The Kayaba Ku-4 was a

research aircraft An experimental aircraft is an aircraft intended for testing new aerospace technologies and design concepts. The term ''research aircraft'' or ''testbed aircraft'', by contrast, generally denotes aircraft modified to perform scientific studies, ...

built in Japan in 1940 to investigate the possibilities of

tailless aircraft In aeronautics, a tailless aircraft is an aircraft with no other horizontal aerodynamic surface besides its main wing. It may still have a fuselage, vertical tail fin (vertical stabilizer), and/or vertical rudder. Theoretical advantages of the ...

designs. It followed designer

Hidemasa Kimura Hidemasa (written: 秀政, 秀匡 , 秀征 or 英正) is a masculine Japanese given name. Notable people with the name include: *, Japanese sumo wrestler *, Japanese samurai *, Japanese golfer *, Japanese footballer *, Japanese samurai *, Japanese ...

's successful Ku-2 and Ku-3 designs for the

Imperial Japanese Army The was the official ground-based armed force of the Empire of Japan from 1868 to 1945. It was controlled by the Imperial Japanese Army General Staff Office and the Ministry of the Army, both of which were nominally subordinate to the Emperor o ...

. While these previous aircraft had been gliders, however, the Ku-4 was to be a powered by a pusher engine. It had a low, swept wing, and like the Ku-2, fins at the wingtips. Work on the prototype was well advanced by April 1941, but the following month, Kimura's relationship with the Army soured following the crash of the Ku-2. The Ku-4 was cancelled, and Kimura eventually received only ¥17,000 of the ¥200,000 that had been promised for the development of his tailless designs.

Specifications (as designed)

References

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日本飞翼的短暂研究
{{Japanese Army Glider Designation System 1940s Japanese experimental aircraft Tailless aircraft Kayaba aircraft