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Japan's Kawasaki Ki-78 high speed research


  • Kawasaki Ki-78 high speed research



Initially a civilian project to break the world air speed record, it was taken over by the Imperial Japanese Army in 1941 and designated the Ki-78. The goal was to have the aircraft fly 528 mph / 850 kph.

The Aeronautical Research Institute at the University of Tokyo had a team led by Shoroku Wada that designed the aircraft. Mineo Yamamoto worked on the fuselage design, Eichiro Tani the wing, and Seichi Kurino and Shojiro Nomua the engine.


The wings had a laminar flow section to minimize resistance.

Due to the small wing size Fowler and split flaps were used for landings.


A Daimler-Benz DB 601A (1,175 HP) engine was installed. A first for Japanese aircraft, a water-methanol injection system was installed to allow boosts of power to 1,550 HP.

Radiators were installed on the fuselage sides to allow for more air cooling.


In May 1941 a wooden mock-up was constructed.

The first prototype was flown on December 26, 1942. At low speeds it was very hard to handle.

During the prototype's 31st flight, on December 31, 1943, the Ki-78 was able to fly 434.9 mph / 699.6 kph at 11,539' / 3,527 m.

Too many modifications would have been required to achieve the target speed so after the 32nd flight on January 11, 1944, the project was suspended.


  • Prototype: 1
    • Manufacturer: Kawasaki Kokuki Kogyo K.K. at Gifu
    • Production: September 1941 - December 1942


Type High Speed Research
Crew 1
Engine (Type) Daimler-Benz DB 601A
Cylinders Inverted V 12
Cooling Liquid
Net HP 1,175
Propeller blades 3 metal
Span 26' 2 21/32"
8 m
Length 26' 6 29/32"
8.1 m
Height 10' 7/8"
3.07 m
Wing area 118.403 sq ft
11 sq m
Empty 4,255 lb
1,930 kg
Loaded 5,071 lb
2,300 kg
Speed at 11,485' / 3,500 m 435 mph
700 kph
Service ceiling 26,245'
8,000 m
Range 373 miles
600 km


  1. Japanese Aircraft of the Pacific War, René J Francillon, 1970
20th Century American Military History Crucial Site