GB647908A - Jet propulsion unit - Google Patents

Abstract

647,908. Jet propulsion plant for aircraft; turbines; compressors. PACKARD MOTOR CAR CO. Aug. 20, 1947, No. 23108. Convention date, Sept. 27, 1946. [Classes 110(i) and 110(iii)] [Also in Group XXXIII] A jet-propulsion plant for aircraft has a two-stage axial flow turbine 47 driving a centrifugal compressor 23 and a jet-augmenter rotating in the opposite direction and comprising two turbine stages 82, 84 and an augmenting fan provided by extensions 85 of the second stage turbine blades. Air for the augmenting fan may be drawn through boundary layer slots in the aeroplane surfaces. The working fluid may be reheated, at high loads, by burning fuel injected into the stream, at 130, Fig. 3, between the two turbines, at 131, between the stages of the augmenter and. at 132, in the zone where the gas and air mix. The impeller 23 of the centrifugal compressor delivers to an unbladed diffuser 27 followed by an inturned annular chamber of increasing cross-section with curved guide vanes 33. The air is heated in an annular combustion chamber 40 and passes to a two stage turbine 47 which drives the compressor. The jet-augmenter is independently mounted on bearings 102, 110, Fig. 3. The blades 82, 84 have divided roots intercalated with the grooved rims of the rctors 100, 101 and are pivotally secured by pins 114, 115. Labyrinth packings are provided between the inner shroudings 124 of the running blades and stator parts 122, 121, and 123. The blades 84 are hollow. The bearing 102 is carried by a part 103, 104, 105 which is supported from the outer structure by arms 106. These arms pass through stream-lined guides 90 and are secured by bolts 107 within hollow guides 91 which divide the air entry 66 of the jetaugmenter. The bearing 110 is carried by several radial rods 111 which pass through hollow guides 93, dividing the flow to the propulsion jet, and are slidingly mounted in the outer structure. The jet-augmenter is cooled by air taken in between the casing part 73 and a conical wall 150. This air is drawn through the guides 90 and between the arms 104 into the hollow rotor by an inward-flow fan 151. Some of. the air is re-circulated around the bearing 102 by fan blades 153. Some passes through holes 155, 156 and escapes into the gas stream. Some flows through holes 161. 162 to cool the bearing 110 and some flows through holes 157 into the hollow blades 84 and escapes at the blade tips. The remainder flows through the open end 163 of the shaft and all the cooling air eventually joins the jet stream. Reference has been directed by the Comptroller to Specification 583,111.