George Forty on Panzers vs T34, March 1943

[JasonC]

Paul said "which limits T-34 76mm AP shell to ~0-900m penetration [½ hits]"

Find me a Russian 76mm that will penetrate the front of a 30+50 StuG in CMBB at 900m, or at 500m, not half the time but ever.

This comment was so amusing given the current state of CMBB that it inspired the following test.

Same StuGs in the same firing lanes as before. 900m away at the other end, in the different lanes - 85mm AA in 2, dug in in scattered trees. SU-85s in 2. (This is September 1943 to make them available). KV-85s in 2. Two trials. After that, the SU-85 vs. StuG fest. 3 lane each feature 2 SU-85s against 1 StuG, the other 3 each feature 3 SU-85s against 1 StuG. All regulars, all start buttoned.

68 85mm rounds hit the StuGs. 8 hits were effective. The best 2 were upper hull partial penetrations that caused -1 crew and gun damage. Both StuGs so hit reversed off the field alive. 3 were track hits that caused immobilization. In one of those 3 cases, subsequent hits persuaded the crew to bail. 2 were ricochets with internal flaking that caused 1 crew casualty. In one case the StuG recovered fully, in the other it was already immobilized by a track hit and this was the hit that persuaded them to bail.

The last, 8th effective hit was a side hull KO that occurred after one StuG crew momentarily panicked and fast moved forward and then turned broadside toward 2 SU-85s (after killing one in its "lane"). This StuG was hit 13 times, including 4 internal flake results, mostly without going past "shaken". When 2 flake hits occurred within about a second and a half, they went to panic for about 3 seconds and pulled their suicidal "boner".

One 85mm AA survived by making the crew of its StuG bail. It's first shot was a track immobilization, that is how it got so lucky. Another had the crew broken but still at the gun at the end. None of the lone AFVs survived. In the multiple tests, 3 lived in one lane by gun damaging their StuG with a partial pen early on, 2 lived in the lane with the panicked StuG, and 1 lived in another lane after the other partial pen gun damage result made its StuG reverse off the map.

In all, about 1 in 4 of the 85mm weapons lived. The StuGs suffered one actual KO - the panicker hit from the side - one bailout after immoblization, 2 gun damaged but lived, and 2 immobilized but lived - out of 18 StuGs.

These were not 76L42s. These were not 76L51s. These were 85mm. These were not Tigers at the other end, they were early model III G StuGs.

No doubt the faithful will now explain to you why it is all perfectly reasonable. It has to do with air pockets, and German physics in 4 volumes, and untersomething, and the ambient temperature when the ammunition was tempered in Petropavlovsk, and probably the homoousin, and transubstantiation, and slavic engineering that makes metal twice as dense half as effective.

Next we will have power-ups. But if you want to kill a StuG, take a captured StuG. If you absolutely must, use something western lend lease. Never under any circumstances use anything made in Russia.

(PS - actually, the 57mm is allowed, if rarity is off. There were over 7K of them but they are 80 to 150 rarity, while Tiger Is get as low as 10).

[ November 17, 2003, 08:32 PM: Message edited by: JasonC ]

[JasonC]

My "crib sheet" for those playing along at home.

"Why did Tigers make a tactical difference?" wonders Rexford. And well he might, because his StuGs are already stronger than real world Tigers were, and have been out for a year. GD has a flock of them. The Russians don't seem to notice. Well, they must only be countering the MBT GD was using a year earlier.

"Shell broke up". This result indicates that German Physics is responsible for the continued life of your fine armored fighting vehicle.

"Internal flaking". This result indicates a brew up and fire. If a crew casualty is also noted, it means nobody got out. These harsh results have been slightly toned down in the interest of replay value and the tourist trade.

"Partial penetration". Like "a little pregnant", this is as bad as it gets for favorite phillies. Imagine a small replica of Hiroshima and you have the historically accurate idea. You should exit what is left of this vehicle to save VPs. Note that "total write offs" only refer to vehicles left on the field, so it is essential to the Cause to get these puppies out of here.

