spells of favorable weather for practice, they learned much from their experiments. They were pleased with the efficiency of wing-warping to obtain lateral balance, and the horizontal rudder for fore-and-aft control worked better than they had expected. Though Wilbur and Orville believed that fore-and-aft balance and lateral balance were equally important, they were gratified that fore-and-aft balance was so easily attained. They made careful measurements of lift, drag, and angle of attack. The main defect of the glider was its inadequate lifting power. This might be due, the brothers conjectured, to insufficient curvature or camber of the wings which did not have the curvature used by Lilienthal, or perhaps even the Lilienthal tables of air pressure might be in error.
Although important strides had been made toward solving the problem of control, Wilbur and Orville lacked opportunity for sufficient practice since they did not get much time in the air. There still remained much for them to learn before solving the major problems of how to (1) design wings properly, (2) control the aircraft in flight, and (3) provide power, in order to build and fly a powered machine. They knew that they must learn how properly to build and control a glider before attempting to add a motor. “When once a machine is under proper control under all conditions,” Wilbur wrote his father from camp, “the motor problem will be quickly solved. A failure of motor will then mean simply a slow descent & safe landing instead of a disastrous fall.” They looked forward to the next slack season in the bicycle business so that they might resume experiments with a new glider.
Glider Experiments, 1901
In July 1901 the Wrights returned to Kitty Hawk during a downpour of rain immediately after a storm had broken anemometer cups at 93 miles an hour. There followed a miserable week spent fighting mosquitoes, “which came in a mighty cloud, almost darkening the sun.” They attempted to escape by going to bed early, wrapped up in blankets with only noses protruding cautiously from the folds. But the July heat became unbearable beneath the blankets. When they partly uncovered, the mosquitoes again swooped down upon them, forcing a perspiring retreat once more behind blankets. But Wilbur and Orville pushed forward good-humoredly and energetically to solve the problem of flight.