Gaijin Calculator overhaul

I made a suggestion thread with more up to date information.

7 Likes

APCR is a little bit tricky. For whatever reason, much of the US APCR was tested against softer plates, so the penetration was higher.

Using this chart for 76mm M93, we see that it will open around 9.7” (246mm) of vertical plate, but these charts were likely using 220 BHN target plate.

Spoiler

Other players I interact with have access to a calculator specifically for early tungsten carbide APCR cores. That calculator produced a value of around 225mm for M93, so I decided to use that as the basis for my calculator changes.

What I found is using a K factor of 1800, the core diameter, mass, velocity and 10% of the carrier weight matches the number produced by the calculator.

76mm M93

Spoiler

90mm M304

Spoiler

I used a few examples that I know of to show what the results would look like. I can do more later if I have the proper information.

2 Likes

See linked suggestion.

2 Likes

I can give you the calculator that Gaijin uses on the wiki for AP rounds.
It is as follows:

function gun_go() {
    var kfbr = 1900;
    var caliber = Number(document.getElementById('gun_caliber').value);
    var mass = Number(document.getElementById('gun_mass').value);
    var speed = Number(document.getElementById('gun_speed').value);
    var tnt = Number(document.getElementById('gun_tnt').value);
    var apcbc = document.getElementById('gun_APCBC').checked;
    tnt = (tnt / mass) * 100;
    var kf_apcbc = (apcbc) ? 1 : 0.9;
    if (tnt\u003C 0.65) {
        knap = 1;
    } else if (tnt\u003C 1.6) {
        knap = 1 + (tnt - 0.65) * (0.93 - 1) / (1.6 - 0.65);
    } else if (tnt\u003C 2) {
        knap = 0.93 + (tnt - 1.6) * (0.9 - 0.93) / (2 - 1.6);
    } else if (tnt\u003C 3) {
        knap = 0.9 + (tnt - 2) * (0.85 - 0.9) / (3 - 2);
    } else if (tnt\u003C 4) {
        knap = 0.85 + (tnt - 3) * (0.75 - 0.85) / (4 - 3);
    } else {
        knap = 0.75;
    }
    document.getElementById('gun_rezult').value = (((Math.pow(\nspeed, 1.43) * Math.pow(mass, 0.71)) / (Math.pow(kfbr, 1.43) * Math.pow(caliber / 100, 1.07))) * 100 * knap * kf_apcbc).toFixed(2);
}

In “non-javascript” terms, it is this:
image
With “APCBCorNot” being a 1.0 or 0.9 value depending on if it has the APCBC box ticket or not.

In javascript, \u003C is equivalent to the “lesser than” symbol, <, so basically there’s multiple “tiers” of the penalty that can be done by explosive filler. For example, for M82 APCBC has 0.140 kg of explosive filler, 10.91 kg of weight, so (0.140/10.91)*100 gives us 1.28322. This value is greater than 0.65, but lesser than 1.6, so it falls into the 2nd “if” (1st “else if”).
image

image

This also means if a round has an explosive filler that is lower than 0.65% of the total weight of the round, it ends up getting no penalty to it’s penetration. Which makes total sense since, after all, fuses don’t exist and it’s not like you need to make a cavity to put the explosive filler inside the round (literally sweating sarcasm).

2 Likes

How angry it makes me when people demonstrate en masse on the subject of the economy, and instead they say nothing on the subject of penetrations, which is much more important than, instead of costing 5000, a tank costs 6,300 to repair it.

2 Likes

That’s interesting. I didn’t realize it was a tiered penalty. I found that the HE filler penalty can range from 0-25%., so mine penalty was linear. Now it makes sense why mine was slightly off.

Is there any way you can do the same for the APCR calculator?

1 Like

Sure, the problem is that, from what I can see, the APCR calculator in the wiki does not match the in-game performance of APCR.

For example… This is M93 in the game right now:
image

And this is what you get when you input the corresponding values into the wiki calculator (damageCaliber as core caliber, damageMass as core weight):
image

M93 has 190 mm of pen point blank, so unless I’m doing something wrong, the wiki calculator is wrong.