"Immobilization". This means you lost a tank to your military inferiors. It is all Goerings fault! Remember that if you are asked. Anything so lost can be described as "destroyed by crew" later.

"Knocked out". Refers to foreign equipment. Hit "enter" at the end of a scenario to view the number of enemy vehicles you have LOS to during the game.

"Rarity". A premium on lend lease, doubled for captured equipment. Anything effective the enemy actually had in massive quantities will be noted this way, to warn you that it is not like his usual equipment. For own side forces, this denotes a production run with two digits. Feel free to take all there were for your little battle - they had to be somewhere, after all.

At some point the humor possibilities of it all will be noticed by someone less clueless than myself. Then stand back. In the meantime, I will limit myself to noting the abstract possibility that perhaps an effect or two (hardened this, shatter that, ammo quality the other) might somewhere along the way have been double counted.

What else can one conclude when those *defending* the modeling involved think 76mm AP is supposed to be half effective up to 900m, when the reality is 85mm AP has about a 3% chance of a partial penetration at that range?

[Jeff Duquette]

Thanks Paul. Sorry to be a chuckle-head but I have several more areas of clarification...if you would be kind enough to continue to indulge me

Paul Said: For example 37mm Vs 45mm SHS of T-34 glacis is [45mm/37mm/2 ^0.2]*1.2 or 49mm @ 60°...while if 75mm hits thats

[45mm/75mm/2 ^0.2]*1.2 or 42mm @ 60°.

How are you accounting for the angle of attack? Should “Te” be 49mm/COS(60)

And

42mm/COS(60) for the 75mm dia projectile attack example?

=================================

I am assuming the 1.2 multiplier is a function of the homogeneous hard armor on the T34?

The RHA multiplier being 1.0;

FHA multiplier is 1.3; and

SHS multiplier is 1.2.

Is this correct?

==================================

In one of your earlier posts you indicated:

So 3cm FH @ 10° t/d should become

(3cm/7.6cm/2)^0.2 x 1.3[Te FH] => 0.723 x 3cm x 1.3 = 2.82cm @ 10°= 2.9cm

This looks to me like you divided the resultant 2.82cm by COS(10-deg) to get the final thickness of 2.9cm…although I am getting 2.86cm after dividing by COS(10). You rounded up? Was this in fact what you were doing?

In addition the 50cm Stug-111 plate…shouldn’t the final thickness or “Te” be modified by its angle of inclination as well? 52cm/COS(10)???

[JasonC]

P.S. 24 hits by US 75mm from Shermans also at 900m, yielded 1 KO, 5 no significant damage partial pens, and 7 flakes. Head to head or 2 to 1 odds, only one outlier lane lost. StuGs killed 14 out of 15 Shermans, Shermans got 1 out of 6 StuGs.

The Brit 6 pdr is the first effective gun. In 24 hits delivered by Valentine IXs (2-3 per lane) or Churchill IIIs (2 per lane), I recorded 5 full penetrations - 1 a brew up, 2 KOs, 1 gun damage with shock and -1 crew, and 1 no significant damage - plus 16 partials, of which however a whopping 11 were no significant damage, 2 were shock and -1 crew, 3 were KOs. The last 3 hits were track no significant damage, flaking (alerted only), and shell broke up.

Thus only 25% actually kill, while another 1/8 (about) did something. The StuGs took with them 4 Valentines IXs, gun damaged and shocked one Churchill III, and shocked another Churchill III. Head to head the edge is definitely to the StuG for any of these, but there is at least a chance with the rare 57mm varities, which there isn't with single AT guns, T-34s, Shermans, SU-85s, or KV-85s.

This is Tiger performance, at a minimum.

[Paul Lakowski]

Haven't got a clue what Jasons on about so I'll just let it alone for now.....

