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Aviation History
1959
1959 - 0793.PDF
390 FLIGHT AERO ENGINES 1959 . . . shortly to go into service with Bomber Com-mand. With a fully variable Solar afterburner, engines of this family can give greatly aug-mented thrust, and even at an early stage the BO1.7R was rated at a reheat thrust of 24,000 lb.Early this year it was announced that the Olympus had been selected as the powerplantof the Vickers/English Electric TSR.2 multi- purpose tactical aircraft for the Royal Air Force.References: July 4, 1952; Dec. 9, 1955 (his- tory and description of 100 series); Feb. 15,1957 (note on 200 series); Mar. 7, 1958 (exten- sive report on service experience of 100 series). Orpheus This simple single-shaft turbojetwas first run on December 11, 1954, and flew as the powerplant of the prototype FollandGnat light fighter the following July at an initial restricted rating of 3,285 lb. The firstgeneration of Orpheus comprise the 700 series of engines for the Folland Gnat (at the BOr.2rating of 4,520 lb) and the 800 series of power- plants (at the BOr.3 rating of 4,850/5,100 lb)for a wide range of military and civil aircraft. The engine illustrated is in production atBristol for the Fiat G.91 light attack machine for NATO, and licences for its manufacture areheld by Fiat (Italy), B.M.W. (West Germany), Hindustan Aircraft (India), and, as extensionsof earlier agreements, SNECMA (France) and Wright Aeronautical (U.S.A.). Total runningtime of these engines amounts to some 15,000 hr, and BOr.3s with user squadronsare being sampled to establish an initial over- haul life of 150 hr. A de-rated version intended for training air-craft, such as the Gnat T.I and Fuji TIF-2, is the BOr.4 or Mk 100 rated at 4,230 lb.Other variants of these first-generation engines include a transport version (the BOr.3/5Mk 810, rated at 5,100 lb and incorporating bleed-air anti-icing and additional accessories),and a full reheat version of the 700 series which might well prove suitable for the pro-jected Gnat Mk 2. For the future, a revised series of Orpheusis now on test in which major modifications, apparently including the addition of a zerostage on the compressor, raise both the mass flow and pressure ratio. The most importantmember of the new family is the BOr.12, which has easily achieved its brochure thrustof 6,810 lb at the design turbine-entry tem- perature and with a specific consumption wellbelow the estimated value. Flight testing and the completion of a full type test on this engineshould take place during 1959, and production deliveries are scheduled to be made in abouttwelve months' time. As the BOr.l2SR the engine is being offered with Bristol simplifiedreheat for military aircraft, in which form it will have an initial afterburning rating of8,000 lb. A commercial variant of the BOr.12 would weigh 1,220 lb (120 lb more than themilitary engine) and with a two-position nozzle would be rated at 7,130 lb dry. Fan deriva-tives of the Orpheus are also believed to be under development, and a suggested configura- Bri.tol Sirfdeley Orpheus BOr.12 Military single-shaft turbojet. Multi- stage compressor, can-annular combus- tion chamber and (probably) single-stage turbine. Overall diameter, 32.4in; length as depicted, cold, 98.325 in; dry weight, 1,100 Ib; max sea-level rating, 6,810 Ib dry. Other data are restricted. The BO.12SR gives 8,000 Ib thrust with simple reheat. Orpheus BOr.3 Mk 803 (not illustrated). Military single-shaft turbojet similar in general appearance. Overall diameter, 32.4in; length, intake to exhaust cone, 75.45in; equipped dry weight, 825 Ib; max sea-level rating, 5,000 Ib at 10.000 r p.m. (s.f.c. 1.06); corresponding mass flow and pressure ratio, 84 Ib/sec and 4.4:1. Bristol Siddeley Thar BT.1 Super- sonic ramjet for propulsion of the Bloodhound surface-to-air missile.Double- shock intake, ram-driven fuel turbo- pump feeding annular injection manifold and convergent/divergent fixed-geometry nozzle. Overall diameter, 15.75in; length, 94.5in; approximate equivalent horse-power, 130,000 at Mach 3 at sea- level; all other data are restricted. tion consists of matching upstream stages fromthe low-pressure compressor of an Olympus with an Orpheus gas-producer. References: July 5, i957; history and descrip-tion; Feb. 13; 1959, extensive outline of development and cutaway drawing. Proteus During the past ten years thedesign of the Proteus has been radically altered and improved and, although handicapped byits early conception, the current Proteus is undoubtedly the most reliable large turbopropin the world, besides being a magnificent piece of machinery in its own tight. The first ver-sion to enter service was the Mk 705 which, as the powerplant of the 15 Britannia 102s ofB.O.A.C., started carrying fare-paying pas- sengers in February 1957. These engines arerated at 3,480 s.h.p. (3,900 e.h.p.) and during the 24 months that they have been in servicetheir overhaul life has risen from 500 to 2,000 hr. This rate of progress is unequalledby any other aero engine, civil or military, piston or turbine, and Bristol Siddeley andB.O.A.C. expect appreciably longer periods to be authorized during the coming year. An up-rated version of the 705 is the P:oteus 706, and a modification to the compressor resultsin the Proteus 716 rated at 4,440 e.h.p. For the bulk of the production Britanniasthe more powerful Proteus Mk 755 was evolved. This engine differs from the 705 chiefly inhaving improved material specifications (includ- ing Nimonic 100 blades in the first turbinestage) and a redesigned power-turbine assembly; these changes permit an increase in flame tem-perature to give a brochure figure of 4,120 e.h.p. The production engines have consistently givenat least 40 h.p. more, the shaft power