Patent ID: 7143983

Claim:
An airfoil having an outer surface with an upper side, an opposing lower side, a leading edge, and a trailing edge, the airfoil comprising: an inlet located on the outer surface of the airfoil; an upper outlet located on the upper side of the airfoil and a lower outlet located on the lower side of the airfoil, each outlet positioned in fluid communication with the inlet and positioned forward of the trailing edge of the airfoil; wherein the upper and lower outlets are positioned so that when a portion of air flowing adjacent the outer surface is diverted into the inlet and out the outlets, the portion of air causes an attached air flow to become separated from the outer surface downstream of each of the outlets through which the portion of air flows, substantially forward of the trailing edge of the airfoil; and at least one valve between the inlet and the outlets for controlling air flow from the inlet to the outlets.