Patent GB-204380-A (GB)
Title: Improvements in or relating to the automatic control of aircraft
IPC: B64C1/00
Filed: 1922-06-26
Abstract: 204,380. Vickers, Ltd., and Vickers, O. H. D. June 26, 1922. Hunting and differential switches; mercury switches.-In automatic lateral, directional and fore-and-aft control systems for aircraft, a follow-up device is provided by means of which the controls are moved definite distances according to the extent of the deviation for which it is required to correct. Lateral correcting device. This consists of an annular tube M, Fig. 2, in the lowest portion of which rests a mercury globule m, which when moved to one side or the other bv a lateral deviation connects a contact m<2> to one or more of a number of contacts m<1> leading into the tube on either side of the globule and connected to adjacent segments of a follow-up commutator N on a shaft j<1>. A circuit is thereby completed over a brush n for a reversible electric motor J, and for a relay o which closes a circuit for a magnetic clutch K, which clutches a worm-wheel j, driven by the motor J to a shaft j<1>. The shaft j<1> carries on its lower end an internallythreaded sleeve j<4> engaging the threaded end of the pump control shaft h which according to the direction of the rotation of the motor J, is raised or lowered to vary the delivery rate of the variable pump H and effect an appropriate correcting movement of the ailerons. The motor J stops when the brush n in its circuit engages a segment connected to a contact m<1> not touched by the globule. At the same time the relapse of the relay o declutches the worm-wheel j and the reaction of the pump H returns the commutator N to its neutral position, where it is centralized by the engagement of a spring-pressed plunger j<5> in a notch on a ring j<7> on the sleeve j<4>. If the resultant correction is insufficient the above cycle of operations is then repeated. Directional correcting device. The servomotor unit is controlled by a reversible electric motor associated with a follow-up commutator N, Fig. 3, in a manner similar to the control of the lateral correction servo-motor unit. The circuits are however under the control of a gyroscope of the type employed in Reid rate-of-return indicators as described, for example, in Specification 164,396. The gyro wheel P is mounted in the gimbal p<1> to precess around the horizontal axis p, and has its precessional movement opposed by springs. Any turning movement of the aircraft turns the gyro axis, and the resultant precession moves contact surfaces p<2>, p<3> attached to the gyrowheel casing and connected to the motor, under one or more stationary contacts q carried by the fixed ring Q and connected to the segments of the commutator N. Fore and aft correcting device. In general construction and operation this resembles the device described in Specification 204,139, in which an air-pressure incidence correcting device is differentially combined with a statoscope altitude correcting arrangement The air pressure tube device comprises negative and positive pressure tubes B, B<1>, Fig. 1, communicating with air-boxes b, b<1>, the inner faces of which are connected by a tubular member b<2> carrying four contacts c, c<1> adapted to engage contacts e<1>, e<2> movable either to the right or left along a screw e rotatable in one or other direction by two electromagnets d<6>, the circuits of which are prepared at predetermined intervals by clock mechanism d<7> and completed by the statoscope control. The statoscope consists of an air-chamber D terminating in a U-tube d in the lowest portion of which rests a mercury globule, which when the altitude changes is moved to one side or the other and bridges a pair of contacts d<3>, d<4> led into the tube d. A circuit is then closed at predetermined intervals over the clock d<7> for one or other of the magnets d<6> which rotates the screw e and moves the contacts e<1>, e<2> to the right or left. If the deviation of altitude or incidence is sufficient to require a correcting operation the contact e<1> engages a contact e, and a contact e<2> engages a contact c<1>, thereby completing a circuit over contacts e<2>, c<1> in the appropriate direction for the motor J, and energizing the magnetic clutch K over contacts c, e<1>. The subsequent controlling operation by the motor J is the same as that described with reference to the lateral correcting device. The follow-up commutator device may be dispensed with. Specifications 188,944 and 104,745 are also referred to.