GB784013A - Improvements in jet propulsion engines with pulse-jet units - Google Patents

Abstract

784,013. Generating combustion products under pressure. SOC. NATIONALE D'ETUDE ET DE CONSTRUCTION DE MOTEURS D'AVIATION. July 27, 1955 [July 28, 1954], No. 21730/55. Class 51 (1). [Also in Group XXVI] A jet propulsion engine comprising one or a number of pulse jet engines arranged within a ram jet nacelle having at its inlet a diffuser and at its outlet a discharge nozzle in which the exhaust pipes of the jet engines are arranged to discharge each into an ejector tube arranged to suck air which has passed over the pulse jet unit or units has supplementary fuel injected into the gas flow from the combustion chambers of the pulse jet units upstream of the outlet orifices of the ejectors. A ram jet nacelle 1 having an inlet diffuser 5 and a discharge nozzle 3 surrounds a number of pulse jet units p1, p2. The inlets of the pulse jet units which are formed by aerodynamic valves 4 are located at the downstream end of the diffuser 5. The exhaust pipes 7 of the pulse jet units discharge into the ejectors 8 which are arranged to suck air which has passed over the pulse jet units. Supple- .mentary fuel is injected at 10 into the exhaust .pipes 7. This fuel is ignited automatically as soon as the supply valve 11 is opened by the hot gas discharged from the pulse jets. The fuel injectors may be arranged in the front portion of the ejectors. The wake created by the ejectors stabilizes the flame, but stabilizing screens may be provided, if required. The fuel injectors may be arranged between the outlet of the exhaust pipes 7 and the inlet to the ejectors 8, or inside the divergent portion of the ejectors. Due to the turbulence in the ejectors 8 the fuel may be injected at low pressure and without vaporization and the fuel injectors may be arranged to face other than in the transverse direction. The outlets 12 of the ejectors are preferably arranged at a distance upstream of the discharge nozzle 3 which is great enough to allow of completion of the combustion before the nozzle and before the commencement of che convergent portion 13. The ram jet nacelle 1 is partitioned between the planes containing the inlet and outlet orifices of the ejectors. The partition has a fixed part 15 on which are pivoted movable shutters 16. The movable shutters 16 are operated by manual control or automatically as a function of the dynamic pressure of flight so that at low aircraft speeds all of the air passing through the cowling passes through the ejectors and at high speeds is by-passed round the ejectors direct to the discharge nozzle 3. The pulse jet engines are mounted in the nacelle by radial arms 19 attached to the aerodynamic inlet valves 4 and by radial arms 21 provided with collars 20 that support the exhaust pipes. Specifications 715,323, [Group XXVI], 743,492 and 743,498, [Group XXVI], are referred to.