Kawasaki Ki-78

The Kawasaki Ki-78, originally given the designation KEN III (Kensan III - research III), was a high speed research aircraft, also intended to attempt breaking the World Absolute speed record.

Design and development
The Kawasaki Ki-78 was a high-speed research aircraft developed to investigate laminar profile wings with high wing loadings. Early in 1938 a high-speed research program was started at the Aeronautical Research Institute of the University of Tokyo for a small single-seat aircraft.

The Ki-78, designed at the Aeronautical Research Institute and built at Kawasaki Kokuki Kogyo K.K. to investigate flying behaviour at very high speed, featured a streamlined minimumcross section fuselage fitted with a licence-built Daimler-Benz DB 601A engine. For short duration power boost, methanol/water injection was used, and cooling was improved by a 60 hp turbine driven cooling fan for the radiators.

All-metal construction was used in combination with a small thin wing with a laminar flow profile and sharp leading edge.

Operational history
By the outbreak of the war, the whole project was taken over by the Imperial Japanese Army, who gave it the military type designation Ki-78. Kawasaki received the order to build two prototypes of the Ki-78, construction of which was started in September 1941. The first was completed more than a year later and was flown for the first time on 26 December 1942. A feasibility study to improve the KI-78 flight performance showed that extensive airframe modifications were needed and consequently the project was officially terminated after the 32nd flight on 11 January 1944, the second Ki-78 was never completed.