The
aerodynamic principles of planes can be demonstrated quite simply. A wing
is not a flat board; it is convex above and concave below, both curves
tapering gently to the trailing (rear) edge. This shape is called an aerofoil
and its curvature is the chamber. As the airstream meets the leading (front)
edge of the wing, it parts to pass over and under the aerofoil. The air
passing over the upper surface is forced to speed up over the camber and
its pressure drops. The reason for the pressure drop was first explained
by the Swiss physicist Daniel Bernoulli (1700-82).
This diagram shows the movement of air around
the aerofoil at diferent angles of attack. Notice the change forces as
you increase the angle of attack.