PZ IVs vs. Shermans

Rocket-Man

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I am working on a scenario that will pit PZ IVs vs. Shermans. To see how the two tanks compare, I set up a test with 40 tanks firing at each other at 1000 meters as shown in the picture below. For the test I used all regular tanks and gave each command tank a +1 command with no moral bonus. The Panzers were IVHs and the Shermans were III (mid). FOW was set to none for the tests, all tanks started buttoned and none of them were moving. All tests were done in Hotseat mode.





Much to my surprise the Shermans consistently beat the PZ IVs. I ran the test multiple times and each time the Shermans would win. I then reran the test ten times and counted how many tanks from each side survived the turn. Out of 400 Shermans, 210 survived and out of 400 PZ IVs, 177 survived. Survival was determined as not knocked out, abandoned, gun damaged or immobilized.

Being an engineer, I had to look at the underlying numbers to see if this result made any sense.

The Sherman III (mid) has an armor quality of 90%, giving it an effective frontal armor thickness of:

Turret: 80.1mm @ 0 degrees
Upper hull: 45.9mm @ 56 degrees
Lower hull: 45.9mm @ 15 degrees

The PZ IVH has an armor quality of 95%, giving it an effective frontal armor thickness of:

Turret: 47.5mm @ 10 degrees
Upper hull: 76mm @ 10 degrees
Lower hull: 76mm @ 14 degrees

Using my armor penetration spreadsheet, which calculates values for armor penetration at intermediate angles and ranges, at 1000m the Shermans gun can penetrate:

82.8mm @ 10 degrees
77.5mm @ 14 degrees

And the PZ IVs gun can penetrate:

116mm @ 0 degrees
50.7mm @ 56 degrees
106.4mm @ 15 degrees

Meaning the Shermans gun has the following percentage over the minimum penetration power against the PZ IVs armor:

Turret: 174%
Upper hull: 109%
Lower hull: 102%

and the PZ IVs gun has the following percentage over the minimum penetration power against the Shermans armor:

Turret: 145%
Upper hull: 110%
Lower hull: 230%

Meaning both of them can easily penetrate each others turret, they have an almost equal chance of penetrating each others upper hull and the PZ IV can easily penetrate the lower hull of the Sherman while the Sherman can barely penetrate the PZ IVs lower hull.

Now take into account the fact that the PZ IV has a silhouette of 94 while the Sherman has a silhouette of 100, the PZ IV has good optics to the Shermans standard optics and the PZ IVs gun is higher velocity than the Shermans gun and these results don’t make any sense (as an aside, if immobilizations were counted as surviving, the Shermans would have done even better).

Next, I ran some tests to determine why I got the results I did, and I will post my findings at a later date.
 

Rocket-Man

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Also, one of the funny things about these tests was that at the end of the turn there was always as many burning PZ IVs as there were Shermans, even though Shermans have the "burns easily" trait and PZ IVs don't.
 

Michael Dorosh

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This is another argument in favour of extended "designer's notes" on the part of the developers, in order to explain anomalies like these that fly in the face of what one would expect to find. Certainly a "test" like this in a conventional game system would likely produce different results, though that would be an interesting proposition. Would be very interesting to see a lineup of the same tanks on an ASL board and see if the intervention of "fate", "luck" or "The Cubes" would be responsible for the variances you have presented here.
 

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One thing that is not shown in the statistics but (I believe) is modelled in the game is the weight of the AP shell.

The Sherman fires a heavy AP shell and the PZIV a lighter AP shell.

It is just speculation, but it may provide the missing piece of this puzzle.
 

Rocket-Man

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One thing that is not shown in the statistics but (I believe) is modelled in the game is the weight of the AP shell.

The Sherman fires a heavy AP shell and the PZIV a lighter AP shell.

It is just speculation, but it may provide the missing piece of this puzzle.
Looking around the internet, I find that the Panzer IVs 7.5 cm KwK 40 L/48 gun fired the Panzergranate 39 APCBC shell and it weighed 6.8 kg. The Shermans 75-mm Tank Gun M3 fired the APC M61 shell and it weighed 6.79 kg. So according to these numbers they shells weighed the same amount. However, these numbers come from the internet so I can not guarantee their accuracy. Can anybody verify them?
 

