Patent GB-847953-A (GB)
Title: Improvements in or relating to power plant
Inventor: KERRY THOMAS HENRY
IPC: F02K7/08
Filed: 1957-09-27
Abstract: 847,953. Gas turbine plant. ROLLS-ROYCE Ltd. Sept. 15, 1958 [Sept. 27, 1957], No. 30440/57. Class 110 (3). An air intake for a supersonic aircraft engine comprises an outer wall structure surrounding a central body to form an intake passage, the centre body having a portion which projects forwardly beyond the leading edge of the outer wall structure and is shaped to create shockwaves tending to come to a focus just outside the leading edge so that a build-up of pressure occurs in the intake passage and aperture means on the external surface of the centre body to allow air to pass through the centre body to the power plant for ancillary purposes. The power plant shown, Figs. 1 and 2, comprises a pair of gas-turbine jet-propulsion engines 10, 11 enclosed in a cowling 12 which is spaced from the engines to form an air passage 13. The engines 10, 11 discharge through a common outlet 15 having a fairing 16 forming a convergentdivergent propulsion nozzle. The passage of the gases through the outlet 15 creates an ejector effect which creates an air flow outside the engines in the passage 13. This reduces the decrease in efficiency of the nozzle at off-design conditions and also cools the engines. At the design conditions the ejector effect is small and most of the air flowing in the passage 13 flows through the opening 16b and slots 16c. The inlet opening 14, Figs. 1 and 2, is rectangular and the shorter sides 12b project beyond the leading edges 12a and are joined by a fixed cross-strut 18. The strut 18 forms the leading edge of a centre body 19 which defines with the wall portions 12c, a wall 20 and a pair of hollow fairings 17, a pair of intake ducts separated by the fairings 17. The centre body 19 comprises a pair of flaps 22, Fig. 5, pivoted at their forward edge to a hinge-pin 23. The shape of the flaps 22 is such that at supersonic flight speeds shock-waves are created which tend to focus just outside the leading-edge 12a thereby causing a build-up of pressure within the air intake. The rearward edges of the flaps 22 are connected by links 24 to nuts 25 working on threaded members 26 rotatably mounted in bearings 27, 29 spaced across the intake. Each threaded member has a sprocket 31 rotated by a chain 32 driven by a motor 35 which may be operated by a fluid. The rearwardly-adjustable section of the centre body 19 comprises a pair of flaps 37 pivoted at 38 which carry lugs 42 connected to the links 24 by links 43 so that the flaps 37 are adjusted simultaneously with the flaps 22 and the linkage is such that as the flaps 22 move apart, the flaps 37 also move apart but to a lesser extent. The area of the opening 47 is arranged to decrease as the flaps 22 move towards one another. This operation of the flaps also increases the throat area of the intake. Instead of the linkage 43, brackets may be attached to the flaps 37. Each of these brackets has a cam slot which engages a pin on the links 24. The air passing through the centre body is led through holes in the walls 20 and then into the passage 13. The flaps 22 may be adjusted by the motor 35 so as to give the desired relationship between Mach number and quantity of abstracted air and the throat area. The motor 35 may be responsive to the air temperature within the intake and is arranged to control the flaps 22 so that as the Mach number increases, the quantity of air abstracted first falls and then remains substan. tially constant. Specification 847,952 is referred to.