Additional details may now be published of the development of the Rolls-Royce Avon turbojet that has been effected during the past four years. Performance prediction for the early Avons was very conservative, the experimental RA.2 having a rating of but 6,000 lb. This was later raised to 6,500 lb in the RA.3 which went into production in June, 1950, to power the Canberra.
Parallel with RA.3 production, further development was carried out to meet fighter requirements, to incorporate full anti-icing and to increase thrust. The outcome of this development was the RA.7, which was put through a 150-hour type-test in March,1952, at a rating of 7,500 lb thrust. Engines of this rating were flown at the S.B.A.C. displays of 1950, 1951, and 1952. In September last, delivery of the RA.7 to aircraft constructors began, while development work on re-heat produced the RA.7R, which successfully passed its 150-hour type test in January of this year at a rating of 9,500 lb thrust.
Source: Flight International
