GB622837A - Improvements in or relating to helicopters - Google Patents

Abstract

622,837. Helicopters. FIRESTONE TIRE & RUBBER CO. Sept. 21, 1946, No. 28339. Convention date, Oct. 4, 1945. [Class 4] A helicopter is provided with a tail rotor for balancing the reaction torque of the main lifting rotor, the tail rotor having control mechanism for simultaneously varying the pitch of the blades, and further mechanism for changing its direction of thrust. In the arrangement shown in Fig. 4, the pitch of the rotor blades 18 is adjusted by push rods 28 connected to arms 27, the rods being actuated by an axially-movable member 30 controlled by worm-gearing operated by a cable 31. The rotor is tilted bodily in the vertical plane by a worm 38 gearing with a toothed ring 21, the worm being operated by a cable 41. In the alternative arrangement shown in Fig. 7, variation of the direction of thrust in the vertical plane is effected by cyclical adjustment of blade pitch, the outer member 47 of a swash plate connected to the blade arms 27 by rods 45 being tilted by an arm 53 controlled by a cable 41. Collective pitch control is effected by axial displacement of the swashplate 47 through a lever 54 actuated by a quick-acting screw 57 controlled by a cable 31. In a third embodiment, Fig. 11 (not shown), the swash plate is mounted on gimbals, so that the rotor thrust line may be tilted in any direction. As shown in Fig. 10, the tail rotor may be so arranged that its thrust line 64 is normally inclined forwardly at a small angle.