Duct pressure actuated nozzle

In a variable area convergent-divergent nozzle for use on an aircraft powered by a jet engine having an inner and an outer casing with a cooling air flow passage therebetween, the improvement comprising, a series of converging flaps pivotally mounted in the flow path of the engine exhaust, a corresponding series of forward pressure flaps integral with said coverging flaps, both of said series of flaps mounted for rotation about a common pivot point, an aft pressure flap pivotally mounted on the aft end of each of said forward pressure flaps and extending rearwardly therefrom, means for sealing the area outside said forward and aft pressure flaps to create a pressure cavity between the outer casing of the jet engine and the pressure flaps, the aft ends of said aft pressure flaps being pivotally attached to said sealing means, a diverging flap pivotally mounted on the aft end of each of said converging flaps, and means for controlling the flow of cooling air into and out of the pressure cavity to cause the pressure therein to be increased and decreased, respectively, causing said integral converging and pressure flaps to move inward and outward, respectively, in response to the requirement of the aircraft.