Ki-91 Japanese Superfortress

[Would you like to see this in-game?]
  • Yes
  • No
0 voters
[What engines it is supposed to have?]
  • HA42-21 (ha214 L )
  • HA42-41
  • no
0 voters

Ki-91 Heavy Bomber
What is the ki-91? It is a heavy strategic bomber whose purpose was to attack distant American bases.It was to be Japan’s largest aircraft after the H11K and Japan’s heaviest aircraft. It was a powerful, larger and better armed one than the B-29, so much for the introduction, now a suggestion.
The history of this aircraft begins in July 1943 with the cancellation of the Ki-68 and Ki-85 aircraft, i.e. the G5N aircraft for the army. It was then ordered that Kawasaki Aircraft build a long-range strategic bomber under the name ki-91. Kawasaki decided to send its best engineers to this project with Chief Engineer Takeo Doi.The Army required the aircraft to reach 580 km/h at an altitude of 10,000 m with a cruising range of 9,000 km with a load of 4 tons of bombs or 8 tons of bombs with a shorter range. It was also assumed that it would be able to carry troops and be armed with 12 20mm cannons.These requirements resulted in the fact that the machine will have enormous dimensions: total length 33.35 m, width 48.0 m, height 10.0 m, height 3.3 m in hull cross-section, width 2.3 m and total weight of 58,000 kg. Although the Japanese industry did not have sufficiently powerful engines and did not have the technology of airtight cabs, the Kawasaki plant took on the task.In April and May 1944, two full-size wooden models were created. Tests on these mock-ups showed that it would be a promising design, so a prototype was commissioned.In June 1944, the preparation of the production line in Gifu began. The first prototype was to be completed in June 1946 and was to have no chamber to speed up production and begin flight testing. After successful tests, a second prototype with a pressure chamber was to be built.During this time, American bombing of Japan intensified, which resulted in engineers and materials being needed elsewhere (building interceptors) and the destruction of the prototype during the Gifu bombing, so in February 1945 the program was halted. By this time, the aircraft was 60% complete, which means they probably weren’t ready until the Japanese surrender anyway.

Wooden mockup and technical drawings

Проект тяжелого бомбардировщика 川崎 キ91 (Kawasaki Ki-91)_ Япония - Альтернативная История


This aircraft was an all-metal, free-flying medium-wing aircraft, powered by four eighteen-cylinder, turbocharged twin-star Mitsubishi Ha42 engines with a power of 1864 kW (2500 hp) each, driving four-bladed, variable-pitch metal propellers with a diameter of 4.4 m. The 27,500-liter fuel tanks were located in the fuselage and wings.The hull has a semi-monocoque structure, housing airtight cabins for eight crew members. A classic free-floating tail.Three-support landing gear with front support retractable in flight. The main one, consisting of two sets of two wheels each for the engine nacelles and the front, one-wheeled for the recess in the fuselage. Straight wings with a trapezoidal outline and high elongation.

Highly accurate 3d model

Kawasaki Ki-91 3D Model by ChipBassChaos (

the aircraft was supposed to be powered by Ha42 engines, but it is not known exactly which version, many sources claim that it was the Ha42-21 (Ha214 L) engine, but there is a possibility that it was powered by the Ha42-41 engine, which still exists and is in the Smithsonian National Air and Space Museum.Now I will give you the technical specifications of these motors for comparison

HA42-21 (ha214 L )

  • Model: Air-cooled, double star-18 cylinders
  • Size(Length/Width/Height): 2,130mm/1,340mm/1,340mm
  • Weight: 1,280kg
  • Capacity: 54.1L
  • Turbocharger: Turbocharger + centrifugal 2-speed supercharger
  • Other: Water & Methanol Injection System
  • Take-off power: 2,500 hp / 2,600 rpm +600mmHg
  • Power : 1st gear full throttle: 2,300 hp/2,400 rpm / Boost+400 mmHg (altitude: 2,000 m)
  • Power : 2nd gear: 2.310 hp / 2.400 rpm / boost + 400 mmHg (height 7.600m)
Pictures of the Ha42-21 (Ha214 L) engine



  • Model: Air-cooled, double star-18 cylinders
  • Size(Length/Width/Height): 2,352mm/1,340mm/1,340mm
  • Weight: 1,235kg
  • Capacity: 54.1L
  • Turbocharger: External Twin Superchargers
  • Other: Water & Methanol Injection System
  • Take-off power: 2,400 hp / 2,600 rpm
Pictures of the Ha42-41 engine


Sources say that it was armed with four twin turrets and one quadruple turret. These turrets are equipped with Ho-5 cannons.Two cannons in a remote-controlled turret located under the fuselage in the front part of the fuselage, another two in a remote-controlled turret located under the fuselage behind the wings. Two - in a mobile firing station in the nose of the machine, two - in the tail turret and two - in a position located on the fuselage of the aircraft. The location of the next two cannons is unknown, probably one of the emplacements was supposed to have a quadruple set of barrels.The aircraft was to carry between 4000kg and 8000kg of bombs in the bomb bay.

