Aeroelastic Wing with Leading- and Trailing-Edge Control Surfaces

It is wellknown that the effectiveness of a trailing-edge controlsurface can be substantially diminisheddue to the elastic twist of an airfoil or wing.This aeroelastic phenomenon is known as control surface reversal when the lift or rollrate vanishes at a sufciently large ratio of ow dynamic pressure to wing stiffness. However, a leading-edge control surface can be used to counteract control surface reversal, and indeed, in principle, a leading-edge control surfacemay entirely cancelthe tendency of thetrailing edge control surface to underg o reversal. Moreover, analysis showsthat by using a simple control strategy onecan use a combinationof leadingandtrailing -edge control surfacerota tio ns to maintain lift and roll effectiveness and minimize control surface rota tions. The bene cial effects of leading edge control surfaces on control surface reversal are known to practioners. However, the present simple model makes these especially transparent and sug gests an advantageous strategy using a combination of leading and trailing-edge control surfaces.