Patent GB-1026968-A (GB)
Title: Control apparatus e.g. for controlling movable parts of a supersonic intake
Inventor: SIMPSON JAMES REGINALD
IPC: F15B21/00
Filed: 1963-12-24
Abstract: 1,026,968. Fluid-pressure servomotor systems. ROLLS-ROYCE Ltd. Dec. 17,1964 [Dec. 24,1963], No. 51018/63. Heading G3P. [Also in Division F1 A supersonic intake of a gas turbine engine is provided with ramp parts, movable by a common ram to vary the effective area of the throat and also movable into and out of a position in which there is a gap between them through which a throat bleed may be taken. The lower surface of the intake is provided with a dump flap and a spill flap, each actuated by a separate ram, the dump flap being selectively pivotable about its leading or trailing edge while the spill flap is only pivotable about its leading edge. During supersonic flight, the ramp parts are positioned to focus the three shock waves and the dump and spill flaps match the flow throught the intake with that through the engine, the dump flap being used as a coarse control and the spill flap as a fine control. The dump flap is pivoted about its trailing edge for speeds below Mach 0.5 5 to provide extra flow, at speeds between Mach 0. 5 and Mach 1. 6 the dump flap is closed and the pivot is moved to the leading edge and at speeds between Mach 1. 6 and Mach 2.2 th dump flap is opened about the leading edge pivot and the dump and spill flaps are positioned to maintain the final shock wave in thedesired position. The system for controlling the ramps and flaps comprises a lever 55, Fig. 3 (not shown) subjected to forces responsive to pressures in chambers 50, 59 which pressures act on evacuated bellows 51, 61,fixed to levers 53, 63 which act on the lever 55. The lever 55 controls leakage of fluid from a conduit 67 fed from a supply 41 through restrictor 71 and cylinder 70. A piston 73 in the cylinder 70 has differential areas 74, 75, the smaller area 74 being subject to the supply pressure fed through passage 76. The piston 73 is thus moved with changes of pressure in conduit 76 under the control of the lever 55 and in so doing moves the ramps through a lever 82 and link 84 and acts through a cam 113 and lever 115 to move a pivot 57 of the lever 55 to provide a feedback. The pressure Ps fed to chamber 59 is measured by a forwardly facing pilot tube in the air intake and the pressure p L in chamber 50 is the static pressure in the intake. The pivot 57 is thus positioned in response to the quotient Ps/L which is the value of the local Mach number at the air intake. The lever 82 is carried by a movable pivot 85 which is normally in the position shown in response to pressures acting on a piston 90 but in the event of fluid failure or the manual opening of a solenoid valve 104, the pivot moves to the dotted line position 85<SP>1</SP> where the ramps are lowered irrespective of the position of the piston 73. A second leve 125 controls the leakage from a conduit 141 in a similar manner to lever 55 in response to pressure p L fed to chamber 120 and a pressure Prp from a rearwardly facing pitot tube in the intake, fed to chamber 130. The conduit 141 is fed from the supply conduit 41 through conduit 144 and restrictor 142. The pressures upstream and downstream of the restrictor act on the opposite sides of a differential piston 147 to adjust the pivot 136 through levers 152, 153. The position of the pivot 136 provides a valve of the quotient Prp/pL which is representative of the position of the final shock wave. Rotation of levers 151,153 to position the pivots 57, 136 also causes rotation of cams 136,161 to move a crosshead 162 which crosshead thus moves if the position of the final shock wave moves. The crosshead 162 positions a rod 163 connected through a lost motion connection 168 to a rod 167. The rod 167 acts through a lever 169, Fig.4, (not shown) pivoted at 171, to actuate a valve 170 controlling the connection of conduits 193, 196 with a supply conduit 183 or exhaust conduits 184, 185. The conduits 193, 196 lead to the opposite ends of a cylinder 195, Fig. 5 (not shown) which houses a piston 200 connected by a lever 204 and link 205 to the spill flap. A second piston 285 is connected by a lever 296 and link 297 to the dump flap. Both sides of the piston 285, which are of equal area, are connected to the supply 41 through restrictor 275, 282 and exhaust of pressure is controlled by valves 265, 266 actuated in response to the position of the piston 200, which acts through a member 260 on a rod 261 carrying valve actuating fingers 263, 264. The pivot 171 of lever 169 is movable in a slot of plate 173 which bears against pistons 242, 243 subjected on opposite sides to the pressures across orifices 187,191 in exhaust passages 184,185. Thus when valve 170 is moved a large distance in response to a large movement of crosshead 162, the piston 200 is moved rapidly and thus provides a large flow in the exhaust passage 184 or 185. The restrictor 187 or 191 thus increases the pressure differential acting on opposite sides of piston 242 or 243 and the pivot 171 is moved towards its null position. The valve 170 controls piston 200 as described above to actuate the spill flap and when the piston is moved fully to the left, corresponding to the spill flap being fully open, the valve 266 is opened to cause movement of the piston 285 to the left to open the dump flap. When the dump flap is opened too far, the crosshead 162 will act to move the piston 200 to the right thus closing the valve 266 and locking the position of piston 285. If the piston is then moved fully to the right to close the spill flap, the valve 265 is opened to close the dump flap. Restrictors 274, 282 in the supply lines to the piston 285 may be of different sizes to cause the rate of opening of the dump flap to be greater than the rate of closing. Both the levers 204 and 206 have movable pivots 210, 301 similar to the pivot 85 whereby the flaps are opened in response to fluid failure or manual actuation of a solenoid valve.