Flaperons

Flaperons are combined ailerons and flaps. They increase the effective angle of attack of a portion of the wing, raising lift and increasing drag. They are often used to reduce landing speed. However, if the ailerons are near the tip of the wing, they can make tip stalls more likely. Many computer transmitters have a preprogrammed mix available for this function for use on models where the two ailerons are controlled by one servo each.