Originally posted by Jeff Duquette:

Thanks Paul. Sorry to be a chuckle-head but I have several more areas of clarification...if you would be kind enough to continue to indulge me

Paul Said: For example 37mm Vs 45mm SHS of T-34 glacis is [45mm/37mm/2 ^0.2]*1.2 or 49mm @ 60°...while if 75mm hits thats

[45mm/75mm/2 ^0.2]*1.2 or 42mm @ 60°.

How are you accounting for the angle of attack? Should “Te” be 49mm/COS(60)

And

42mm/COS(60) for the 75mm dia projectile attack example?

Yes usually I don't include the angle since its a property of the projectile penetration...IE if the effective resistances is 49mm @ 60°, then you have to find out at what range 37mm can penetrate 47mm @ 60°...which is none existance.

So for the 75mm the range at which a 42mm can be penetrated @ 60° should be about 1/2 hits @ 1400m

=================================

I am assuming the 1.2 multiplier is a function of the homogeneous hard armor on the T34?

The RHA multiplier being 1.0;

FHA multiplier is 1.3; and

SHS multiplier is 1.2.

Is this correct?

Yep with RHA being referenced to BHN 275 rolled plate.

SHS depends on the amount,450BHn is about 1.25 while 380BHN RHA is going to be around 1.1

==================================

In one of your earlier posts you indicated:

So 3cm FH @ 10° t/d should become

(3cm/7.6cm/2)^0.2 x 1.3[Te FH] => 0.723 x 3cm x 1.3 = 2.82cm @ 10°= 2.9cm

This looks to me like you divided the resultant 2.82cm by COS(10-deg) to get the final thickness of 2.9cm…although I am getting 2.86cm after dividing by COS(10). You rounded up? Was this in fact what you were doing?

In addition the 50cm Stug-111 plate…shouldn’t the final thickness or “Te” be modified by its angle of inclination as well? 52cm/COS(10)???

Yes but strickly speaking the angle should be an expression of the projectile.

And yes to the 52mm FH plate....but usually at shallow angles the COS of the angle is sufficent especially when the projectile is blunt like many soviet WW-II and modern penetrators. When you get into ogive penetrators the projectile will slide and exagerate the LOS penetration through the angled armor.

[ November 17, 2003, 11:30 PM: Message edited by: Paul Lakowski ]

[JasonC]

"Haven't got a clue what Jasons on about..."

That game we all play. Heard something about it on a forum somewhere. Anybody else ever actually use it, or do you all just lovingly look over the numbers?

[Mr. Tittles]

Heres a pic that shows the uber-playdoo that was put on uber-stugs.

http://home.t-online.de/home/a.m.ackens/stugii~1.htm

Lots of good pics. The stug upper frontal armored areas are too complicated to be represented in the game.

[A.E.B]

Hi all

I believe JasonC is positing the mild suggestion that the STUG III F/G frontal armour may be a tad over-modelled in CMBB which results in slightly non-historical performance verse allied AP projectiles.

Then why do my god-damned STUGs always die??? Oh, the incompetence, I forgot!

Out of curiosity, does anyone have a picture of a STUG that has been KOed by a frontal penetration? I have checked my collection and (a) knocked out STUG pics are rare, and ( those pictures I do have of knocked out STUGs don't show frontal penetrations.

Given the cramped conditions inside a STUG, it appears that just about any round that penetrates the front armour will hit something or someone vital.

So are STUGs turretless Tiger Is in disguise? I can't find sufficient information on how they were destroyed to make a judgement.

Regards

A.E.B

[Michael Dorosh]

I'll interrupt the catfight to note

a) AEB - you made short work of MY damn StuGs in our current PBEM which you owe me a turn for

JasonC - I've emailed you a couple of times but haven't heard from you since the end of our last PBEM. If you have no interest in continuing with the other project you suggested, fine, but please let me know. Otherwise, you need to know your email or mine are conspiring not to work.

