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Rolls Royce Avon

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Rolls-Royce Avon

The Rolls-Royce Avon was the first axial flow jet engine designed and produced by Rolls-Royce. Intended as a jet successor to the Merlin, introduced in 1950 it went on to become one of their most successful post-World War II engine designs. It was used in a wide variety of aircraft, both military and civilian, as well as versions for stationary and maritime power.

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An English Electric Canberra powered by two Avons made the first nonrefuelled nonstop transatlantic flight by a jet, and a BOAC de Havilland Comet 4 powered by four Avons made the first scheduled transatlantic crossing by a jet airliner.

Production of the Avon aero engine version ended after 24 years in 1974.

The current version of the Avon, the Avon 200, is an industrial gas generator that is rated at 21-22,000shp. As of 2011, 1,200 Industrial Avons have been sold, and the type has established a 60,000,000 hour record for its class.

Design and development

The engine was initially a private venture put forward for the English Electric Canberra. Originally known as the AJ.65 for Axial Jet, 6,500 lbf the engine was based on an initial project concept by Alan Arnold Griffith. which combined an axial compressor with a combustion system and single-stage turbine using principles proven in the Rolls-Royce Nene engine. The Avon design team was initially headed by Stanley Hooker until the development of the engine was moved from Barnoldswick to Derby in 1948 and Hooker subsequently left the company, moving to Bristol Engines. Design had started in 1945 and the first engine ran on March 25, 1947, with a 12-stage compressor. The engine was difficult to start, would not accelerate and broke first-stage blades. Two-position inlet guide vanes and compressor bleed were among the design changes which allowed the engine, as the RA.2, to run a 25-hour test and fly in the two outboard positions on the converted Avro Lancastrian military serial VM732, from Hucknall on August 15, 1948.

The first production engine, which needed a two-stage turbine, was the RA.3, or Avon Mk 101.

The Avon 200 series was a complete redesign with very little in common with earlier Marks. Differences included a completely new combustion section and a 15-stage compressor based on that of the Armstrong-Siddeley Sapphire. The first application was the Vickers Valiant.

Operational history

The engine entered production in 1950 as the RA.3/Mk.101 with 6,500 lbf (29 kN) thrust in the English Electric Canberra B.2. Similar versions were used in the Canberra B.6, Hawker Hunter and Supermarine Swift. Uprated versions followed, the RA.7/Mk.114 with 7,350 lbf (32,700 N) thrust in the de Havilland Comet C.2, the RA.14/Mk.201, 9,500 lbf (42 kN) in the Vickers Valiant and the RA.26, 10,000 lbf (44 kN) used in the Comet C.3 and Hawker Hunter F.6. An Avon-powered de Havilland Comet 4 flew the first scheduled transatlantic jet service in 1958. The highest thrust version was the RA.29 Mk.301/2 (RB.146) used in later versions of the English Electric Lightning. It produced 12,690 lbf (56,450 N) and 17,110 lbf (72,770 N) with afterburning. Other aircraft to use the Avon included the de Havilland Sea Vixen, Supermarine Scimitar and Fairey Delta2.

The RA.3/Mk.109 was produced under licence by Svenska Flygmotor as the RM5, and an uprated RA.29 as the RM6 with 17,110 lbf (76,110 N) thrust. The RM5 powered the Saab Lansen and the RM6 powered the SAAB Draken and night fighter version of the Lansen.

300 Avon 113s, and a larger number of Avon 203s were produced under license in Belgium by Fabrique Nationale.

In the US the RA.28-49 was used in the VTOL Ryan X-13 Vertijet aircraft.

In Australia, the Avon was used by Commonwealth Aircraft Corporation in the CA-27 Avon-Sabre.

The Avon continued in production for the Sud Aviation Caravelle and English Electric (BAC) Lightning until 1974, by which time over 11,000 had been built. It remained in operational service with the RAF until 23 June 2006 in the English Electric Canberra PR.9.

Initial design work was done on the 2-spool RB.106/RB.128 as an Avon successor for large supersonic fighters.

