Angle of attack

Angle of attack is a term used in aerodynamics to describe the angle between the wing's chord and the apparent wind, effectively the direction that the aircraft is currently moving in. The amount of lift generated by a wing is directly related to the angle of attack, with greater angles generating more lift. This remains true up to the stall point, where lift starts to decrease again. Planes flying at high angles of attack can suddenly cross the stall point if a strong wind changes the apparent wind direction, an effect that is seen primarily in low-speed aircraft.

In military terminology, angle of attack is often referred to as alpha, the symbol used to denote it on most diagrams. Using a variety of high-lift devices and additional aerodynamic surfaces like leading edge extensions, fighter aircraft have increased the potential flyable alpha from about 20 degrees to over 45, and in some designs, 90 degrees or more. That is, the plane remains flyable when moving at right angles to the direction of motion.

See Also

• Angle of incidence