[A.E.B]

Michael

a) AEB - you made short work of MY damn StuGs in our current PBEM which you owe me a turn for

With a couple of SU76i's none the less. I believe that German tankers killed by SU76i's are excluded from Valhalla!

I am currently at work. I'll send the turn when I get home.

Regards

A.E.B

[Paul Lakowski]

Originally posted by JasonC:

"Haven't got a clue what Jasons on about..."

That game we all play. Heard something about it on a forum somewhere. Anybody else ever actually use it, or do you all just lovingly look over the numbers?

I don't have any numbers or the game so I don't know what your refering to?

[White Phosphorus]

I know it is not kosher to refer to other wargames, but in Steel Panthers T-34s had a,b,c,d versions which had alternating armor thickness 5-7mm. And somebody on the forums was so impressed with the detailed modeling that he posted an article about Soviet T-34 production that argued that few factories actually produced T-34s with the specified armor thickness, but made some plates 5-7-10mm thicker then specks. Which might explain the discrepancy in the various AARs.

This was so long ago I don't think I'll be able to dig it up.

[JasonC]

Paul, you said, this "limits T-34 76mm AP shell to ~0-900m penetration [½ hits]" In CMBB, a Russian 76mm AP shell doesn't have a snowball's prayer in a warm place of penetrating the StuGs in question. At 900m, at 450m, 1/2 hits, a quarter hits, any hits.

In CMBB, at 900m, only 3% of Russian 85mm (in fall 1943) will penetrate the StuGs in question. So your comment is a bit of a screamer to us CMBB players.

Yes, I know that means the problem is CMBB, that its StuGs are overmodeled. But that is the subject of this thread - or one of them. And your pocket theories are one of the explanations peddled by those defending that overmodeling.

As though every 76mm, not half of them - vs. every StuG in the bunch, not some that happened to have warping large enough to matter - oh and just for kicks 97% of the 85s - always failed for that reason.

[ November 18, 2003, 04:59 AM: Message edited by: JasonC ]

[JasonC]

"it appears that just about any round that penetrates the front armour will hit something or someone vital."

Tell the sods using lend lease in my tests. Out of 21 penetrations and partial penetrations by Brit 6 pdr, 12 did no significant damage. Ditto for 6 out of 7 US 75mm partials.

Mike - email is fine, just busy. We can start the grand GD at Kursk idea certainly.

[Kozak]

I Think Jason is right . The Stug is overmodeled. My uncle ran into them a lot being in command of a recon company. He was not more overawed of them then any other German vehicle.

Again, this is anecdotal, but the biggest "fear factor" they had regarding the Stug was not the armour, but that it was so low they couldn't spot it before it got the drop on them. IRL, Stugs were not used like tanks, Wittman notwithstanding.

Once they spotted it the T34 driver would try to move laterally to it at top speed to force the Stug to churn its tracks to traverse the gun outside of 15 degrees or to reposition. The resulting blast of black diesel exhaust would tell the wingman where to shoot. That may save the lead tank...or not. In open country at top speed you could outflank it, because once you were outside its cone and stalking it, it was meat..except for its wingman. Probably why one of the gents did not see a lot of frontal penentrations in photos.

Stug's of all marks could be penetrated from the front by the T-34/76 and the complex front actually created some shell traps. In this era they were more afraid of the PZIV with the zippy quick turret with dedicated gunner and commander.

The biggest concern they had was hitting, not penetrating. They had a healthy respect for german optics and gun/ammo accuracy, but never awe. They had scepticism about their own, but not to the point of despair. The "safe distance" was any distance they could get first hit in without getting hit. Closer was better. If you fired and missed, you gave away your position and the German would likely get you.

Never did they think in the T34 that "we are outside their penetration capability". Getting hit was exceedingly unpleasant even without penetration. If CMBB undermodels something its the momentary shock of having your bell rung, literally. Also, because the quality of the construction of the tanks was so variable, they did not know if they had a "Monday Morning model" or not. They just did not risk getting hit.

