Vickers F.B.5

The Vickers F.B.5, Fighting Biplane 5, known as the Gunbus, was a British two-seat pusher military biplane of the First World War. Armed with a single .303 inch Lewis gun operated by the observer in the front of the nacelle, it was the first aircraft purpose-built for air-to-air combat to see service, making it the world's first operational fighter aircraft. Vickers began experimenting with armed aircraft in 1912, and the F.B.5 followed the Destroyer (the E.F.B.1) and later E.F.B. designs. It first flew on 17 July 1914, powered by a 100 hp Gnome Monosoupape nine-cylinder rotary engine, and was simple and conventional compared with its predecessors. By the end of 1915 the Fokker Eindecker had outclassed it, and it was fully withdrawn from front-line service by July 1916, with the rest used as trainers. Twelve were built under licence in Denmark and served with the Danish Army Air Corps until 1924.