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Kawasaki Ki-91

Imperial Japan (1945)
Picture of Kawasaki Ki-91 Heavy Bomber Aircraft Proposal

An Allied air raid during early 1945 ended development of the Kawasaki Ki-91 four-engined heavy bomber for Japan.


Detailing the development and operational history of the Kawasaki Ki-91 Heavy Bomber Aircraft Proposal.  Entry last updated on 2/6/2018. Authored by Staff Writer. Content ©www.MilitaryFactory.com

The Kawasaki Ki-91 represented a rare four-engine heavy bomber initiative of the middle-to-late war years for the Japanese Empire. The Ki-91 gained steam at a time when the Japanese military was reeling from consistent losses in-the-field and air supremacy was being lost on a month-to-month basis. It would seem prudent that fighters and interceptors would be the call of the day as it became in Germany but this four-engined "heavy" was still pushed through by Kawasaki.

The design was to feature a wingspan reaching 157.4 feet with a length of 108.2 feet - dimensionally larger than even the famous American Boeing B-29 "Superfortress" (141.2 foot wingspan, 99 foot length). Loaded weight was estimated at 127,870 pounds. The bombload was to be in the 8,820 lb range (decidedly less than the Superfortress' 20,000lb load limit) and the aircraft defensed by no fewer than 12 x 20mm cannons - two fitted to a nose turret, two in a dorsal turret, four across two ventral turrets (one forward, the other aft), and four to complete a turret at the tail - one of the best-armed bombers of the war to say the least. The large aircraft would be powered by 4 x Mitsubishi Ha-214 "Ru" engines developing upwards of 2,500 horsepower each and estimated performance specs included a maximum speed of 360 miles per hour with a ferry range out to 6,215 miles (the B-29 managed a speed of 360mph with a ferry range out to 5,600 miles).
Outwardly, the aircraft was to be given a stepped cockpit approach meaning the flight deck sat out from the fuselage contours and held its own window panels (unlike the streamlined form of the B-29). The fuselage would be a rounded rectangle in profile with slab sides, the shape broken up some by the placement of several observation bubbles about her design. Glazing would be featured at the nose and around the cockpit with vision ports located throughout the rest of the fuselage and at gun positions. Mid-mounted monoplane wings were used, each featuring a pair of engine nacelles along their leading edges. The tail unit would consist of a single, rounded vertical fin coupled to a pair of low-mounted horizontal planes - these surfaces seated ahead of the tail turret. A tricycle undercarriage would be employed which was a departure of the "Tail dragger" configuration of old.

Design work on the aircraft began in May of 1943 and progress was such that by the end of 1944 the first prototype was being built while Kawasaki lines were gearing up for serial production. However, an Allied bombing raid during February 1945 destroyed much of what was to make the Ki-91 possible, forcing the program to be halted and ultimately abandoned in favor of fighters and interceptors to contend with the American B-29 presence over the Japanese homeland.






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Relative Maximum Speed Rating
Hi: 400mph
Lo: 200mph
    This entry's maximum listed speed (360mph).

    Graph average of 300 miles-per-hour.
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Unit Production Comparison
Comm. Market HI*: 44,000 units
Military Market HI**: 36,183 units
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0


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  ** Military Market High belongs to Ilyushin Il-2.


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Origin: Imperial Japan
Year: 1945
Type: Heavy Bomber Aircraft Proposal
Manufacturer(s): Kawasaki - Imperial Japan
Production: 0
Status: Cancelled
Global Operators:
Imperial Japan (cancelled)
Historical Commitments / Honors:

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Measurements and Weights icon
Structural - Crew, Dimensions, and Weights:
Unless otherwise noted the presented statistics below pertain to the Kawasaki Ki-91 model. Common measurements, and their respective conversions, are shown when possible.

Operational
CREW


Personnel
10


Dimension
LENGTH


Feet
107.94 ft


Meters
32.9 m


Dimension
WIDTH


Feet
157.38 ft


Meters
47.97 m


Weight
LOADED


Pounds
128,000 lb


Kilograms
58,060 kg

Engine icon
Installed Power - Standard Day Performance:
4 x Mitsubishi Ha-214 Ru engines developing 2,500 horsepower each.

Performance
SPEED


Miles-per-Hour
360 mph


Kilometers-per-Hour
580 kph


Knots
313 kts

Supported Weapon Systems:

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Graphical image of an aircraft conventional drop bomb munition
Armament - Hardpoints (0):

PROPOSED:
2 x 20mm in nose
2 x 20mm cannons in dorsal turret
2 x 20mm cannons in forward ventral turret
2 x 20mm cannons in aft ventral turret
4 x 20mm cannons in tail turret

OPTIONAL:
A bomb load of up to 8,820 pounds held internally.
Variants: Series Model Variants
• Ki-91 - Base Series Designation; prototype destroyed in Allied air raid during February of 1945.