Japan's interest in tailless aircraft during World War II was minimal
compared with that of the other warring powers. Efforts centred around the
glider designs of the Kayaba Works and the Mitsubishi attempts to copy the
German Messerschmitt Me 163 rocket fighter.
The Kayaba gliders were developed to investigate the
characteristics of tailless aircraft, and other than a 1938 private
venture, the HK-1, were sponsored by the Japanese Army. The HK-1 was
designed by Dr. Hidemasa Kimura based on an idea by pioneer aviator Kumazo
Hino, the first person to fly an airplane in Japan, in 1910. Tests with
the HK-1 led to Army interest, and Dr. Kimura, later to become Professor
of the Science and Engineering Department, Nippon University, during the
post-war years, responded with the KU-2. Working with Kayaba's Chief
Designer Shigeki Naito, Kimura designed a single-seat model that flew 270
flights between October 1940 and May 1941.
Designed bv Dr. Hidemasa Kimura, manufactured by the Ito Airplane Works in
1938, the HK-1 was a private venture to investigate tailless
characteristics. Wing span was 34.8 feet, length 11 feet, weight 448
Dr. Kimura, in collaboration with designer Joji Washimi,
next produced a more advanced version of the KU-2 in 1941. The KU-3 was a
two-place experimental craft with no vertical control surfaces. The
leading edge of the wing was "cranked," incorporating sections of
different angles of sweepback, with three control surfaces arrayed along
the trailing edge of each wing. Over 60 flights were flown before the lone
KU-3 crashed in 1941.
The KU-2 (above) and the KU-3 (below) were designed in1946 by Dr. Kimura
for the Japanese Army. The vertical fin and rudder of the KU-2 were
replaced in the KU-3 by a horizontal control surface. Both gliders used
ailerons and elevators in the trailing edge.
Dr. Kimura carried the KU-3 design one step further. A
powered version, the KU-4, was designed, but abandoned by the Japanese
Army before it was built. It marked the end of any significant tailless
aircraft development in Japan until 1944.
The appearance of American B-29 Super fortresses over
Japan in 1944, produced an urgent need for a high performance interceptor.
Inspired by the Me 163 Komet, Mitsubishi engineers, using a German Walter
HWK 109-509 rocket motor and an instruction manual for the Me 163B,
designed the J8M1 Shusui (swinging sword) for the Japanese Navy,
and the Army version, designated Ki-200. A glider version, the MXY-8, was
also developed to provide data on handling characteristics of the J8M1 and
to be used for rocket pilot training. A prototype glider was flown in
early 1945, and subsequently placed in production. Similar training
gliders were planned for the Army's Ki-200.
These MXY-8 Shusui gliders were used to train pilots to fly the J8M1
rocket interceptors. Glider training took place at Kashiwa Air Base in
Japan. The Japanese Army called the glider "Shusui Light Glider"; later on
heavy gliders, about the same weight, structure, and appearance of the
rocket fighter, were programmed.
A special corps of potential rocket pilots began
training at Kashiwa Air Base in the spring of 1945, conducting test and
training flights in preparation for the day when the rocket-powered
fighters would be available. That day never came. The J8M1 first flew on
July 7, 1945, but an engine failure shortly after takeoff resulted in a
disastrous crash, killing the test pilot. There were no more flights prior
to war's end, although J8M 1 production was underway, and a J8M2 and an
advanced Ki-200, designated Ki-202, were planned.