Patent GB-125090-A (GB)
Title: Improvements in or relating to Means for Controlling Aeroplanes.
Inventor: SPERRY LAWRENCE BURST
IPC: B64C13/24
Filed: 1916-05-05
Abstract: 125,090. Sperry, L. B. May 5, 1916 Steering and balancing. - A device for at.tachment to aeroplanes enables any of the following four systems of balancing control to be employed at the option of the pilot: (1) direct manual control; (2) manual control through a relay, (3) automatic control by means of a gyroscopic pendulum through a relay, and (4) auxiliary manual control acting upon the automatic control. When the automatic control is in use, the manual control levers follow the movements of the stabilizing-planes and serve to train pilots. In connexion with the automatic control, an anetnometric device causes the aeroplane to vol-plane should the speed fall below a critical value. Fig. 1 shows, in plan. the gyroscopic control, which comprises a pendulous gyrostat having its spinning axis vertical. The gyrostat is mounted on pivots 27, 28 in an horizontal ring 29 pivoted about pivots in brackets 30, and a roller on the lower end of the gyrostat engages a channel 33 in a U-shaped member 31 pivoted about axes normally in alinement with the pivots 27, 28. Electric contacts 35, 36, similar to those described in the above-mentioned Specification, for controlling a servo-motor are mounted on the member 31 to control the longitudinal balance, and similar contacts 35<1>, 36<1> are mounted on the ring 29 to control the lateral balance. Brushes 135, 135<1> cooperating with the contacts 35, 36, 35<1>, 36<1> are each carried by an arm mounted on a gear segment 37. This segment and a segment 41 mounted on the same axis gear individually with two intermeshing pinions 43, 44 carried by an arm on a pulley 42. The pulley 42, Fig. 8, is engaged by cords 25<1> led to a hand-lever to enable the machine to be adjusted by hand while the automatic control is in operation. The segment 41 is connected by a link 45 to an arm 46 having a segment 47 gearing with a pinion on a drum 49 from which cords 19 lead to the servo-motor so as to form a follow-up connexion with it. The longitudinal control is fitted with an additional brush 149, Fig. 1, fixed to the frame in a position relative to the contacts 35, 36 corresponding to the usual gliding angle. This brush is normally out of circuit; but should the speed fall below a critical value, an anemometer device 151 causes the brush 149 to be put in circuit and the brush 135 cut out, so that the aeroplane is automatically vol-planed and the auxiliary manual control also rendered inoperative. The control planes are actuated through a servomotor comprising electromagnetically-operated clutches and a shaft driven continuously by a wind-motor in a manner similar to that described in the above-mentioned Specification. The windmotor also drives an electric generator for supplying current to the gyrostat and various circuits, or for signal lights, wireless sets, &c. It is mounted close behind the propeller, so that the apparatus is energized as soon as the engine is etarted. The servo-motor is fitted with (a) means for disconnecting it mechanically from the control planes, and (b) with means for preventing further operation when the control planes have reached their limit of movement. (a) The drums controlling the planes are mounted on the shafts of gear-wheels 66, Fig. 9, driven by pinions 65 on the clutch shafts. The pinions 65, normally held in operative position by springs, can be slid out of engagement by levers 84, 84<1> connected to a sliding rod having a T-shaped end 82 adapted to be engaged by a wedge-shaped slide 80. The slide 80 may be operated by a cord 88 and returned by a spring 188. (b) A three-armed lever 70, 73, 74 pivoted at 69 has the arm 70 engaged by a spiral groove 67 in the gear-wheel 66 so as to hold the arms 73, 74 normally in mid-position. At either of the extreme positions, projections on the arms 73, 74 depress one or other of two flexible strips 76, 78 and break one or other of the contacts 77, 79 in the control circuit. The manual control levers are each connected by wires 3 to a drum 4', Fig. 4, mounted beside a second drum connected to it by a lost-motion device consisting of prongs 120, 121 embracing the spokes 123 of the drum 4<1>. A spring 93 normally keeps the spokes 123 midway between the prongs 120, 121. Cords lead from the second drum to a drum on the servo-motor. The second drum carries a casing 96 containing two contacts 6, 7, between which is a contact 100 carried by a lever pivoted at 98 and having a forked end 97 engaging a projection 99 on the drum 4'. Relative movement between the drums brings the contact 100 into circuit with one or other of the contacts 6, 7, and the servo-motor is brought into operation, the cords from the servomotor causing the second drum to follow the movement of the drum 4'. A switch enables either the contacts 100 or the contacts on the gyroscopic device to control the servo-motor or cut out both at will. To prevent hunting when the automatic control is in operation, a constant pull is exerted on the stabilizing-plane by a spring acting on the manual control lever. When the contact 100 is not in circuit, the drum 4<1> controls the stabilizing planes, after the slight lost motion has been taken up, through the second drum and the servo-motor drum which turns idly. One of the cords from the second drum may be led direct to the stabilizing plane, the other cord being passed over the servo-motor drum and connected to the plane; or separate connexions from the second drum may be led to the servo-motor and planes. Relay devices similar to those described may be used to actuate the rudder. Specification 10377/15 is referred to. Inclination indicators, applications of. - The member 31 has a pointer 112 moving over a cylindrical scale, and the ring 29 has a pointer 109 moving over an annular scale, so that the inclination of the aeroplane about both axes may be read from one point.