Flaps vs Slats: What’s the Difference?


Airplane wings

Airplanes are often equipped with multiple hinge-like control surfaces on their wings, including flaps and slats. In their default position, flaps and slats remain flush with the wings. Pilots can lower these control surfaces, however, to increase lift or drag.

What Are Flaps?

Flaps are control surfaces connected to hinges that are used to generate lift. They are found on the trailing edge of an airplane’s wings, meaning they run along the backside of the wings.

For additional lift and drag, pilots can extend the airplane’s flaps. Flaps are connected to wings via hinges. Extending them downward will then change the way in which air flows over the wings. It will essentially divert air around the flaps, thus increasing lift and drag.

What Are Slats?

In addition to flaps, many airplanes have slats on their wings. Slats are hinged control surfaces — just like flaps. They are also used to lift and drag.

Pilots can leave the slats in their default position so that they are flush with the airplane’s wings, or they can extend the flaps downward. Extending the slats will change the way in which air flows over the wings, resulting in increased lift and drag. Because they share so many similarities, many people assume that slats are the same as flaps.

Difference Between Flaps and Slats

There are several key differences between flaps and slats, one of which is their location. Flaps are always located on the trailing edge of an airplane’s wings, whereas slats are located on the leading edge of an airplane’s wings.

While they can both affect the airplane’s lift and drag, flaps and slats are often used for different purposes. Pilots typically use flaps during takeoffs and landings. Once airborne, though, pilots may use slats to prevent stalling. Extending the airplane’s slats can help to prevent stalling.

There are many different types of flaps as well. Plain flaps, for instance, are characterized by a basic hinge-like design in which the flap can be extended downward. Plain flaps are the most common, but there are many other types of flaps available, such as split.

Split flaps live up to their namesake by featuring a split design. When extended, the upper part of a split flap will remain flush with the wing, whereas the bottom part will extend downward. Other common types of flaps include fowler, slotted, junkers, gourney, zap and krueger.

In Conclusion

Airplanes don’t have completely flat, smooth wings. Most airplanes have multiple hinge-like control surfaces on their wings, such as flaps and slats. Flaps are found on the trailing edge of the wings, whereas slats are found on the leading edge. They can both increase the airplane’s lift and drag, but slats are better suited for preventing stalling.

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