Final answer:
Washout, also called wing twist, is a design feature of an airplane's wing where the angle of incidence decreases from the root to the tip of the wing. This promotes stability and prevents excessive wingtip stalling. It also improves the roll characteristics and handling of the aircraft.
Step-by-step explanation:
In aviation, washout refers to a design feature of an airplane's wing where the angle of incidence decreases from the root to the tip of the wing. This creates a twist in the wing, known as wing twist. The purpose of washout is to promote stability and prevent the wing from stalling excessively at the tips.
By having a lower angle of incidence at the wing tips, the outer portion of the wing produces less lift compared to the inner portion. This helps to prevent the wingtip from stalling first during flight, which could lead to a loss of control. Additionally, washout can also improve the roll characteristics and handling of the aircraft.
For example, in a typical airplane, the root of the wing may have an angle of incidence of 4 degrees, while the tip may have an angle of incidence of 2 degrees. This gradual reduction in angle along the wing span helps to ensure a smoother flow of air and a more stable flight.