GB925301A - Improvements in or relating to power transmission drives to rotary wing aircraft rotor systems - Google Patents

Abstract

925,301. Rotary wing aircraft. K. H. WALLIS. Nov. 15, 1961 [Nov. 18, 1960], No. 39640/60. Class 4. A rotary winged aircraft has a rotor head movable in relation to the aircraft fuselage for flight control, which has a flexible rotary drive for transmitting the engine power to the rotor head. The aircraft comprises an airframe 11, main wheels 12, nose and tail wheels 13, 14, a fin and rudder 15, engine 17 driving a propeller 19, pylon structure 23 supporting a rotor head 22 which may be pivoted fore and aft by a control rod 27 connected to control column 25. The propeller drive shaft 18 is engaged by a roller 20 which transmits the drive to the rotor through a flexible shaft 36, 37, epicyclic gear box 54 which includes a freewheel and a pinion 32 in mesh with an internally-toothed gear wheel 31 secured to the rotor shaft 30. Opposed rotor blades 24 are mounted on a teetering hinge comprising a bracket 28 pivoted at 29 on a vertical shaft (not shown) projecting upwardly from a control plate 39 to which the upper end of control rod 27 is pivoted. The rotor head comprising bracket 28, shaft 30 and gear 31 is mounted on the vertical shaft by taper roller bearings (not shown) and control plate 39 is mounted by a universal joint 40 of the form described in Specification 925,302. Arms 46 on opposite sides of the rotor shaft are biased inwardly by springs 48 to prevent the rotor teetering at low speeds, weights 47 on the arms causing them to move outwardly to free the rotor as rotor speed increases. A rotor brake 53 operated by manual control 49, is provided. Bowden cables 45 control a cam device 33, 34 to free pinion 32 from gear 31 to permit the rotor to auto-rotate as described in Specification 925,303.