![]() On the other hand, the wings of the Bleriot 11 that made the first aerial crossing of the English Channel had a great deal more camber than they needed.Ī number of early airplanes had sail-like wings, consisting of a single skin sewn to spars and ribs. The Brazilian Santos-Dumont, whose 1906 Paris flights in his huge 14-bis (“Number 14 encore”) are considered by some to have been the first true powered flights because his airplane rolled and rose under its own power (the Wrights employed a catapult and rail to get airborne in 1903), used very little camber, perhaps because he knew that it made an airplane want to dive. When we arrive at the beginning of the 20th century, we find the Wrights conducting systematic wind tunnel experiments to determine not only the best amount of camber to use, but also the best fore-and-aft distribution of curvature. The fact that camber was actually beneficial seems first to have been appreciated - at least in writing - by an English civil engineer of the 18th century, John Smeaton, who noted that curving the surfaces of their blades improved the performance of windmills. Thin surfaces restrained by a supporting structure naturally bellied out under air pressure, assuming what we now call a “cambered” - that is, arched - shape. Neither the feathers of birds nor the fabric of sails and windmill blades had any thickness to speak of, and so the earliest lifting surfaces were just that: surfaces. It was also perfectly evident to any thinking person that what kept birds and bats aloft was the large flat surfaces attached to their arms. Two early applications of it, the windmill and the fore-aft rigged sail, date back at least 800 years. That flat surfaces in the wind could produce the sideways force that we now call lift was a very ancient observation. ![]() ![]() A flat sheet makes a perfectly serviceable wing. Model planes with flat sheets of balsa wood for wings fly nicely so do airplanes made of folded paper, and bumblebees and butterflies.
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