Dev server "Leviathans" ~ Datamined oddities, Soyuz SAP, Roma SAP&AP, dispersions

Machinery of War Discussion Navy
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I’m posting this to showcase a couple of oddities that I have found while quickly looking through Gszab99i’s WT Datamine repository, some of which are quite upsetting.
The repository can be found at: https://github.com/gszabi99/War-Thunder-Datamine/tree/master/aces.vromfs.bin_u/gamedata/weapons/navalmodels_weapons

Disclaimer: This is the dev server, things are subject to change. I do not know how exactly the devs choose the “demarrePenetrationK” value, they have not stated how. The judgements I make are based on the basic shell properties, as well as some past decisions by the devs.
I have not gone too deeply into some other shell characteristics like steel composition, hardening pattern, cavity size, cap properties, which may or may not have influenced the devs’ decisions. This is all to say that my judgements may be incorrect.

To start: How is the penetration value of SAP shells found? It’s pretty simple, you take the penetration of the shell using the Demarre formula https://wiki.warthunder.com/jacob_de_marre and then you apply a coefficient called demarrePenetrationK with a maximum value of 1. A shell with a coefficient of 0.57 has 57% of the penetration of an AP shell of the same stats.

First thing, Roma’s AP shell. For some reason, the AP shell has a coefficient of 0.88. This is very strange, because all AP shells are supposed to have a coefficient of 1.
Roma ap demarre

Because of this, Roma loses a fair bit of pen compared to the expected value from the calculator:
Roma ap demarre calculator
roma ap stat card
(note the stat card values start at 1km, so slightly lower speed)
Considering that the Italian AP shell was given a small bursting charge so as to improve penetration, this is quite the loss.

Onto SAP shells. Now, I do not know how the devs choose the coefficient value, but I do know that they look at the charge/mass ratio of the shell to see whether it should be set as SAP or AP (see the whole Dunkerque discussion). I am going with the assumption that C/M ratio should also affect the coefficient. Besides, it also makes sense, a larger bursting charge means a larger cavity and worse penetrating abilities.

We saw from the devserver that Soyuz’s SAP shell has very high penetration, especially considering the large amount of explosives inside. Yet her C/M ratio is fairly high at 7.94%. It is possible that the SAP and its cap could be quite hard, but the cavity should still be too large for such penetration values.
souyz demarre

Once again, Roma is being badly treated, her SAP shells get a K value of 0.55, yet her C/M ratio is fairly small for a SAP shell, at 3.58%, and it’s known that the shell did have hard caps.
littorio sap demarre
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If anything, Roma’s SAP should have a higher K coefficient than that of Soyuz.

Lastly, dispersion. Dispersion is given by two values, “maxDeltaAngle” and “maxDeltaAngleVertical”.
In brief, Littorio and Richelieu got the short end of the stick when it comes to dispersion. They both have the values “maxDeltaAngle”: 0.34, “maxDeltaAngleVertical”: 0.39. This is among, if not the worst dispersion values in game. For comparison, Iowa, Bismarck, Colorado, Soyuz, and Yamato have dispersion values of 0.22 and 0.24 in horizontal and vertical respectively.

There are talks out there about how the Italian 381mm dispersion issue is overblown and only happened in one occasion (Vittorio Veneto off Gavdos).
Even if dispersion were to be a balance tool, which would be fine, it’s still mind boggling for it to be used against Roma when she already has an anemic fire rate, and gets penetration robbed from her.

What’s difficult about all this is that we can’t use datamines to report issues with the game. So if we’d need to find other ways to go about doing this.
Hopefully these things change by the time the update goes live.

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Definitely Roma’s AP and SAP should be fixed, as she’s already suffered with long reload

About this, afaik the known ‘AP’ penetration of soviet 16’’ on navweap is actually SAP’s. If then, high penetration of SAP ingame makes sense
image

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image-20
They changed the pen a little bit (still far from being correct). Could You check the files for see what was modified?

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PenetrationK is now 0.91.

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Roma’s AP? Why developers not keep PenetationK on 1 like other AP?

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Thanks, still lower than what It should be.

