Vickers F.B.25

Derived from the abortive F.B.23 design intended as a successor to the F.B.9, the F.B.25 two-seat night fighter was conceived to fulfil the same requirement as the Royal Aircraft Factory's N.E.1. Completed in the early spring of 1917, the F.B.25 carried its two crew members in staggered side-by-side seats, the gunner being positioned ahead and to starboard. Like the N.E.1, the F.B.25 was intended to carry the Vickers-built Crayford rocket gun with which it was supposed to attack hostile airships, and a small searchlight was originally to have been mounted in the extreme nose of the nacelle. The intention was to power the F.B.25 with the 200hp Hispano-Suiza eight-cylinder water-cooled engine, and in order to minimise the risk of the aircraft turning over during a nocturnal landing, it was proposed to provide a nosewheel. In the event, non-availability of a 200hp unit dictated installation of a 150hp Hispano-Suiza, and neither searchlight nor nosewheel was fitted. A two-bay unstaggered equi-span biplane with tailbooms converging in elevation to meet at the rear spar of the tailplane, the F.B.25 carried its unusually wide nacelle at mid wing-gap. As well as the Crayford rocket gun, an interesting feature was the oleo-pneumatic undercarriage. Flight testing revealed poor characteristics, and when sent to Martlesham Heath in May 1917 (where it was eventually to crash), the official reports were singularly unflattering, dismissing the F.B.25 as wholly unsuited for night fighting.