Kawasaki Ki-100
The Kawasaki Ki-100 was a single seat fighter operated by the Imperial Japanese Army Air Service during the Second World War. Based on the Kawasaki Ki-61 (Allied code name Tony), it replaced the inline V-12 Kawasaki Ha-40 engine with a Mitsubishi Ha-112-II radial powerplant. Unreliability and short supply of the Ha-40 was already causing concern when a bombing raid on 19 January 1945 destroyed its production plant. This left 275 Ki-61 airframes with no engines.
Tests with three Ki-61 airframes fitted with the Ha-112 were undertaken, with excellent results. The change from an in-line to radial engine reduced weight with the removal of the radiator and coolant tank. The engine was also lighter. As a result, the wing loading decreased improving take off and landings, maneuverability and turn radius.
Kawasaki Ki-100 Photographs
Ki-100 (prototypes)
Ki-100-I-Ko
The 271 Nakajima Ki-100-I-Ko were built from existing Ki-61 airframes modified to accept the Ha-112 radial engine. All had the original faired-in rear fuselage.
Ki-100-I-Otsu
The 118 Nakajima Ki-100-I-Otsu were purpose built for the new engine, with an improved canopy and cut down rear fuselage. This version also featured a modified oil cooler under the engine in a more streamlined fairing.
Ki-100-II
The Ki-100-II was fitted with a turbocharged water-methanol injected engine for improved high-altitude performance, mainly to improve interception capabilities against the Boeing B-29 Superfortress, but only three prototypes were built, and none were used operationally
