GB1050923A - - Google Patents

Abstract

1,050,923. Aircraft engine air intakes. BRISTOL SIDDELEY ENGINES Ltd. Aug. 23, 1963 [Aug. 23, 1962], No. 32444/62. Headngs B7G and B7W. [Also in Division F2] An aircraft has an air intake for propulsion plant, comprising an inverted valley-shaped ramp having a pair of flat surfaces 16 meeting at a ridge line 17 in a fore-and-aft plane of intake symmetry and straight leading edges 19 diverging rearwards from a pointed forward end 20, and a member 21 carrying a lip 22 which bridges the valley downstream of the point 20. Figs. 1 and 2 show the complete aircraft, having wings 12 variable in sweep. A secondary ramp is formed by flat surfaces 25 meeting in a ridge line 26, and having leading edges 27 on surfaces 16, and trailing edges 29 defining the intake aperture with lip 22. The passenger cabin is shown at 13. At the design Mach number, a primary shock wave extends from the edges 19 in the plane of those edges and lip 22, and a secondary shockwave extends from the edges 27 in the plane of those edges and lip 22. During cruise, propulsion is solely by ram-jet engine having one or more combustion chambers 15, Fig. 5, and a nozzle formed by surfaces 31a, 31b, the undersurface 32 of the fuselage, and flaps 30. During take-off and acceleration up to Mach 3, gas turbine engines 14 are used, the secondary ramp being lowered about pivot 65 by jack 66 so that ridge 24 is parallel to ridge 17 to provide an air intake, and surfaces 31a and 31b being lowered and raised by jacks 88, 89 respectively to form an exhaust passage. Flap 30 is pivoted to the fuselage at 78, and the flat member 21 is supported by pivot 30a on flap 30 and by bell crank levers 74 connected to jacks 70. At higher speeds when the gas turbines are shut down, jacks 70 and 95 are operated to raise member 21 approximately parallel to itself to reduce the combustion chamber cross-section, and to lower flap 30 to increase the nozzle exit area and, according to the Provisional Specification, the lifting component of thrust. Supersonic diffusion is obtained during operation of the gas turbine engines by a change in the slope of the ridge 17 at 90. The secondary ramp has two skins 52, 54, the former, in the cruise position, abutting surfaces 16 while the latter defines a gap 44 for removal of the boundary layer (see Division F2). The gas turbine engines may be replaced by ducted fans driven by turbines operating on fuel and oxidant carried by the aircraft. Rocket boosters may assist take-off and acceleration through the transonic range.