GB806038A - Thrust-reversing means for a jet propulsion engine - Google Patents

Abstract

806,038. Jet propelled aircraft. ARMSTRONG SIDDELEY MOTORS Ltd. April 15, 1957 [April 27, 1956], No. 12946/56. Class 4. [Also in Group XXVI] An aircraft jet propulsion engine thrust reversal means includes a nozzle movable axially away from the end of the jet pipe, and a plurality of segments pivoted to the nozzle for swinging movement to an operative position in which they form a conical baffle closing the nozzle inlet when the nozzle is in its downstream inoperative position, the nozzle being fast with a plurality of axially slidable rods carrying a series of thrust-reversal rings coaxial with the jet pipe and of curved cross-section concave upstream. Fig. 2 shows a jet pipe 10 supporting a wall 11 and a housing 12, on the forward face 20 of which are mounted jacks 15 having piston rods 14 mounting thrust reversal rings 13 and the nozzle 16, and jacks 22 having piston rods 23 passing through apertures in the rings 13 and pivoted to links 27, Fig. 6, pivoted to the baffle segments 24 which are hinged to the nozzle at 31. In the inoperative position, all the jacks are retracted, and the rings 13 lie inside the housing 12 and the segments 24 lie between the jet pipe 10 and wall 11. To reverse the thrust, the jacks 15 and 22 are extended, and the nozzle, rings, and segments move bodily downstream. The pistons 23a of jacks 22 then abut stops, but the pistons 14a of jacks 15 continue moving and the relative movement between. the nozzle and rods 23 swings the baffle segments through the position of Fig. 6 to that of Fig. 2. The jet pipe is cut away as at 24a, Fig. 2, to accommodate this swinging. On reverting to normal operation, the reverse sequence takes place. Fig. 7 shows a hydraulic control circuit comprising a reservoir 38, pump 39 and a valve 32. With the valve in the position shown, pressure fluid passes through conduits 41, 42 valve bores 44, 45 and conduits 46, 47 to the jacks 15 and 22. These extend equally until piston 23a abuts its stops, when piston 14a alone moves to swing the segments. The jacks exhaust through conduit 49 and a valve bore 60. On reversing the valve by a lever 33, pressure fluid passes through conduit 40, valve bore 43, and conduit 49 to return piston 14a jack 15 exhausting through valve bore 50. Jack 22 is not free to exhaust through valve bore 51, however, until piston 14a has moved sufficiently to open a valve 34 in conduit 52. By this time the baffle segments have been retracted, and the nozzle, rings and segments move upstream together.