Patent GB-597246-A (GB)
Title: Improvements in aircraft
IPC: B64C29/02
Filed: 1945-05-23
Abstract: 597,246. Aircraft. DEHN, F. B. (Bell Aircraft Corporation). May 23, 1945, No. 12916. [Class 4] An aircraft, shown in take-off position in Fig. 1, is provided with coaxial propellers 3, 4 and with wings 2 (the axis of rotation of the propellers is generally chordwise of the wings) and is capable of vertical ascent and descent and also of horizontal flight; the wheels 7 and legs 8 for supporting the craft on the ground. are capable of retraction. Control of the attitude of the craft is obtained by means of a a rotating fly-wheel device which may be of the kind described in Specification 580,231. Fig. 6 shows partly in section the nose of the aircraft with the drive for two propellers, the blade angle control for pitch control and feathering of the upper propeller (which is a helicopter rotor) for manoeuvring, and automatic feathering for stability. A fixed mast 40 has within it a driving shaft 42 extending beyond the mast and bearing a gear 50, contained within a rotatable casing 60 and meshing with planet-wheels 54 of a spider carrying a shaft 62 for universally mounting the hub 66 of the upper propeller ; the planetwheels 54 also mesh with a ring gear on the inside of the casing 60, which is thus rotated to drive a lower ring gear meshing with planetwheels 55 of a second spider fixed to a shaft 63 carrying the hub 67 of the lower propeller, which is an ordinary screw propeller and is driven in the opposite direction to the first propeller, the central gear 51 meshing with the planet-wheels 55 being fixed on the mast 40. The gearing produces equalization of the torques exerted by the engine on the two propellers. The enginedriven shaft is connected to the driving-shaft 42 by a splined sliding shaft 43 which is drawn down by the steep thread on the shaft 44 when that is set in motion by the engine, the' connected system of rings and rods shown also descending. The limits within which the shaft 43 can be moved are set by stops provided in a vertically adjustable cylinder 45 surrounding the connection of shafts 43, 44. A free-wheel device 44a allows free rotation of the upper propeller and maintenance thereby of the fly-wheel rotation. The rotating control fly-wheel 70 automatically stabilizes the aircraft by inclining, through the agency of rods 80 and rings 78 and 75, the hub 66 of the upper propeller when deviation of the craft occurs and so producing a restoring force ; the plane of the fly-wheel can be adjusted by control rod 150 and means may be provided for restricting the fly-wheel movement to put it out of action when necessary. Adjustment by hand wheel 48 of the cylinder 45 produces vertical movement of the rings and rods to alter the pitch of the two propellers as required for vertical or horizontal flight of the aircraft. The upper propeller shown in plan, Fig. 8, and which has a constant velocity ratio joint, comprises an outer piece 100 rolling on balls moving in curved tracks in the inner piece 66. Each blade is mounted by a ball-bearing 103 on a ball-ended stud screwed into piece 100 and is cormected by a nut 107 fitting over the bearing; a resilient sleeve 106 between the stud and bearing allows the blade to pivot on the stud end. The leading edge part 110 of the blade is made of heavier material than the remainder of the blade, suitable materials being duraluminum and light wood, or steel and heavy wood. Cooling air for the engine is admitted through openings in the bottom of the fuselage or in the wings. Specification 568,548 and U.S.A. Specification 2,300,268 also are referred to.