 hile Wilbur was wading through books and papers on aeronautics, he carefully
observed buzzards flying near the bluffs that overlook the Great Miami River near Dayton.
Gradually, he came to the conclusion that birds balance themselves in flight by adjusting
the shape and position of their wings. The brothers read another book, Animal
Locomotion, or Walking , Swimming, and Flying, With a Dissertation on Aeronautics, by
James Bell Pettigrew, which confirmed this. "The thought came to me," wrote
Wilbur, "that possibly [a bird] adjusted the tips of its wings…so as to present
one tip at a positive angle and the other at a negative angle, thus…turning itself
into an animated windmill, and that when its body had revolved…as far as it wished,
it reversed the process."But how could they imitate this in an aircraft? All the devices that Wilbur and Orville could envision for adjusting wings seemed too complex or too heavy to be of much use. Then in July of 1899, Wilbur picked up a long, slender cardboard box that had once held an inner tube. He noticed that when he twisted the box, one end turned up while the other turned down. In his mind’s eye, the sides of the box became the wings of a biplane. With a set of cables, he could twists the wings just as he twisted the box. When one end of the wings was turned up, this would increase the lift at that end. Where the other end turned down, the lift would decrease. The difference in lift would cause the biplane to roll to one side or the other. Within a few days, Wilbur built a biplane kite with a wingspan of 5 feet. He fitted it with controls that allowed Wilbur to twist or "warp" the wings from the ground -- this would roll the kite. It also had a movable tail to control pitch. Control lines ran between the four forward corners of the kite to the ends of two sticks, one in each of Wilbur's hands. When he angled the sticks in opposite directions, the wings would twist one way or the others, causing the kite to roll right or left. When he angled his hands in the same direction, the tail would turn up or down, pitching the kite up or down. When flown in early August, it worked perfectly. Orville was camping with friends at the
time and Wilbur, too excited to wait for him to come home, rode his bicycle out to the
camp to tell him the good news. Immediately, the brothers began to plan a glider with
"wing warping" controls. |
Click on a
photo to enlarge it. Click on the box to see how Wilbur twisted it.
|
 Repeat the experiment that launched the Age of Aviation. In Will & Orv's Workshop, you can find plans for building and flying wing-warping kites.
|
 An historic replica on the right, the Not Quite Wright Kite on the left. |
