tiger spalling

[vossiewulf1212]

Now I'm confused. Before you said other tests showed the Sherman wasn't dominant at long ranges.

Also, from that thread you linked, Vanir Ausf B says:

"The Sherman is a better tank in general, but not in all circumstances. The 2 things the Pz IV had over the Sherman was a main gun with better accuracy and armor penetration, and better optics. In a head-to head duel the distance at which the Pz IV begins to gain an edge over the Sherman is around 800-900 meters. That is where the Sherman's main gun begins to lose it's ability to penetrate the Pz IVs upper front hull*."

That is what I understood to be the case, which is why I expected the Pz-IVs to dominate at 1500m, when I'm seeing the exact opposite.

[__Yossarian0815[jby]]

By coincidence I was just today reading a Brit report on firing tests against a Tiger I hull. In one instance they found a shard of the roof armor embedded in the commander's seat. Ouch!

Does it say when that Tiger I was built? Did a bit of superficial googling and there was one site quoting russian sources saying that the Tiger II hab a lot of spalling (albeit against 100mm and higher soviet calibers) due to shoddy late war materials. Unlike the Tiger I that was built when the Germans had access to all necessary metals and didn´t spall as easilly.

[Vanir Ausf B]

You really need to tell us what version of the Pz IV you are using in your tests. To the Sherman's 75mm gun there is a big difference between 50mm of upper hull armor and 80mm of upper hull armor. Unless CMFI only has one type of Pz IV?

[dieseltaylor]

Can I add to VAB's request. Always report the precise tank model and gun as otherwise its pretty useless for anybody else who may have relevant tests, or anecdote, or War Department reports.

I am willing to bet that relating a spalling test on Tigers with spalling evident that the gun was very likely not a 75mm Sherman gun. As for 14.5mm ATG's knocking out vision blocks I think a moments reflection will show that thousands of rounds of HV tungsten bullets aimed deliberately at vision blocks may well be effective but actually it does not seem a fair extrapolation to take this too far.

[akd]

Now I'm confused. Before you said other tests showed the Sherman wasn't dominant at long ranges.

Not dominant through accuracy. Remember, you specifically said the Sherman was more accurate at long range, when in fact your test, like all duel tests, is not a test of tank v. tank accuracy but of group v. group winningness, which is a chaotic combination of many variables. You are also testing protection, terminal effects, morale, C2, etc.

Also, from that thread you linked, Vanir Ausf B says:

"The Sherman is a better tank in general, but not in all circumstances. The 2 things the Pz IV had over the Sherman was a main gun with better accuracy and armor penetration, and better optics. In a head-to head duel the distance at which the Pz IV begins to gain an edge over the Sherman is around 800-900 meters. That is where the Sherman's main gun begins to lose it's ability to penetrate the Pz IVs upper front hull*."

That is what I understood to be the case, which is why I expected the Pz-IVs to dominate at 1500m, when I'm seeing the exact opposite.

Yes, but if you keep pushing the range up, Sherman's better armor becomes less vulnerable to PzIV gun while the PzIV's turret (and hull on early versions) remains vulnerable to the Sherman's gun.

[vossiewulf1212]

You really need to tell us what version of the Pz IV you are using in your tests. To the Sherman's 75mm gun there is a big difference between 50mm of upper hull armor and 80mm of upper hull armor. Unless CMFI only has one type of Pz IV?

Sorry, yes should have done that. They're a mix of G Late and G Latest with 2 H Early. I was trying to test what would be typical in the game so I did not alter the makeup of the company the game gave me, I selected a Regular exp Panzer battalion and removed everything but the first Pz-IV company.

[vossiewulf1212]

Not dominant through accuracy. Remember, you specifically said the Sherman was more accurate at long range, when in fact your test, like all duel tests, is not a test of tank v. tank accuracy but of group v. group winningness, which is a chaotic combination of many variables. You are also testing protection, terminal effects, morale, C2, etc.

Ah, understand now thanks. That being said I've now run this a bunch of times and although I haven't counted all the hits (with 34 tanks blasting away that's not easy), on the face of it I see no hit advantage for the IVs. The IVs usually get off the first shot (and I mean the first single shot then the first Sherman will generally fire less than a second later), but the Shermans seem to find the range first. And once they have the range, they really don't miss at all subsequently, even when some of the IVs decide they have someplace else to be and start reversing to find someplace out of LOS- they'll get hit over and over while moving at 1500 yards.

The not missing once they get a hit thing applies to both sides, the IVs keep hitting Shermans that have popped smoke and are reversing too. I also find that weird because at these ranges we're dealing with lots of round drop so the danger zone should be smaller and the need for corrections greater.

And although I see a few hits on Shermans with not even spalling, it's only a few- pretty much everything is partial or penetration.

