by John Traveler

Created on: September 14, 2008

For millions of years humans have watched winged creatures soar high in the air above, and as many have themselves dreamed of one day escaping the bond of gravity to match this alluring aerial feat. Many with dubious fascination, binding feathers to their appendages, have tempted fate to float off yonder precipice; only then to find their bodies in a tangled and broken profusion at the bottom, should they have been so lucky enough to have survived the event. After centuries of dreaming and the process of trial and painful error, two brothers Orville and Wilbur Wright succeeded where others before them had failed. They first took to the air with winged craft in 1903, but how?

The Wright's had been experimenting for several years, and in 1902 made a key discovery. They found that an airfoil provided greater lift than a surface, in this case a wing, that is flat on top and bottom. An airfoil is essentially a geometric plane which is flat on one side and curved or convex on the other. The air passing over the top - convex side - of the airfoil, having to travel further to reach the trailing edge of the plane or wing, must travel farther to get there. Air traveling under the wing -on the flat side- reaches the back of the wing faster than air traveling over it. This relative differential of air velocity also represents a difference of air pressure; it being lower on the top of the wing and greater on the underside. This pressure differential produces a dynamic referred to by aeronautical engineers as "lift," and its how air plains fly, but there is a little bit more to it. Getting up there is one thing, staying up there an entirely different scenario; as the Wright brothers would learn.

As lift is generated by air passing over and under the wing, the force of gravity is overcome and the wing begins to ascend. But how do you get the wind moving over the wing or the wing moving through the air in the first place. Well, for one thing, this is why planes always take off into the wind. For another, it brings to mind a second dynamic of flight which is called "drag." Drag is essentially the aggregate force of gravity and air resistance which is always trying to slow an air craft down, and bring it back to earth. The force of gravity is of course overcome by the dynamic of lift. In fact, in the case of a glider, gravity actually creates lift by increasing the gliders downward motion and thus accelerating the velocity of air passing over the wing surface, generating lift.

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