BAT FK.22 Bat / Bantam II
The first design by Frederick (Frits) Koolhoven after joining the British Aerial Transport Company (B.A.T.), the private-venture F.K.22 single-seat fighter flown in September 1917 was of wooden construction with a monocoque fuselage. Powered by a 120hp A.B.C. Mosquito six-cylinder radial engine, it displayed sufficient promise to win an official contract for a batch of six development aircraft. The first and third of these were powered by the 170hp A.B.C. Wasp seven-cylinder radial (F.K.22/1) and the second by a 100hp Gnome Monosoupape nine-cylinder rotary (F.K.22/2), the remaining three eventually being completed as prototypes for the F.K.23.
The F.K.22/2, retroactively named Bantam II, was the first to fly, commencing its trials in December 1917 and being delivered to Martlesham for official trials on 19 January 1918. Armament comprised two synchronised 7.7mm Vickers guns, and this prototype, later re-engined with a 110hp Le Rhone 9J nine-cylinder rotary, was eventually assigned to the Central Flying School at Upavon.