So anyway I still am finding these results odd. So the Shermans had a slight protection advantage at that range, I would think the supposed gunnery advantage of the IVs would at least make it even, when it's more like the Germans getting a good face-kicking. I was trying to balance a scenario and although at shorter ranges the rule of thumb I used for CM (about 1.20 Shermans for each IV) for balance seems to apply still, at longer ranges that's at least reversed.

[dieseltaylor]

In my tests using ten firing lanes at around 1800m - and given it was Version 1.01 of CMBN - not to be relied upon I was amazed at the difference in spotting times for each tank on tank.

However the point about once a hit was made the next would also be on target I did find slightly unreal. I chose the longer range as the superior German optics should provide for greater hit probability. This I did not see. I have not bothered testing since as without CMBN 2.00 there seems little point in wasting anymore time on it.

So if anyone has information on the quality of US and German gunsights out to 1800metres I would be interested. It should be pointed out that 1800m is not a normal combat range and that it would be rare for a tank to fire at that range as it would reveal its position with small chance of a first round hit.

[Vanir Ausf B]

The effects of optics in CM are big black hole. Testing has shown that they appear to affect spotting in some way and therefore who gets the first shot. I am not aware of any evidence that optics affect accuracy. My assumption based on previous testing is that tank cannon accuracy is a straight function of muzzle velocity which is then modified by crew quality and movement modifiers. This is how it worked in CMx1 and I've seen no evidence to suggest it's any different in CMx2. If anyone knows differently they are keeping it to themselves.

With Pz IVs vs. Sherman battles the extra 30mm of front hull armor on the later G and H models is major factor. In CM the Sherman 75 begins to lose its ability to penetrate the 80mm front hull at around 800-900 meters. That could be different in CMFI if the Shermans are assumed to be firing uncapped AP rather than the APCBC they shoot in CMBN (Pz IV front hull armor is face hardened). But the point is that with the Pz IV the idea is to stay in the habitable zone above where the Sherman can penetrate the Pz IV hull but below where the Pz IV loses it's ability to penetrate the Sherman hull, because if it becomes a contest as to who can penetrate the other's turret first the Pz IVs thin turret becomes a decisive liability.

In reality it was SOP for Pz IVs to open fire on opposing tanks at 1200m. Sherman crews are on record as stating that in these engagements it was almost always the Pz IVs who fired first and their first shots hit with greater frequency than the Shermans did.

[vossiewulf1212]

The late Gs and Hs die just as quickly, and I see no problems for the M4s penetrating the hulls. I see an occasional spalling but most are full penetrations.

I'm willing to accept that long range gunnery in CMx2 is kaka for a few reasons, if that's just the case. I was also trying to make sure what I was remembering of the relationships between the two in terms of guns/armor/optics was correct.

It's frustrating as it makes creating a map with long range gunnery options difficult, as the balance (at least in what I'm seeing) between the two main medium tanks diverges from what one would expect in reality and seems to be quite different from that inside 1000 yards (in which case the advantage goes to the IV, since it will get the first shot downrange most often).

If anyone else wants to try this test out, let me know and I'll send map/save along.

[Vanir Ausf B]

If you are getting frequent upper front hull penetrations at 1500 meters that is odd. My back of the envelope math shows M62 APCBC penetration of FHA at 0° and 1500m to be 74.42mm. Late Pz IV upper hull is 80mm @ 10°. And I thought that prior to 1944 US Shermans mostly used uncapped M72 AP ammo which penetrates only 41.48mm 0° FHA @ 1500m, but I could be mistaken.

Unfortunately I don't have CMFI so I can't test it myself.

[siffo998]

as far as i know the late IV G models used 50mm hull armor + 30mm extra armor riveted on top. the quality of these riveted armor was bad and often caused armor failure when hit.

maybe this causes the frontal hull penetrations at 1500m (at least for the G versions).

in addition i can remember that i have read that us armor mainly used M62 shells from 1943 onwards.

[siffo998]

If you are getting frequent upper front hull penetrations at 1500 meters that is odd. My back of the envelope math shows M62 APCBC penetration of FHA at 0° and 1500m to be 74.42mm. Late Pz IV upper hull is 80mm @ 10°. And I thought that prior to 1944 US Shermans mostly used uncapped M72 AP ammo which penetrates only 41.48mm 0° FHA @ 1500m, but I could be mistaken.