In addition they were at a systematic disadvantage in reacting to a sudden threat. In the T-34/76, because the commander was the gunner, there was an inevitable delay that occured as follows: commander sees target, commander shouts to driver (only guy in tank with intercom) to skew whole tank at target, commander gives hand signal to loader what to load, commander takes his eye off the target and drops down into turret, tries to reaquire target through the sights following the gun barrel as a pointer now that the driver has completed the skew, fires, tries to see fall of shot through sights, can't, curses, etc. etc.

Meanwhile the German commander is outside keeping an eye on the target, watching fall of shot, telling the drver and gunner to adjust, advising loader as to next round. etc.

[Sergei]

Originally posted by A.E.B:

Given the cramped conditions inside a STUG, it appears that just about any round that penetrates the front armour will hit something or someone vital.

I wouldn't be so worried about frontal penetrations as I would be about the total lack of flank armour... not to mention that the tracks are cut so it cannot move.

[Jeff Duquette]

Thanks Paul.

[Mr. Tittles]

Notice the varying angles of protection offered by the angled plates.

The upper hull area (it has the small headlight in the center thats shaped like a German helmet), has a decent slope to it. Was this 80mm or 50+30mm? If so, it would be tiger-esque. But it is a small percentage of protected area. The lower frontal hull area (not in drawing), is more vertical.

The outer upper superstructure also has decent sloped areas (these are the parts that were widened). I am refering to the plates that seem to overlap the fenders and go up to the outer roof. But are they 80mm or 50+30mm? Perhaps only 50mm?

The area above the driver is steeply sloped and was usually reinforced with tracks/cement.

The vulnerable gun shield is actually in a recessed area. It does form a shell trap to fire directly at it.

[ November 18, 2003, 12:30 PM: Message edited by: Mr. Tittles ]

[Mr. Tittles]

If a Stug is 'track-down' and facing you, you would be in big trouble. The combination of low height and well protected 'top' areas being exposed could spell doom. The driver's visor, being nearly at track top level, would aid him in getting a good position. Since the gun is nearly at this same level, less top area is exposed.

But I think that IF the stug is so invulnerable to 85mm guns, its because the game can not model the complicated shape of the stug. A bad abstraction or a mis used angle/thickness may be in the program.

Later stugs, with the Saukopf and additinal track/cement should be tougher but not that tough.

[JasonC]

The reason the in-game StuG is invulnerable even to 85mm seems to be double counted shatter. At that range CMBBs own numbers would have the 85mm punching through more than 100mm. Upper hull hits on StuG, the common hit and the weaker slope, are nearly flat.

A linear interpolation of 1/3rd of the difference between 0 and 30 is going to make it look harder than it actually is, because the effect of slope is rising. Which means the interpolated rated ability of the 85 is 99mm penetration. In reality, only 3% penetrate and those only partially.

If you look at Russian guns that do kill, the SU-152 and SU-122 HEAT (the latter sometimes only shocks in my limited experience), both are well over 100mm.

The lend lease marginal killers - 1/4 of the time, with many partials that don't do anything - are rated 84mm to 90mm. Meaning, with 15-20% more penetration than the 74, and with APCBC as the ammo type, you are getting a portion (only) going in. The armor could be plus 10% thickness for layering instead of minus 7.5% But there isn't double counted layer boost plus shatter. Presumably because APCBC shouldn't shatter to begin with.

But the 85 should be well past that, with 133% of the base armor. Instead they just shatter (shell broke up, a third to half the time). The round with less penetration rating goes in most of the time (though partial, and 1/4 kills). Suggests this is meant to be shatter gap behavior.

It is just that it is on top of overmodeled layering. Shatter gap from a 74mm base might happen out to 90mm, but not to 100mm equivalent penetration. Moreover, there is no window in which one or the other doesn't get you, range wise.

