Wallis' design for the huge six-engined Victory Bomber drew upon his prior experience and expertise. Wallis was an expert on geodetic airframe construction, having previously used it in designs such as the Wellesley (1935) and Wellington (1936), and naturally used it again for the Victory Bomber; also, all existing Vickers tooling was for this construction method. His specification was for a 50-ton (45 tonne) bomber that could fly at high altitude, being calculated to give the bomb maximum impact speed, at a speed of over a distance of . It would carry a single "earthquake bomb". Defensive armament was minimal; speed and height would be its chief defence with one quad-gun turret in the tail position for any fighter aircraft that did attempt to reach it. The bomber would benefit by climbing to altitude while over Britain, where fighter defences could protect it. Due to the high altitudes that bombing missions would take place at, the crew compartment was pressurised.