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Are you talking the AP projectile or the whole shell?

The German 75mm shell could weigh more, because it has more propellant.
 

Rocket-Man

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Are you talking the AP projectile or the whole shell?

The German 75mm shell could weigh more, because it has more propellant.
I am pretty sure those numbers are for just the shell itself. See here for the Panzergranate 39:

Panzergranate 39 or Pzgr. 39 was a German armor-piercing shell used during World War II. It was manufactured in various different calibers and was the most common anti-tank shell used in German tank and antitank guns of 50 to 88 mm calibers.

The shell was of APCBC-HE-T construction meaning that it consisted of the shell body fitted with penetrating and ballistic caps, an explosive filler and a tracer unit that was incorporated into the base fuze]. Phlegmatized PETN or RDX were commonplace as the explosive filling. Pzgr. 39 was only used in guns firing fixed ammunition. Exactly the same Pzgr. 39 shells of a certain caliber could be fitted to different cartridge cases. For example the 7.5 cm Pak 40 L/46 antitank gun and the 7.5 cm KwK 40 L/48 tank gun fired the same projectile, even though they had completely different cartridge cases.

Different versions of the shell were made, but the changes were usually minor. For instance, in the 88 mm Pzgr. 39-1 version the quality of steel was improved. The 75 mm Pzgr. 39/42 of KwK 42 and Pak 42 guns had two driving bands instead of one. In the Pzgr. 39/43 of KwK and Pak 43 guns, the driving bands were made wider than those of Pzgr. 39-1. The widening took place because the high gas pressure in these long-barreled guns presented certain problems when firing the older Pzgr. 39–1 shells with narrower driving bands. The abbreviation 'FES', found on many Pzgr. 39 rounds indicates the presence of sintered iron driving bands.
Technical data of 75 mm Pzgr. 39 FES

  • Weight, complete with fuze: 6,8 kg
  • Explosive filler: 18 g of RDX and wax (90/10)
  • Number of driving bands: 1
  • Material of driving band: sintered iron
  • Shell diameter at driving band: 77,4 mm
  • Shell body diameter: 74,5 mm
  • Fuze: Bd.Z. 5103
    • Type: base fuze
    • Weight with tracer unit: 107 g
    • Tracer burning time: 2 s
So again, it looks like both guns fired the same weight shell.

I have a theory about why I got the results I did. It involves projected frontal area, multiple angles on the front of the PZ IV and CMs limit of three angles per side of each AFV. However I want to do a little more testing before I post my findings.

EDIT: I should probably define terms here. I am assuming the "shell" is the part of the "round" that actually is fired out the end of the gun. The "round" is the entire assembly that is placed inside the gun before firing and includes the "shell" and the brass casing holding the powder that expels the shell out of the gun. If I have my terms defined incorrectly let me know.
 
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Rocket-Man

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This is another argument in favour of extended "designer's notes" on the part of the developers, in order to explain anomalies like these that fly in the face of what one would expect to find. Certainly a "test" like this in a conventional game system would likely produce different results, though that would be an interesting proposition. Would be very interesting to see a lineup of the same tanks on an ASL board and see if the intervention of "fate", "luck" or "The Cubes" would be responsible for the variances you have presented here.
A detailed developers guide would have definitely been helpful with CM. I have been trying to figure out just how CM models hits on tanks and I think I have a good idea how it is done, but some insights from the developers would make the exercise much easier.

It would be interesting to see how other games handle the Sherman vs PZ IV match up but I don't have any games myself that can do the job. Perhaps somebody reading this forum can run some tests in another game system and let us know the results.
 

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It should be noted that CM waters down the German tank modeling, considerably IMO in both CMBB and CMAK.

