The Ki-102 Otsu

The Ki-102 Otsu may very well be one the most gimped, misrepresented aircraft in the game. It is missing its proper bombload and rockets, AP rounds for the 57 mm cannon, armor, and bulletproof glass. Where Japan sorely misses out on diverse CAS options, the Ki-102 is a promising candidate, especially considering the Otsu is the specific ground attack variant. However, it is very disappointing to see it in its current state.

Multiple reports have been made on the matter over the decade, but it remains to be fixed. I’m hoping that with this new forum, a new suggestion can be made. If anyone has any sources on the matter, I wouldn’t mind writing a new report.

Additionally, I think Japan is missing a technical moderator, which is why updates and fixes come so slowly.

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Do you have a source for the AP rounds?

Personally I’ve yet to see a source for it, but if you do have one I’d recommend you compile a bug report in Gaijin’s bug report website.

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https://www.reddit.com/r/Warthunder/comments/25a03n/should_the_ki102s_57mm_ho401_cannon_be_treated_as/

According to Japanese Wikipedia it should have AP / HEAT rounds

Not very authoritative, I know. But i sadly cannot read Japanese

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Trying to look for the source

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The sources and info here can be used to try to recreate these bug reports

Spoiler

Found this old bug report on the AP from 2017 made by @aizenns
ID: 0053852 09/Feb/17 Ki-102 otsu have 57mm AP-shell - Documented Bug Reports - Windows - War Thunder - Official Forum

2016 bomb bug report
ID:0038776 17/01/16 Ki-102 otsu missing bomb load - Documented Bug Reports - Windows - War Thunder - Official Forum

More bug reports
Ki-102 critical munitions errors - Already Reported & Solved Issues - War Thunder - Official Forum

ID: 0038776 Ki-102 Otsu missing its bombs. - Already Reported & Solved Issues - War Thunder - Official Forum

[1.75.0.100] Ki-102 otsu missing bomb load - Documented Bug Reports - Windows - War Thunder - Official Forum

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Translation No. 80, 18 July 1945, KI-102 handling instructions. Report No. 3-d(65), USSBS Index Section 6.

Ki-148 could also be suggested maybe it was intended to use it but i don’t think it did before the war ended.
image

Are we allowed to make bug reports as suggestions?

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Idk. Anyone can say that. I mean the ammo is probably interchangable but whether it was used is questionable.
The Ho-401 HE round is lighter than the tank 57mm shells, hence why it has a velocity of 495m/s, while tank shells are more in the 350-380m/s range.

Recoil of the heavier shells would also be a lot worse. The Ho-401 HE only weighs 1.47kg compared to the tank HE with 2.3kg or the APHE with 2.58kg with a velocity of mearly 350m/s.

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Hope for big bomb

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Ho-401 was rated to fire an AP shell, as it was an explicitly marked round produced for the gun.


https://www.jacar.archives.go.jp/das/image/C14010978900?IS_KIND=SimpleSummary&IS_STYLE=default&IS_TAG_S1=InD&IS_KEY_S1=ホ四〇一&

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That’s great to hear.

Also big thank you to @Fireraid233 for digging up those documents.

I think this might be enough to make a new bug report, but the problem of Japan not having a technical moderator is concerning (if true). When China got a new technical moderator, the amount of vehicles they got vastly increased.

Additionally, the Ki-102 getting the Ki-148 should be fine, as the vehicles in the game are based on both theoretical capabilities (in terms of armament). The Maus did receive the 12,8/8,8 Pzgr.TS, for example. Other top-tier jets in the game also have their theoretical loadouts as well.

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Also do we need know the penetration values of the AP shell? Or is using one of those formulas for armor penetration good enough

Yeah but no info on the actual shell. So how would you implement a shell where you don’t know anything about it? The Type 90 57mm APHE has a mere 350m/s velocity. Trying to hit any ground target from the air with that is going to be hard even with mouse aim.
Just try the US 75mm with HE and try to hit any targets in test-drive. And then imagine having a gun with even less velocity.

The Ho-401 HE with 495m/s can be pretty decent at overpressuring open top vehicles but hitting any target that would be vulnerable to APHE with 350m/s would be immensely challanging.

So, I have my doubts that it’s the same shell.

For what it is worth, it certainly does not specify what sort of AP shell it is, but we can reasonably assume it to be an APHE shell of sorts. I also have my doubts that it would be compatible with or identical to Type 92 AP, but there is nevertheless no denying that AP was afforded for the gun.

In practical terms I’d wager there are a few possible ways the devs could tentatively introduce the ammunition, ranging from making a round with identical mass and ballistics to the Ho-401 HE shell and giving a placeholder bursting charge or even no bursting charge until further information is revealed, to just using Type 92 as a placeholder, although my biggest gripe with doing that would be that Ho-401 ammunition is 57x121 and Type 92 APHE is 57x184, so there’s a dimensional incompatibility to consider.

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Is it? The Type 90 and Type 97 cannons both seem to have a 121mm propellant case, the same as the Ho-401.


oh, Indeed they do, the numbers I have written down are erroneous there, my mistake.

I’m still not certain they would be compatible since the dimensions for the complete projectiles are still different, and that could lead to a multitude of issues when loaded if they were not designed to be compatible, but the difference nominally is quite a bit smaller.

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Say that to the NS-45 AP-T projectile…

Gaijin simply copied the weight and speed of the 45 mm BR-240SP APBC round that is found on the 45 mm 20-K cannon of the BT-7 and other tanks, even though the NS-45 is physically incapable of firing this round at that speed (the casing is significantly smaller). And all that because there is just absolutely no information on the actual AP round fired from the NS-45, other than the fact that one did seemingly exist.

So while I understand the concern, I don’t think it’s something that Gaijin cares too much about assuming you can indeed prove that some sort of AP round was created for the cannon, and it’s not too unrealistic.

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I’d really like to see a lot of the Japanese tech tree vehicles receive TLC, and Receive stuff us japain players desperately need.
Absolutely want the Ki-148 in the game for the Ki-102 Otsu, it would be perfectly balanced and follows similar logic to several dozen in game additions to vehicles and as vehicles.

P.S if anyone knows how to find gaijin accepted historical documentation and stuff, let me know, I’d love to start compiling and submitting reports.

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TLC? care to explain it? Aside that look at the old wt forums

Hopefully this means the Japanese tree can actually get fixed, sadly, I don’t believe it will get any better

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Time/Tender (depends who ya ask.) Love, and Care