an enlarged 707A. Later, this 707A was used to test the compound leading edge sweep subsequently used on all Vulcans. Although the first Vulcan prototype was already flying, a second 707A WZ736 was built to speed the development programme, making its maiden fight on 20 February 1953. The final variant was the two-seat 707C; originally four examples were ordered by the RAF for use in orientation training revolving around flying aircraft with delta wing configurations. The 707C had "side-by-side" seating with dual-controls but the production order was cancelled with only the sole prototype, WZ744 built. The 707C had its maiden flight on 1 July 1953 and was ultimately employed in other research that did not involve Vulcan development. Even after the Vulcan development phase was over, the four surviving 707s, in individual bright blue, red, orange and silver (natural metal) colour schemes, continued in use as research aircraft. After the compound sweep investigation and a period with the Royal Aircraft Establishment (R.A.E) carrying out handling trials with powered controls, the first 707A went to the Aeronautical Research Laboratories in Australia for low-speed delta wing airflow measurements. The second 707A was also at the R.A.E from June 1953 for aerodynamic and later, automatic control investigations. The Avro 707B joined the R.A.E. in September 1952 and was one of the aircraft used by the Empire Test Pilots School from January to September 1956, when it was damaged on landing, and broken up at R.A.E. Bedford. The two-seat 707C joined the R.A.E. January 1956; perhaps its most substantial research contribution was to the development of fly-by-wire control systems, one of the first of their kind, and fitted with a side stick controller. This aircraft was flying with the R.A.E. until September 1966 when it achieved its full airframe time. The Avro 707s made public appearances at the Farnborough Airshows in both September 1952 and 1953. In 1952, the first prototype Vulcan flew with the 707s A and B and in 1953, the four surviving 707s flew alongside the first two Avro 698 Vulcan prototypes. Surviving aircraft No 707s are now airworthy. Both examples of the Avro 707A variant survive. One, WZ736, was preserved in Great Britain at the Museum of Science and Industry in Manchester, but has been transferred to the Boscombe Down Aviation Collection at Old Sarum, while the other, WD280, is preserved in Australia at the RAAF Museum at Point Cook,