The Rolls-Royce Avon was the first axial flowjet engine designed and produced by Rolls-Royce. Introduced in 1950, the engine 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.
Production of the Avon aero engine version ended after 24 years in 1974. Production of the Avon derived industrial version, currently produced by Siemens, continues to this day.
The current version of the Avon, the Avon 200, is an industrial gas generator that is rated at 21,000–22,000 shp (15.7–16.4 MW). 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.
Design work began in 1945. The Avon design team was initially headed by Stanley Hooker assisted by Geoff Wilde. Development of the engine was moved from Barnoldswick to Derby in 1948 and Hooker subsequently left the company, moving to Bristol Engines.
The first engine ran on 25 March 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 Lancastrianmilitary serialVM732, from Hucknall on 15 August 1948.
The first production engine, which needed a two-stage turbine, was the RA.3, or Avon Mk 101. Several modified versions of this design were produced in the Mk. 100 series.
The Avon 200 series was a complete redesign having 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.
A Mark 122 – The rear fuselage of the Hawker Hunter can be removed for engine maintenance
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 32 Lansen and the RM6 powered the Saab 35 Draken and all-weather fighter version of the Lansen (J 32B).
300 Avon 113s, and a larger number of Avon 203s were produced under licence in Belgium by Fabrique Nationale.
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 and designations
Rolls Royce Avon RA.3 Mk.101 at RAF Museum Cosford
The original designation, standing for Axial Jet 6,500 lbf thrust
Prototype engines for testing and development.
Pre-production engines for testing – 6,000 lbf (26.69 kN)
Civil designation for the first Avon production mark. First avon with a two-stage turbine. – 6,500 lbf (28.91 kN)
Civil designation for the uprated version of the Avon RA.3. Electrically started. – 7,350 lbf (32.69 kN)
The RA.7 with reheat. Meant for use with an afterburner. Explosive-cartridge started. – 3,400 kp (7,495.72 lbf) without afterburner, 4,420 kp (9,744.43 lbf) with afterburner.
Civil designation for the uprated version of the Avon with can-annular combustion chamber and Sapphire style compressor – 9,500 lbf (42.26 kN)
Production engine developed from the RA.7 – 8,050 lbf (35.81 kN)
Production engine developed from the RA.7R. Same as the Avon Mk.21.
Military designation for the RA.7 Avon – 7,350 lbf (32.69 kN)
Same as the Avon Mk.23 – 3,630 kp (8,002.78 lbf)
Australian version built on license by CAC for the CAC Sabre Mk.31 – 7,500 lbf (33.36 kN)
Afterburning Swedish version built by RR and on license by SFA for the Saab 32A/C. Same as the RA.21R. Designated RM5A1. – 3,460 kp (7,627.99 lbf) without afterburner, 4,445–4,700 kp (9,799.55–10,361.73 lbf) with different afterburners.
Improved Mk.21 with increased diameter on the engine outlet for more power. Built by RR and on license by SFA for the Saab 32A/C. Designated RM5A2. – 3,460 kp (7,627.99 lbf) without afterburner, 4,445–4,700 kp (9,799.55–10,361.73 lbf) with different afterburners.
Same as the Avon Mk.115. Non-afterburning Swedish version built by RR for the Hawker Hunter Mk.50. Designated RM5B1. – 3,519 kp (7,758.07 lbf)
Non-afterburning Swedish version built by RR for the Hawker Hunter Mk.50. Designated RM5B2.
Non-afterburning Swedish version built by RR for the Hawker Hunter Mk.50. Designated RM5B3.
Australian version built by CAC for the CAC Sabre Mk.32 – 7,500 lbf (33.36 kN)
Avon Series 200
Avon Series 200 are uprated military versions of the Avon with can-annular combustion chamber and Sapphire style compressor.
– 9,500 lbf (42.26 kN)
Afterburning Swedish version built by RR and on license by SFA for the Saab 32B. Same as the RA.24R. Designated RM6A. – 4,880 kp (10,758.56 lbf) without afterburner, 6,500 kp (14,330.05 lbf) with afterburner.
Afterburning Swedish version built by RR and on license by SFA for the Saab 35A/B/C. Designated RM6B. – 4,890 kp (10,780.60 lbf) without afterburner, 6,535 kp (14,407.21 lbf) with afterburner.
Afterburning Swedish version built by RR and on license by SFA for the Saab 35D/F. Same as the RA.29R. Designated RM6C. – 5,765 kp (12,709.65 lbf) without afterburner, 7,800 kp (17,196.06 lbf) with afterburner.
Avon 300-series scaled-down by Westinghouse to 105 lb/sec airflow to produce 6,200 lb thrust.
Avon Series 500
Avon Series 500 are civilian equivalents to the military Avon Series 200 variants.
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%. An example can be found at Didcot Power Station in the United Kingdom where four Avon generators are used to provide Black start services to assist in a restart of the National Grid in the event of a system-wide failure, or to provide additional generating capacity in period of very high demand.
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.
Several Avon-powered Hawker Hunter aircraft remain airworthy in private ownership in 2010.