Long 88mm lacking punch?

Ari Maenpaa · August 29, 2000

<BLOCKQUOTE>quote:<HR>Originally posted by cbo:

Unfortunately, I do not have a cross-section of the 8,8cm PzGr 39-1, but I would be surprised if it did not look like the other rounds with the blunt penetration cap.

Basing on the picture in "Tiger I & II: Combat Tactics", page 8, the cap of 8,8 cm Pzgr 39-1 Al Kwk 43 is blunt indeed.

Ari

PzKpfw 1 · August 31, 2000

BTT

Regards, John Waters

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Make way evil, I'm armed to the teeth and packing a hamster!

Juardis · August 31, 2000

OK, at the risk of sounding, oh, I don't know, well, at the risk of pissing someone off, I'd just like to ask this question to BTS.

Have you read the posts since your last response to this thread, and if so, is there something that you're considering doing with regards to the 88L71?

If not, that's cool since, as has been said many times here already, it shouldn't matter that much in CM1. But I was just curious if "the opposition" (for lack of a better phrase) has persuaded you into thinking that there is a good physical reason for the 88L71 to be more powerful than the other armament as quoted in the various text books (specifically Jentz in relaton to all the other Jentz data)? It sure sounds plausible to this recruit. I mean, that is what you were after wasn't it? A physical reason for the increased penetration?

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Jeff Abbott

Claus B · August 31, 2000

<BLOCKQUOTE>quote:<HR>Originally posted by Ari Maenpaa:

Basing on the picture in "Tiger I & II: Combat Tactics", page 8, the cap of 8,8 cm Pzgr 39-1 Al Kwk 43 is blunt indeed.

Ari<HR></BLOCKQUOTE>

Thanks Ari.

Claus B

August 31, 2000

<BLOCKQUOTE>quote:<HR>Originally posted by Juardis:

I was just curious if "the opposition" (for lack of a better phrase) has persuaded you into thinking that there is a good physical reason for the 88L71 to be more powerful than the other armament as quoted in the various text books (specifically Jentz in relaton to all the other Jentz data)? It sure sounds plausible to this recruit. I mean, that is what you were after wasn't it? A physical reason for the increased penetration?<HR></BLOCKQUOTE>

Yes that's what we're after. But so far I haven't seen any convincing evidence yet - just conjecture. So currently there are no plans to change the 88 L/71 in CM. The discussion has certainly been interesting though.

Charles

PzKpfw 1 · August 31, 2000

As my original questions still stand unanswered I thought I'd post a summery drawn from various posts here concerning this thread note this is a compilation of what has been posted by everyone. This is not saying all the below is correct etc, its a summery of relevant data to the thread.

1). The US & Brit LF test plate was 240 - 250BHN which was the same BHN of the plate used on their tanks, which would have BOOSTED actual penetration results for all German ammunition.

2). US Army Febuary 1945 live fire tests produced penetration results very close to the Wa Pruf 6 KwK.43 results.

3).Calculation based penetration data concerning the KwK.43 is all inconsistant Ie, Hogg, & Senger und Etterlin. While Wa Pruf LF data is consistant Ie, Spielburger & Jentz also see # 2.

4). The British 1950 report which is the basis for all CMs calculations has limitations In that It can only compensate for mass, diameter, and velocity of the projectile, & hardness of the target plate.

The formula can't distinguish between rounds with different nose shapes, or different hardness, and materials, nor does it predict the angle-dependant performance of armour piercing caps. It can't predict the performance of face hardened armour vs shot, & Its correction for angled armour is flawed compared to penetration charts vs. angle, with curves.

the formula was generally accurate for AP

shot. Accuracy was found to be better than 2% velocity(roughly 21 f/s), provideing the baseline 3% Cr.Mo. steel was used, but when other types of steel were used as a target the formula's accuracy dropped, and deviations of as high as 150 f/s were noted.

5).The German wartime penetration data @ 0^is consistant with CMs values.

6). CMs calculation of penetration at 0^ to date seem very close to published refrence data. The calculation of slope effect @ 30deg with wpns above 75mm may contain discrepencies which also relates to # 4, Ie:

90mm T33 APCBC 854m/s @ 30^ Source: Hunnicutt's Sherman

500yds - 119mm

1000yrds - 117mm

90mm T33 APCBC 854m/s @ 30^ Source: CM data

500ms 137mm

1000ms - 125mm

7). BTS stated The 88 L/71 MV was 29% greater than the 88 L/56, which is about the same as the difference between the 75L/48 & 75L/70 guns. And Jentz' figures indicate that the penetration increase in KwK.43 vs KwK.42 is an unbelievable 65% compared to the expected 38% increase.

8). CMs penetration calculations vary in range from 1.24 to 1.30. The 76mm, 90mm and 17pdr all have a ratio between 0deg and 30deg around 1.20 to 1.30 while the 8,8cm KwK 43 is 1.08 to 1.14 which again may relate to # 4.