Source text

General characteristics

  • Crew: 8
  • Length: 33.35 m
  • Wingspan: 48 m
  • Height: 10 m
  • Wing area: 224.0 m2
  • Empty weight: 34 000 kg
  • Gross weight: 58 000 kg
  • Powerplant: 4 × Mitsubishi Ha-42 Ru 18-cylinder air-cooled radial piston engines
  • Propellers: 4-bladed constant-speed propeller


  • Maximum speed: 580 km/h (360 mph, 310 kn) at 9,808 m (32,178 ft)
  • Range: 9,000–10,000 km (5,600–6,200 mi, 4,900–5,400 nmi)
  • Service ceiling: 13,500 m (44,300 ft)
  • Time to altitude: 8,000 m (26,000 ft) in 20 minutes 30 seconds


  • 4 x turret with twin Ho-5 cannons
  • 1 x turret with quad Ho-5 cannons
  • Bomb Charge - max. 8000 kg

This aircraft would be something between the B-29/TU-4 and the G8N, providing great payload with great defensive armament. Unfortunately, Gaijin made my favorite planes, i.e. bombers, pointless except for a few cases, so I hope that this plane will also be that case and will be playable. On its own, it will be easy to make it not too OP.Japan lacks support aircraft for most of the game, as Japanese planes have a small bomb payload and the Ki-91 has a pretty cool payload that will ensure that it can wreak havoc on tanks and bases in air and ground battles.
Finally, I apologize for the linguistic and logical errors because unfortunately English is not my main language and I had to use google translator.

Sketches and art

OIP (1)

Comparison of sizes on models



Special thanks to the user

  1. @Teh0
Online Sources

Hikoki:1946 (
Nakajima G5N/G8N - Heavy Bombers (
キ91 (航空機) - Wikipedia
土井武夫 - Wikipedia
ハ42 (エンジン) - Wikipedia
1/144 scale Kawasaki Ki-91 - Japan final heavy bomber in Second World War (
キ91 (ききゅういち)とは【ピクシブ百科事典】 (
Kawasaki Ki-91 (キ-91) - Passed for Consideration - War Thunder - Official Forum
[MATEVER1.5: 川崎 キ-91 試作重爆撃機 アニグランド社製 1/144]
Kawasaki Ki-91: Photos, History, Specification (
Kawasaki Ki-91 Long Range Heavy Bomber Project | Secret Projects Forum
Japanese Aircraft of WWII: Search results for ki-91
Kawasaki Ki-91 – Samoloty 1.5 (
Kawasaki Ki-91 - Wikipedia
Kawasaki Ki-91 – Wikipedia, wolna encyklopedia
Kawasaki Ki-91 (
Kawasaki Ki 91 : Kawasaki (
Ha-214 Ru / MK10C (Ha-42-21 Ru) : Japonsko (JPN) (
Уголок неба ¦ Kawasaki Ki.91 (
Mitsubishi Ha 42 Model 41 Ru (Ha 214 Ru), silnik gwiazdowy 18 | Narodowe Muzeum Lotnictwa i Przestrzeni Kosmicznej
Silniki Mitsubishi | Wprowadzenie do samolotów japońskiej armii i marynarki wojennej (
陸軍爆撃機(キ91) | 日本陸海軍機入門 (
三菱 ハ42-21ル(ハ214ル)航空機用空冷星型エンジン - 観光列車から! 日々利用の乗り物まで (

Book sources
  • 雑誌 航空ファン 1997 2 No.92 イラストレイテッド 日本陸軍機 Number Catalog, Bunrindo Co.,Ltd, 1997, T1003719022003
  • X-Planes of Imperial Japanese Army & Navy 1924~45, Nohara, 2000, ISBN 476633292X
  • Japanese Secret Projects Experimental Aircraft of the IJA & IJN 1939-1945, Edvin Dyer, 2009, ISBN 978-1857803-174
    *Test engines, specifications and performance. Report No. 16i(7)

for what? bombers are dead class in this game.

+1, hell yeah, love bombers and WW2 stuff, even if this was an unfinished project


And No one cares.

@Grzegames Seems more like 2 were mounted to the front for the top turret, 2 on the lower front turret, 2 in the top rear turret, 2 in the bottom rear, and 2 in the back. So my guess 2 were pointed to the sides.
However, it is possible there were several iterations.

I’m pretty sure the right engine should be Ha-42-21Ru or rather Ha-214Ru, since it’s an Army aircraft. I think L is a missinterpreted ル = Ru, which indicates turbocharger. During the war turbochargers were quite popular in quad-engine bombers as their size wasn’t as much of an issue as in fighter planes. Furthermore Ha-42-41 appears to be less powerful at all altitudes.

In this picture the rear turret has four cannons.


The Ki-91, like the B-29, was to have a pressure chamber and could not have beam gunners

Most sources say 8 20mm cannons, some 9 cannons, others say they were supposed to have 10 cannons, and others say they were supposed to have 12 cannons

I understand well that bombers suck, there are only a few useful bombers in the game, everyone can check that this is my favorite air class

Is this a paper plane?

it is not a paper airplane. About 60% of the prototype was created, as well as engines especially for it.

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These three books say there should be 12x 20mm Ho-5 cannons and 2500hp Ha-214Ru engines. The last one also specifically mentions the tail turret having four guns.

雑誌 航空ファン 1997 2 No.92 イラストレイテッド 日本陸軍機 Number Catalog, Bunrindo Co.,Ltd, 1997, T1003719022003

X-Planes of Imperial Japanese Army & Navy 1924~45, Nohara, 2000, ISBN 476633292X

Japanese Secret Projects Experimental Aircraft of the IJA & IJN 1939-1945, Edvin Dyer, 2009, ISBN 978-1857803-174


It’s not my fault that the Americans claim that the HA42-41 is an engine from the Ki-91

1 Like


Well, then I’m unsure. Cause 8 seems too little and 12 seems like too much.
So 10 is the only reasonable answer but that would involve side gunners. Cause ain’t no way Japan figured out how to stuff 3 20mm cannons into those turrets.

At the moment there are 10 of them, in addition you can add 2 cannons to any turret

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I think this bomber has a place in War Thunder, but Gaijin may reason Japan doesn’t need it with the G5N and G8N :(

every vehicle has its place in War Thunder. The G5N is a total piece of junk, and the G8N is often ineffective as a bomber because it is slow.

That’s your opinion man not everyone’s

Did i said that this is everyone’s opinion?