| 摘要 |
1,085,090. Jet-propulsion nozzles. GENERAL ELECTRIC CO. Sept. 16, 1965, No, 39554/65. Heading F1J. In a jet-propulsion engine, a convergentdivergent jet nozzle having a throat 17 is formed by a circumferentially-arranged series of flaps 16 each pivoted to the tailpipe 12 at 15, and a circumferentially-arranged series of flaps 40 pivotally connected at 45 to a circumferentiallyarranged series of flaps 49 each pivoted to the engine housing 10 at 51. Gas-tight seals are provided between axially-adjacent flaps and also at the hinges 45 and 51, but an annular gap 65 is left between the flaps 16 and 40. Air from the engine inlet duct passes through passage 66 between the housing 10 and tailpipe 12 and enters the jet nozzle through the gap 65 to cool the flaps 40. The size of the throat 17 is controlled by actuators 23 connected via an axially movable ring 20, links 26, bell cranks 27 and links 30, 35 to the flaps 16, 40. Actuators 56 are connected by an axially movable ring 58 and links 61 to the flaps 49, whereby the flaps 40, 49 are movable to vary the nozzle exit area 41. The position of maximum area, shown dotted, is used for supersonic flight. The gap 65, which has an ejector action on the air flowing through it, varies slightly in size according to the positions of the flaps, the size being a minimum at low ratios of exit area to throat area. Nevertheless, the air flow at low aircraft speeds exceeds that needed for cooling purposes. This excess flow reduces spillage at the air intake and the resultant aerodynamic drag, and, by increasing the mass flow through the engine, increases efficiency. A lost-motion connection between the actuators 23 and 56 is provided by links 74 each pivoted at 76 and connected at 70 to the ring 20 and at 80 to a collar 82 slidable on the ram 57 of an actuator 56. This ensures that the throat area is always smaller than the exit area. If operation of either set of actuators 23 or 56 tends to cause the ratio of throat area to exit area to approach unity, each collar 82 comes against a stop 84 thereby causing movement of the other set of actuators to prevent the ratio from exceeding the limit. The linkages between the actuators and the flaps may comprise rollers engaging cam tracks.
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