It should be one or the other. Either you can model pocket variable effects on layering as "usually 74mm, but occasionally a random number higher from 0 to 24". Or you can model it as 74mm, but a shatter problem (not for APCBC, only for AP). Instead the 85mm seems to get both, while the 57s get some layered armor boost but don't have shatter thrown in as well. (Being lend lease, lol).

What you can't do is say, "74 actually resists as 98" - not occasionally but all the time. Plus 20% shatter gap unless the round was made west of the Oder.

The LL 57s should be going through these things like a hot knife. The better one has around 88mm rated with APCBC. It is 20% over the actual protection, with no shatter to contend with. But only 3/8 do anything and only 1/4 kill. The kill behavior on the full pens is about 60% KO, 20% shock, 20% no damage, which seems reasonable for a round of that energy. The problem is nearly all the hits are made partial pens, when only a small number should be. That to me means the 30+50 is being modeled, sans shatter, as way more than it ought to be.

The 85s should also be going through these things like a hot knife. 100mm Tiger fronts, plus shatter, causing failure is annoying but believable - US 76mm faced a similar problem. But 74mm to 80mm, overpenetrated by 5/4 to 4/3, is not going to fail that way.

It seems to me somebody counted 30+50 not as 74 with occasional shatter-like problems (which might make some 76s, or US 75s, fail when they otherwise wouldn't) but as 86-92 (74 or 80, plus half of maximum possible "24 for bubbles" idea, always instead of varying) *plus* shatter like problems for anything but APCBC. And that is double (if not triple) counting.

Thus my testbed's name - "uberstug"...

[ November 18, 2003, 01:53 PM: Message edited by: JasonC ]

[Redwolf]

Originally posted by Kozak:

Once they spotted it the T34 driver would try to move laterally to it at top speed to force the Stug to churn its tracks to traverse the gun outside of 15 degrees or to reposition. The resulting blast of black diesel exhaust would tell the wingman where to shoot.

Diesel StuG?

In this era they were more afraid of the PZIV with the zippy quick turret with dedicated gunner and commander.

But the StuG has dedicated loader and commander, too. The Panzer IV's advantage is a cupola which is higher to start from and has larger vision slits (with covers).

In any case, if he wasn't afraid of StuGs in a 76mm T-34 then that is something to take into account.

[Sergei]

Originally posted by redwolf:

But the StuG has dedicated loader and commander, too. The Panzer IV's advantage is a cupola which is higher to start from and has larger vision slits (with covers).

I somehow think that Kozak was comparing Pzkpfw IV to an early model T-34 (commander as gunner). But first-hand experiences, when passed through a middle-hand, can be rather unclear. What StuG's are we talking about, IIIB or IIIG?

[Redwolf]

Note that CMBB has a number of different models for the upper hull armor.

- StuG IIIF(late) to IIIG (early) have 50+30mm/10

- IIIG (middle) has 80mm/10

- IIIG (late mid) to IV have 80/curved

Since BFC doesn't publish the rounding geometry that is assumed for hit computations this is basically useless.

I assume it is supposed to model the Saukopfblende, but given that this si such a minor part of the surface that would lead to overmodeling (especially when comparing to the Pz IV which doesn't get its 30mm gun mantlet taken into account at all).

Jason, did you conduct your tests with a 80mm solid StuG to test your theory that the layering leads to overmodeling?

[Paul Lakowski]

Jason Lower hull is 80mm @ 20-30°...the resistance is ~ 7cm @ 30° and the penetration of 76mm APC is ~ 7cm @ 700-900m 1/2 hits.

I'll add more later

[Kozak]

Originally posted by Sergei:

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

But the StuG has dedicated loader and commander, too. The Panzer IV's advantage is a cupola which is higher to start from and has larger vision slits (with covers).

I somehow think that Kozak was comparing Pzkpfw IV to an early model T-34 (commander as gunner). But first-hand experiences, when passed through a middle-hand, can be rather unclear. What StuG's are we talking about, IIIB or IIIG? </font>