Avro 707A

When Avro won the 1947 competition for a jet bomber to carry Britain’s atomic bomb, its design was a huge tailless delta, a shape nobody in Britain had flown. To learn how such a wing behaved before the bomber flew, the company built a series of small single-engined research aircraft at roughly one-third scale, each with a single Rolls-Royce Derwent. The first, the 707 VX784, flew from Boscombe Down on 4 September 1949, but crashed near Blackbushe on 30 September, killing Avro’s test pilot Eric Esler; the cause was traced to the aircraft’s airbrake controls, not to the delta wing.

The 707B VX790 followed in September 1950 for low-speed handling, with an intake on its back behind the cockpit. The 707A, flown from Boscombe Down on 14 June 1951 by WD280, was the high-speed aircraft: its wing was a scale copy of the Vulcan’s, with letterbox intakes in the wing roots like the bomber’s. Its findings, including the buffeting that led to the kinked leading edge of the Vulcan B.1’s wing, came too late to shape the first Vulcan prototype, which flew in August 1952, but they fed straight into the production bomber.

A second 707A, WZ736, flew in February 1953 and the two-seat 707C WZ744, built for delta familiarisation, in July. The order for further 707Cs to train RAF pilots was cancelled, and the surviving 707s spent the rest of the 1950s and the 1960s on research for the Royal Aircraft Establishment, including early work on automatic throttle control. WD280 went to Australia for low-speed research and is preserved there. In Britain WZ736 is on show with the Boscombe Down Aviation Collection at Old Sarum, and the Avro Heritage Museum at Woodford keeps WZ744 in store.