Unfortunately I don't have CMFI so I can't test it myself.

well i was a bit curious so i started some testing:

a platoon of pz IV H early (first one with full 80mm frontal hull armor without the riveted 30mm)

against

a platoon of shermans M4A1

open terrain without any obstacles. 1500 + distance. three test runs.

and i`ve clearly seen that all upper and lower front hull hits caused partial or full penetrations at the panzer IVs...

according to my knowledge and vanirs data this should be impossible (1500+ distance).

by the way i`ve seen a frontal superstructere hull hit at a panzer IV and it just caused armor spalling so after looking at a panzer IV picture like the one at wiki:

http://de.wikipedia.org/w/index.php?title=Datei:PzIV.Saumur.000a5s6s.jpg&filetimestamp=20070930034759

iam assuming that the frontal superstructere hull is the top hull part (where the mg is located) it should be 80mm thick (a sherman m4a1 should not be able to penetrate those part with its M3/L40 gun - armor spalling seems ok though).

the frontal upper hull seems to be the heavily sloped part (where a part of the track is placed in the picture). it should be 50mm thick and due to the steep slope (my guess is 60°) a sherman should also not be able to penetrate those part at 1500m distance.

the lower frontal hull seems to be the part of the frontal hull directly under the part with the tracks. it should be also 80mm thick (some degree inclined). it should be also impossible to penetrate at 1500m for the shermans gun.

my guess is that something is messed up with the armor data of the panzer IV or the penetration values of shermans main gun (M3 / L40) are too high.

[siffo998]

well small update after some further testing shows:

some armor spalling hits at the lower frontal hull and a partial penetration at the superstructere hull (same distance as above).

upper frontal hull hits seem to be always penetrations (even at 1500m) which seems really odd especially if you consider that this part is heavily sloped.

[Bastables]

The effects of optics in CM are big black hole. Testing has shown that they appear to affect spotting in some way and therefore who gets the first shot. I am not aware of any evidence that optics affect accuracy. My assumption based on previous testing is that tank cannon accuracy is a straight function of muzzle velocity which is then modified by crew quality and movement modifiers. This is how it worked in CMx1 and I've seen no evidence to suggest it's any different in CMx2. If anyone knows differently they are keeping it to themselves.

With Pz IVs vs. Sherman battles the extra 30mm of front hull armor on the later G and H models is major factor. In CM the Sherman 75 begins to lose its ability to penetrate the 80mm front hull at around 800-900 meters. That could be different in CMFI if the Shermans are assumed to be firing uncapped AP rather than the APCBC they shoot in CMBN (Pz IV front hull armor is face hardened). But the point is that with the Pz IV the idea is to stay in the habitable zone above where the Sherman can penetrate the Pz IV hull but below where the Pz IV loses it's ability to penetrate the Sherman hull, because if it becomes a contest as to who can penetrate the other's turret first the Pz IVs thin turret becomes a decisive liability.

In reality it was SOP for Pz IVs to open fire on opposing tanks at 1200m. Sherman crews are on record as stating that in these engagements it was almost always the Pz IVs who fired first and their first shots hit with greater frequency than the Shermans did.

Does not change your points but: the PIV ausf J had RHA front plates due to cost and recognition that opponents were widely using capped armour piercing shells and shot. Personally I think it was due to cost as things like removing the turret motor all indicate a manufacturing imperative of driving costs down.

J's were first contacted by the allies in 44.

[vossiewulf1212]

well small update after some further testing shows:

some armor spalling hits at the lower frontal hull and a partial penetration at the superstructere hull (same distance as above).

upper frontal hull hits seem to be always penetrations (even at 1500m) which seems really odd especially if you consider that this part is heavily sloped.

That's exactly what I saw. Those rounds should be on the edge of being able to penetrate 50mm, especially as the incidence angle is not 0 degrees. They definitely shouldn't penetrate 80mm.

BTW which side won in your tests?

my guess is that something is messed up with the armor data of the panzer IV or the penetration values of shermans main gun (M3 / L40) are too high.

That is what I think as well.

[John Kettler]

Bastables,

My recollection was that removing the turret motor for the Panzer IV/J had a lot to do with the overwhelming demand on the German electrical manufacturers, as well as simplifying manufacture, but what I've read strongly suggests that this was one of a series of things making the Ausf J the Panzer IV "monkey model." Without power traverse, the IV J entered the realms the M10 had been in since initially produced, as the War Department M10 training film clearly demonstrates. Would imagine the gunner got a sore arm initially while learning to traverse the turret. Even more exciting was dealing wit the same turret while on a a slope.

Regards,

John Kettler

[Bastables]

The J was all about simplifying and making it cheaper to manufacture, single piece hatches deletion of return rollers, mesh skirts as opposed to solid.

Same thing with the panther and the G chassis, simplified turret traverse for the planned small turret dropping of FH armour for the glacis. But they never considered hand cranking the panthers or the tigers

As opposed to going through with redesigning a hydraulic turret transverse system ala panther/king tiger for the PIV they just deleted it. If it was just concerns about "electrical" manufactures they would have found a way to provide some form of powered transverse. The chassis was a dead end as soon as they found they could no longer up armour the turret from 5cm or up gun it. They noted it was strained by the addition of 8cm hull armour on the vertical faces.