Either way, here is the wiki APCR calculator:

function gun2_go() {
    var caliber = Number(document.getElementById('gun2_caliber').value);
    var shell_mass = Number(document.getElementById('gun2_shell_mass').value);
    var core_mass = Number(document.getElementById('gun2_core_mass').value);
    var speed = Number(document.getElementById('gun2_speed').value);
    var pallet_mass = shell_mass - core_mass;
    var kfbr = 3000;
    var part_pallet_mass = (core_mass / shell_mass) * 100;
    var kf_pallet_mass = (part_pallet_mass \ u003E36.0) ? 0.5 : 0.4;
    var calculated_mass = core_mass + (kf_pallet_mass * pallet_mass);
    document.getElementById('gun2_rezult').value = ((Math.pow(speed, 1.43) * Math.pow(calculated_mass, 0.71)) / (Math.pow(kfbr, 1.43) * Math.pow(caliber / 10000, 1.07))).toFixed(2);
}

It is a bit more complex and Gaijin pretty much calculates a sort of “average mass” before using the same formula as done for normal AP rounds, except without the explosive filler penalty or capped/uncapped round modifier.

I’d like to add that I’m not the one that obtained this javascript, I’m basically copy pasting from Discord messages where I asked how the calculators worked.

1 Like

Yeah, I forgot the wiki APCR calculator never worked. Do you know anyone that can datamine the in game calculator?

Unfortunately I don’t, otherwise I would’ve definitely asked them. I am also interested in how the APDS calculators work. They seem to behave similarly to APCR where the weight of the overall projectile contributes quite a bit to the overall penetration, but I’d really like to actually know precisely how it is done.

Edit to clarify: The wiki calculators are relatively easy to obtain because they are in the script of the internet page itself, which can be accessed with inspect element and such, assuming you know where to look (I didn’t and still don’t, which is why I had to ask for the javascript on discord rather than getting it myself). The script for WarThunder is… a lot less accessible. We can get the values through datamines, yes, but not the script, and this script is what makes the values work the way they do.

1 Like

Using the combination of my suggested changes and ballistics data I’ve found online for US rounds, here is what the 76mm would look like all together. The ballistics calculator only worked in fps and yards, but the penetration values are in millimeters.

IMG_5756

1 Like

Wow, that’s a massive buff to APCR. It might actually be able to penetrate something!

2 Likes

76mm APCR is under performing by quite a bit. Other rounds are underperforming as badly. Not sure why the 76mm is so far off.

1 Like

M304 has 287 mm of pen but that’s because it has a 38.1 mm core instead of the 48 mm it should be. It’s pretty much the only APCR that isn’t entirely bad and yet the only reason for it is because Gaijin has implemented it incorrectly.

Edit: On a side note I feel like 299 mm might be too low for M304? But I guess I need to make more research on that.

1 Like

US APCR cores tend to be half the bore diameter, so 90mm APCR would have a 45mm core. But 48mm would be the high end of the tolerance.

M304 was around 315mm using softer target plates. ~300mm works for the proper target hardness.

So long as it works out to it going through the Panthers UFP at least from roughly 450 yards/411 meters away.

I don’t have the exact APCR slope modifiers but based on what I could come up with, it would pen to about 400 yards.

I can give them.

Weirdly enough, APCR does actually have different slope modifiers for different D/T ratios, although it only ranges from 0.5 to 1.0 (in short, APCR can’t overmatch armor, but it can undermatch armor).

For 55º, it’s a 3.4 to 3.3 multiplier for APCR, for 0.5 and 1.0 D/T ratio. Since the core is 38.1 mm and we are shooting an 80 mm plate, it should use the 3.4 value, giving us 272 mm effective.

On another note, could you show what your APCR calculator says about BR-365P, 367P, 412P Russian APCR rounds (assuming all of these have accessible real life data, if you can’t get any data on them I can just provide the in-game values) and the T44 and M332 HVAP rounds?

I’ve found an old forums post about the penetration of M304 that says it should have 317 mm of point blank pen.

I’m not quite qualified enough or awake enough to check the sources used and if the math has validity so I’ll leave it here.

If you can find information on the Russian rounds, I’ll check it.

T44 is 351mm.
M332 is 349mm.

Here is BR-365P
IMG_5758

Velocity I found at 1000 meters is 751 m/s which works out to 124mm. Not quite the 130mm claimed but reasonably close.

I made a few more charts.

This is the 90mm M3

105mm T5
IMG_5766

120mm T53 with T116 APBC. T116 was developed into the M358 used by the M103.
IMG_5767