Patent GB-141082-A (GB)
Title: Improvements in or relating to automatic stabilising or controlling means for aircraft
IPC: B64C1/00
Filed: 1918-02-26
Abstract: 141,082. Perkins, R. Roze-. Feb. 26, 1918. Steering and balancing.-An automatic stabilizing-apparatus for aircraft comprises a mercury column forming a gravity switch which is subjected to the influence of wind pressure or suction, or both, produced during flight so that the effect of centrifugal force or inertia on the mercury column is counteracted and the relative displacement between the mercury and its container is ensured, whereupon electric circuits are closed and the controls actuated through a fluid-pressure relay. For lateral balancing, the mercury column is arranged transversely and its ends are connected to Venturi or like tubes at the wing-tips in such a way that the effect of centrifugal force upon the mercury is counteracted. For longitudinal stability, the mercury column is set longitudinally and its ends connected to a Venturi tube at the middle of the wing span in such a way that suction acts on the forward end of the mercury column and pressure upon the rear end, wherehy the effect of the inertia of the mercury is counteracted. Fig. 5 shows the mercury column K<1> arranged to engage contacts 1 - - 10 or 1<x> - - 10<x> so as to close circuits controlling electro-magnets G<2>, H<2>, G<x2>, H<X2> actuating valves G, H, G<x>, H<x>, Fig. 8, admitting or exhausting air from a double piston B, B<x>, Fig. 1, which engages a sector D connected to the aircraft controls. Normally, the exhaust valves H, H<x> open the piston chambers to atmosphere at H<5>, H<x5>, the inlet valves G, Gx being closed. The sector D is provided with contacts 1<a> - - 10<a> and 1<xa> - - 10<xa> arranged in conjunction with a fixed double contact 12, 13 and connected respectively to the corresponding contacts 1 - - 10 and 1<x> - - 10<x>, so that when relative movement of the mercury column occurs, the corresponding exhaust valve is closed and the inlet valve opened, whereupon the sector is actuated until the inlet valve is de-energized, i.e. through an arc corresponding to the movement of the mercury column. As the machine rights itself in response to the control surfaces, and the mercury column leaves its furthermost contact, the exhaust valve is de-energized. As the ex. haust valve opens, its armature closes contacts 17, 18, thereby closing an independent circuit 20, 22, 23 through contacts 19, 21 at the sector so as to operate the other inlet and exhaust valves to admit air to the other piston-end and return the apparatus to the normal position. The contact 19 then becomes disengaged from the contacts 21, and all the valves are de-energized. In a modification, both piston-ends are normally subject to air pressure, and movement of the mercury column exhausts one side. In another modification, the mercury container is provided with only one contact at each side (namely 1 and 1<x>) and is geared to the sector D by wheels M<1>, M<2>, Fig. 14, so that when the mercury engages either of the contacts and completes a circuit to move the sector, the movement of the sector restores the container and breaks the circuit; as the aircraft rights itself, contact is made at the opposite end of the mercury so as to restore the controls to normal position. The automatic apparatus may be put out of action to allow manual operation by the usual control gear, by means of a valve J, Fig. 8, which is connected by pipes J<1>, J<x1> to the two sides of the piston, by pipes G<5>, G<x6> to the valves G, G<x>, and by a pipe J' to the air supply. Normally, the pipes J<1>, J<x1> are closed, and the pipe J<8> is open to the pipes G<6>, G<x6>, but by rotation of the handle J‹, the supply J<8> may be closed and the pipes J<1>, J<x1> opened to atmosphere at J<7>, J<x7> to render the automatic control inoperative. The handle J‹ may also operate a switch cutting off the current. The mercury tube for longitudinal balance may be adjusted manually to alter the angle of flight, by means of cords N<1>, Fig. 14, connected at N<6> to the support carrying the mercury tube and passing round pulleys N<2>, N<20>, the pulleys N<2> working in slots N' and being carried by the gearwheel M'. Inclination indicators, applications of.-The transverse mercury tube may swerve as an inclinometer and also to show when the machine is deviating from its course.