GB772878A - Improvements in or relating to rotary wing aircraft - Google Patents

Abstract

772,878. Rotary wing aircraft. UNITED AIRCRAFT CORPORATION. Nov. 10, 1954 [Nov. 24, 1953]. No. 32529 /54. Class 4. [Also in Group XXIX] A helicopter comprises main and auxiliary rotors driven by an engine at a predetermined speed ratio and each having variable pitch blades, and a control arrangement for adjusting the auxiliary rotor blade pitch in response to engine manifold pressure. As described, the auxiliary rotor is an anti-torque rail rotor. In Fig. 3, three rods 86 from the cyclic pitch lever rock levers 62 mounted on a shaft 60 to actuate through bell-crank linkages, servomotors 76a, 76b and 76c to adjust a conventional swash plate. The shaft 60 is movable bodily by rotation of shaft 50 connected to dual control collective pitch levers 46. Shaft 50 also actuates through a bell crank linkage, the throttle 113 of the engine, so as to maintain engine speed constant as the rotor collective pitch is altered. The pitch of the tail rotor is adjusted by cables 144 Fig. 4, anchored to a quadrant 138 controlled by a hydraulic servomotor 164, the valve rod of which is controlled by a lever 190 having two inputs, one from a lever 128 adjustable by a cable 120 from the pilot's rudder pedals, and also providing a mechanical feed back signal, and the other from a bellows 162 connected internally to the engine intake manifold. As the engine power output is varied the bellows 162 feeds a signal to lever 190, and the quadrant 138 is rocked until lever 128 gives an equal and opposite feed back signal. At the same time, the pilot has an overriding control through cable 120. The servomotor 164 is of the type in which manual control is automatically established if the hydraulic pressure fails. Specifications 554,497 and 655,217 are referred to.