What are the two main types of flaps on an aircraft?

The two main types of flaps on an aircraft are plain flaps and slotted flaps. Plain flaps are the simplest form of flaps, consisting of a hinged section on the trailing edge of the wing that can be deflected downwards to increase lift during low-speed operations like takeoff and landing. This configuration alters the wing's camber but does not increase the wing's surface area significantly.

Slotted flaps, on the other hand, feature a slot that allows high-energy air to flow from the upper surface of the wing to the lower surface as the flap is deployed. This design helps delay airflow separation, providing greater lift and extending the aircraft's stall angle. The interaction of the flap with the airflow significantly enhances lift performance, particularly at lower speeds.

Both types of flaps are critical in aviation for enhancing an aircraft's performance during specific phases of flight, especially during takeoff and landing, where increased lift is essential.