It was a hang glider crash. A fatal hang glider crash. It was an October lesson that confirmed how the brothers were going to approach flight.

The death of British pioneer aviator Percy Pilcher in October of 1899 supported theories about controlled flight for the brothers. Pilcher had a workable wing design, but did not have a suitable system to control roll.*

The Wrights were convinced by the news about Pilcher. Many aviators were trying to fly. But these aviators they didn’t know how to design their aeroplanes. And they didn’t know how to control their flight.

The Orville and Wilbur needed to practice flying. Without crashing. And they needed to control roll.

Earlier that summer, in 1899, the Wrights had been observing large birds in flight above the Great Miami River, and theorized that birds changed the angle of their wings to make their bodies roll right or left, tilting one wing up and the other wing down at the same time. If the wing on one side of the aeroplane met the air at a greater angle than the opposite wing, it would create more lift on that side, and bank —and therefore turn— the aeroplane.

And during that summer, at The Wright Cycle Company at 1127 West Third (near the Intersection of West Third at Williams) Wilbur was engaged in a conversation with a customer while he was idly twisting a bicycle inner tube box. Twisting the box created what’s called a helicoidal twist. It was Wilbur’s eureka moment. It showed Wilbur how the Wrights were going to tilt one wing up, and the other wing down at the same time. It was the solution he needed for wing warping.

They designed and tested a kite that proved their wing warping theory. The wing warping on the kite was controlled by four lines tied to a pair of sticks held by the operator. Tilting the sticks in opposite directions caused the wing structure to twist. Twisting the wings structure in opposite directions increased the air pressure on one wing while decreasing it on the other. The resulting effect lifted one wing and lowered the other. They controlled roll. And they practiced their flying while they were safely on the ground – the lesson learned from Percy Pilcher.

That 1899 kite lead to the design and construction of the 1900 Wright Glider. Big and stable enough to carry a human in flight, the 1900 Wright Glider was made possible by testing roll control, and practicing flying while on the ground.

*Pilcher’s designs were later proven to be successful. In 2003, aerobatic studies by Cranfield University had concluded Pilcher’s powered aeroplane design was capable of flight, but only after the University added the Wright brothers’ innovation of wing warping to Pilcher’s design. For safety. And the successful test of Pilcher’s design was completed only 100 years after Orville’s first successful flight.