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Why it isn’t 1 though? The Roma AP shell has 1,15% of explosive mass, the lowest ratio of explosive in all of the new BB shells, anything less than 1.0 feels wrong.

Also what about the bad dispersion? Are you still believing the old war propaganda myth that Italian BB were inaccurate when there have been tons of books and articles about how Italian guns dispersion was in line with the dispersion of comparable foreign guns?

Edit: And What about the pitiful 0.55 coefficient of the SAP shell, that gives her a worse penetration than the SAP of the Francesco Caracciolo? The ratio of the explosive and the shell weight is still one of the smallest ones in game…

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What even is this coefficient? I asked @Smin1080p_WT and he said that penetration of naval AP shells is calculated by de Marre formula in the same way as all the other AP shells in game.

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I don’t know…

Roma’s shells are already the highest penning 381s in the entire game; and, according to your post, they should have a higher penetration than even Iowa or Yamato’s AP shells.

Is that actually possible?

To me, it seems like they fine-tuned the formula for a realistic adjustment rather than maliciously nerfed it. I find unlikely the idea of Roma’s 381s penetrating more than Yamato’s 460s, to be honest.

And, for the record, I never questioned or debated that Roma’s 381s were the highest penning 381s; I could even expect a 800+mm pen value, as per historical records. I just found the specific suggested 900+ mm figure a bit weird.

EDIT: I just realised that there was a misunderstanding on my part; I read the 0m value as 1,000m value; so I naturally thought that value was too high! But no, it’s perfectly fine and reasonable, nevermind my confusion.

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since Roma’s guns had a longer range than Yamato’s guns while having 10 degrees less elevation (35 vs 45) it’s absolutely realistic. I don’t think you find unrealistic for the German 75mm gun on the Panther to penetrate more than the SAV 105mm gun.

Penetration is influenced by speed, mass (total and explosive mass) and hardness of the projectile. Roma had very hard AP rounds with little explosive mass, the highest mass of all 15 inches guns and a 850 m/s speed (at 0 metres). Sure a 460mm bullet will lose less energy through distance, but that’s another topic.

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it is very much possible.
caliber isnt the only thing that affects penetration. a higher velocity smaller round will pen more than a slower velocity bigger round.

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So they make stuff up, tell me something new instead.

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When You have the highest muzzle velocity of any gun yeah You achieve better pen and better range.

The fact that You find this unlikely does not change reality. If a shell Is harder and faster it will pen more.

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Italian 381 mm guns were quite long ( 381/50) and had really high average pressure. They fired above average weight shells ( 884,8 kg ) at 850 m/s which was really high inital velocity. There was not a lot of bursting charge and sectional density was rather high. OTO Melara gave number of 814 mm of KC at 0 meters.

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clearly needed for someone like you mate…

as for your second point, probably cause half the italian shit that gets implemented for italy gets cucked HARD by gaijin.

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Thanks for the info!

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Definitely wish to see this fixed, this is unacceptable, to deliberately modify the formula simply to nerf the guns here is not okay, it would be less egregious if it at least matched historical figures, the advantage of this gun is that its within 16" level ballistic parameters.

Dispersion is historical along with Richelieu. Iowa should also have high dispersion iirc (not seen it in-game) and based on what we know about dispersion and how it works Sovetsky should potentially have some of the highest dispersion in-game.

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I’m not very sure we should consider that data, as if I recall properly we used tables that tended to undervalue the armour penetration. The de marre formula properly applied should be good enought.

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Soviet 100mm shells penetrate more than most 122mm ones, I don’t see how Roma’s penetration would be unrealistic. As mentioned a few comments above, smaller shells with higher velocity will penetrate more than larger shells with lower velocity.

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Of course; that’s why I never found strange the idea of Roma’s shells penetrating high 700s, or even low 800s.

I always knew that Roma’s 381s were the highest penning ones, I never debated that.

I only found strange the 900+ mm figure, since that’s even more than the manufacturers themselves stated.

EDIT: I just realised that there was a misunderstanding on my part; I read the 0m value as 1,000m value; so I naturally thought that value was too high! But no, it’s perfectly fine and reasonable, nevermind my confusion.