Sherman in CM:AK - peeve

[roqf77]

"I now picture roqf77 dancing around the house singing:

"if i were an ituitinist Ya ha deedle deedle, bubba bubba deedle deedle dum"

how did you get that picture?

[flamingknives]

Too much Massive Attack for rune.

Although I have a sneaking suspicion that I've heard it more recently.

[Andreas]

Originally posted by John D Salt:

</font><blockquote>quote:</font><hr />Originally posted by flamingknives:

I should have been expecting that...

Indeed, if you were a logical positivist, you should have been able to make a verifiable prediction of it.

All the best,

John. </font>

[flamingknives]

If he was giggling into his beard, there's no way on this earth that you'd hear it.

[Andreas]

It'll reverberate through the earth.

[Soddball]

Your sig looks good Andreas. It's all lies though. I only ever charge a fair price.

Can we get back to the major point, though, which is that I don't suck at CM, BFC suck at making it which is why the ghosts of 20,000 Sherman Tankers are mocking me.

[Andreas]

Originally posted by Soddball:

I only ever charge a fair price.

That statement and my sig are not mutually exclusive.

But you don't want to get my view on UK government tendering, I hope/guess/believe/pray.

All the best

Andreas

[Bigduke6]

Rune,

Well, you know what you know about how the game was designed. You definately trump me there.

Me, I am quite aware of the penetration definition Valera referred you to. I first became aware of it in the 1980s, when it was my job to know stuff about Soviet weapons. The Russian Battlefield source for most of its data is a book called "Russkaya Artilleria" (Russian Artillery) which as nearly as I can tell reprints data from Red Army technical pubs on the weapons themselves.

I am also aware of another similar definition which gives the Soviet definition of penetration which is 75 per cent of rounds tested penetrating fully equally an across-the-board definition of penetration at that angle and thickness. I have no idea which definition is correct.

I am also aware that Soviet armor penetration tables, especially later-war when things were moving fast, were as a rule "low-ball" numbers, as they were data given to armored vehicle crews as absolutely dependable data. In other words, the round probably would perform in the field a little bit better than the official rating as listed in the manual.

I am also aware that during later part of the war the Soviets simply did not do thorough testing at all ranges to produce neat penetration data, but rather obtained some basic numbers at critical ranges, and then extrapolated the rest.

I am even aware that there is some evidence - not that I'm saying it's conclusive - that the Brinell hardness of Soviet plate used in the testing that they did, was perhaps slightly higher than in German tests.

And I know the Soviets for practical purposes improved all of their basic AP rounds throughout the war, including particularly the key 76.2mm and 85mm calibers.

Which leads me to the rhetorical question: Were you aware of all that stuff, three years ago?

[John D Salt]

Originally posted by flamingknives:

</font><blockquote>quote:</font><hr />Unfortunately I don't think we're likely ever to get a really good theory of rigid-body penetration, since at penetrator velocities over about 1000 m/sec it all becomes plastic flows, and I bet this is the sort of stuff Mr. Incendiary Cutlery's colleagues spend their time pottering with.

Most, but not all. There's plenty of sub km/s stuff going on to be worried about. </font>

[flamingknives]

Fragments, and some of the armour systems are a bit pricey and/or complex. AIUI.

[Michael Emrys]

Originally posted by Soddball:

I only ever charge a fair price.

That should go down in history alongside such other famous claims as, "The check is in the mail," and "I only want to put my hand on it, baby."

Michael

[Egbert]

Originally posted by Sergei:

</font><blockquote>quote:</font><hr />Originally posted by Bigduke6:

To my mind this methodology - using math and firing range date to determine your armor effectiveness modeling in a computer wargame - is risky.

What is the alternative? Should Einstein have refrained from predicting black holes because he hadn't witnessed them IRL? </font>

[rune]

Bigduke,

I know Lorrin and John Waters were in the beta, and both are quite knowledgable [massive understatement] on penetration values and effects. Matter of fact, they used German test firings of Russian weapons AND American test firings of Russian weapons, along with Valera's numbers. Here is an example:

"Russian firing tests supposedly indicated the following results for 45mm, 57mm and 76.2mm APCR against Tiger II side armor (80mm at 25 degrees from vertical hull side);

"The Russian tactics for combating the Tiger II were found in the following pamphlet written by Lt. Col. J. D. Skrobow and Lt. Col. A. N.Bukirew on ?The German heavy tank "Tiger-B" (Koenigstiger) and How To Combat It?, translated by the 17 .Armee on 4 February 1945:

...

