Martinsyde F.3

The Martinsyde F.3 is considered as the inmediate predecessor of the widely known Martinsyde F.4 Buzzard which is regarded as one of the best (if not the best) fighters of the World War I.
It started its life as a private venture from designer G.H. Handasyde who designed the F.3 as a single-bay staggered biplane made out of conventional wood with fabric skinning and was powered by a 285hp Rolls-Royce Falcon III engine.
It was completed in autumn of 1917 and was officially tested on 3rd October. Six more prototypes were ordered and an agreement was signed to start manufacturing it.
As it was powered by the Falcon engine and the Bristol F.2 fighter had priority for the supplies of those engines, the decission of refitting it with an Hispano-Suiza engine was taken, which led to the creation of the Martinsyde F.4 Buzzard and therefore the F.3 was abandoned.

Sources:
1. http://1000aircraftphotos.com/Contributions/SmithGaryL/12236.htm
2. Salamander Books - The Complete Book of Fighters