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 in (7.7 mm) 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.
Read more about Vickers F.B.5: Design and Development, Operational History, Variants, Operators, Specifications (Vickers F.B.5)