Wilbur and Orville Wright, both engineer brothers, studied results of Germany’s Otto Lilienthal to improve their airplane flight experiments and calculations. The Wright gliders of 1900 and 1901 used wings like Lilienthal’s, and the brothers relied on his calculations for determining coefficient of lift. When the Wrights compared their results with those of Lilienthal, they found only small disagreements. With the coefficients of lift and drag holding up to their scrutiny, the Wrights turned their attention to the only other possible source of error in the equations, the Smeaton coefficient of air pressure. The Wrights built lift balance after discovering a discrepancy between actual and predicted values for lift and drag. The brothers plotted out the relationship among lift, thrust, weight, and drag. The Wrights figured out that the margins are a tribute to their genius. Perhaps all they proved in 1903 was that flight was possible on a cold and windy day in North Carolina.