GB572417A - Improvements in helicopters - Google Patents

Abstract

572,417. Helicopters. WEIR, Ltd., G. & J., and PULLIN, C. G. May 24, 1943, No. 8186. [Class 4] A helicopter of the kind having a single tiltable rotor with articulated blades is provided with an auxiliary rotor, for compensating the torque reaction, arranged within a normally transverse duct at the rear of the aircraft. The duct may have adjustable parts to vary the direction of the reaction on the helicopter, or the whole duct may be rotatable about a vertical axis independently of or with the rotor. In the latter case, the duct and rotor may be set fore and art of the machine to assist propulsion during high-speed horizontal flight, and steering effected by adjustment of the duct about its vertical axis. In one form, the auxiliary rotor comprises a hub 42, with blades 43 variable and reversible in pitch, which is driven from the main engine through shafts 37, 40 and gear-boxes 39, 41. The rotor is enclosed by a duct 44, 45, in two parts of which the rear part 45 is adjustable about a vertical axis by worm gear 50, 51 and sprocketwheel 53 controllable through cables 54 from the pilot's cockpit. The blades 43 have eccentric pins 56 engaged by a groove in a striker 57 movable by a rack 59 and worm 60 controlled through a sprocket 61 and cables 62 from the rudder bar. Branch cables 64 are connected to a rudder 24. The pitch change gear is enclosed by a fairing 47a having radiating blades 48 secured to the fixed part 44 of the duct. A fairing 47b encloses the gear-box 41. In another form, the blades 43 are fixed to the hub and the blades 48 are adjustable to control the flow through the duct by mechanism similar to that shown for adjusting the blades 43 in Figs. 2 and 3. In these two forms the part 45 of the duct is mounted on a spherical seating and provision may be made for tilting the part 45 in a vertical plane. In another form, the whole of the duct is adjustable about a vertical axis, together with the motor, the speed of which is controlled by a change-speed gear in the gear-box 39 under the control of the pilot.