GB614676A - Improvements in or relating to rotary wing aircraft - Google Patents

Abstract

614,676. Rotary-wing aircraft. FORSYTHE, A. G. (Doblhoff, F. L.). July 19, 1946, No. 21663. [Class 4] A rotary-wing aircraft has an engine which drives a propeller at the nose for forward flight and also a compressor mounted within the body of the aircraft, this compressor supplying a fuel - air mixture through ducts to jets in the tips of the rotary-wing blades, the mixture being ignited just prior to its ejection at the jets, whereby the rotary wing is rotated to lift the aircraft. As shown in Fig. 1, the engine 10 drives a variable-pitch propeller 14, on the shaft of which is a fan 11 to cool the cylinders, and at its rear, through a clutch, a rotary compressor 21. The compressor 21 draws air from a duct 20, which is fed by the fan 11, and delivers it through a central hub to channels within the hollow blades 24 of the rotary wing leading to the tips thereof, the blades having a central spider mounting 81, Fig. 5, permitting the usual drag and flapping movements. The engine 10 also drives a pump supplying fuel to the inlet 51 of a control box, Fig. 7, having diaphragms 59 and 61, a loading spring 64 and an adjusting screw 66. Space 68 has an opening 69 which is connected to the delivery pipe of the compressor 21, the pressure therein acting to deflect diaphragms 59 and 61, thereby depressing the needle valve 57 which permits a quantity of fuel, varied with the compressor delivery pressure, to pass in addition to that passing through the fixed jet 53. The fuel outlet from the control box 55 is connected to a vaporizer, heated by exhaust gases from the engine 10, and the fuel then passes to the delivery pipe of the compressor 21, in which, mixed with air, it passes to the central distributing chamber of the rotary wing. This chamber has a fixed lower part rigid with the aircraft frame and an upper part, in gas-tight engagement therewith, but rotating with the blades 21. These parts may be in the form of a hemispherical bowl, Fig. 1, or of an annular ring, Fig. 5. The air-fuel mixture passes by means of flexible tubes 31. into the hollow blades 24, and is ignited at a distributer box 32a, having partitions 32, through which it passes to be ejected at the jets 25. For starting, sparking-plugs 33, located just inward of the distributer boxes 32a and supplied by cables passing down the hollow central axis of the rotor to slip-rings connected to a suitable power source, are used to ignite the mixture, the fuel for which may be petrol or paraffin. The air duct 20, beneath the aircraft, has a vertically pivoted nozzle 26 at its rear end connected to the pilot's rudder bar, by means of which the air stream may be directed to either side to provide lateral control when the aircraft is hovering. Alternatively, a small propeller, located at the tail of the aircraft, may be used.