Patent GB-480776-A (GB)
Title: Improvements in or relating to automatic steering gear for aircraft
IPC: G05D1/02
Filed: 1936-06-23
Abstract: 480,776. Fluid - pressure servomotor-control systems. SPERRY GYROSCOPE CO., Inc. June 23, 1936, No. 17456. Convention date, July 19, 1935. [Class 135] An automatic pilot for aircraft is provided with an arrangement for the blind landing of the craft comprising means actuated by a landing beam receiver for altering the relation between a control surface and a gyroscope which through this control surface normally maintains level flight, so as to cause descent along a landing beam. A complete automatic pilot is shown diagrammatically in Fig. 1. The vertical rudder 3 is controlled by a directional gyroscope 5 or other direction-finding compass while the elevator 1 and ailerons 2 are controlled by a gyroscope 4. The vertical gimbal of the gyroscope 5 carries a semicircular valve plate 8 adapted to co-operate with a pair of ports 6, 7, leading to the opposite sides of a diaphragm 91 for actuating a relay valve 6<1> controlling the operation of the rudder power device 31. The gyroscope 4 has two semicircular plates centrolling the elevator and ailerons servomotors through relays 4<1>, 51. Air is continuously exhausted from the casings of both gyroscopes by a vacuum pump 10 through reducing valve 11 while a pump 12 exhausts air from the relays 41, 5<1>, 61. In the case of each servomotor a follow-up movement is transmitted from the power device through a cable 54, differential gear 50 and toothed wheels 55, 56 to the member in which the ports 6, 7 are formed. Local adjustment is obtained through a handle 117 acting as one element of the differential gear. Distant adjustment either by hand from a remote point on the 'aircraft or by radio from a distant transmitting station is effected through rotary motors 40 connected through reduction and worm-gearing to another element of the differential gear. The rotary motors each comprise a pair of notched discs having teeth or vanes facing in opposite directions working in conjunction with a pair of air nozzles. The supply to the motor 40 connected with the rudder system is controlled by a diaphragm actuated piston relay valve under the control of a rotary cylindrical valve actuated by a radio direction indicator 16. This indicator is connected through a suitable receiving circuits to a directive loop antenna 14 and a non-directive antenna 141. The supply to the motor connected with the elevator system is controlled by similar control and relay controlled by an up-and-down indicator 25<1> connected through a landing beam receiver 60 operated from landing antenna 190. These two adjusting motors and the one connected with the aileron system may also be supplied under the control of a manually operated valve device (Fig. 17). This device comprises three pairs of oppositely mounted piston valves, members of each pair being alternatively operated by the movement of a universally mounted control rod 137. This rod is slidably mounted in a ball so that a notch in one end may be moved into engagement with a locking pin 160 and secured in this position by a spring catch 178 thus holding the rod in neutral. In order that the aircraft may fly directly towards its destination by a straight ground track regardless of side wind an additional directional or drift gyroscope 13 is provided which operates to position the loop antenna. The casing of this gyroscope' is mounted to turn in upper and lower bearings and is coupled to the loop antenna so as to turn with it. The vertical gimbal carries a semicircular valve plate adapted to vary the relative pressures acting on the two sides of a diaphragm 73 which actuates a two-way switch 75 controlling the operation of a reversible electric motor 77 connected by worm-gearing with the support for the antenna 14. Specification 451,843 is referred to. Reference has been directed by the Comptroller to Specification 427,422.