Aircraft engine leading edge auxiliary air inlet

Claim 1

A primary and an auxiliary inlet system for the forward cowling forebody of an aircraft power plant comprising: a continuous leading edge structural ring which defines the inlet highlight area and extends aft a distance less than the maximum thickness of said forebody, and exterior foil pivotally mounted with respect to said ring and which forms a portion of the exterior surface of said forebody in a first position, an interior foil pivotally mounted with respect to said ring and which forms a portion of the interior surface of said forebody in a first position, wherein said exterior and interior foils are mechanically biased into said first positions and are responsive to changing flight conditions to move from said first positions to second positions wherein they coact to form one wall of a continuously converging auxiliary air passageway which directs auxiliary air longitudinally aft and outwardly along the interior wall of said forward cowling for boundary layer control, and wherein said interior foil pivots inwardly toward the centerline of said cowling about a point located near its forward edge to its second position wherein it effectively reduces the throat diameter of said primary inlet and cooperates with said structural ring to provide a bellmouth-shaped surface having a continuously negative rate-of-change of slope from its forward edge to its aft end where the slope of said surface approaches a parallel to the centerline of said cowling.