The Thrill of Invention
A dedicated craftsman explores the invention of the airplane by recreating its predecessors.
- By Tom Crouch
- Air & Space magazine, May 1998
(Page 4 of 7)
The 1900 glider featured ash ribs bent to shape with steam, but even during the short service life of the aircraft, the ribs gradually flattened out. On the way to Kitty Hawk, Wilbur had intended to buy 18-foot lengths of spruce to serve as wing spars. But he could find no lumberyard that carried spruce in that length, and he was forced to settle for white pine spars two feet shorter.
"The covering of the machine was French sateen [a closely woven cotton], and it was put on the bias, so that no wire stays were needed to brace the surfaces diagonally," Wilbur wrote. Applied this way, so that the fibers aligned like cross-bracing wires, the fabric became a key element of the structure, holding the ribs and spars in place and distributing flight loads across the wing. The result was a tough, flexible wing capable of absorbing punishment that would probably break a more rigid structure.
The career of the first full-scale Wright aircraft lasted less than two weeks, from October 5 to 18. It was apparent from the outset that the wings developed far less lift than the calculations based on the Lilienthal tables had predicted. After one or two tries, the notion of tethering the kite to a tower was abandoned.
Since prevailing winds were almost never strong enough to lift the weight of a pilot, virtually all of the 1900 tests were conducted with the machine flown as an empty kite, or carrying a load of sand or chain. The brothers turned the situation to their advantage, measuring the actual performance of their glider and setting the stage for the creation of accurate aerodynamic tables.
They attached a grocer's scale to the kite line to measure the combined lift and drag force on the kite. They used an anemometer to record wind speed and measured the angle of the line to the horizontal with a clinometer. With that information, they calculated that their wings were generating only two-thirds the lift predicted by Lilienthal's table. They offered Tom Tate, the young son of one of their local helpers, some thrilling rides and thereby calculated the drag of an upright body. And they demonstrated the effectiveness of their control system with separate lines running to an operator on the ground.
To attempt some free glides, they moved to the nearest elevation, some small dunes known locally as the Kill Devil Hills, about four miles south of Kitty Hawk. Having lugged the glider part of the way up the slope of the tallest (100-foot) hill, they found the wind gusting to 25 mph. "As we hadÉno experience at all in gliding," Wilbur wrote, "we deemed it unsafe to attempt to leave the ground."
The next day was calmer and Wilbur made a dozen free glides totalling less than two minutes. The day produced one other pleasant surprise: They had planned for the pilot to run along the ground for takeoff, assume a prone flying position between the two halves of the lower wing, then land on his feet. They discovered, however, that two men could launch the glider, and that the pilot had no trouble landing while prone.
At the end of the day they returned to Kitty Hawk alone, having abandoned the machine that first carried them into the sky on the spot where it made its last landing. Mrs. Addie Tate, postmistress of Kitty Hawk and the brothers' hostess on the Outer Banks, asked them for the fabric to make dresses for her two daughters. The skeleton of the machine remained at the base of the Kill Devil Hills for some months, finally disappearing in a July 1901 gale. The 1900 Wright kite/glider is the least documented of the three vehicles. There are no contemporary drawings of either of the first two machines. Worse, in the entire collection of Wright photos, there are only three images of the 1900 machine. The brothers took a picture of Tom Tate proudly displaying a large drum fish with the glider in the background, but they neglected to photograph the details of the glider during assembly, the tower from which they flew it, or any of the free flights.