Rolls Royce Olympus

Origins

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. 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 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. 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. 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.

Initial Development

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.

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

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. The thrustmeter showed 10,000 lbf (44 kN). 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. The somewhat revised BOl.1/2B, ran in December 1951 producing 9,750 lbf (43.4 kN) thrust. 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). (Fitted with more powerful Mk 102 engines, the Canberra increased the record to 65,876 ft (20,079 m) in August 1955.)

Variants

BOl.1/2A

BOl.1/2B

BOl.1/2C

BOl.2

BOl.3

Of all the early initial developments, BOl.2 to BOl.5 (the BOl.5 was never built), perhaps the most significant was the BOl.3. Even before the Vulcan first flew, the Olympus 3 was being suggested as the definitive powerplant for the aircraft. In the event, the 'original' Olympus was continuously developed for the Vulcan B1. The BOl.3 was described in 1957 as "a high-ended product intermediate between the Olympus 100 and 200 series."

BOl.4

BOl.5

not built

BOl.6

(Mk.200)

BOl.7

(Mk.201)

BOl.7SR

BOl.11

(Mk.102)

BOl.12

(Mk.104)

BOl.21

(Mk.301)

BOl.21R

not built, proposed for R.A.E. Missile (A) designed to meet O.R. 1149 issued May 1956.

BOl.22R

(Mk.320)

BOl.23

not built, proposed with a 301 compressor, 22R turbine and reheat to give 25,000 lb at take-off (reheat).

Olympus Mk 100

(BOl.1/2B) Similar to Olympus Mk 99 rated at 9,250 lbf (41.1 kN) thrust for second Vulcan prototype VX777. First flew September 1953.

Olympus Mk 101

(BOl.1/2C) Larger turbine, 11,000 lbf (49 kN) thrust for initial production Vulcan B1 aircraft. First flew (XA889) February 1955.

Olympus Mk 102

(BOl.11) Additional zero stage on LP compressor, 12,000 lbf (53 kN) thrust for later production Vulcan B1 aircraft.

Olympus Mk 104

(BOl.12) Designation for Olympus Mk 102 modified on overhaul with new turbine and burners, 13,000 lbf (58 kN) thrust initially, 13,500 lbf (60 kN) thrust on uprating, standard on Vulcan B1A.

'Olympus 106'

Used to describe the development engine for the Olympus 200 (BOl.6). Possibly a corruption of BOl.6 (Olympus 6).

Olympus Mk 97

This early engine tested an early annular combustion chamber. It was test flown on Bristol's Avro Ashton test bed WB493.

Olympus Mk 201

(BOl.7) Uprated Olympus Mk 200. 17,000 lbf (76 kN) thrust. Initial Vulcan B2 aircraft.

Olympus Mk 202

Disputed. Either Olympus Mk 201 modified with rapid air starter, or Olympus Mk 201 with redesigned oil separator breathing system. This was the definitive '200 series' engine fitted to Vulcans not fitted with the Mk 301. The restored Vulcan XH558 is fitted with Olympus Mk 202 engines.

'Olympus Mk 203'

Very occasional reference to this elusive mark of engine can be found in some official Air Publications relating to the Vulcan B2. It is also noted in a manufacturer's archived document dated circa 1960.

Olympus Mk 301

(BOl.21) Additional zero stage on LP compressor. 20,000 lbf (89 kN) thrust. Later Vulcan B2 aircraft plus nine earlier aircraft retrofitted. Later derated to 18,000 lbf (80 kN) thrust. Restored to original rating for Operation Black Buck.

Olympus 510 series

With a thrust in the region of 15,000 lbf (67 kN) to 19,000 lbf (85 kN), the 510 series were civilianised versions of the BOl.6. A team was sent to Boeing at Seattle to promote the engine in 1956 but without success.

Olympus 551

The Olympus 551 'Zephyr' was a derated and lightened version of the BOl.6 and rated at 13,500 lbf (60 kN) thrust. The engine was the subject of a licence agreement between Bristol Aero Engines and the Curtiss-Wright Corporation - the engine being marketed in the US as the Curtiss-Wright TJ-38 Zephyr. There were hopes to fit the Olympus 551 to the Avro Type 740 and Bristol Type 200 trijet airliners which did not progress beyond the project stage. Curtiss-Wright also failed to market the engine.

