Ki-91 Japanese Superfortress

Unfortunately, we have no flight performance data. Maybe it might be easier to estimate for a bomber. They literally did it for the J6K

Did he said you said this is everyone’s opinion?

I forgot Ki-91 was listed in these. They also confirm the quad turret.


from: Physical description of aircraft. Report No. 19b(7)

engine data from: Test engines, specifications and performance. Report No. 16i(7)

2500hp take-off with 2600rpm and +600mmHg
2300hp 1st stage at 2000m with 2400rpm and +400mmHg
2310hp 2nd stage at 7600m with 2400rpm and +400mmHg

It has bit different rpm and boost compared to other engines of it’s family.


The reason why the Smithsonian says “Ha-42-41” is the engine of Ki-91 is that they mixed up which engine theirs is. They titled the engine in their inventory “Ha 42 Model 41 Ru (Ha 214 Ru)”, which doesn’t exist.

There is Ha-42-41 and Ha-42-21 (Ha-214 Ru). The Ha-42-41 was just a prototype version of the 31 testing a two-speed reduction gear.

Ki-91 was to use Ha-214 Ru, and later Ha-50 (3000hp) if it was developed.


Thanks for the information, so I can throw the Ha42-41 engine into oblivion. Thank you very much (Mr. Biden) for your help :D

As an italian and japanese main this situation reminds me of the Piaggio P.133. It was like 90% complete before it got bombed into oblivion. The “fun” fact tho is that there seems to be much more documentation on the Ki-91 than on the P.133 which we don’t accurately know what it could’ve looked like (contrary to the Ki-91). Anyway it’s a cool bomber (even tho my fav remains the G8N1) +1


As a Japanese, I would sacrifice my soul for this


we know how it was made (many projects and render are avaible)
Btw +1, it could be an interesting bomber for japan

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