| 摘要 |
726,591. Jet-propulsion nozzles. UNITED AIRCRAFT CORPORATION. April 14, 1953 [April 26, 1952], No. 10140/53. Class 110 (3). A propulsion nozzle for a jet propulsion engine comprises a series of overlapping flaps pivotally attached to the downstream end of a convergent duct, a divergent duct,attached to and downstream of the convergent duct and means for moving the flaps outwardly to form a smooth wall between the convergent and divergent ducts and inwardly to form a convergent propelling nozzle. The propulsion nozzle shown comprises a convergent duct 14 which carries a supporting ring 12 and a divergent duct 20 downstream of the ring 12. The ring 12 supports a number of pivoted overlapping flaps 18 which are actuated by a ring 36 through links 38. The ring 36 is operated by a piston 50 in a cylinder 52 to which fluid under pressure is introduced by tubes 54, 56. In the position shown in full lines, the flaps 18 form a convergent nozzle at the end of the convergent duct 14. This position is used when the flow in the duct is subsonic. When the piston is forced to the other end of the cylinder 52, the flaps 18 are moved to the position shown dotted in which they form a part of the inner surface connecting the convergent part 14 and divergent part 30 of the duct. This position is used when the flow is supersonic. The flaps 18 have curved plates 66 which seal the gaps between the flaps as they are moved to the open position. The actuating ring 36 is supported by flutes 62 in the outer casing 64 of the duct. When the exhaust duct is used with a turbo-jet engine with reheating in the duct, cooling air is supplied to the flaps 18 from the compressor of the engine. This cooling air flows over the inner surface of the flaps 18 and divergent duct 20 as indicated by the arrows. Some of this cooling air may flow through the hollow flaps 18.
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