Mk.320

The performance specification for the BAC TSR-2 was issued in 1962. It was to be powered by two BSEL Olympus Mk 320 (BOl.22R) engines each rated at 19,610 lbf (87.2 kN) dry and 30,610 lbf (136.2 kN) with reheat at take-off. The engine, which was re-stressed for supersonic flight at sea level, and over Mach 2.0 at altitude, and featured much use of high-temperature alloys such as titanium and Nimonic, was a cutting edge derivative of the Olympus Mk 301 with a Solar-type afterburner. The engine first ran in March 1961, soon achieving 33,000 lbf (150 kN), and was test flown in February 1962 in an underslung nacelle in the belly of Vulcan B1 XA894 and was demonstrated at the Farnborough Air Show in September. In December 1962 during a full power ground run at Filton, the LP shaft failed. The liberated turbine disc ruptured fuel tanks and the subsequent fire completely destroyed the Vulcan.On its first flight in September 1964 the engines of the TSR-2 were scarcely flightworthy being derated and cleared for one flight. Nevertheless, the risk was deemed acceptable in the political climate of the time. With new engines, the TSR-2 XR219 flew another 23 times before the project was cancelled in 1965.

Olympus 593

The Rolls-Royce/Snecma Olympus 593 was a reheated version of the Olympus which powered the supersonic airliner Concorde. The Olympus 593 project was started in 1964, using the TSR2's Olympus Mk 320 as a basis for development. BSEL and Snecma Moteurs of France were to share the project. Acquiring BSEL in 1966, Rolls-Royce continued as the British partner.

593D

Formerly Olympus 593. 28,100 lbf (125 kN) thrust. (the 'D' in the engine designation equalling 'derivation' - for smaller, short-range version of Concorde that was later cancelled)

593B

Flight test and prototype aircraft. 34,370 lbf (152.9 kN) thrust with reheat. (the 'B' in the engine designation equalling 'big' - for long-range Concorde that subsequently entered service)

593-602

Production. Annular combustion chamber to reduce smoke

593-610

Last production. 38,075 lbf (169.37 kN) thrust with reheat.

Curtiss-Wright TJ-32

Examples of the BOl.1/2A were delivered to Curtiss-Wright in 1950. The engine was Americanised during 1951 and flew under a Boeing B-29 testbed as the TJ-32.

Curtiss-Wright J67

To meet a USAF demand for an engine in the 15000 lb thrust class, the engine was the subject of a development contract, redesigned and designated J67. Development was protracted and in 1955, the USAF announced that there would be no production contract for the present J67. Several aircraft had been intended to receive the J67 including the Convair F-102 Delta Dagger.

Curtiss-Wright T47

The T47 was an attempt to produce a turboprop based upon the J67.

TJ-38 Zephyr

See Olympus 551 (above).

Variant notes

Second-generation Engines

The initial design of the second-generation 'Olympus 6' began in 1952. This was a major redesign with five LP and seven HP compressor stages and a canullar combustor with eight interconected flame tubes. In spite of a much greater mass flow, the size and weight of the BOl.6 was little different from earlier models.

Rival manufacturers Rolls-Royce lobbied very hard to have its Conway engine installed in the Vulcan B2 to achieve commonality with the Victor B2. As a consequence, Bristol undertook to complete development using company funds and peg the price to that of its fully government-funded rival.

Olympus Mk 200

(BOl.6) 16,000 lbf (71 kN) thrust. First B2 (XH533) only.

Civilianised Olympus

Plans to civilianise the Olympus go back as far as 1953 with the unveiling of the Avro Atlantic airliner based upon the Vulcan. However, most of the civilian derivatives, except for supersonic airliners, were developed from the BOl.6.

Thin-wing Javelin

One project that got beyond the drawing board was a supersonic development of the Gloster Javelin, the P370, powered by two BOl.6, 7, or 7SR engines. The design evolved into the P376 with two BOl.21R engines rated at 28,500 lbf (127 kN) with reheat. Eighteen aircraft were ordered in 1955. The project was abandoned the following year.

Afterburning Olympus

As early as 1952, Bristol had considered the use of reheat, or afterburning, to augment the thrust of the Olympus. Initially, a system called Bristol Simplifed Reheat was devised which was tested on a Rolls-Royce Derwent V mounted in an Avro Lincoln. Later it was tested on an Orenda engine in Canada and on an Olympus Mk 100 in the Avro Ashton test bed. Fully variable reheat became possible after an agreement with the Solar Aircraft Company of San Diego which manufactured bench units for the Olympus Mks 101 and 102. An afterburning Olympus was just one proposal for the Vulcan Phase 6, a 350,000 lb aircraft with a 13/14 hour endurance.

