GB839230A - Improvements relating to variable jet nozzles - Google Patents

Abstract

839,230. Jet-propulsion plant. GENERAL MOTORS CORPORATION. Jan. 12, 1956, No. 1168/56. Class 110 (3). A turbo-jet engine exhaust duct comprises a jet nozzle surrounded by and spaced from a concentric shroud nozzle, each nozzle being formed by overlapping flaps pivoted at their upstream ends for shifting radially in or out to vary the jet nozzle area and render its configuration either convergent or convergentdivergent interconnections between the flaps of the two nozzles so that they shift together, actuating members movable axially of the nozzles to apply a force for shifting the nozzle flaps about their pivots, and cam-and-slot devices to convert that axial motion into pivotal motion of the flaps. In Fig. 6 the exhaust nozzle is defined by overlapping flaps 50 of generally T-section, each pivotably secured to the end of the exhaust duct 26. Side plates attached to each flap are each provided with an arcuate cam slot 64; a hoop 70 passes through all the cam slots and is attached by longitudinal bars 68 to the actuating cylinder 36 which can be moved longitudinally by a piston and cylinder. A shroud nozzle encircles the exhaust nozzle and comprises a number of overlapping staves 72, each pivotally secured to the shroud duct 38 and each connected by a pivoted link 80 to a corresponding flap 50 of the exhaust nozzle; thus when the exhaust nozzle is moved from the convergent position shown in Fig. 6, to the convergent-divergent position, the shroud nozzle moves in sympathy. Fig. 1 shows the engine 10 mounted in a nacelle 12. Some of the air entering the inlet passes round the outside of the engine and passes between the exhaust duct 26 and the actuating cylinder 36 and some air passes between the actuating duct 36 and the shroud duct 38.