(AIAA Paper 99-0655), AIAA Journal, Vol. 39, No. 10, pp. 2021-2024, Oct. 2001. The approaches of compressible dynamic stall control using real-time airfoil adaptation and slatted airfoils are compared. Each method attempts to solve the unsteady flow separation and the underlying causes differently. The approaches lead to unexpected results: For the slatted airfoil, dynamic stall alleviation on the main airfoil with a fully stalled slat occurred, and for the shape adapting airfoil, leading-edge attached flow with trailing-edge separation was obtained. In both cases, no dynamic stall vortex was present. As can be expected, the control effectiveness of each method varies over the full cycle and depends on the Mach number due to the new factors introduced by the use of the methods. These issues are addressed. U.S. Army Research Office, Research Grant MIPR8BNP-SARO07