In
aviation, a spoileron is a
aircraft control surface which effects
roll control, like an
aileron, via the
mechanism of a
spoiler. Ailerons work by changing the amount and direction of
lift produced by a
wing - increasing the lift of one wingtip and reducing the other causes the
plane to
roll. Ailerons are linked, so that one goes down when the other goes up, and vice versa. Spoilers work by increasing the
parasitic drag of the wing - they can't reduce the drag produced. Spoilerons are spoilers which can be deployed
asymmetrically so that one wing produces more drag than the other.
The drag
differential causes the aircraft to
yaw in the direction of the wing with greater drag. In
swept wing aircraft this yaw change also results in a roll change, and thus a
turn of the aircraft is achieved. Conventional aircraft use ailerons for the roll change and a
rudder or rudders for the roll change. The conventional approach affords more precise and direct control, but requires more mechanical complexity. Spoilerons are used in rudderless aircraft, such as
rigid wing hang gliders.