The Vickers Wellesley was a British 1930s light bomber built by Vickers-Armstrongs for the Royal Air Force. While it was obsolete by the start of the Second World War, and unsuited to the European air war, the Wellesley was successfully used in the desert theatres of East Africa, Egypt and the Middle East.
The design originated from the Air Ministry Specification G.4/31 which called for a General Purpose aircraft, capable of carrying out level bombing, army co-operation, dive bombing, reconnaissance, casualty evacuation and torpedo bombing. The Vickers Type 253, which used a radical geodesic airframe construction that was derived from that used by Barnes Wallis in the airship R100, was tested against the specification along with the Fairey G.4/31, Westland PV-7, Handley Page HP.47, Armstrong Whitworth A.W.19, Blackburn B-7, Hawker P.V.4 and the Parnall G.4/31. The Type 253 was declared the winner, with 150 being ordered.
The Vickers Type 246 monoplane, which used the same geodetic design principles for both the fuselage and wings, was then built as a private venture, first flying on the 19 June 1935 and offered to the RAF. This had superior performance, but did not attempt to meet the multi-role requirements of the specification, being designed as a bomber only. An initial order for 96 Type 246s was substituted for the Type 253 order. The RAF ultimately ordered a total of 176 as the Wellesley, to a newly written specification 22/35, with a 14-month production run starting in March 1937.
The Wellesley was a single-engined monoplane with a very high aspect ratio wing, and a manually operated, retractable undercarriage. As it was not known how the geodetic structure could cope with being disrupted by a bomb bay, the Wellesley's bomb load was carried in two streamlined panniers under the wings. The Wellesley Mk I had two separate cockpits, but this was changed in the Wellesley Mk II to a single-piece cockpit canopy covering both the pilot and navigator positions.
The RAF received its first Wellesleys in April 1937, serving with No.76 Squadron at Finningley, and eventually equipped six RAF Bomber Command squadrons in the UK. Five aircraft with provisions for three crew members were modified for long-range work with the RAF Long-Range Development Flight. Additional modifications included the fitting of Pegasus XXII engines and extra fuel tanks. On 5 November 1938, three of them under command of S/L R. Kellett flew non-stop for two days from Ismailia, Egypt to Darwin, Australia (7,162 miles, 11,525 km) setting a world distance record. All three aircraft succeeded in breaking the existing record, but No. 2 aircraft landed in West Timor, 500 miles short of the final objective. The Wellesley's record remained unbroken until November 1945.
The primary use of the Wellesley during the Second World War was in overseas theatres of operation, mainly in the Middle East, with only four examples remaining in Britain at the start of the war. Among its significant wartime operations was the bombing of Addis Ababa in August 1940, remaining in the region until 1941 performing maritime reconnaissance duties.
While the Wellesley was not a significant combat aircraft, the design principles that were tested in its construction were put to good use with the Wellington medium bomber that became one of the main types of Bomber Command in the early years of the European war.