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
If I do not mistake current HE filling weight is different so it can be useful for bug reports
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.
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.
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?
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.
Is it me or does it say 680m/s for the Ho-5s AP round?
Maybe some type of container, flare, incendiary or other type of “special bomb” which often has non regular mass
I see. So looks like it shouldn’t has 2 250kg bombs (if another sources won’t be found)
Report done with what we have. Still we should try to figure more details about those two HE rounds used by Ho-203 and Ho-204. They are close to the same weight. It’s obvious the first one has much larger HE filler, while the latter has far more incendiary mixture in it.
https://community.gaijin.net/issues/p/warthunder/i/PluDQsRYVBYb
“Ordnance Technical Intelligence Report Number 19” lists an Incendiary round only for Ho-204, so I guess that must have been developed later. Should we go with the higher HE filler?
Here is the cover page.
The cover of the industry journal.
The specifications table for the ammunition was published in an article contributed to an industry journal by a technical officer of the Japanese Army.
Former Director of the 1st Army Technical Research Institute, Retired Major General Koshirō Kuwata, “Overview of Gun and Ammunition Design and Ballistics (8), Reference for Ammunition Design Part 4”
元第一陸軍技術研究所所長 桑田小四郎少将『銃砲と弾薬の設計の概要および弾道(8) 弾薬設計の参考 その4』
@skultew1234, could you please add my source to the existing bug report on the Ho-401 ammo?
There goes Ho-203 and Ho-204 AP round report as well. Just say if I missed some good source or something important.
https://community.gaijin.net/issues/p/warthunder/i/N4YZBGaji4kP
Of course.
According to this pages, other rounds should be different? For example Ho-155 ammo now has 30mm HE from Type 5 but here is written 22.5g of HE filler
I noticed the 37mm fire rates are also wrong. Think I’ll report them tomorrow.
Ho-203 now does 300rpm, while sources state 100-140rpm. How did it get this far off?
Ho-204 does 360rpm, but should do 400rpm. I guess some source might have had 360, cause it’s not that far.
That makes perfect sense.
Ho-155 fires much lighter rounds than the Type 5. Its overall performance is lower, with the advantage of it being that it is lighter.
Yes, but for a heavyer 123g round, i suppose thats the High hardenes 3rd type projectile, while in game is a 119g round (iirc) tho would 4g make a 25m/s difference?
It’s a bit weird that’s the case, since the Ki-45 could carry two 250kg bombs side by side. But it is what it is.
In March 1945, the TAIC estimated and reported the firing rate of the captured Ho-203 to be 300 rpm. However, in a subsequent report in July 1945, they corrected the firing rate to 140 rpm.
Similarly, the TAIC reported that the Ki-45 Kai Otsu was equipped with a 37 mm Type 98 tank gun. I thought this was a mistake by the TAIC, but the Americans strongly insisted in multiple reports that the captured Ki-45 Kai Otsu was equipped with the Type 98 tank gun, which had an improved muzzle velocity compared to the Type 94 tank gun. Comparing this with official documents from the Japanese Army and recently published Japanese books, it appears that the 37 mm Type 98 tank gun is indeed correct, rather than the 37 mm Type 94 tank gun. This has already been reported.
https://community.gaijin.net/issues/p/warthunder/i/fdLrkw2Tx0IN
I assume the RPM stays the same at… 18 RPM?
According to a Japanese source, in the Ki-45 Kai Otsu, the rear gunner acted as the loader, resulting in a firing rate of only 2 rpm. Similarly, in the Ki-46-II equipped with a tank gun, the pilot had to load while handling the control stick, limiting the firing rate to one shot every three minutes. The development of the Ho-203 autocannon, with a firing rate of approx. 120 rpm, was welcomed by Ki-45 pilots.
In the game, the firing rate is similar to that of the ace Type 95 Ha-Go, so it seems that the rear gunner with the highest loading skill is on the Ki-45 Otsu.
Somewhere I read that Ki-45 Kai Otsu was very rare. If I remember right, only 20-40 were made and only 1 or 2 squadrons used them. Have you found more about them?