Regards, John Waters

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Make way evil, I'm armed to the teeth and packing a hamster!

[This message has been edited by PzKpfw 1 (edited 09-01-2000).]

PzKpfw 1 · August 31, 2000

<BLOCKQUOTE>quote:<HR>Originally posted by Ben Galanti:

Just a quick correction on the CM data for the 17 pdr at 30 degrees.

500m -- 201mm

1000m - 190mm

It had be listed as 190mm for both in a couple of posts. They're pretty close to the hunnicut values, but the yards to meters thing also needs to be adjusted for.

Ben<HR></BLOCKQUOTE>

Ok Ben .

Hunnicutt's 17LB APDS Performance @ 30^ in ms

457ms - 208mm

914ms - 192mm

I noticed both the 90mm M304 APCR-T data & the 17lb APDS data changed in 1.05, their both much closer to Hunnicutts data now.

Regards, John Waters

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"Make way evil, I'm armed to the teeth and packing a hamster!".

[This message has been edited by PzKpfw 1 (edited 08-31-2000).]

Dittohead · August 31, 2000

Didn't the Germans have depleted uranium rounds?

Ville · August 31, 2000

Propably not. There wasn't lot of uranium lying around in 1945.

August 31, 2000

No, I've read also that uranium was used to some extent, or at least experimented with, by the Germans late in the war as a substitute for tungsten, which they were short of. From what I am aware of the main problem, aside from the radiation, is how to mill it into shape. Milling it has actually given the soviets trouble until fairly recently, and was part of the reason, AFAIK, Desert Storm went so smoothly. It probably would have been easier to find for them than the wolfram ore used to make tungsten.

PzKpfw 1 · August 31, 2000

<BLOCKQUOTE>quote:<HR>Originally posted by machineman:

From what I am aware of the main problem, aside from the radiation, is how to mill it into shape. Milling it has actually given the soviets trouble until fairly recently, and was part of the reason, AFAIK, Desert Storm went so smoothly. It probably would have been easier to find for them than the wolfram ore used to make tungsten. <HR></BLOCKQUOTE>

While the Iraqi T-72's only had access to export 125mm 3BM12 & 3BM15 APFSDS rounds, the Russians have had their own APFSDS-DU round since the 80s which is the 3BM32 as well as the newer tungsten cored 3BM42 & are useing or developing a new 3BM44 APFSDS round now IIRC.

Its not that well known but the US was actualy more woried about 125mm HE/Frag rounds, then Iraqi KE rounds as the 125mm HE/Frag impact could theoreticly open the M1A1's armor exposing the inner layers to follow up hits.

To this end US M1's were feild modified with xtra spaced plates added to the glacis etc, as well as a priority rush on getting the newer M1A1HA's to the Gulf before the ground war began.

Their also has been some political fallout recently over the US use of the M829A1 APFSDS-DU round in the Gulf concerning the enviromental after effects & speculation that the US will soon design a new 120mm KE penetrator from a another mateial possibly going back to tungsten.

Regards, John Waters

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Make way evil, I'm armed to the teeth and packing a hamster!

[This message has been edited by PzKpfw 1 (edited 08-31-2000).]

aka_tom_w · September 1, 2000

Sorry nothing really new here..

Still hoping we find more information to indicate physical proof that the long 88 as modeled in CM is lacking the penetration values it seemed to have had a reputation for amongst WW II Allied tank crews.

-tom w

[This message has been edited by aka_tom_w (edited 09-01-2000).]

PzKpfw 1 · September 1, 2000

<BLOCKQUOTE>quote:<HR>Originally posted by aka_tom_w:

Sorry nothing really new here..

Still hoping we find more information to indicate physical proof that the long 88 as modeled in CM is lacking the penetration values it seemed to have had a reputation for amongst WW II Allied tank crews.

-tom w

Heh Tom ppl are working on it, also remember that it is only BTS's opinion that is reflected in their KwK.43 penetration values, in CM. Its their game they can make it penetrate 10mm @ 100ms if they want .

I'd sugest reading the summary I think it highlights whats been presented by both sides to date quite well. As for proof Its been what 55 years?, and the Russian's captured the German Arty & AT testing grounds along with all the paperwork, except what was submitted to Wa Pruf, Waffamt etc. Soviet data I'm told on the penetration for the KwK.43 is identical to Wa Pruf data, no suprise their , another avenue would be to contact the Russians & request a search for the proveing grounds data.

Till the dimensions ,etc of the 8.8cm Pzgr.39 round our established etc, their will be little new data.

Regards, John Waters

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Make way evil, I'm armed to the teeth and packing a hamster!

[This message has been edited by PzKpfw 1 (edited 09-01-2000).]

IntelWeenie · September 1, 2000

<BLOCKQUOTE>quote:<HR>Originally posted by PzKpfw 1:

Their also has been some political fallout recently over the US use of the M829A1 APFSDS-DU round in the Gulf concerning the enviromental after effects & speculation that the US will soon design a new 120mm KE penetrator from a another mateial possibly going back to tungsten.

