Slat
Slats are small aerodynamic surfaces on the leading edge of an airplane wing which, when deployed, allow the wing to operate at a higher angle of attack. Lift is a product of angle of attack and speed, so by deploying slats an aircraft can take off or land in a shorter distance by increasing the angle instead of having to fly faster.
Slats were first developed by Handley-Page in 1919; licensing the design became one of their major sources of income in the 1920s. The original designs were in the form of a fixed slot in the front of the wing, a design that was found on a number of STOL aircraft. During World War II German aircraft commonly fitted a more advanced version that pushed back flush against the wing by air pressure to reduce drag, popping out on springs when the airflow decreased during slower flight. In the post-war era slats have generally been hydraulically or electrically operated, allowing for more complex and efficient designs.
Today slats are generally one of several high-lift devices used on airliners, complex flap systems running along the trailing edge of the wing as well.
See also