Olympus driving aft fan

BS.81 rated at 28,000lb. As an alternative to afterburning a fan mounted at the trailing edge of the wing was proposed for the Vulcan Phase 6. The fan was driven by a turbine in the engine exhaust at the end of the jetpipe.

Vectored thrust Olympus

A vertical take-off Vulcan was proposed in 1960. It used 4 vectored-thrust Olympus as well as 10 lift engines.

Derivitives

Rolls-Royce Marine Olympus

Industrial power generation

The Olympus entered service as a peak demand industrial power generator in 1962 when the Central Electricity Generating Board (CEGB) commissioned a single prototype installation at its Hams Hall power station. Power was provided by an Olympus 201 exhausting through a two-stage turbine powering a Brush synchronous alternator providing 20 MW at 3000 rpm. By 1972, the CEGB had installed 42 Olympus generating sets. Olympus engines are also used to provide back up power in case of a loss of grid electrical power at some of Britain's nuclear power stations.

Many sets were exported and many found use on offshore platforms. By 1990, over 320 sets had been sold to 21 countries, many of which remain in service.

Applications

Avro Vulcan

BAC TSR-2

Proposed aircraft applications

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

C104 which led to the C105 Avro Arrow: BOl.3

Avro 718: BOl.3 The Type 718 was a military transport aircraft with up to 110 seats.

Avro 739 to OR339 (the requirement that culminated in TSR2): BOl.21R

Avro 740: 3 x Mk 551

Avro 750: 2 x Mk 551

Avro Vulcan Phase 6 (B3): BOl.23, a development of the Mk 301. 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.

Bristol T172: B.E.10

Bristol T177

Bristol T180

Bristol T198: Mk 591. Early supersonic airliner design (132 seats). The engine was a civilianised BOl.22R.

Bristol T201: Mk 551

Bristol T202

Bristol T204 to OR339: BOl.22SR (simplified reheat)

Bristol T205: Mark 551

Bristol T213

Bristol T223: Mk 593. Later supersonic airliner design (100 seats). Engine as Mk 591 with zero stage LP compressor and cooled HP turbine.

de Havilland design to OR339: BOl.14R, BOl.15R. Developed from BOl.6R.

Handley Page HP98: Pathfinder variant of Victor.

Handley Page Victor B1: Mk 104

Handley Page Victor Phase 3

Handley Page HP107

Handley Page Pacific

Hawker P.1121: BOl.21R

Hawker P.1129 to OR339: BOl.15R

Martin/General Dynamics RB-57F Canberra: Mk 701 developed from Mk 301.

Gloster P492/3: Mk 591

Republic F-105 Thunderchief: BOl.21 for possible sale to RAF.

Saab 36

Saab 37 Viggen

Vickers VC10: Development of Mk 555 with aft fan.

Engines on display

Bristol Aero Collection Kemble Airfield - Mk 104, 593B

Imperial War Museum North, Manchester - Mk 101

RAF Museum Cosford - Mk 320

Gatwick Aviation Museum Charlwood Surrey - Two Mk 320

Yorkshire Air Museum Elvington, North Yorkshire - Mk 593

Brooklands Museum Weybridge, Surrey - Mk 593B

Montrose Air Station Heritage Centre - Bristol B.E.10

Museum of Science and Industry (Manchester) - Mk 202 (Engine is displayed as a Mk 201 but its ECU plate reveals it as a Mk 202)

Specifications Olympus 101

Data from The Operational Olympus Flight and Lecture Notes, Vulcan Bristol Aero Engine School

General characteristics

Type: Axial flow two-spool turbojet

Length: 152.2 in (12.68 ft; 3.87 m)

Diameter: 40 in (3.3 ft; 1.0 m)

Dry weight: 3,615 lb (1,640 kg)

Components

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

Performance

Maximum thrust: 11,000 lbf (49 kN)

Specific fuel consumption: .817 lb/(lbf·h) (23.1 g/(kN·s))

Power-to-weight ratio: 3.04:1

Specifications Olympus 301

Data from [5] flightglobal

General characteristics

Type: Axial flow two-spool turbojet

Length: 131 in (10.9 ft; 3.3 m)

Diameter: 44.5 in (3.71 ft; 1.13 m)

Dry weight: 4,290 lb (1,950 kg)

Components

Compressor: Axial 6 LP stages, 7 HP stages

Combustors: Cannular 10 flame tubes

Performance

Maximum thrust: 20,000 lbf (89 kN)

Power-to-weight ratio: 4.66:1