In 311 Sqn Bomber Command livery.

The Wellington (nicknamed the ‘Wimpey’) was a twin engine medium bomber, in service with the RAF at the outset of WW2, carrying a crew of six. It was the best of its type available to the RAF until the heavy four engine bombers became available from 1942. Design and development of the aircraft was conducted at Vickers Aviation Ltd, who in 1932 commenced work against Air Ministry Specification B9/32 for a medium bomber. The company chose a high aspect ratio wing for the prototype, which was named the Vickers Crecy before the name Wellington was adopted. In its initial form the aircraft carried no defensive armament. A revised Air Ministry specification B29/35 was drawn up for the aircraft and after a number of modifications had been made, the Wellington first flew in December 1937, against which the Ministry ordered the first 180 aircraft for the RAF. The nominal bomb payload was up to 4,500lb (2,041 kg). After a short period of change, the defensive armament standardised on six 0.303 inch (7.7 mm) Browning machine guns. Two each were installed in Frazer-Nash powered gun turrets in the nose and tail of the aircraft. The remaining two guns were mounted in the central fuselage sides and operated manually.

The first squadron deliveries commenced in October 1938 from when the Wellington was set to supersede its less capable counterparts. Early Wellingtons used Bristol Pegasus radial engines. As more power was required and to comply with wartime availability, different Marks employed up-rated Pegasus engines, the Bristol Hercules and Pratt & Witney Twin Wasp radial engines and the Rolls Royce Merlin (in line) engine. By the end of 1939 it was clear that the Wellington was vulnerable to enemy fighter action and from 1940 onwards the aircraft was generally used in the night bombing role. It was to continue service through WW2, changing from its bombing role in 1942/43, to provide other duties for offensive and defensive operations by RAF Coastal Command. The aircraft was also used for training, conversion and experimental activities. The Wellington remained in service throughout the war and more than 11,000 were produced.

In 311 Sqn Coastal Command livery.

The aircraft became well known for its ‘geodetic’ structural design adopted by Barnes Wallis from his experience with airships. The technique involved assembling a duralumin lattice framework built up between longitudinal beams, to form the required external shape. All the loads and moments would be carried by the basket like structure. Wooden battens were attached to the framework and onto these were attached the fabric external surface of the aircraft, with multiple doping for strength and rigidity. This gave a low ratio of structural weight to overall aircraft weight, thus increasing the maximum payload weight, fuel, etc. Opponents of geodetic aircraft construction claimed that it was a step backward in time from the newly acquired technology of metal monocoque and semi-monocoque thin walled structures.

The main geodetic disadvantages were related to speed of production and assembly, including difficulties when integrating cut-outs into the airframe. At higher aircraft speeds, especially near the maximum design values, the doped fabric skin could warp and tear; the more so if battle damage had been sustained. The fabric was also vulnerable to fire compared with a metal airframe skin. However, the Wellington, with so much clear space within its structural envelope, proved capable of being brought home to land after sustaining large amounts of hostile damage.

Wellington III specifications:

© 2010 Victor K L Marshall M Sc, C Eng, M I Mech E

Article last updated: 14 February 2017