The Avro 707 (also known as Type 707) is a British experimental aircraft built to test the tailless thick delta wing configuration chosen for the Avro 698 jet bomber, later named the Vulcan. In particular, the low-speed characteristics of such aircraft were not well known at the time. Aerodynamically, it was a one-third scale version of the Vulcan. Design and development The 707 was a "proof-of-concept" delta design that was principally the work of Stuart D. Davies, Avro chief designer. The diminutive experimental aircraft initially incorporated a wing with about 50° sweep, without a horizontal tail on a fin with trailing edge sweep. The trailing edge of the wing carried two pairs of control surfaces: inboard elevators and outboard ailerons. Retractable airbrakes were provided above and below the wings. The prototypes were ordered by the Ministry of Supply to Specification E.15/48. The aircraft were produced quickly using a few components from other aircraft including the first prototype using a Gloster Meteor canopy. The 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 707s were powered by a single Rolls-Royce Derwent centrifugal turbojet. The air intake on the first prototype and later 707B was located on the upper rear fuselage. Five 707s were built altogether. Operational history The first, the Avro 707, VX784 first flew from Boscombe Down on 4 September 1949 with Squadron Leader Samuel Eric Esler, DFC, AE, at the controls. The prototype crashed less than a month later, on 30 September, near Blackbushe, 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 707B was given the same dorsal engine intake as the 707, although this was later modified to a NACA design. It first flew on 6 September 1950. Both these aircraft were built to test low speed characteristics. The third aircraft, designated 707A, WD280 was built for higher speed testing. Experience with the dorsal intake of the earlier 707 and 707B had shown that as speed increased, the cockpit induced turbulence which interrupted the intake airflow, so the intakes were moved to the wing roots. When the Vulcan appeared, it looked very much like