Martinsyde F.1The Martinsyde F.1 was a British two-seat biplane fighter designed and built by Martinsyde Limited, only two prototypes were built.Design and developmentThe F.1 was designed as a fighter for the Royal Flying Corps and it was a large tractor biplane powered by a Rolls-Royce Mk III piston engine. It had two tandem open cockpits with unusually the observer forward and the pilot behind. A rectangular aperture was cut-out of the upper wing above the observer's cockpit which would allow the observer to use a gun. It was tested at Martlesham Heath in July 1917, where it demonstrated good handling but was criticised for the awkward crew arrangement. It was not ordered into production and only one prototype was built. It continued in use at Farnborough until after the end of the war.