GB580231A - Improvements in aircraft - Google Patents

Abstract

580,231. Helicopters. DEHN, F. B. (Bell Aircraft Corporation)..June 23, 1944, No: 11988. [Class 4] The rotor 3 of a helicopter is pivoted on a mast 1 carried by the fuselage 2, and a rotating flywheel 4 is also mounted on the mast to which it is inclinable as shown so that in general the plane of the fly-wheel is maintained in its relation to the horizontal. The lift of the rotor 3 acts along the line OL at an inclination to the mast and being above the centre of gravity W will tend to pull the mast to a vertical position. If the fly-wheel is adjusted by. the pilot so that its plane is inclined to the horizontal the reactions between the rotor and fly-wheel tend to bring the rotor parallel to the fly-wheel so that forward flight, for example, may be obtained by giving a suitable forward inclination to the fly-wheel. As shown in Fig. 6, the fly-wheel 34 is universally jointed to a rotating shaft 44 inside the mast 31, on which is mounted in bearings a rotating sleeve 33 ; a shaft 46 of a motor in the fuselage drives the two rotating parts, a greater speed being given to the flywheel. The rotor blades 60, 61 are mounted in a ring 59 universally jointed to a boss 33a on the sleeve 33 as shown in horizontal section, Fig. 7. Control of the feathering of the blades is exerted by the fly-wheel 34 through a rod 68 pivoted at its upper end to a control plate 63 connected through bearings 62 to the flywheel, the lower end of the rod being pivoted to the ring 59. Inclination of the fly-wheel is accompanied by a similar inclination of the control plate 63 which produces an inclination of the ring 59 to determine the feathering of the rotor blades. The pilot's control of the flywheel is exerted through an arm 75 connected by a bearing to an inclinable plate 71 which is connected by three vertical rods 72 to the control plate 63. A plate 73 with slots'for receiving rods 68 and 72 is rigidly mounted on the upper end of rotating sleeve 33 and drives the control plate 63 and the plate 71 through the rods, the plates 63 and 71 being maintained parallel by rods 72. In a modified construction, a pair of weighted inertia bars is combined with the rotor blade system for purposes of control.