page_title: Vickers Wellington
section_title: Design
hierarchical_section_title: Vickers Wellington / Design
caption_attribution_description: English: IWM caption&#160;: 15-year-old cadet Tommy McMordie from Luton Air Training Corps (ATC) in a Wellington bomber's rear turret at No 12 Operational Training Unit (OTU) at Chipping Warden, Northamptonshire.
context_page_description: The Vickers Wellington is a British twin-engined, long-range medium bomber. It was designed during the mid-1930s at Brooklands in Weybridge, Surrey. Led by Vickers-Armstrongs' chief designer Rex Pierson; a key feature of the aircraft is its geodetic airframe fuselage structure, which was principally designed by Barnes Wallis. Development had been started in response to Air Ministry Specification B.9/32, issued in the middle of 1932, for a bomber for the Royal Air Force.
  This specification called for a twin-engined day bomber capable of delivering higher performance than any previous design. Other aircraft developed to the same specification include the Armstrong Whitworth Whitley and the Handley Page Hampden. During the development process, performance requirements such as for the tare weight changed substantially, and the engine used was not the one originally intended.
  The Wellington was used as a night bomber in the early years of the Second World War, performing as one of the principal bombers used by Bomber Command. During 1943, it started to be superseded as a bomber by the larger four-engined "heavies" such as the Avro Lancaster.
context_section_description: The Vickers Wellington was a twin-engined long-range medium bomber, initially powered by a pair of Bristol Pegasus radial engines, which drove a pair of de Havilland two-pitch propellers. Various different engines and propeller configurations were used on different variants of the aircraft, which included several models of both the Bristol Hercules and the iconic Rolls-Royce Merlin engines. Recognisable characteristics of the Wellington include the high aspect ratio of its tapered wing, the depth of its fuselage, and the use of a tall single vertical stabiliser on its tail unit, which reportedly aided in recognition of the type.
  The Wellington typically had a crew of five. The bomb-aimer was located within the aircraft's nose. The Wellington could be fitted with dual flight controls, and specialised dual-control conversion sets were developed for the purpose of performing training upon the type. The cockpit also contained provisions for heating and de-icing equipment, which was introduced on later models of the Wellington. The Wellington Mk I had a maximum offensive bomb load of 4,500 lb (2,000 kg), more than one-fifth of the overall aircraft's 21,000 lb (9,500 kg) all-up weight. Additional munitions and an expanded bombing capacity were a recurring change made in many of the subsequent variants of the Wellington developed during the war, including the carrying of ever-larger bombs.
  Defensive armaments comprised the forward and tail turret gun positions, along with a retractable revolving ventral turret. Due to the high cruising speeds of the Wellington, it had been realised that fully enclosed turrets, as opposed to semi-enclosed or exposed turrets, would be necessary; the turrets were also power-operated in order to traverse with the speed and manoeuvrability necessary to keep up with the new generations of opposing fighter aircraft. Due to the specialised nature of increasingly advanced turrets, these were treated as ancillary equipment, being designed and supplied independently and replacing Vickers' own turrets developed for the aircraft. The turrets initially used a Nash & Thompson control unit, while each position was equipped with a pair of .303 in (7.7 mm) Browning machine guns. On many Wellington variants, the Vickers-built ventral turret of the Mk I was replaced by a Nash & Thompson-built counterpart as standard.
  A key innovation of the Wellington was its geodesic construction, devised by aircraft designer and inventor Barnes Wallis. The fuselage was built from 1,650 elements, consisting of duralumin W-beams which formed into a metal framework. Wooden battens were screwed to the beams and were covered with Irish linen; the linen, treated with layers of dope, formed the outer skin of the aircraft. The construction proved to be compatible with significant adaptations and alterations including greater all-up weight, larger bombs, tropicalisation, and the addition of long-range fuel tanks.
  The metal lattice gave the structure considerable strength, with any single stringer able to support a portion of load from the opposite side of the aircraft. Heavily damaged or destroyed beams on one side could still leave the aircraft structure viable; as a result, Wellingtons with huge areas of framework missing were often able to return home when other types would not have survived, leading to stories of the aircraft's 'invulnerability'. The effect was enhanced by the fabric skin occasionally burning off leaving the naked frames exposed.
  A further advantage of the geodesic construction of the wings was its enabling of a unique method for housing the fuel, with each wing containing three fuel tanks within the unobstructed space provided between the front and rear spars outboard of the engines. A disadvantage of the geodesic fuselage structure was its insufficient lengthwise stiffness: when fitted with attachment for towing cargo gliders, its structure "gave" and stretched slightly. So, while the airframe continued to be structurally sound, the forces in the long control runs of cables and push-pull rods to the empennage grew 
caption: The tail turret of a Wellington, 1942
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