Tuesday, February 10, 2009

Great Moments in Aviation, Part V

Meanwhile, across the English Channel, big things were also happening in England at the end of the 18th Century. The next important development in flight involves a man who is the most important figure in aviation that you've probably never heard of: Sir George Cayley.

Cayley was probably the first figure in aviation history to go about it in a scientific, systematic way. He spent a lot of time in the early 19th Century testing different wing shapes, finding out which ones worked best. He tested different configurations of wing and tail. His experiments led him to develop an efficient cambered airfoil, and he also discovered the beneficial effects of dihedral on a glider's stability. He set all of this out in his three-part treatise "On Aerial Navigation", published between 1809 and 1810. But, most importantly, in 1799 he etched this drawing onto a silver disc, preserved in the Science Museum of London:

The important thing about this image is that here, Cayley clearly separates the functions of lift, propulsion, and control. Prior flying machines attempted to do all with a flexible bird-like wing. This is the key conceptual breakthrough that eventually made powered flight feasible. Propulsion was a problem that Cayley never did solve, though. Although he experimented with gunpowder-fired internal combustion engines, they simply did not provide enough power-to-weight to make a flier work. He then turned his attention exclusively to gliders.

His diligent research paid off, though not quickly. He did not build a full-size man-carrying glider until 1853. But in 1853, man finally experienced gliding flight. It was a short flight, close to the ground, and nothing like soaring with the birds. Not yet. But a gigantic step had been taken.

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