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.

In the first stages of a Fowler flap's extension, there is a large increase in lift but little increase in drag, making the setting ideal for takeoff in a large jet. As they continue to extend, the flaps move downward creating a little more lift but a lot more drag, ideal for landing.

B-747 with Fowler flaps (with multiple slots) extended on landing. Source: Wikicommons. Author: Faisal Akram, 2012.

Related articles

• Flaps
• Lift
• Drag
• High Lift Devices
• Slats
• Krueger Flaps
• Asymmetric flaps