Reduction of Transient Adverse Effects of Spoilers

Abstract

A method is proposed to reduce the adverse lift and moment induced on an airfoil during the rapid deployment of its spoiler. The idea is to introduce a gap between the airfoil surface and the extended spoiler such that the flow through the base-vented spoiler abates the effects of the starting vortex shed from the spoiler tip. Results from an experimental study, which is carried out to demonstrate the effectiveness of the idea, substantiate that the magnitudes of adverse lift and moment decrease with increasing gap size. In addition, variations of the angular speed, deflection of the spoiler, and the angle of attack may also influence the adverse effects.