Patent GB-780681-A (GB)
Title: Improvements in or relating to aircraft or missiles propelled by a ram jet unit
Inventor: EGGERS GERHARD
IPC: F02K7/18
Filed: 1955-07-13
Abstract: 780,681. Self-propelled missiles. SOC. NATIONALE D'ETUDE ET DE CONSTRUCTION DE MOTEURS D'AVIATION. July 13, 1955 [Aug. 9, 1954], No. 20309/55. Class 9(2) [Also in Group XXVI] An aircraft or missile comprising a ram jet unit having a generally cylindrical combustion chamber and a discharge nozzle formed with a flared wall towards the rear of the unit and a rocket extending inside the ram jet combustion chamber has unilateral connecting means supporting the rocket against the flared wall to ensure the propulsion of the aircraft or missile by the rocket and to enable the rocket to be automatically jettisoned when it is exhausted. A ram jet S comprises an intake diffuser 3, a combustion chamber 7 convergent-divergent and a propulsion nozzle'8. The diffuser 3 is formed between the cowling 1 and a central faired body 2 which is connected to the cowling by arms 5. The body contains a reservoir 4 of fuel which may be for example butane or propane. The fuel is conveyed to a burner 6 through a fuel-suction arrangement and a vaporization device and forms a layer of inflammable gas which enters the air stream in a direction perpendicular or inclined to the direction of air flow. The supply of fuel to the burner 6 is controlled by a valve (not shown) which is held in the closed position by an axial rod 10 rigidly fixed to the front or upstream portion of the rocket F. This rocket which is mounted on the axis and inside the ram jet comprises a combustion chamber 11 closed at one end by a base 12 and discharging through a propulsion nozzle 13. The combustion chamber 11 contains a cartridge or hollow cylindrical block of powder 14. This block is fixed so as to close a series of orifices 15 leading into a precombustion chamber 16 formed by a cowling 17 so that a zone of high turbulence at low speed is created in the vicinity of the burner 6. Orifices 18 are provided in the cowling 17 to allow the combustion gases to escape. The rocket F is coupled to the ram jet S by wedge-shaped spaced supports 19, which coact with the flared terminal portion of the ram jet propulsion nozzle 8. For launching the combined rocket and ram jet are mounted vertically. The cylindrical block of powder 14 is then ignited and the combustion gases pass through the propulsion nozzle 13. Shortly before the end of the burning of the powder 14, the orifices 15 are opened and small flames enter the pre-combustion chamber 16. At the same time an electric signal transmitted through the cable 22 places the fuel valve in the slightly open position. A small flow of fuel passes into the precombustion chamber 16 and is there ignited. At this moment, the combined apparatus has reached a speed sufficient to ensure starting uo of the ram jet. When the combustion of the block 14 is complete the rocket thrust falls to zero, and the effect of the pre-combustion chamber causes the drag of the supports 19 to increase, so that at this moment the rocket leaves the ram jet. The rod 10 is then removed from the body 2 and the fuel supply valve to the burner 6 opened fully. The arrangement is such that the maximum flow of fuel is injected wheni the cowling 17 is downstream of the burner 6 so that the fuel is readily ignited. The tail fin 20 of the rocket is used to displace the centre of thrust towards the rear of the aircraft or missile to ensure stability of the combined aircraft or missile and rocket.