The Vickers FB5 was a ''Pusher'' design Fighter Aircraft, deployed in 1915. The ''Pushers'' were a Class of Aircraft which placed the Aircraft's propeller behind it's Engine (providing force rearward or to ''push''). This was opposed to a traditional ''Front Mounted'' Engine propellant system. Early Aircraft (including the World's first sustained flight ''Wright Flyer'' – used this form of system). The Vickers FB5, nicknamed The ''Gunbus'' is credited with being the first ''operational Fighter'' built specifically for ''War Service'' (Air Combat). Over 225 FB5s were constructed. The Gunbus Model was deployed with several Squadrons in France – seeing limited but robust combat. They would be replaced in 1915 with evolving Front Facing Engine Systems. The FB5 was crewed by (2). The ''2nd'' Seat (which would later be placed behind The Pilot), was in The Vickers FB – located forward and below in an extended nacelle. They measured 30-feet with a wingspan (bi-wing) of 37-feet. Power was provided by a single Gnome Monosoupage 9 cylinder rotary Engine. It provided 100-HP. The rated airspeed was 75-mph. It's operational ceiling was 9,000-feet. Armament included (1) .303 Vickers Machine Gun, mounted in the nacelle and operated by The Observer (Gunner).