The first flight of the Ki-78 took place on December 26, 1942, during which poor controllability at low flight speeds and extremely low stall characteristics were discovered. The aircraft turned out to be heavier than in the design and estimate documentation, which increased the already high specific wing loading. Even with special flaps, takeoff and landing speeds remained high and reached 205 km / h and 170 km / h, respectively. In addition, at a relatively low speed of 635 km / h, elevator flutter was detected, to eliminate it, horn compensation was installed on the rudders.
Flight speed tests began in April 1943, and in the 31st flight, December 27, Ki-78 at an altitude of 3527 m developed a maximum speed of 699.6 km/h, which was significantly less than the expected speed of 850 km / h. Research has shown that significant modifications to the airframe were necessary to improve the Ki-78's flight characteristics, and as a result, after the thirty-second flight, on January 11, 1944, the Ki-78 test program was officially terminated. The second Ki-78 was never completed.
- Record aircraft Kawasaki Ki-78 / Ivan Byakin /
- Japan Aviation. / Andrey Firsov /
- Encyclopedia of Military Equipment / Aerospace Publising /
Ki-78 survived the war, but did not arouse interests of the Americans and in 1945 it was destroyed at the Gifu factory airfield.