Aileron

Let's start with some misconceptions of mine that have been dispelled since I started reading about aviation last fall.

Misconception № 1

An airplane wing generates lift because of its shape, Bernouli something, etc. This was fed to me in grade school and I now think the lesson was not on aerodynamics, but on questioning the questionable. Several simple observations don't jive with this explanation, e.g. (1) Airplanes can climb and descend on command; that is, lift can be altered in-flight rather precisely, yet the wing shape doesn't change. (2) Airplanes can fly upside down. If an airfoil was shaped to direct lift up, flying upside down should be impossible, but it's not. And (3) aerobatic wings are perfectly symmetrical. The shape theory would conclude that such planes are incapable of flight, but they fly quite well.

A better theory is that airfoils are designed so that air attaches to the airfoil surfaces as it flows around them. This allows the airfoils to guide and change the direction of the air, a process called flow turning. If air is directed downwards, the wings are forced upwards. The amount of redirection can be changed by changing the angle at which the airfoils meet the oncoming air (angle of attack).