A mechanism called LEEMA (Leading Edge Electro Magnetic Airfoil) has been developed under an Army Phase II SBIR to address limitations in aerodynamic performance of rotorcraft. LEEMA continuously deforms the leading edge of the blade through the use of electromagnetic drivers embedded in the airfoil to respond to changes in advancing and receding aerodynamic regimes. For receding blades, the additional leading edge camber can increase the maximum lift coefficient by up to 30%, substantially increase the available rotor lift capability, and reduce or eliminate dynamic stall problems. For advancing blades at low angles of attack and high Mach number, the removal of droop significantly reduces the shock loss occurring on the suction side surface near the leading edge, and reduces drag and noise associated with these shocks. Force measurements, low speed motor stepping, heat transfer experiments, and analysis have been done and confirm basic operation of the deformable skin and drivers.
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