The Wellington used a unique geodetic construction designed by the famous Barnes Wallis which built up the fuselage from a number of steel channel-beams that were formed into a large network. This gave the plane tremendous strength because any one of the stringers could support some of the weight from even the opposite side of the plane. Blowing out one side's beams would still leave the plane as a whole intact. Wellingtons with huge holes cut out of them continued to return home when other planes would not have survived.
However the construction system also have a distinct disadvantage, in that the contruction time was considerably higher than for other designs using monocoque construction techniques.
It was particularly effective in North Africa, where it could fly faster than most of the Italian fighters, and carried a heavier bomb load than the Italians.
Deployed in 1937, the prototype first flew on 15 June 1936; some were used as trainers until 1953.
Mk IC was crewed by 6, a pilot, radio operator, navigator/bomb aimer, observer/nose gunner, tail gunner and waist gunner. two 1050hp Bristol Pegasus XVIII 235 mph. ceiling of 19,000 ft range of 1,805 miles. eight 0.303 machine guns 4,500 lbs of bombs.
The Mk.X introduced a fuselage structure of light alloy, instead of steel. There were also prototypes and a small production series (about 60) of the Mk.V and Mk.VI, with early cabin pressurisation systems, which did not enter service. Wellingtons were built with Pegasus, Hercules, Merlin or Twin Wasp engines.
Number built totalled 11,461 of all versions including 3,804 Wellington Mk.X