Spoilers

When an airplane touches down, you would have noticed some rectangle plates sticking vertically up on the wings. They are called spoilers and pilots deploy them on landing to destroy lift and increase aerodynamic drag (braking).

Spoilers are hinged surfaces or plates installed forward of the flaps on the upper surface of the wings. Their primary purpose is to assist the pilot in dumping lift. Like flaps, spoilers can also be used to steepen the decent path, and/or reduce airspeed.

When deployed, spoilers disturb the streamlined airflow, thereby increases the static pressure over the wing. (Low air velocity; high static pressure). High static pressure destroys the lift.

Spoilers are used for:

1. slowing a plane down known as aerodynamic braking.
2. increasing the rate of descent
3. initiate a rolling motion of an aircraft when paired with ailerons.
4. increase the efficiency of wheel brakes.