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Yes, that is correct. The Japanese designation is substitute shells, which are training rounds. These substitute shells are made from inexpensive railway steel bars and are filled with sand to match the projectile weight of HE shells. Substitute shells already exist as practice shells for the 20 mm Ho-5 cannon and the 37 mm Ho-204 cannon in the game.
57 mm HE Substitute Shell for Ho-401
- P - Practice shell
- Projectile Weight: 1,550 g
- Muzzle Velocity: 520 m/s
- Armour piercing (mm): 35.14
(Note: The specifications for projectile weight and muzzle velocity vary slightly depending on the source, but the highest performance data has been adopted.)
There exists an AP shell for the Ho-401, but its specifications are unknown. Therefore, I would like to suggest adding a substitute shell to the game as a literal replacement for the AP shell. The Ki-102, which often encounters lightly armored LVT amphibious tanks in the Pacific theater, should be able to sink them with HE shells and the substitute shell.
I believe that “Ho-401 Kou (ホ401甲)” is a typographical error for “Ho-401 You (ホ401用)”. “用” means “for”. In the old Japanese book I have, it was also written as “Ho-401 Kou”, but in newer publications, it has been corrected to “Ho-401 You”. It means HE shell for Ho-401.
Ho-401 Aircraft Cannon Specifications
- Manufacturer: Japan Special Steel Co., Ltd.
- Mechanism: Recoil-operated
- Caliber: 57.0 mm
- Overall Length: 2,000 mm
- Weight: 150 kg
- Muzzle Velocity: 500 m/s
- Rate of Fire: 80 rounds/min
- Recoil: 1,000 kg
- Ammunition Used:
- HE shell, HE substitute shell, and AP shell for the Ho-401
- Complete Round Weight: 2,100 g
- Projectile Weight: 1,500 g
- Mounted on Aircraft: Ki-102
- Inspection Completed: March 1944
Jiro Sayama. “Japanese Army Air Weapons.” 2021. ISBN-13: 978-4769831976. p. 616
I submitted a bug report to add substitute shells for the 37 mm Ho-203 cannon to the game based on this reasoning. Historically, the Ki-45 Kai Hei equipped with the Ho-203 was deployed not only to fighter squadrons but also to assault and light bomber squadrons for use as a ground attack aircraft. Therefore, within the game, anti-tank attack means are necessary, but it lacks general-purpose bombs and HEAT cluster bombs. Adding substitute shells in place of AP shells would be a provisional solution. I would like to submit a similar bug report regarding the Ho-401. If you have any opinions or suggestions, please let me know.
https://community.gaijin.net/issues/p/warthunder/i/1hGg9PM0LHCP
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Autocannon by Anthony G. Williams and some other source state that Ho-203 cartridge was based on those used by Type 11 Infantry Gun. Of course a lighter HE shell was developed to improve velocity, but it wasn’t enough and Ho-204 used the same shell with larger propellant. In game Ho-204 appears to be using a 600g ground use HE, while it should have 475g HEI with 32g HE filler. Right now I’m not sure about the filler type.
TM 9-1985-5 Japanese Explosive Ordnance 2 also states Ho-203 and Ho-204 used the same shell. It also mentions that all 37mm AT-guns used the same Type 94 AP round, but unfortunately it doesn’t have anything about Type 1 AP round.
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 “Bunrindo Number Catalog” lists an AP round for Ho-204 with 726g projectile weight and 1236g full weight and muzzle velocity just 525m/s. The projectile weight matches Type 1 APHE. CINCPAC Bulletin 85-45 Japanese Projectiles Vol 1 has Type 1 APHE.
Ordnance Technical Intelligence Report Number 19, Ordnance Department, 13.3.1946 also lists AP round for both Ho-203 and Ho-204.
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Thank you tester!
Here are some other related issues:
Ki-102a (Ko) Fighter variant / Ki-102b (Otsu) lack of bombs // Gaijin.net // Issues
Ki-102 armor // Gaijin.net // Issues
Ki-102b lacking bombs // Gaijin.net // Issues
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anyone know if the Ki-102 otsu could carry a 800 kg bomb?
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Go ahead :)
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Since I am very slow at writing reports, could you please write the bug report? 🙂
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Hmm? It says “800 x 1” in the manual though, doesn’t it?
Manual mention only 500kg
tbh it mention only one 250kg bomb but probably it could take more?
Is there any more source about 2 250kg bomb than book where it was mentioned? Because in manual only 1 250kg mentioned. And looking in the bomb racks looks like 2 250kg can’t be fitted because of sizes
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Ah okay, I was looking at this
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I didn’t check this one properly when I made the report. It’s surprisingly detailed. To me it looks like the racks could be too close together to fit two 250kg bombs side by side.
You can copy the 100kg bomb and fit it where the 50kg bomb is. Seems to still fit there.
The next page lists 4x100kg and oddly even 2x250kg.
- 4x50kg
- 4x100kg
- 1x250kg or 2x250kg
- 1x500kg
- 1x800kg This one isn’t in the manual, so it must be something they added later.
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It was mentioned in US document about Kamikaze what was shared in @tester188 report
But I am not sure where from is 2x250 or even 2x500 in some books
Mistake?
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Data from Japanese sources that may be useful for bug reports.
| Caliber | Cannon | Ammo type | Projectile weight | Explosive weight |
|---|---|---|---|---|
| 57 mm | Ho-401 | HE | 1.550 kg | 0.310 kg |
| 40 mm | Ho-301 | HE | 0.570 kg | 0.060 kg |
| 37 mm | Ho-204 | HE | 0.475 kg | 0.045 kg |
| 37 mm | Ho-203 | HE | 0.475 kg | 0.045 kg |
“Weapons and Technology (268) (兵器と技術)” edited by the Japan Association of Defense Industry. September 1969. pp. 37-38
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If I do not mistake current HE filling weight is different so it can be useful for bug reports
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Right now the fillers in game are:
Ho-203 - 35g TNT
Ho-204 - 30g RDX
Only other source I have claims 32g. Quite a difference to 45g.
“The ammunition for the Ho 204 uses the same projectile as the Ho 203 ammunition, but the case is longer.”
Pages before that list two different HE rounds. Could these have 32g and 45g fillers?
By the way that’s the first source where I have seen Ho-401 and Ho-155 HE filler weights.
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I think 2x250kg is just a guess made by authors. If plane can carry 4x100kg, 1x500kg or even 1x800kg bomb, then why not 2x250kg? Well many planes could, but in Ki-102 case, it’s limited by the racks. Even from the photos and manual rack picture, I thought there would be two large bomb racks side by side, but apparently no.
Page 207 from manual. You can see how bomb #1 switch goes to two solenoids, while all the rest go to just one. It’s obviously meant for releasing 250kg, 500kg and 800kg bomb.
I have no idea about those 120kg or 150kg bombs mentioned at the bottom. Never seen such in any Japanese documents.
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No way, a source that straight up says the 57mm shell containted 310g explosive?
I tried to convince Gaijin is was more but without a source they just left it as it is.
And even the 250g on the ground cannon HE is missing a huge junk of explosive since it has a giant detonator, which the Devs won’t acknowledge.
But to be fair the source you provided also only list 250g for the ground cannon HE.
https://community.gaijin.net/issues/p/warthunder/i/YlOfYmOahWh4
Does someone want to make a new report with that source?
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Too late:
https://community.gaijin.net/issues/p/warthunder/i/3IftSUGSlcRh
@tester188 Maybe you can provide a title page for the source? Usually they want that, and I don’t have acess to that source beyond what you provided.
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