| Olympus | |
|---|---|
 | |
| Preserved Bristol Siddeley Olympus Mk 301 Engine Change Unit (ECU) complete with ancillaries and bulkheads. | |
| Type | Turbojet |
| National origin | United Kingdom |
| Manufacturer | Bristol Aero Engines Bristol Siddeley Engines Limited Rolls-Royce Bristol Engine Division |
| First run | 1950 |
| Major applications | Avro Vulcan BAC TSR-2 |
| Developed into | Rolls-Royce/Snecma Olympus 593 Rolls-Royce Marine Olympus |
TheRolls-Royce Olympus (originally theBristol B.E.10 Olympus) was the world's second two-spoolaxial-flowturbojet aircraft engine design, first run in May 1950 and preceded only by thePratt & Whitney J57, first-run in January 1950.[1][2] It is best known as the powerplant of theAvro Vulcan and later models in theConcordeSST.
The design dates to a November 1946 proposal byBristol Aeroplane Company for a jet-powered bomber, powered by four new engines which would be supplied byBristol Aero Engines.[3][4] Although their bomber design was ultimately cancelled in favour of the otherV bombers, the engine design's use of twin-spool layout led to continued interest from theAir Ministry and continued development funding. The engine first ran in 1950 and quickly outperformed its design goals.[5]
Initially used in the Vulcan, later versions addedreheat for use in the supersonicBAC TSR-2. Bristol Aero Engines merged withArmstrong Siddeley Motors in 1959 to formBristol Siddeley Engines Limited (BSEL), which in turn was taken over byRolls-Royce in 1966. Through this period the engine was further developed as theRolls-Royce/Snecma Olympus 593 for Concorde.
Versions of the engine were licensed toCurtiss-Wright in the US as the TJ-32 or J67 (military designation) and the TJ-38 'Zephyr', although none saw use. The Olympus was also developed with success asmarine and industrialgas turbines, which were highly successful. As of 2018, the Olympus remains in service as both a marine and industrial gas turbine.
At the end of World War II, the Bristol Engine Company's major effort was the development of theHercules andCentaurusradialpiston engines. By the end of 1946, the company had only 10 hours ofturbojet experience with a small experimental engine called thePhoebus which was thegas generator or core of theProteusturboprop then in development.[6] In early 1947, the parentBristol Aeroplane Company submitted a proposal for a medium-range bomber to the samespecification B.35/46 which led to theAvro Vulcan andHandley Page Victor. The Bristol design was theType 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). Thepressure 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-stageturbine. 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") withoutsurge.[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]
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 acannular system: a hybrid of separate flamecans and a trueannular 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 projectedF-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 aCanberraWD952 which first flew with these engines derated to 8,000 lbf (36 kN) thrust in August 1952. In May 1953, this aircraft reached aworld 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 aTBO of 250 hours.[17]
The Olympus was developed extensively throughout its production run, and the many variants can be described as belonging to four main groups.
Initialnon-reheat variants were designed and produced byBristol Aero Engines andBristol Siddeley and powered the subsonicAvro Vulcan. These engines were further developed byRolls-Royce Limited.
The first reheat variant, the Bristol Siddeley Olympus Mk 320, powered the cancelledBAC TSR-2 supersonic strike aircraft. ForConcorde, this was developed during the 1960s into theRolls-Royce/Snecma Olympus 593, being further developed through several subsequent versions to eventually provide reliable airline service. The Olympus 593 is a prime example of "propulsion and airframe integration". To optimise the performance of the engine when used at speeds from takeoff up to Mach 2 on Concorde, a variable intake and a variable throat nozzle with thrust reversing system were developed.[18] Looking ahead to future supersonic transports, due to noise limits for supersonic transport category airplanes,[19] studies were conducted on ejector suppressors, leading to the conclusion that "a new, low bypass ratio version of the 593 could be suitable for future generations of supersonic transport aircraft".[20]
The AmericanCurtiss-Wright company tested a license-developed version known as the J67 and aturboprop designated TJ-38 Zephyr. Neither design was produced.
Further derivatives of the Olympus were produced for ship propulsion and land-based power generation.
Over the years, the Olympus was proposed for numerous other applications including:
Data from"The Operational Olympus".Flight. Archived fromthe original on 29 July 2013. andLecture Notes, Vulcan Bristol Aero Engine School
Related development
Comparable engines
Related lists
{{cite web}}: CS1 maint: archived copy as title (link){{cite web}}: CS1 maint: archived copy as title (link) Avro Type List[1] Avro Heritage
