200 Years Ago

September 6, 1809: Sir George Cayley completed a detailed essay about his theories and research regarding heavier-than-air flight entitled "On Aerial Navigation." Sir Cayley, sometimes called the Father of Aviation, was the first to identify the four aerodynamic forces of flight weight, lift, drag, and thrust, and their relationship. He was the first investigator to apply the research methods and tools of science and engineering to the solution of the problems of flight. He also described many of the concepts and elements of the modern airplane, and was the first to build a successful human-carrying glider.