The Vimy was powered by a range of different engines. Owing to engine supply difficulties, the prototype Vimys were tested with a number of different engine types, including Sunbeam Maoris, Salmson 9Zm water-cooled radials, and Fiat A.12bis engines, before production orders were placed for aircraft powered by the 230 hp (170 kW) BHP Puma, 400 hp (300 kW) Fiat, 400 hp (300 kW) Liberty L-12 and the 360 hp (270 kW) Rolls-Royce Eagle VIII engines, with a total of 776 ordered before the end of the First World War. Of these, only aircraft powered by the Eagle engine, known as the Vimy IV, were delivered to the RAF. Due to the number of engine types used there are multiple conflicting official reports on the production numbers of each sub-variant of the Vimy.