Military Wiki
Role Heavy bomber
Manufacturer Kawasaki Aircraft Industries
Primary user Imperial Japanese Army Air Service (planned)
Produced 0 (1st prototype 60% complete)

The Kawasaki Ki-91 was a Japanese heavy bomber developed by Kawasaki Aircraft Industries during the later years of World War II.


In early 1943, following the cancellation of the Nakajima Ki-68 and Kawanishi Ki-85 due to the failure of the Nakajima G5N, Kawasaki responded to the Imperial Japanese Army's requirement for a long-range bomber of similar size and performance to the B-29 Superfortress with the Ki-91. Like the G5N, Ki-68, and Ki-85, the Ki-91 was to be capable of launching attacks on the continental US from Japan. In April 1944, a wooden mockup was built for inspection, and by May production of the first prototype was ordered. Construction of the prototype began in June, but the first B-29 raids on Japan were underway beginning that month. In February 1945, the first Ki-91 prototype was 60 percent complete when a B-29 air raid damaged the facility in Gifu Prefecture where the Ki-91 prototype was being built, bringing the program to a halt.[1]


The Ki-91 was a design for a heavy bomber similar in size and bombload to the B-29 Superfortress and Convair B-32. It had a bigger wingspan and fuselage than the B-29 and B-32, and featured a pressurized cabin to allow high altitude flights. However, the prototype was to lack a pressurized cabin, but production aircraft would be built with the pressurized cabin.[1]


Data from [1]

General characteristics

  • Crew: 8
  • Length: 32.97 m (108 ft 2 in)
  • Wingspan: 47.9 m (157 ft 2 in)
  • Height: 9.99 m (32 ft 9 in)
  • Wing area: 223.99 m2 (2,411.0 sq ft)
  • Empty weight: 33,999 kg (74,955 lb)
  • Gross weight: 57,999 kg (127,866 lb)
  • Powerplant: 4 × Mitsubishi Ha-214 Ru 18-cylinder air-cooled radial piston engines, 1,900 kW (2,500 hp) each
  • Propellers: 4-bladed constant-speed propeller


  • Maximum speed: 580 km/h (360 mph; 313 kn) at 9,808 m (32,178 ft)
  • Range: 9,000–10,000 km (5,592–6,214 mi; 4,860–5,400 nmi)
  • Service ceiling: 13,500 m (44,291 ft)
  • Time to altitude: 8,000 m (26,000 ft) in 20 minutes 30 seconds


  • Guns:
12x 20 mm (0.787 in) machine guns
  • Bombs: up to 4,000 kg (8,800 lb) of bombs


  1. 1.0 1.1 1.2 Dyer, Edwin M. III (2009). Japanese Secret Projects:Experimental aircraft of the IJA and IJN 1939–1945 (1st ed.). Hinkley: Midland publishing. pp. 14–16. ISBN 978-1-85780-317-4.

Further reading

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