GB563427A - Improvements in helicopters - Google Patents

Abstract

563,427. Helicopters. WEIR, Ltd., G. & J., and PULLIN, C. G. Aug. 17, 1942, No. 11493. [Class 4] The torque reaction of the lifting rotor of a helicopter is compensated by a jet reaction device discharging laterally at the rear of the airframe. The jet is supplied by a mechanical blower, and the energy of the discharge is increased by the transfer of waste heat from the rotordriving engine. The discharge is controlled automatically to balance any variation of torque and can also be controlled manually or the direction of the jets can be varied or their position selected for steering the aircraft or for balancing rolling moments. Fig. 1 shows a monocoque fuselage having an upturned rear end supporting a stabilizing plane 24, rudder 25 and a laterally directed jet nozzle 44. The aircraft is supported by a rotor 26, 27 driven through a gear box 30, shaft 29 and gear box 31 from a flexibly mounted engine 32. The fuselage has a continuous duct in three sections extending from a semi-circular air inlet 43 to the nozzle 44. The rear section is formed by the fuselage shell 45 and a fairing 46, a central section 47 is supported by the engine and connected to the rear section by flexible connections 48, and a forward section comprises a flexible wall 49 connected to the rear edge of the air inlet, and a lower flexible portion 49a connected to a bulkhead 50. The air inlet has movable gills 81. The engine is enclosed by a fairing 51 connected by flexible portions 56 to the bulkhead 50 and enclosing an annular passage in which run the blades 54 of a blower 53 driven from the engine 32. The blades 54 run between fixed guide blades 57, 58 extending across the passage. The air-cooled cylinder heads are enclosed in a separate casing 59, Fig. 2, having an inlet 60 on the pressure side of the blower, and to compensate for the increased resistance the flow is accelerated by an auxiliary blower 62, driven by the engine. The air after cooling the engine is discharged through a tubular extension 61 into the main duct 47. The flow is additionally energized by a blower 70 driven by an exhaust gas turbine 69 supplied from the exhaust manifold extension 67 and the exhaust gases are finally led to the nozzle 44 through an inner conduit 75. In.another form the blower 62 is arranged at the forward end of the casing 59. The manifold extension 67 and a branch 68 leading to atmosphere arecontrolled by butterfly valves actuated by a governor device driven by the engine so that exhaust gases are not allowed to flow through the extension 67 until a predetermined engine speed is reached. The valves may be mechanically actuated from a centrifugal governor or hydraulically by a pump which depresses a piston against a spring loading to admit pressure fluid to a cylinder for actuating the valves. The angle of the blades 54 of the blower 53 or of the guide vanes 57 is automatically controlled by a torque measuring device housed in the gear-box 30. This comprises a lever 85, Fig. 5, carrying planet pinions 83 gearing with a sun-wheel 82, driven from the .engine, and an annulus 86 connected to. the rotor hub. As the lever 85 is displaced against the tension of a spring 86<1> a master cylinder 88 displaces liquid through a conduit 91 to control the angle of the blades 54, or 57. A branch conduit, not shown, from the conduit 91 enables the blades to be adjusted by movements of a rudder bar 38 to effect steering movements when flying vertically or hovering. Alternatively the rudder bar may control the gills 81. Another form is described in which the blower 53, 54 is arranged to the rear of the engine, the drive for the blower and the lifting rotor being at the rear end of the engine. Fig. 15 shows the blower 53b, 54b and the rotor shaft driven by a gas turbine 131 the exhaust from which discharges into the conduit leading to the jet at the rear of the aircraft. A subsidiary blower 133 takes in air through conduits 134 from the annular space behind the blower blades 54b and delivers it through two pipes 135 to combustion chambers 136 from which it is led to the turbine through pipes 137. The jet nozzles may be elongated horizontally as shown in Fig. 1 and be surrounded by an open-ended convergent nozzle to entrain additional air or a number of nozzles 142, Fig. 16, may be arranged side by side and selectively supplied to vary the moment of the jet about the centre of gravity of the aircraft. Alternatively they may be controlled by iris diaphragms connected to levers 144 and/or swivelled about vertical axes by arms 147.