A leading edge slot on a Stinson 108-3. This type of slot is partial-span

A Zenair CH 701 STOL showing its fixed, full span leading edge slots in flight

Leading edge slots are an aerodynamic device used on fixed wing aircraft. Stinson 108-3 aircarft on skiis at Cobden Ontario Feb 2005 File links The following pages link to this file: Slot ... Stinson 108-3 aircarft on skiis at Cobden Ontario Feb 2005 File links The following pages link to this file: Slot ... Download high resolution version (884x476, 50 KB)Zenair CH 701 STOL aircraft in Flight File links The following pages link to this file: Slot ... Download high resolution version (884x476, 50 KB)Zenair CH 701 STOL aircraft in Flight File links The following pages link to this file: Slot ... Aerodynamics is a branch of fluid dynamics concerned with the study of gas flows, first analysed by George Cayley in the 1800s. ... An aircraft is any machine capable of atmospheric flight. ...

A leading edge slot is a fixed (non-moving) opening behind the wing’s leading edge. The slot does not operate at low angles of attack, like those found in cruise flight. At low angles of attack the airflow just passes over and under the slot. 1970 Model American Aviation AA-1 Yankee showing the wings straight leading edge The Leading edge is that part of the wing that, when it is in motion, first contacts the air. ... In this diagram, the black arrow represents the direction of the wind. ...

At progressively higher angles of attack air starts to move through the slot from the higher pressure air below the wing to the lower pressure air on top of the wing. The mixture of the air coming over the leading edge and through the slot is more energetic and thus sticks to the upper surface of the wing to a higher angle of attack than if the slot were not there.

Leading edge slots are generally of two types: those that are full-span and those that are partial-span.

Full span slots are generally found on Short Take-off and Landing (STOL) aircraft, like the Zenair CH 701 STOL, and their primary purpose is to lower the stall speed of the aircraft, allowing slower landing speeds and short landing rolls.

Partial-span slots are usually found only on the outboard portion of the leading edge of the wing where they ensure that that part of the wing will remain unstalled at higher angles of attack than the inboard portions of the wing. This ensures the wing root stalls first and contributes to docile stall behaviour and maintaining aileron control throughout the stall. Using slots in this manner produces a similar result to employing washout on a wing, but through a different means. An example of an aircraft with partial span slots is the Stinson 108. The Stinson 108 was a popular general aviation aircraft produced by the Stinson aircraft company from immediately after World War II to 1950, when the company was bought by Piper aircraft. ...

Slots naturally exact a penalty on the aircraft they are used on. This is because at cruise airspeed they create some drag compared to a non-slotted wing and so reduce cruising speed.

One way to reduce the cruise drag of slots is to make retractable slots. These are called leading edge slats. Slats work in the same way as slots but slats retract at higher speeds when they are not needed. Slats, in turn, are heavier and more complex than slots. 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. ...