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Aviation History
1952
1952 - 1582.PDF
688 FLIGHT AIRSCREW TURBINE (TWO-STAGE) TURBINE ENTRY NOZZLE INTERMEDIATE TRANSMISSION SHAFT INTEI EXHAUST DUCT AXIAL COMPRESSOR DATA Length, airscrew con* to jtt pip* .,. Diameter Weight, here, dry Reduction gear ratio Airscrew rotation Max. i.l. power Max. compreaaor r.p.m Airscrew turbin«, r.p.m. Minimum idling ipeed (compressor; Minimum idling; fuel consumption ... REAR.BEARING OIL-DRAIN TURBINE ENTRY DUCT (8 SEGMENTS) AIRSCREW-DRIVE TOOTHED-COUPLING 8ft 4.5in 3ft 3.5in 2,*50 lb 0.09: 1 L.H. tractor 4,100 s.h.p. 12,000 10,700 7,200 400 Ib/hr COMPRESSOR-DRIVE TOOTHED-COUPLING COMBUSTION CHAMBER IN making this fine study of the Proteus 705 our artist John Ferguson has arranged ' the main section-planes to show, in the top portion of the drawing, the flow of air through the entry and the compressor and into the diffuser, whilst the lower section indicates the flow-path out of the diffuser, through the combustion chamber and so to the turbine. PROTEUS 705 serves as the front diaphragm of a built-up drum in which are supported the four shafts carrying the planet pinions of the epicyclic train. Front support for the output shaft and reduction gear is vested in a large ball thrust-race housed in the forward mouth of the gear casing, thrust loads being conveyed from shaft to bearing through the medium of the transfer muff by means of which oil for airscrew actuation is delivered from a stationary source to a rotating destination. From the muff, oil is delivered through drillings through the shaft wall to a transfer unit carried within the hollow core of the shaft, and thence through co-axial tubes to the airscrew. Oil from the transfer muff is also taken through drillings to lubricate the planetary gears. In conformity with past Bristol practice, the fixed annulus gear is not rigidly anchored, but "floats" on the planet secondaries and is "fixed" by reacting against the eight torquemeter assemblies equi-spaced around its periphery and pin-jointed to carrier lugs on the interior of the gear casing. The planet pinion- shafts are white-metalled for the secondary pinions, to which the primary planet pinions are splined, and likewise the sun-gear shaft runs in white-metal bearings, the front bearing being in the tail of the airscrew shaft, and the rear bearing housed in the bore of the rear diaphragm of the planet carrier drum. The rear bearing for the reduction gear as a whole is a roller housed in the centre wall of the gear case. The inner race of this bearing is carried on the shaft of a dished spur gear, the bore of which is splined to the planet-carrier diaphragm. This gear meshes with a pinion splined to a bevel shaft for drive take-off to the accessories gearbox. The accessories drive is from the bevel shaft—which lies parallel with, and vertically below, the axis of the engine—down through a vertically dependent bevel shaft to a bevel box bolted beneath the gear casing and housing a bevel quill-shaft: this quill-shaft terminates in a coupling for connection to a torque-shaft which would extend back to the accessory gearbox usually mounted behind the firewall. The spur wheel serving as primary input to the drive transmission also performs the same function for the driving trains of the various engine auxiliaries which are grouped around the gear casing. An interesting structural side issue in this connection is that the auxiliary drives are fitted in the inner drum of the gear casing as a complete sub-
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