GB556866A - Improvements in and relating to helicopters - Google Patents

Abstract

556,866. Helicopters. WEIR, Ltd., G. & J., and PULLIN, C. G. April 22,1942, No. 5425. [Class 4] [Also in Group XXVI] A helicopter having a lifting rotor com prising hollow blades through which a stream of heated air or gases is fed to nozzles at the blade tips for driving the rotor, is provided with a blower driver from an internal combustion engine, the residual heat of combustion being trans red to the blower effluent before deliver to the blades through a central conduit In an alternative form a blower coupled to a gas turbine takes in air at one end of a casing and delivers it to a combustior chamber from which the expanding gases flow through the turbine and discharge into the central conduit. In one form a blower 31 driven from a reciprocating engine 23 takes in air, from an opening at the forwarc end of the aircraft through a pipe 32, anc delivers it through two conduits 35, 36, or opposite sides of the blower, to a closec casing 26, surrounding the cylinder heads to cool them, after which it passes through a pipe 38 to a heat exchanger 39 heated by the exhaust gases from the manifold 41. The exhaust gases may be discharged directly to atmosphere through a pipe 42, or, as shown in Fig. 5, the cooled gases may be discharged into the stream delivered from the heat exchanger. Alternatively the exhaust gases may be discharged directly into the stream through the pipe 38 without passing through a heat exchanger. A branch pipe 43, Fig. 2, may deliver air to the carburetters 45 to boost the engine. The heat exchanger 39, Fig. 5, comprises a casing with two endplates 46, 47 perforated to hold a series of tubes 48 through which the air passes on its way to the central conduit 22. The exhaust gases entering at 41 circulate around the pipes and are constrained to take a helical path by a baffle 49. Fig. 8 shows the form in which a two stage blower comprising rotor blades 68, 67 on opposite sides of stationary blades 69 is coupled through a shaft 63 to a turbine 65 behind fixed guide blades 73. Air entering the forward end 59 of the casing is delivered to a combustion chamber 58 supplied with fuel through injection-devices 76 and the combustion products, after driving the turbine,. are delivered to the conduit 22. U.S.A. Specification 2,092,077 is referred to.