On the eastern front there was a huge disparity in tank kills between German and Soviet. The Germans had better tank crews and with much more experience (until very late in the war when the Russians started gaining in experience) with far superior optics and to-hit ratios from everything I have ever researched, both via internet and book. Yet if you'd care to test the Russian vet tank vs any German armor the to-hit is virtually identical. There was a discussion about this over at Band of Brothers, and Death Dealer pointed me to a BFC post where it was admitted that the actual difference between German and Russian to-hit accuracy in CM was only 1 to 2%, and then only in extremely long ranges. So the so called modeled German Optics are usually only window dressing at best, and a hinderance at worst - Regs and under suffer a penalty with some optics and Hot weather and proximity (too close) also gives penalties.

I had put that to the test a while back pitting 10 Nashorns, with their excellent long 88 and great optics vs 10 t34/85s, all vets and at about 500 mtrs. The results were that when all units were pre-targeted with commander exposed the Nashorns got a small edge in kills - maybe 60% if IIRC. If buttoned and pre-targeted the Ts won by about that same margin. If all tanks were left to find their own targets then the Ts wiped out the Nashorns big time. So in spite of vastly superior optics and guns the Ts won anyway. The justification was that 500 mtrs was too close for the Nashorn optics. Funny but it seems that a distance of over 5 US football fields is hardly all that close. And as to 88 accuracy I've found that they miss as often as any other gun for the most part in CM, while actual WWII German tests had shown an extremely high rate of first shot kills because of the high velocity and extremely flat trajectory combined with great optics; something not modeled in CM.

What all this means is that CM to-hits and to-kills are tweaked by watering down the chances rather than being historically accurate for the German armor. Based on that I'm not surprised with your results with the superior Shermans.

The armor ratings were also watered down in many cases for the panzers, as was the hull rotation times (much slower in CM than RL).
 
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Rocket-Man

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Interesting information Lurker. I was not around in the early days of CM so I was not aware of any of the history behind the design decisions made. As Micheal Dorosh said, some designers notes would have been extremely helpful.
 
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Rocket-Man

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To understand what was happening in the PZ IV vs. Sherman duels, I again ran a series of tests with the parameters the same as before. I then watched and counted where the PZ IVs were getting hit. I ran a total of 5 tests with 40 tanks per side and the results were as follows.

Area - # of Hits - Percentage - Percentage w/o Gun and Track
Turret: 56 : 26% : 28%
Upper Hull: 113 : 52% : 56%
Lower hull: 32 : 15% : 16%
Gun: 6 : 3%
Track: 9 : 4%
Total hits: 216

Next I calculated the projected frontal area of each part of the PZ IV using a scaled drawing I found on the web (note that this model might not be 100% accurate, but it is certainly accurate enough for my purposes). I have marked each area in different colors as shown in the picture below.



Red is the turret, blue is the upper hull, orange is the lower hull, light blue is the tracks and yellow is the gun. The purple area is the gun mantle and the areas outlined in green are places where the slope of the armor does not match the slope in CM. This can be seen from the picture below.



For reference, the CM stats for the PZ IVHs frontal armor are as follows:

Turret: 50mm @ 10degrees
Upper hull: 80mm @ 10 degrees
Lower hull: 80mm @ 14 degrees.

Since CM only uses three areas to represent all the armor of a tank, it can clearly be seen that this does not allow the modeling of the intricacies of the PZ IV armor.

From the drawing above, the percentage projected frontal area of each section of the PZ IV, ignoring the gun and the tracks for now, are as follows:

Area - % of total
Turret: 24%
Upper hull: 43%
Lower hull: 33%

Comparing these numbers to the percentage of hits on each area excluding gun and track hits gives us the difference between how often an area of the PZ IV is hit versus how big that area of the PZ IV actually was:

Area Difference
Turret: +4%
Upper hull: +13%
Lower hull: -17%

So for the PZ IV, the reasons they are so susceptible to the Sherman III is as follows:

1) The areas of their frontal armor that had a greater slope than the one used in CM does not provide them any protection.

2) Turret and Upper Hull hits are a greater percentage of hits than the projected frontal area of the PZ IV would indicate.

3) Lower hull hits, where the PZ IV has the best armor protection, are much lower than the projected frontal area of the PZ IV would indicate.

Of course this is all in addition to the points Lurker brought up.

I guess the bottom line is that recreating historical OOBs in CM will not allow you to closely duplicate what actually happened in real life. So for you scenario designers out there who are designing “historical battles” you will definitely need to tweak the experience levels and the force mixes to get historical results. Although I’m sure most of you, unlike me, already knew this.
 
