Vickers Type 253

The Vickers Type 253 was a single-engined two-seat biplane general-purpose military aircraft built to a 1930 government specification, often known as the Vickers G.4/31. It won a production contract, but this was transferred to the company's monoplane equivalent, the Wellesley, and only one Type 253 was built. In April 1932 the Air Ministry awarded Vickers a contract for a single prototype under Specification G.4/31 for a Westland Wapiti replacement able to carry out level bombing, army cooperation, dive bombing, reconnaissance, casualty evacuation and torpedo bombing. It competed with the Handley Page HP.47, Fairey, Westland, Armstrong Whitworth, Blackburn, Hawker and Parnall entrants. It used a Pegasus IIM3 radial with a Townend ring in a two-bay unstaggered biplane. Its fuselage frame, designed by chief structural engineer Barnes Wallis, was a step toward his geodetic frames, with four light-alloy longerons joined by oppositely handed helical channel members.