Patent GB-611398-A (GB)
Title: Lifting rotors with variable pitch blades and aircraft provided with rotors
IPC: B64C27/54
Filed: 1946-04-30
Abstract: 611,398. Helicopters; aircraft controls. JAYER, P., and CASSY, R. April 30, 1946, No. 13087. Convention date, Jan. 9. [Class 4] A rotor head 3, shown in side elevation, Fig. 1, as installed in an aeroplane in flight towards the left of the Figure, carries two blades mounted in parallel sleeves 4, 5 and having their pitch controlled by coupling members 14, 15 pivotally attached to crank-levers 9, 10 on the blade shafts and to a controllable ring 23 below; a driving shaft 1 causes rotation of the head 3 and the attached parts including ring 23 which is guided by ball-bearings 24 on a central hub 25. The ring 23 is pivotally mounted by trunnions 21, 22, shown in plan, Fig. 3, as mounted in central bearings of swing rods 18, 19, borne at each end by members 14, 15; the ring 23 as it rotates with head 3 always conforms its plane to that of central hub 25 which is capable of being tilted forwardly or backwardly about transverse trunnions 27 which are fast with a sleeve 28 vertically adjustable upon a stationary lining 2 supporting the driving shaft 1. A pair of levers 29, which are rigidly connected with hub 25 enable the pilot to tilt the hub and so vary the incidence of the rotor blades through the connecting members 14, 15. A'small adjustment of sleeve 28 in either direction of rotation about the vertical can also be effected by means of levers 29 used so as to turn hub 25 about a vertical axis; this adjustment is used to alter the direction of the tilt of the hub. Twin rotors I, II may be arranged transversely of the aircraft, shown for example in plan, Fig. 13, as adjusted for climbing and advancing in the direction of arrow 38, the two lines 21, 22 showing the lines of maximum tilt in positions obtained by angular adjustment of the sleeves 28 supporting the trunnions 27. A diagram is given for the twin rotor system, of the pilot's control levers, which include in addition to a joy-stick two other levers, both adjustable in planes parallel to the longitudinal plane of symmetry of the aircraft; both of these latter levers have locking means. Raising of the hub 25 of either rotor may be produced by acting upon the associated sleeve 28 with a pivoted lever controlled by a transverse movement of the joystick. The forward movement of the joy-stick produces angular adjustments of the sleeves 28 of the two rotors to obtain the positions of maximum tilt shown in Fig. 13; the centre of pressure CP is thus brought in front of the centre of gravity CG; backward movement of the joy-stick brings the CP behind the CG. Transverse movement of the joy-stick to the right acts through cables and levers to lift sleeve 28 of the right-hand rotor and thus reduce its lifting thrust to produce an inclination of the aircraft about its longitudinal axis; a similar result is obtainable for the left-hand rotor by leftward control movement. One of the other control levers can be used to produce simultaneously similar upward or downward movements of the sleeves 28 of the two rotors, thus obtaining similar tilting of their hubs 25; only vertical thrust components are produced by the thus lifted rotors, and with the lowered positions the undriven rotors rotate automatically for gliding downwardly when the engines are cut off; breaking of the cables transmitting this control will produce the latter condition automatically. The remaining control lever is employed to swing levers 29 forwardly or backwardly to tilt hubs 25 of the rotors correspondingly or to maintain them horizontal.