Patent GB-656518-A (GB)
Title: Improvements in or relating to means for controlling the depth and altitude of subaqueous and airborne self-propelled craft
Inventor: MCKISSACK JOHN
IPC: F42B19/04
Filed: 1947-06-20
Abstract: 656,518. Gyroscopic apparatus. VICKERSARMSTRONGS, Ltd. June 20, 1947, No. 16373. [Class 97 (iii)] [Also in Group XXIX] In apparatus for automatically controlling the depth of subaqueous self-propelled craft or the altitude of aircraft, the means for actuating the elevators is controlled by means responsive to changes in the depth of immersion or altitude of the craft and a corrective signal is applied to the latter means in accordance with the precessional movements of the inner gimbal 34 of a restrained gyroscope, the outer gimbal 21 of which has a resilient connection 36 with the inner gimbal and is precessed by means also controlled in accordance with changes in the depth of immersion or altitude of the craft. The gimbal ring 21 is operated by rack and pinion mechanism 23, 24 by gyroscope precessing mechanism 1 comprising a bellows 4 exposed through a connection 2 to the barometric pressure or the hydrostatic pressure at the level of the craft and operating through a tie rod 5 a valve 16 controlling a servopiston 20 (see Group XXIX) operating the rack 23. The gyroscope which is arranged with its spin axis in the fore- and-aft direction A has the inner gimbal 34 coupled to a bracket 21<SP>1</SP> projecting from the outer gimbal by a leaf-spring 36. Movements of the inner gimbal 34 are transmitted to elevator actuating mechanism 25 through a frictionless pick-off comprising an air jet 341 co-operating with the ends of pipes 31, 32. The elevator actuating mechanism 25 is similar to the gyroscope precessing mechanism 1 and comprises a bellows 104 subject to the barometric or hydrostatic pressure and controlling a servopiston 120 by means similar to that in the mechanism 1. The tie rod 105 however carries an additional piston or diaphragm 28 capable of slight movement in a cylinder 29 to which the pipes 31, 32 are connected. Further, the pivot 111<SP>1</SP> of the follow-up lever 111 is adjustable along guides 27 to govern the datum pressure and therefore the datum altitude or depth. The tie rod 105 is thus adjusted in accordance with changes in level of the craft from a predetermined altitude or depth of immersion and through the gyroscope in accordance with the rate of change of altitude or depth of immersion and with the angular velocity of pitching of the craft. The datum pressure may be varied by a timing mechanism, a drive from the engine, a distance recording fan, a homing device, or by a motor under radio control. According to the Provisional Specification the leaf-spring 36 may be replaced by a link or links connecting the inner gimbal and the elevator actuating mechanism so as to resist the couple acting on the gimbal 34, or by a hydraulic or pneumatic device comprising a piston or diaphragm connected to the gimbal 34 and causing fluid pressure to be transmitted to the elevator actuating mechanism. Further, to counteract the deleterious effects of rolling or yawing two or more gyroscopes may be used, at least one of which is caused to precess. In a modified arrangement, the pressure connection 102 on the elevator actuating mechanism is dispensed with and the elevators are actuated by a further mechanism which gives the elevators a movement proportional to the displacement of the ram of the mechanism and another proportional to the displacement of the outer gimbal of the gyroscope relative to the craft.