Not 20's 0r 30's but did not now were to put it. High-speed flight tests were started in April 1943, and during the Ki-78’s 31st flight on December 27, the aircraft achieved its maximum speed of 434.7 mph (699.6 km/h) at 11,572 ft (3,527 m). This was considerably less than the program’s speed goal of 528 mph (850 km/h). A study showed that extensive airframe modifications were needed to improve the Ki-78 flight performance. Consequently, the project was officially terminated after the aircraft’s 32nd flight on January 11, 1944. Only one prototype was built. The unique Ki-78 survived the war but was crushed by American forces at Gifu airfield in 1945.