All of the anti-tank guns in the Red Army can penetrate every armor plate on the Tiger-B ____with the exception of the front plates____.

...

Firing trials have revealed that the side armor on the turret and superstructure of the Koenigstiger can be penetrated at ranges up to:

-0 meters by the 45 mm anti-tank gun (sub-caliber and AP)

-600 meter by the 57mm anti-tank gun (sub-caliber)

-400 meters by the 76 mm ZIS-3 anti-tank gun (sub caliber)"

If we apply a 1.23 slope multiplier for 25 degree slope against tungsten core ammo and multiply by the 80mm side hull armor on Tiger II (superstructure side), we obtain 98mm vertical resistance.

The 76mm HVAP based penetration estimates for 76.2mm APCR predict 96mm vertical penetration at 400m, which is close to the estimated resistance of the armor.

45mm APCR is predicted to penetrate 120mm at 0m in the DeMarre equation analysis, which looks high. If the 120mm DeMarre penetration estimate at 0m is multiplied by 75mm (Russian figure at 500m) divided by 86mm (DeMarre estimate at 500m), the result is 105mm which looks high unless smaller APCR has higher slope effects.

If the 57mm APCR penetration is assumed to take place with a 30 degree side angle, the estimatedarmor resistance is 142mm vertical while the HVAP based penetration estimate is 150mm and the Russian figure is 135mm.

The above analysis shows that there are problems with the 76mm HVAP based estimates for 45mm APCR penetration, and the 57mm APCR DeMarre estimates are not consistent with firing tests against Tiger II side armor."

What I find funny is there are people arguing the Russian values are too high, and others too low. For something as well tested and known about, I am amazed 60 years later there is still debate.

Rune

[WineCape]

Ehh,

Gents, must have missed it with all this dastardly complex spindle: give me the reason for BFC's design decision to NOT give any slope to the Sherman M4 front turret. The only explanation was from Rexford, which I assume speaks for BFC on this regard:

"CMBO attempts to model the ballistic resistance of the turret front/mantlet as opposed to the thicknesses and angles."

BFC reasoned that the front turret of the vanilla Sherman, with angle, resisted actually on their evidence at 89mm/0 deg. for wargaming reasons.

"Since CMBO does not treat the area as a complicated curved arrangement with all of the peculiarities and vulnerabilities, a single vertical 89mm plate is used, which seems reasonable for wargaming."

Soddball's question still stands for CMAK/CMBB:

"CM:BO didn't treat the area as a complicated curved arrangement, but CM:BB and CM:AK do have the 'curved' value for armour plate, and I can't help but feel that the Sherman would have been a logical choice for this 'curved' value."

Mr. Salt, warp your brain rather around THAT.

[ August 05, 2005, 10:48 AM: Message edited by: WineCape ]

[flamingknives]

Uh-oh. Difference in convention. CM uses angle from the vertical, so could we stick to that to avoid confusion?

Note: alt-0176 ought to give º (degree sign) on a PC.

[WineCape]

Got that flamingknives. Thank you. Edited above post.

[HeinzBaby]

Sherman's have a problem??

Hell, I just lost 3 PzIVH's (hunt)to 2 of them in a firefight, thought it would be a walk in the park...

There has to be a some random - 'fuzzy logic'involved or just put it down to dumbarse bad luck.

Bah!

[roqf77]

bad luck. sherman pv 4's are about even from my experience. mark 4 seems better ambushing and defending. and the sherman is better att attcking from a tank v tank perspective.

[Bigduke6]

Rune,

The arguement continues in places like this forum because CM is not just a computer program that models AP engagements, but a computer program that models WW2 tactical-level combat.

That was useful information from that Rexford post you attached. JasonC responded to that information, in the very next post, this way:

"Sounds like the formula with the 1.07 exponent underestimates the importance of the shell diameter to plate thickness factor. If the exponent of that term were more like 1.5, I think you'd see a more realistic relationship between the small 45mm penetrator and the larger ones. 45mm HVAP outperforming 76mm HVAP by a factor of 1.25 is not plausible on its face."

The arguement doesn't stop there, of course. The thread goes on for about 8 pages.

The issue comes down to what you take as your starting point. My approach is general historical. I go with the combat accounts, the received wisdom from war participants.

If for instance actual Red Army veterans and the official documents their army produced say the 76.2mm gun was good to engage German 80mm armor at a range of 500m or so, on the average, then I believe them. I conclude a proper computer engine aiming at modeling WW2 combat should replicate that.

