AVRO 707
The Avro 707 originated as a "proof-of-concept" delta wing aircraft that was principally the work of Stuart D. Davies, Avro's chief designer. It was a relatively compact aircraft that initially incorporated a wing with about 50° sweep, without a horizontal tail on a fin with trailing edge sweep. The trailing edge of this wing carried two pairs of control surfaces: inboard elevators and outboard ailerons. These flight surfaces worked in conjunction with a conventional rudder. Retractable airbrakes were also provided above and below the wings. The aircraft featured all-metal stressed-skin construction. The Avro 707 programme provided valuable insights into the Vulcan's flight characteristics, most of the information coming from the second and third prototypes which flew before the Vulcan.
All Avro 707s were powered by a single Rolls-Royce Derwent centrifugal turbojet engine. The air intake on the first prototype and later 707B was located on the upper rear fuselage. Some aircraft were outfitted with ejection seats. In total, five Avro 707s were completed.
On 4 September 1949, the first Avro 707, VX784, performed its maiden flight from RAF Boscombe Down, Squadron Leader Samuel Eric Esler, DFC, AE, was at the controls. Two days later, it was statically displayed at the Farnborough Airshow. However, testing with the first prototype was cut shortly when, on 30 September 1949, it crashed near Blackbushe during a test flight, killing Esler. The next prototype, VX790, renamed the 707B, had a longer nose, different cockpit canopy, a wing of different (51°) sweep and a longer nose wheel leg to provide the high angle of incidence required by deltas for landing and take off. The Avro 707B was given the same dorsal engine intake as the first prototype, although this was later modified to a NACA design. It first flew on 6 September 1950; the aircraft quickly proved to be relatively docile in flight. Both the 707 and 707B were largely flown to test low speed characteristics.
The final variant was the two-seat 707C; originally four examples were ordered by the RAF with the intention of conducting orientation training for flying aircraft with delta wing configurations using the type. The 707C was provisioned with a wider cockpit to accommodate a "side-by-side" seating arrangement and dual flight controls. However, the production order was cancelled; accordingly, only the sole prototype, WZ744, was 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.
The two-seat 707C joined the R.A.E. in 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 numerous public appearances at the Farnborough Airshow throughout the 1950s. During 1952, the first prototype Vulcan flew with the 707s A and B and in 1953, the four surviving Avro 707s flew alongside the first two Avro 698 Vulcan prototypes.
No Avro 707s are presently airworthy. Both examples of the 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, Victoria. Also in Great Britain is WZ744, the single 707C prototype, which was displayed at the RAF Museum, Cosford near Wolverhampton and is currently stored out of public view with its space in the museum's Test Flight hall taken by the British Aerospace EAP.