Rolls-Royce Olympus

At the end of World War II, the Bristol Engine Company's major effort was the development of the Hercules and Centaurus radial piston engines. By the end of 1946, the company had only 10 hours of turbojet experience with a small experimental engine called the Phoebus which was the gas generator or core of the Proteus turboprop then in development.[6] In early 1947, the parent Bristol Aeroplane Company submitted a proposal for a medium-range bomber to the same specification B.35/46 which led to the Avro Vulcan and Handley Page Victor. The Bristol design was the Type 172 and was to be powered by four or six Bristol engines of 9,000 lbf (40 kN) thrust[7] to the Ministry engine specification TE.1/46.

The thrust required of the new engine, then designated B.E.10 (later Olympus), would initially be 9,000 lbf (40 kN) with growth potential to 12,000 lbf (53 kN). The pressure ratio would be an unheard of 9:1.[8] To achieve this, the initial design used a low-pressure (LP) axial compressor and a high-pressure (HP) centrifugal compressor, each being driven by its own single-stage turbine. This two-spool design eliminated the need for features such as variable inlet guide vanes (Avon, J79), inlet ramps (J65), variable stators (J79) or compressor bleed (Avon) which were required on single spool compressors with pressure ratios above about 6:1. Without these features an engine could not be started nor run at low speeds without destructive blade vibrations. Nor could they accelerate to high speeds with fast acceleration times ("spool up") without surge.[9] The design was progressively modified and the centrifugal HP compressor was replaced by an axial HP compressor. This reduced the diameter of the new engine to the design specification of 40 in (100 cm). The Bristol Type 172 was cancelled though development continued for the Avro Vulcan and other projects.[10]

Gas-flow diagram of Olympus Mk 101

The first engine, its development designation being BOl.1 (Bristol Olympus 1), had six LP compressor stages and eight HP stages, each driven by a single-stage turbine. The combustion system was novel in that ten connected flame tubes were housed within a cannular system: a hybrid of separate flame cans and a true annular system. Separate combustion cans would have exceeded the diameter beyond the design limit, and a true annular system was considered too advanced.[11]

In 1950, Dr (later Sir) Stanley Hooker was appointed as Chief Engineer of Bristol Aero Engines.[11]

The BOl.1 first ran on 16 May 1950 and was designed to produce 9,140 lbf (40.7 kN) thrust and to be free from destructive rotating stall on start up to idle speed and to be free from surging on fast accelerations to maximum thrust. The engine started without a problem and Hooker, supervising the first test run and displaying the confidence he had in the design, slammed the throttle to give a surge-free acceleration to maximum power.[12] The thrustmeter showed 10,000 lbf (44 kN).[13] The next development was the BOl.1/2 which produced 9,500 lbf (42 kN) thrust in December 1950. Examples of the similar BOl.1/2A were constructed for US manufacturer Curtiss-Wright which had bought a licence for developing the engine as the TJ-32 or J67 for the projected F-102. The somewhat revised BOl.1/2B, ran in December 1951 producing 9,750 lbf (43.4 kN) thrust.[14]

The engine was by now ready for air testing and the first flight engines, designated Olympus Mk 99, were fitted into a Canberra WD952 which first flew with these engines derated to 8,000 lbf (36 kN) thrust in August 1952. In May 1953, this aircraft reached a world record altitude of 63,668 ft (19,406 m).[15] Fitted with more powerful Mk 102 engines, the Canberra increased the record to 65,876 ft (20,079 m) in August 1955.[16] The first production Olympus, the Mk 101, entered service in late 1952 at a rated thrust of 11,000 lb, a weight of 3,650 lb, and with a TBO of 250 hours.[17]

Over the years, the Olympus was proposed for numerous other applications including:

• C104 which led to the C105 Avro Arrow: BOl.3"[21]
• Avro 718: BOl.3[22] The Type 718 was a military transport aircraft with up to 110 seats.[23]
• Avro 739 to OR339 (the requirement that culminated in TSR2): BOl.21R[22][24]
• Avro 740: 3 x Mk 551[22]
• Avro 750: 2 x Mk 551[22]
• Avro Vulcan Phase 6 (B3): BOl.23, a development of the Mk 301.[24] Different engine configurations, BOl.21, BOl.21/2 and BOl.23, with either reheat or an aft fan, were proposed for this aircraft to provide the required increase in take-off thrust.[25][26]
• Bristol T172: B.E.10[24]
• Bristol T177[24]
• Bristol T180[24]
• Bristol T198: Mk 591. Early supersonic airliner design (132 seats). The engine was a civilianised BOl.22R.[24]
• Bristol T201: Mk 551[24]
• Bristol T202[24]
• Bristol T204 to OR339: BOl.22SR (simplified reheat)[24]
• Bristol T205: Mark 551[24]
• Bristol T213[24]
• Bristol T223: Mk 593. Later supersonic airliner design (100 seats). Engine as Mk 591 with zero stage LP compressor and cooled HP turbine.[24]
• de Havilland design to OR339: BOl.14R, BOl.15R. Developed from BOl.6R.[24]
• Handley Page HP98: Pathfinder variant of Victor.[24]
• Handley Page Victor B1: Mk 104[24]
• Handley Page Victor Phase 3[24]
• Handley Page HP107[24]
• Handley Page Pacific[24]
• Hawker P.1121: BOl.21R[24]
• Hawker P.1129 to OR339: BOl.15R[24]
• Martin/General Dynamics RB-57F Canberra: Mk 701 developed from Mk 301.[24]
• Gloster P492/3: Mk 591[24]
• Republic XF-103[27]
• Republic F-105 Thunderchief: BOl.21 for possible sale to RAF.[24]
• Saab 36[28]
• Saab 37 Viggen[29]
• Vickers VC10: Development of Mk 555 with aft fan.[24]

• Type: axial flow two-spool turbojet
• Length: 127.1 in (10.59 ft; 3.23 m)
• Diameter: 40 in (3.3 ft; 1.0 m)
• Dry weight: 3,615 lb (1,640 kg)

• Compressor: axial 6 LP stages, 8 HP stages
• Combustors: cannular 10 flame tubes
• Turbine: HP single stage, LP single stage
• Fuel type: AVTUR or AVTAG

• Maximum thrust: 11,000 lbf (49 kN)
• Specific fuel consumption: 0.817 lb/(lbf⋅h) (23.1 g/(kN⋅s))
• Thrust-to-weight ratio: 3.04