If I come across firing range data that contradicts that generally-agreed-upon opinion, and I cannot reconcile it with the experiences of the combat participants, then if forced to choose I go with the participants' view. At bottom I am interested in the history of the war, not how weapons performed on firing ranges.

Your approach is as nearly as I can tell diametrically different. You appear to limit your acceptable input for building a game engine to gunnery data from firing range tests. You believe data created on a firing range is more valid, than what the combat participants said. If you have to choose between numbers generated on a firing range, and the reports of the participants, then you go with the numbers on the firing range. If the participant reports contradict the firing range data, you appear to discount the participant reports as unreliable and unscientific.

So I don't think we are ever going to agree. We both think the other person's methodology is flawed.

[JonS]

Originally posted by Bigduke6:

If I come across firing range data that contradicts that generally-agreed-upon opinion, and I cannot reconcile it with the experiences of the combat participants, then if forced to choose I go with the participants' view.

...

Your approach is as nearly as I can tell diametrically different. You appear to limit your acceptable input for building a game engine to gunnery data from firing range tests. You believe data created on a firing range is more valid, than what the combat participants said. If you have to choose between numbers generated on a firing range, and the reports of the participants, then you go with the numbers on the firing range. If the participant reports contradict the firing range data, you appear to discount the participant reports as unreliable and unscientific.

Well, participant reports are unreliable and unscientific, by their very nature. As a real-life example, that had some very serious consequences, consider the 2-pr in the Desert.

For a very long time it was thought that this weapon could not penetrate German armour. This was because hits were often seen to ricochet wildly off into the air. However, it was eventually determined - as a result of firing range trials - that what was happening was that the tracer element at the rear of the round was breaking off on the shock of impact and flying off whereever. Meanwhile the AP core was penetrating, but of course couldn't be seen to be doing so. That had a tremendously demoralising effect on the British tankers and anti-tankers, and led to some desperately unwise tactics.

There was a secondary problem also, in that the prescribed drill for aligning the sight with the barrel actually ensured that they were misaligned, making hits even harder to come by than they should have been. That problem, too, was figured out by someone spending some time on a range.

That said, I basically agree with your points (though I really have no idea how BFC verify/validate their model), but I don't really think either method is The Answer.

Regards

JonS

[rune]

Again you read into this...where did I ever say they just took range firings? The foloow-up by Valera saying they had problems with ammo came from tankers experience, not from range firings. You do realize the CMX1 uses a formula, and NOT tables for penetration data.

The problems with accounts, is as Jon says, along with the "The Sherman is more then a match for the Tiger tank". How much was wrong, how much was because the result was an outlier, how much was just propaganda? I was just reading an American evaluation of the German opinion of the Grant Tank. "The Germans fear the Grant tank with the 75mm in the turret". Umm ok, show me a grant take like that. How about when veteran accounts differ? Have seen a lot of that. Veteran's memory also can be false, just plain remembering wrong. Look at Loza's recollation that they had the Sherman with the 76mm long gun before it was even built. Basically everything has to be factored in and a best guess made.

Rune

[Soddball]

Rune, would your opinion be that a re-evaluation of the Sherman's turret armour rating to 'curved' is reasonable? (Theoretically, of course, we know it's not going to happen).

[JasonC]

So let me just make sure I fully understand the reasoning here. 30+50 nearly flat is greater than 100 and stops 85mm AP at 500m. 51+89 with slope is 89 and won't stop 75mm AP at 1500m. Because Rexford is alleged to have said so, once.

And the moon is a swiss cheese on max magnification on Google, too. People will apparently believe anything. Because they "make men the measure of the arguments instead of arguments measures of the men", is how Ghazali put it.

Is there anybody within the orbit of Mars who thinks it is just a coincidence that the times layered is considered vastly stronger than one plate and the times is it considered drastically weaker just happen to coincide with whether the layered plate is on a German or on an Allied vehicle?

[JasonC]

In case that sailed over anybody's head, we are told a StuG can't be penetrated by a Russian 85mm at 500m in the fall of 1943 even though it has only 80mm of armor "because it is layered", and we are told a Sherman turret can be penetrated by a German 75mm at 1500m even though it has 140mm of armor "because it is layered".

The muzzle velocities of the two guns are almost the same, and the Russian round has about 30% more mass. The plate being penetrated by one and not penetrated by the other differ by nearly a factor of 2 in thickness, and the thicker one has more slope, and is the one being routinely penetrated.

Nobody can possibly believe this, honestly.

[roqf77]

i agree.