Available in Française, Español, Português, Deutsch, Россию, 中文, 日本, and others. fter the 1901 flying season at Kitty Hawk, the Wrights were seriously discouraged. Neither of their gliders from 1900 or 1901 had worked as anticipated or had produced sufficient lift. They had begun to suspect that the data they were working with to design their aircraft was incorrect. This data was gleaned from the experiments of Otto Lilienthal who, before his death in 1896, had designed 16 gliders and made thousands of glider flights, many more than any pilot/scientist before or since. His unquestioned success gave credence to his data. Whatever the accuracy of Lilienthal's data, the Wrights had come to a dead end. They simply did not know what to do to improve the performance of their gliders. If they built a third glider at this point, its design would be nothing more than guesswork. And at their present pace, building and testing one glider per year, it could be several lifetimes before they discovered a workable design. Even then, they wouldn't know if it was the best possible design. They decided to discard Lilienthal's data and generate their own. They built a wind tunnel, the second in America. (The first was built by Alfred Zahm.) Over the winter of 1901-1902, they tested over 200 wing shapes to find the most promising, then thoroughly investigated about 45 shapes to determine the very best. To do this, they built two instruments for their wind tunnel, one to measure lift and another to measure the ratio of lift to drag. When they compiled all their data, they were surprised to find that Lilienthal had been correct. They, in fact, had been at naive in the way they applied his data. Lilienthal investigated a single wing shape that he used for all his gliders and his data was correct for that shape only. The Wrights had presumed that even though they used different shapes, Lilienthal's data for lift and drag would be close enough. They were astonished to find just how much difference in performance there was between wing shapes. Armed with this new knowledge, they felt ready to get back in the air. We built our tunnel and the balance instruments from the same materials that the Wrights used, down to to the used hack saw blades and spoke wire. But despite their crude construction, we found them to be amazingly sensitive.





The Wrights' wind tunnel is little more than a wooden box with a tin scoop on one side to direct and compress the air stream.