The
first Vimy F.B.27 prototype numbered B.9952 was powered by two 200 hp
Hispano-Suiza engines and was then later fitted with two 260 hp Salmson
water-cooled radial engines. The Salmson engine version of the design
was not developed further.
The second Vimy F.B.27 prototype numbered B.9953 was powered by two 260
hp Sunbeam Maori engines. This plane was not tested extensively because
it crashed on an early flight. This is listed as the Mk I.
The third Vimy F.B.27 prototype numbered B.9954 was powered by two 260
hp Fiat A-12 engines. The Fiat version of the F.B.27 was proved to be
good and ordered in quantities. This is listed as the Mk II.
There was a Mk III version listed in the Technical Department
Instruction No. 538A, dated January 1919, powered by two 230 hp B.H.P.
engines but it is doubtful if any airplanes were completed with those
engines.
The Americans were interested in the Vimy and asked if they could have
Liberty engines installed. A trial installation was made but it was
destroyed by fire at Joyce Green.
The first production model was the Fiat powered machine but then in the
summer of 1918 the Vimy appeared in its best-known form with two
Rolls-Royce Eagle IIIs of which the great majority of production
machines had these engines. This is listed as the Mk IV and the first
Vimy to have the Eagle engines was production number F.9569.
The performance of the Vimy IV was excellent and had a top speed of 98
mph at 5,000 feet. Alcock & Brown made the transatlantic flight in a
modified Vimy IV.
Air
speeds are listed for the Vimy by engine type in mph and altitude in
feet.
Hispano-Suiza.
90 mph at seal level.
87 mph at 5,000 ft.
85 mph at 6,500 ft.
Maori (without bombs)
96 mph at 6,500 ft.
89.5 mph at 10,000 ft.
Fiat (without bombs)
96 mph at 5,000 ft.
Eagle (without bombs)
100 mph at 6,500 ft.
96 mph at 10,000 ft.
Salmson 94 mph at 5,000 ft. |