Description

A split flap that slides backwards, before hinging downward, thereby increasing first chord (and wing surface area), then camber. The flap may form part of the upper surface of the wing, like a plain flap, or it may not, like a split flap, but it must slide rearward before lowering. A gap between the flap and the wing forces air from below the flap helping the airflow remain attached to the flap, increasing lift.

First used on aircraft in the 1930s, Fowler flaps are still in widespread use on modern aircraft, often with multiple slots.