The Vickers FB5 Gunbus was based on the company's earlier series of experimental fighter biplanes (EFB1 to 5). Over 200 machines were built with the majority serving over the Western Front with the Royal Flying Corps (only 15 would be supplied to the Royal Naval Air Service), these providing the backbone of British Fighter Aircraft strength for the first two years of the Great War,
Powered by a pusher 100hp Gnome Monosoupape radial engine the Gunbus had a maximum speed of 70 mph with an endurance of some 4 hours and 30 minutes. Detail improvemnets to the design included the replacement of the heavy belt fed Vickers machine gun with a lighter Lewis gun on a pivot mounting.
Superceded by more modern fighters on the Western Front in the Autumn of 1916, the surviving machines wopuld serve for a while in the instructional role, although Vickers would received no further orders for the Gunbus. A small number of machines were built under license by factories in France and Denmark.
