The F.B.5 (Fighting Biplane 5) was a double seat, biplane fighter. The gunner was sitting in front of the pilot and used a 7.7 mm Lewis machine gun. The F.B.5 was ba sed on experimental fighter aircraft; from the E.F.B.1 (1913) to the E.F.B.5 (1914). The First flight of the F.B.5 was in July 1914. On 5th February 1915 the first aircraft were delivered to the No.5 Squadron of the Royal Flying Corps. The No.11 Squadron became on 25th July 1915, the first fighter squadron of history. It was based in Villers-Bretonneux in France. The pilot Gilbert Stuart Martin Insall of this squadron achieved on 7th November 1915, the first victory with an F.B.5. The No.18 squadron of the RFC was founded in November 1915 as a squadron using only F.B.5.