Abstract: A nozzle for a gas turbine engine having a first fixed petal 44 and a second movable petal 46 which is pivotally mounted at a point intermediate its leading edge 46(a) and its trailing edge 46(b). Actuation means 48 are provided to move the nozzle between a first and a second position. In the petals first position, its leading edge 46(a) is positioned forward of and slightly radially inward of the trailing edge 50 of the exhaust duct 52, such that a small ejector gap 54 is provided therebetween and the trailing edge 46(b) approaches the trailing edge 44(b) of the fixed petal, such that the gap therebetween defines the exit area of the nozzle 36. In the petals second position (shown dotted), its leading edge 46(a) is moved radially inwards of its trailing edge 46(b) such that the exit area of the nozzle is defined by the area between the trailing edge 50 of the exhaust duct 52 on the second petal side and the trailing edge of the first petal 44(b).

Abstract: A compound helicopter shown in FIG. 1 of the drawings has wings 12 in addition to a helicopter rotor 14 and has twin powerplants 16 each including a low pressure compressor 18, a core engine 20, a power turbine 22 driven by the core engine and connected through a gearbox 32 to drive the helicopter rotor, and a variable area final, propulsion nozzle 24 which receives the exhaust from the power turbine. Augmentor wing flaps 28 are provided on the wings and fed with air from the low pressure compressor for providing additional lift and thrust from the wings. In operation, at take-off the nozzles 24 are fully opened and all of the power produced by the power turbines 22 is used in driving the helicopter rotor for producing lift. In addition, the augmentor wing flaps 28 are directed downwardly to provide lift. For forward flight the nozzles 24 are closed down, reducing the power to the rotor and slowing it down, while at the same time generating forward thrust.