The Wellington, which served Bomber Command so well in the early years of World War II, is remembered by the RAF and the people of Britain as the 'Wimpey' - a nickname derived from an American cartoon character possessing the proud name J. Wellington Wimpey. It was designed to meet an Air Ministry requirement for a long-range medium bomber under Specification B.9/32 and evolved as a mid-wing monoplane with a fuselage of oval cross-section. Both of these major structures were of the geodetic construction which Barnes Wallis had introduced in the Wellesley. But experience with the latter and development of the geodetic concept made it possible for the individual components (which were built up into the 'basket-weave' structure) to be smaller and
lighter in weight without any loss of structuial integrity by comparison with the Wellesley. Wings, fuselage and tail unit were fabric-covered; power plant comprised two wing-mounted engines; and the tailwheel-type landing-gear units were hydraulically retractable.
'Heavy' defensive armament - comprising five machine-guns in nose and tail turrets and a ventral dustbin - would, it was believed, enable a flight of these aircraft to put up such a curtain of fire that fighter escort would be superfluous. Those who held such beliefs (as for the Boeing B-17 Fortress developed in America) were to discover their error very quickly.
The prototype Wellington made its first flight on 15 June 1936, but it was not until October 1938 that production aircraft began to enter RAF service. Less than one year later (on 4 September 1939) Wellingtons were in action against targets in Germany. Early deployment on daylight raids showed that these and other British bomber aircraft were extremely vulnerable to fighter attack. Following the loss of ten Wellingtons from a force of 24 despatched on an armed reconnaissance of Wilhelmshaven on 18 December 1939, the type was withdrawn from daylight operations. As a night bomber, however, the Wellington proved an invaluable weapon during the early years of Bomber Command's offensive against Germany.
Wellington production was to total 11,461 aircraft and embraced many versions. These included Mk I bombers (782kW Bristol Pegasus XVIIIs) and the DWI with degaussing ring to trigger magnetic mines. Differing engines distinguished the 853kW Rolls-Royce Merlin X-powered Mk II; 1,021kW Bristol Hercules XI Mk III; and Pratt & Whitney Twin Wasp Mk IV. The Wellington Mk V was a high-altitude aircraft with pressurised cabin, no nose turret and increased wing span, followed by the high-altitude Mk VI with 1,192kW Rolls-Royce Merlin 60 or 62 R6SM engines. Mk VII was designated an experimental model and Mk VIII was the first of many reconnaissance versions. Mk IX aircraft were Mk Is modified as troop carriers. The Mk X with Hercules VI or XVI engines was the last bomber. Wellingtons Mk XI, XII and XIII were ASV radar-equipped aircraft for Coastal Command. The Mk XIV with Hercules XVII engines was the final reconnaissance version. In addition to these specific versions there were many variants, and Wellingtons were also used for training and transport.