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[hirr]Leto

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This is a great thread RM... and thanks to the rest of you as well. Unlike the rest of you though, I am giving RM a positive clickie for his efforts!

Cheers!

Leto
 

Rocket-Man

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[hirr]Leto;1099593 said:
This is a great thread RM... and thanks to the rest of you as well. Unlike the rest of you though, I am giving RM a positive clickie for his efforts!

Cheers!

Leto
Thanks Leto. When I am thinking things through I often find it is helpful to write down what I am thinking as it forces me to think through the whole problem. I often find things I missed when I write things down, which is why I went ahead and wrote this thread, to help me to think the whole problem through.
 

CMant

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2) Turret and Upper Hull hits are a greater percentage of hits than the projected frontal area of the PZ IV would indicate.
Is that because when you fire at the front of a Mk 4 you aim at the bottom of the turret ? Of course that assumes they model point of aim .
 

Rocket-Man

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Is that because when you fire at the front of a Mk 4 you aim at the bottom of the turret ? Of course that assumes they model point of aim .
I have never fired a round from a tank gun so I don't know precisely where you would aim, but at 1000 yards away, even with good optics, the relative size of even the PZ IV would appear pretty small. So I guess you would aim at the center of mass, which would definitely move the aim point up from the bottom hull, which would account for some of the discrepancy.

However, even if you were aiming at the center of mass of the PZ IV, the difference between the top and the bottom of the frontal area at 1000m is only .07 degrees of elevation. I doubt the Shermans gun could be pointed with that level of accuracy.
 

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My understanding is that tanks would often have to bracket their rounds for such distances (with the exception maybe of the 88LL), thus a round may fall short then long, etc. At .07 degrees it seems it would be quite difficult to pinpoint a small turret under bracketing. Add weather conditions to this and it's even tougher.
 

Rocket-Man

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My understanding is that tanks would often have to bracket their rounds for such distances (with the exception maybe of the 88LL), thus a round may fall short then long, etc. At .07 degrees it seems it would be quite difficult to pinpoint a small turret under bracketing. Add weather conditions to this and it's even tougher.
Agreed. There would probably be a little bias for hits higher up on a tank rather than lower down, but the difference would be pretty small at all but the shortest ranges in my opinion.

A 21% difference between turret hits and lower hull hits on the PZ IV seems pretty excessive. Now on the Sherman, with its relatively small lower hull compared to its long sloping upper hull and large turret, this type of difference would make a lot more sense.
 

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In CMBO it became kind of a joke to a few of us that if a PZIV were squaring off against any tank that could only penetrate the turret then the turret would be hit 98% of the time regardless of range and in spite of its relatively small size.
 

Rocket-Man

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In CMBO it became kind of a joke to a few of us that if a PZIV were squaring off against any tank that could only penetrate the turret then the turret would be hit 98% of the time regardless of range and in spite of its relatively small size.
I was reading some accounts of the actions between the Canadian 9th Brigade, 3rd Canadian division and the German 12th SS Division on June 7th, 1944 around Authie and Buron where the Canadians described the shells from their Shermans "Bouncing off" the PZ IVs (probably H models, but could have been late G's). In all the tests I ran, numbering probably 6 or 7 hundred tests, I didn't see more than a handful of shells actually richochete off the PZ IVs. Almost every hit to the PZ IVs upper hull penetrated and almost every hit to the turret resulted in a kill, and a high percentage of those resulted in fires.

I don't know what Battlefront has against the PZ IV, but it doesn't seem like the situation got any better after CMBO with the release of CMAK and CMBB.
 
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[hirr]Leto

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If you read further, you'll find that's why the Canucks had to close ground and beat the Germans senseless with hockey sticks.

The thing about these kinds of reports is that it was always dodgy with allied troops in their ability to tell the MK IV from the Tiger... the word "panzer" and Tiger were near synonymous with all but the most vet allied tankers. But I do not recall there being any Tigers in the area during that engagement. I will try to read up on it.

Cheers!

Leto
 
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