 The Tabor was originally planned as a biplane powered by four 600 hp Siddeley Tiger engines.However delays in development of the engines meant these would be unavailable and so the aircraft was redesigned to use six 450 hp Napier Lion engines to give a similar power/weight ratio, and a third, upper wing added.The final design had a wingspan of over 131 ft (40 m), with the central wing of much greater span than the other two.