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Aviation History
1962
1962 - 1016.PDF
1014 FLIGHT International, 28 June 1962 Vulcan test-bed aircraft for advanced supersonic Olympus AERO ENGINES 1962 . . . ratio reheat in both hot and cold flows. In one variant the large volume of low-temperature fan air would be used for flap blowing. Another scheme is to replace the fan by a front reduction gearbox to provide a free-turbine output for large helicopters. BS.81 Under this designation Bristol Siddeley have prepared a project for an aft-fan Olympus. The engine would be rated at 28,0001b, and is aimed at large subsonic transports. BS.94 Several VTOL strike and transport projects specify this lift/thrust engine, which is derived from the BS.75. In some cases a deflector is arranged at the rear, but in most applications the inter mediate casing is modified to provide four rotating nozzles of Pegasus type. Ratings of up to 10,0001b have been mentioned unofficially, and according to one report the most powerful version would have a four- stage fan similar to that specified for the "BS.76/2." BS.100 Most powerful aircraft gas turbine known to be under development, the BS.100 is essentially a new design, although it obviously can draw heavily upon Olympus and Pegasus experience. The fully rated engine would have a thrust close to 40,0001b, which' would enable completely uncompromised VTOL strike and transport aircraft to be designed. Unofficial reports have spoken of a series of scaled versions of the BS.100, the most important of which is probably an engine of around 27,0001b which is specified as the powerplant of the Hawker P. 1154. Key to the BS.100 concept is plenum-chamber burning, and fundamental research into p.c.b., using a Pegasus rig, is being financed by MWDP—an indication of the substantial US interest in this engine. The fully rated BS. 100/3 is specified as the powerplant of the Fokker/Republic D-24, said to be designed for Ml.2 at sea level and more than M2.4 at altitude. The US journal Aviation Week states, "in order to attain lower s.f.c. at high speeds and low altitudes, the BS.100 uses a higher pressure ratio and lower bypass ratio than its Pegasus predecessor." At present aircraft manufacturers in several countries are wishing the UK Government could find some money for BS.100 development, because a more sought-after engine would be hard to find. Olympus Designed to a rating of 9,1401b, this superb two-shaft turbojet exists in three distinct generations. The first is represented by the 13,5001b Olympus 104, which has an unrivalled record of reliability, ease of handling at all altitudes and long overhaul life in the Vulcan B.l. Bristol Siddeley Pegasus on bench test The second generation is the Olympus 201, which powers the Vulcan B.2. These aircraft are now being re-engined with the first of the third generation, the Olympus 301. Obviously incorporating a zero-stage on the compressor, the 301 (BOl.21) is being supplied both in the form of new engines and modification kits to convert Olympus 201s in the field. A military type test at 20,0001b dry was very successfully run in January, and 30,0001b was obtained with reheat in January 1960. Clearly derived from this engine is the Olympus 22R, with Bristol Siddeley Solar variable reheat, which has reached 33,0001b thrust. Flight development, using a Vulcan (see illustration) began in April. Propul-« sion for the BAC TSR.2 aircraft will be provided by two reheat Olympus stressed for supersonic flight at low altitudes. Next variant is the Olympus 593, Bristol Siddeley's proposal for an engine for the projected Anglo-French M2.2 transport. A sub stantial amount of the 593, including all the most difficult portions, will be identical to 22R hardware on which extensive experience has already been obtained. But the fact that the civil engine will have dry ratings in the 28,000-29,O001b-class indicates that its mass flow will be greater, and the elimination of the need to withstand M1+ at sea level will reduce engine weight. Cooled blades will obviously be necessary, and BS have achieved extensive experience with cooled blades on several types of turbojet, one of which runs at a turbine entry temper ature hotter than that of the Olympus 593. Limited or full reheat will be incorporated, the latter being required only for acceleration to supersonic speed at the exceptional height of 48,000ft. Acceleration could take place lower down without reheat, but ground noise would be severe. Take-off noise of the proposed BAC/Sud airliner with four Olympus 593s with unsilenced variable nozzles is estimated at 99 PNdb on an optimum climb-out at 4.2 miles. The installed engine wilt be enclosed in a sleeve, inside which a secondary airflow will provide cooling and fire protection. Intake conditions appropriate to those in cruising flight have been simulated during bench testing. The poten tial market for the engine is put at 400 to 500. Should the French and British Governments agree to go ahead with the programme, the 593 would receive an MoA development contract, while production would be split roughly 60-40 between BS and SNECMA under an agreement recently signed. An industrial Olympus, cleared to burn natural gas, will shortly be in service. Orpheus Planned in 1953 as a simple, cheap and reliable successor to the Nene, this single-shaft turbojet has found major production applications in many countries. The Mk 701 for the Gnat fighter, and the 703 for the Hindustan HF-24, are both licence-built in India; the 803, for the Fiat G.91 family, is made by both KHD in Germany and Fiat in Italy; the 805 has been shipped in quantity for the Japanese Tl-A trainer, and is overhauled in Japan in service in these aircraft; and the Mk 101, a conservatively rated engine for the RAF Gnat T.l trainer, remains in production at Patchway. The more advanced BOr.12 has for some two years been under consideration for future M2 versions of the Indian HF-24. Pegasus Formerly known only by its number, BS.53, the Pegasus is one of the world's most important aero engines. As outlined in our issue dated August 12, 1960, it is the result of a search for a powerplant with vectorable thrust capable of providing propulsive thrust, lift or braking. A high-ratio turbofan, it has four nozzles, one pair for the fan air and the other for the hot jet at the rear. All four nozzles are linked to rotate in unison, and in a V/STOL aircraft the optimum take-off technique is generally to accelerate with nozzles horizontal and then rotate to, say, 60°. The h-p compressor is bled to provide air for air craft stabilization at low forward speeds. The fan and compressor assemblies rotate in opposition, to give a very low resultant gyroscopic couple; other advantages claimed for this type of engine are that ground erosion, gas reingestion, noise and fuel consumption in hovering flight are all relatively low, and that the aircraft can be kept simple. From its inception the Pegasus has been developed in parallel with the Hawker
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