Variants

AJ65
The original designation, standing for Axial Jet 6,500 lbf thrust
RA.1
Prototype engines for testing and development.
RA.2
Pre-production engines for testing. 6,000 lbf (26.69 kN)
RA.3
Civil designation for the first Avon production mark - 6,500 lbf (28.91 kN).
RA.7
Civil designation for the uprated version of the Avon. - 7,350 lbf (32.69 kN).
RA.7R
The RA.7 with reheat
RA.14
Civil designation for the uprated version of the Avon with can-annular combustion chamber and Sapphire style compressor - 9,500 lbf (42.26 kN).
RA.21
8,050 lbf (35.81 kN) Production engine developed from the RA.7.
RA.24
RA.25
Civil Mk.503
RA.26
Further improvements to the Avon 200 series - Civil Mk.521
RA.28
Second generation variant 10,000 lbf (44.48 kN)
RA.29
Civil designation for the Mk.300 series (used by the Sud Aviation Caravelle)
RA.29/1
RA.29/3
RA.29/6
Mk.100 series
Military designation for the RA.3 Avon - 6,500 lbf (28.91 kN).
Mk.114
Military designation for the RA.7 Avon - 7,350 lbf (32.69 kN).
Mk.200 series
Military designation for the uprated version of the Avon with can-annular combustion chamber and Sapphire style compressor - 9,500 lbf (42.26 kN).
Mk.300 series
Developed after-burning engines for the English Electric Lightning.
Avon 504
Civilian equivalent to military Mk.200 variants.
Avon 506
Civilian equivalent to military Mk.200 variants.
Avon 522
Civilian equivalent to military Mk.200 variants.
Avon 524
Civilian equivalent to military Mk.200 variants.
Avon 524B
Civilian equivalent to military Mk.200 variants.
Avon 525
Civilian equivalent to military Mk.200 variants.
Avon 525B
Civilian equivalent to military Mk.200 variants.
Avon 527
Civilian equivalent to military Mk.200 variants.
Avon 527B
Civilian equivalent to military Mk.200 variants.
Avon 531
Civilian equivalent to military Mk.200 variants.
Avon 531B
Civilian equivalent to military Mk.200 variants.
Avon 532R
Civilian equivalent to military Mk.200 variants.
Avon 532R-B
Civilian equivalent to military Mk.200 variants.
Avon 533R
Civilian equivalent to military Mk.200 variants.
Avon 533R-11A
Civilian equivalent to military Mk.200 variants.
Svenska Flygmotor RM5
Licence production of the RA.3/Mk.109 for the Saab 32 Lansen
Svenska Flygmotor RM6
Uprated RA.29/Mk.300 for the Saab Draken
Westinghouse XJ54
Avon 300-series scaled-down by Westinghouse to 105 lb/sec airflow to produce 6,200 lb thrust.

Military aviation

  • CAC Sabre
  • de Havilland Sea Vixen
  • English Electric Canberra
  • English Electric Lightning
  • Fairey Delta 2
  • Hawker Hunter
  • Ryan X-13 Vertijet
  • Saab 35 Draken
  • Saab Lansen
  • Supermarine Swift
  • Supermarine Scimitar
  • Vickers Valiant
  • Civil aviation

  • de Havilland Comet
  • Sud Aviation Caravelle
  • Other uses

  • The Avon is also currently marketed as a compact, high reliability, stationary power source. As the AVON 1533, it has a maximum continuous output of 21,480 shp (16.02 MW) at 7,900 rpm and a thermal efficiency of 30%. In 1982, an Avon engine on gas pumping duty in a Canadian installation ran for 53,000 hours before requiring a major overhaul. In 1994, another industrial Avon engine ran non-stop for 476 days (11,424 hours).
  • As a compact electrical generator, the type EAS1 Avon based generator can generate a continuous output of 14.9 MW.
  • On 4 October 1983, Richard Noble's Thrust2 vehicle, powered by a single Rolls-Royce Avon 302 jet engine, set a new land-speed record of 1,019.46 km/h (633.46 mph) at the Black Rock Desert in Nevada.
  • Survivors

  • Several Avon-powered Hawker Hunter aircraft remain airworthy in private ownership in 2010.
  • Thunder City in South Africa as of 2011 operated two Avon-powered English Electric Lightnings.
  • Engines on display

  • A Mk 524 Avon has been restored at the Museo Nacional de Aeronáutica de Argentina by the Museum Friend's Assn in Moron, Argentina and is now on display
  • An Avon Mk.203 was donated by Rolls-Royce to the National Museum of the United States Air Force in July 1986 for public display.
  • A Rolls-Royce Avon is on public display at the Midland Air Museum.
  • A preserved Rolls-Royce Avon Mk.203 is on display at the Royal Air Force Museum London.
  • A partially sectioned Mk.101 Avon is on display at the Royal Air Force Museum Cosford.
  • A Rolls-Royce Avon is on display at the Australian National Aviation Museum, Moorabbin, Victoria, Australia
  • A Rolls-Royce Avon is on public display at East Midlands Aeropark
  • A Rolls-Royce Avon is on display at the Fleet Air Arm Museum at RNAS Yeovilton.
  • Several RR Avon engines are on display at the Queensland Air Museum, Caloundra, Australia
  • A Rolls-Royce Avon is on display at the Classic Flyers Aircraft Museum, Mt Maunganui, Bay of Plenty, New Zealand.

    Specifications (Avon 301R)

    Data from

    General characteristics

  • Type: Turbojet
  • Length: 126 in (3,200 mm)
  • Diameter: 35.7 in (907 mm)
  • Dry weight: 2,890 lb (1,310 kg)
  • Components

  • Compressor: 15-stage axial flow
  • Combustors: Cannular, 150 lb/s (68 kg/s)
  • Turbine: Two-stage axial flow
  • Fuel type: Kerosene
  • Performance

  • Maximum thrust: 12,690 lbf (56.4 kN)dry/16,360 lbf (72.8 kN) with reheat
  • Overall pressure ratio: 7.45:1
  • Specific fuel consumption: 0.932 lb/(lbf·h) or 26.4 g/(kN·s) (dry) 1.853 lb/(lbf·h) or 52.5 g/(kN·s) (wet)
  • Thrust-to-weight ratio: 5.66:1 (56 N/kg)
  • References

    Rolls-Royce Avon Wikipedia


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