Patent GB-829464-A (GB)
Title: Improvements relating to jet propulsion engines
IPC: F02K7/00
Filed: 1957-09-12
Abstract: 829,464. Jet propulsion plant. HOFFMAN, G. R. Sept. 12, 1957, No. 28781/57. Class 110(3). [Also in Groups XI and XII] A jet propulsion engine comprises an inner tube 12 disposed within an outer tube 10, each tube being open at the upstream end to form an air intake and open at the downstream end, fuel nozzles being disposed in each tube to supply fuel thereto, also ignition means to cause ignition of the fuel and air mixture formed therein. In Fig. 1, the inner tube 12 is supported within the outer tube 10 by means of tubular struts 18, 20, the injectors 70 supplying fuel to the outer tube being supported on the struts 18, while the injectors 74 supplying fuel to the inner tube 12 are supported on a tubular strut 26 extending across the open upstream end of the tube. Fuel is supplied from a supply tank 46 to a chamber 48 which is pressurized by means of air from a compressor 54, the fuel passing through ducts to a ring manifold 72 supplying the injectors 70, and to a ring manifold 76 supplying the injectors 74. A spark igniter 84 is disposed within the inner tube 12 and a flame igniter 86 is disposed within the outer tube 10, being supported on a strut 20. A rotary fuel atomizer disc 78 is disposed within the inner tube 12 to assist in atomizing the fuel supplied by injectors 74. The disc is mounted on a shaft 82 which is rotatably mounted in a fixed shaft 24, the disc being formed with vanes 80 whereby it is rotated by the air-flow through the inner tube. A de-icing device 88, 90 is disposed at the air inlet of each tube, each device comprising an annular strip separated by a small gap; should the gap become closed by the formation of ice, an electrical circuit is closed and the strip becomes heated so preventing further icing. A series of radially-disposed vanes 30 is provided at the air inlet of the inner tube, the vanes being pivotally mounted at their outer ends and carrying bevel pinions 34 at their inner ends, the pinions engaging bevel gears 36, 38 which are rotatably mounted on the fixed shaft 24. The bevel gear 36 is formed with an internal gear 40 which is engaged by a pinion 42 which may be rotated by a flexible shaft 44 so as to enable the vanes 30 to be set at any desired pitch. The bevel gear 38 acts merely as an idler gear. In a second embodiment, Fig. G, the rotary atomizer associated with the fuel injectors of the inner tube 124 is positively driven, the atomizer comprising a series of vanes 120 pivotally mounted on a gear housing 128 which is mounted on a shaft 122 to rotate therewith. The atomizer is driven by means of a flexible shaft 118, pinion 154 and elongated gear 152 on the shaft 122, and the vanes 120 are pivotally mounted at their outer ends in a ring 144 which is rotatably mounted in a U-section track 146 secured to the inner surface of the tube 124. The pitch of the vanes 120 may be varied by longitudinal movement of the shaft 122, the shaft being formed with a helical groove 134 which is engaged by a projection on a bevel gear 130 which engages with bevel pinions 140 each carried by a vane 120. The bevel gear 132 acts merely as an idler gear. The rotary atomizer in this arrangement serves also to increase the pressure within the combustion chamber.