Regards, John Waters

We were told during the war not to closely inspect (read: look for souvenirs) any KO'ed Iraqi tanks due to possible uranium contamination, especially in burt-out vehicles. There was some speculation later about this being one of the causes of Gulf War Syndrome.

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"Belly to belly and everything's better" - Russian proverb

Sten · September 1, 2000

<BLOCKQUOTE>quote:<HR>

Here comes the funny part:

Spielbergers figures for 0deg are:

100 - 220

500 - 205

1000 - 186

1500 - 170

2000 - 154

CMs figures for 0deg are:

100 - 220

500 - 205

1000 - 188

1500 - N/A

2000 - 157

So the German wartime data for penetration at 0deg is not in conflict with CMs data. It is in the calculation of the slope effect at 30deg

that things go wrong.

Spielbergers figures for 30deg are:

100 - 203

500 - 182

1000 - 167

1500 - 150

2000 - 135

CMs figures for 30deg are:

100 - 177

500 - 165

1000 - 151

1500 - N/A

2000 - 121

The relationship between Spielbergers 0deg and 30 deg figures range from 1.08 to 1.14 while CMs range from 1.24 to 1.30. Looking at

the 76mm, 90mm and 17pdr they all have a ratio between 0deg and 30deg around 1.20 to 1.30 while the 8,8cm KwK 43 is down at

1.08 to 1.14 and thus appears to be less effected by slope.

Why?

This thread reminds me of how most of the threads used to look...

Those were the days.

Claus B illustrates an inconsitency that I find intriguing. Why do the 30deg figures vary so much?

"Ground effect" is very important too landing aircraft. Is there such an effect for projectiles?

The factor Lewis suggested, spin, was that more-or-less equal for most WWII guns? Did the 88/L71 differ?

Sten

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Keep your whisky on the rocks and your tanks on the roll.

[This message has been edited by Sten (edited 09-01-2000).]

Paul Lakowski · September 2, 2000

The effect the angle has to do on the projectile has to do with several factors . The CRH[shape of nose IE long and pointy or blunt] value is important. In addtion the lenght to depth ratio[L/d] of the projectile is important as the effect on slope is in the nose, the longer the projectile the less this effects sloped armor.

As a rule long pointy projectiles take a longer route through the armor compared to blunt ones, but the higher the L/d the lower the effect.

Ari Maenpaa · September 2, 2000

I was rereading the thread and spotted this:

<BLOCKQUOTE>quote:<HR>Originally posted by The DesertFox:

But one more remark you might want to check. It occurs to me that the 76L/55 US M1 gun you have in the game is more like a representation of the 76/L62 on the Walker Bulldog which was built in the 1950's ? Why is that ? I could be wrong of course

And please don´t misunderstand all this talk about the game as an attempt to smash it. No that isn´t the intention. It merely is a sign that we all love this game and want it to be as close to realism as possible. You know if we don´t find some big bugs to pick at we start to analyze the details.

Helge

Because I don't have the (re)sources to examine it myself, could You Helge or somebody else give some more detailed info about these two 76s?

Is this the gun in upgunned Shermans?

Maybe this isn't directly under the main topic, but the whole discussion has made me curious.

Thank You.

Ari

aka_tom_w · September 3, 2000

Just checking up on my favourite thread....

what do you think of my new sig file?

-tom w

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<BLOCKQUOTE>quote:<HR> "Following are opinions (very abridged because of the size of this post) of members of the 66th and 67th Armored Regiments and 2nd Armored Division:

The consensus of opinion of all personnel in the 66th Armored Regiment is that the German tank and anti-tank weapons are far superior to the American in the following categories.

Superior Flotation.

Greater mobility. This is directly contrary to the popular opinion that the heavy tank is slow and cumbersome.

The German guns have a much higher muzzle velocity and no telltale flash. The resulting flat trajectory gives great penetration and is very accurate.

The 90-mm, although an improvement, is not as good as either the 75 or 88. If HVAP ammunition becomes available, it will improve the performance of both the 76-mm and 90-mm guns.

German tank sights are definitely superior to American sights. These, combined with the flat trajectory of the guns, give great accuracy.

German tanks have better sloped armor and a better silhouette than the American tanks.

The M24 tank has not been available long, but has created a very favorable impression.

The M4 has been proven inferior to the German Mark VI in Africa before the invasion of Sicily, 10 July 1943. "

-Brigadier General J. H. Collier, Commanding Combat Command "A"

Ari Maenpaa · September 3, 2000

<BLOCKQUOTE>quote:<HR>Originally posted by aka_tom_w:

what do you think of my new sig file?

-tom w

COOL !

Ari

Dittohead · September 4, 2000

Bumping JP

aka_tom_w · September 4, 2000

Good choice to bump Dittohead

Thanks