being 3,705. Last year the 755 was succeeded inproduction by the 761, with slightly redesigned compressor entry guide vanes and electro-polished compressor rotor and stator blading. These improvements combined to raise themass flow and pressure ratio to give a 3 per cent improvement in specific consumption,while at the same time enabling a rating of 4,210 e.h.p. to be established at a reducedcompressor speed. The Proteus 762 has a re-calibrated control unit and slightly differentfuel injectors which permit take-off power to be raised to 4,350 e.h.p. The present standardproduction engine (series 765 or 766) differs only by an adjustment to the governor settingto give greater cruising power, together with a slight increase in take-off power to 4,445 e.h.p.All 761 engines are tested at the latter rating before delivery, and can be converted readilyin the field to the 765 configuation. A related engine is the military Proteus 255 fitted to the20 Britannia 253s of R.A.F. Transport Com- mand. Likewise rated at 4,445 e.h.p. thisengine has water injection to provide maxi- mum power in adverse altitude/temperatureconditions. Future production will centre upon theengine for which data are given in col. 3. This series 770 engine is now in final development,and incorporates labyrinth seals on both stages of the compressor turbine together with aero-dynamic improvements which modify the load- ing on the second stage of the power turbine.The 765 can readily be converted to 770 standard at major overhauls. Mention should also be made of the. 3,800 h.p. Marine Proteusfitted to the Brave class of fast patrol boats of the Royal Navy. Several hundred Proteus havenow been delivered. At the beginning of this year Britannia engines had accomplished482,000 hr and the total Proteus running time is today approximately 550,000 hr. References: June 6, 1952 (full description of705); July 11, 1958 (extensive review of service experience). Bristol Siddcley Proteus Mk 770 (not illustrated). Commercial free-turbine turboprop. Compressor with 12 axial stages and one centrifugal stage, eight combustion chambers, two-stage high-pressure com- pressor turbine and two-stage low-pressure power turbine. Overall diameter (around bulkhead ahead of intake), 40.1 in; length from propeller-cone fitting line to tip of jet-pipe bullet, 113.23in; dry weight to EDM.25, 2,900 Ib; max sea-level rating, 4,130 s.h.p. (4,615 e.h.p.) with s.f.c. of 0.56 Ib/hr/e.h.p.; max cruise, 25,000ft at 300 kt, 2,202 s.h.p. (2,640 e.h.p.) at 11,650 compressor r.p.m. with s.f.c. of 0.484 Ib/hr/e.h.p. Ramjets During the past ten years inten-sive development of ramjets has taken place at Bristol, and the company can fairly claim tobe the most experienced in this field in the western world outside the U.S.A. The firstBristol ramjet was flown in 1952. Since that date development has centred upon the 15.75inunit designated BT.l Thor; in various versions this is the standard powerplant of the twin-engined Bloodhound (Red Duster) surface-to- air missile now in production for R.A.F. FighterCommand and Sweden. Many hundreds of test firings of powerplant-development vehiclesand test vehicles associated with the Blood- hound produced an exceptional degree of reli-ability even before firings of the production-type missile began. In order to achieve uniform flow to theannular centrebody-type intake, and to permit the necessary cooling airflow over the tailpipe,the Thor is designed for external pylon mount- ing. In the Bloodhound it is carried on shoitstruts above and below the body; all fuel and electrical connections are made adjacent to therigid front mounting and the rear anchorage provides for thermal expansion. Ignition isachieved in the Bloodhound by pyrotechnic flares, and the system has been found virtually100 per cent reliable. The Thor fuel system consists of a ram-air turbine-driven centri-fugal pump, a fuel/air ratio control and a Mach number control which reduces the fuelsupply when the chosen cruise Mach number is exceeded. Thor has been in full production for a con-siderable period and a larger unit, giving some- thing like twice as much power, has now beenpublicly displayed. This is the 18in BRJ.801 and it may well be applied to a developed ver-sion of the Bloodhound missile. Bristol are now also thinking in terms of a cruise ramjet.Studies have been published showing very plausible supersonic-transport projects, incor-porating multiple internal ramjets with design points between Mach 3 and Mach 5 at 60,000to 80,000fL Programmes in Coventry (originally Arm-strong Siddeley Motors):— Double Mamba Possibly the last in aunique family of double-turbine powerplants continuously developed since 1945, the cur-rent mark of Double Mamba in production is the ASMD.8 Mk 112. This may only bedescribed as "fitted to the latest types of Gannet," and consists of two ASM.8 Mambapower sections with independent drives to the two units of a counter-rotating, coaxialpropeller. The axial compressors have 11 stages andpass a total mass flow (both units) of 42 lb/sec; the annular combustion chambers each have12 vaporizing burners and the turbines have three stages. Net dry weight is 2,500 lb, andmaximum rating 3,880 ch.p. with a specific consumption of 0.67 lb/hr/e.h.p. References: Mar. 31, 1949 (initial version); Mar. 4, 1955 (development history). Gamma The result of some years of hardwork was the very successful firing—at the first attempt—of the first Black Knight re-entryresearch vehicle at Woomera in September 1958. The powerplant of this vehicle is theGamma 201. The Gamma engine was developed from anR.A.E. design. It incorporates four combus- tion chambers arranged uniformly around thecentral vehicle support on trunnions in order
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