In 1901, the above formula was the accepted equation for calculating the lift of a wing. Though neither had completed high school, each of the Wrights had an excellent working ability in algebra and trigonometry. It was all they needed to find the error in Lilienthal's tables.
The Wrights tested model wings in their wind tunnel using two balances, one for lift, one for drag, or "drift" in their terms. Each converted the performance of the wing into mechanical action. The resulting change in the geometry of the balance gave them a measurable result to record and interpret.
Where was the error?
