In aviation, a spoiler is a device which reduces the
aerodynamic efficiency of the
aircraft for the purpose of increasing
glide angle or
dive speed. Two primary types of spoilers are used:
- A surface normally flush to the top surface of each wing which pivots at the forward edge.
- A surface perpendicular to the airflow which can be extended from within the wing through a slot in the top surface.
The spoilers work by
disrupting the airflow across the wing, increasing
parasitic drag, which reduces the
lift to
drag ratio (
L/D). The lift-to-drag ratio translates inversely to glide angle. All else being equal, an aircraft with spoilers deployed will descend faster than the same aircraft without them deployed.
Spoilers are most often employed in high-performance
sailplanes so they can escape strong lift and
so that they can be brought down quickly without resorting to dangerous
airspeeds. Spoilers are
deployed symmetrically, i.e. by the same amount on each wing at the same time.
(See also
spoileron)