Panther Shot Trap Still Not Trapping

[Vanir Ausf B]

There is a silver lining to this, which my testing of 76mm at 800 meters reminded me of. US 76mm will penetrate the Panther mantlet at ranges well over the 200 to 400 yard maximum that almost all sources give. Penetrations at 800 meters are not uncommon. It's similar to the extra vulnerability given to the Panther turret in CMx1, although in the case of CMx2 I don't think it is intentional.

[Battlefront.com]

Who said it was trying to be helpful? News flash, it is not always about you.

Nor about the topic of the thread and the issue being discussed

I am just trying to correct the unhistorical conventional wisdom others are posting into the thread, so that people don't walk away thinking it must be true since a grog said it and it went unchallenged. The truth has to put its boots on to catch misinformation, wherever it is posted.

No problems. Standard off topic distraction. I just wanted to make sure nobody thought it was relevant.

Steve

[JonS]

The truth has to put its boots on to catch misinformation, wherever it is posted.

And The Source of The Truth would be . . . you, and you alone?

Thank you so much for bestowing your arrogance upon us ignorant mortals.

[Thomm]

Grogs,

Please help me save some time by:

*) pointing me to a cross-section of the 75 mm shell from Vanir's test

*) giving me the outer radius of the Panther mantlet

*) and its thickness (100 mm? 120 mm?)

*) material data for armor (stress-strain diagram if possible)

*) material data for shell (stress-strain diagram if possible)

I can set up a rudimentary finite element analysis of the proplem in half an hour, but I cannot do the research in the same time-frame.

Best regards,

Thomm

[A Canadian Cat]

The truth has to put its boots on to catch misinformation, wherever it is posted.

Duty Calls

[A Canadian Cat]

I can set up a rudimentary finite element analysis of the proplem in half an hour, but I cannot do the research in the same time-frame.

Now that sounds interesting. Are you saying you have a system that can simulate the plasticity of the round and the armour to determine the final ricochet path (if there is one)?

It has been a long time since I did any finite element analysis and then it was all fluid dynamics, so deforming mesh.

[Vanir Ausf B]

*) pointing me to a cross-section of the 75 mm shell from Vanir's test

*) giving me the outer radius of the Panther mantlet

*) and its thickness (100 mm? 120 mm?)

*) material data for armor (stress-strain diagram if possible)

*) material data for shell (stress-strain diagram if possible)

I can find pictures of the 75mm M61a1 shell and cross-section diagrams of shells of the same type, but I have not found a cross-section of the M61a1 itself.

No idea what the exact dimensions of the mantlet are. It is generally described as 100mm thick, but its actual thickness varied along it's curve.

http://www.battlefront.com/community/showpost.php?p=448992&postcount=50

As for the material, all I can tell you about the mantlet is that it is cast armor, although for reasons that are not entirely agreed upon it seems to have resisted more like rolled homogenous.

Don't know much about the M61a1 shell materials except as a APCBC shell it has a penetrating cap of softer metal attached to the main perpetrator, and then a ballistic cap on top of that for improved aerodynamics.

[Vanir Ausf B]

[slysniper]

Duty Calls

Now that is not very nice.

You know Jason has great resourses or at least knows where to find them as to all sorts of data and facts.

Just because he has strong opinions on how to use them, does not make him much different than many others here on this forum.

Just way to many people here that only want to understand things by the way they see it. it is just how people are. (myself included)

And for the record (bottom mantlet hits should be penetrating the top deck about 15% of the time) when hitting on the sweet spot of the curve. - this with all varables possible (what does the game do - I have no clue) Where did I get that number

[A Canadian Cat]

Now that is not very nice.

You know Jason has great resourses or at least knows where to find them as to all sorts of data and facts.

Just because he has strong opinions on how to use them, does not make him much different than many others here on this forum.

It was not meant to be unkind. It was meant for a laugh - hopefully Jason can laugh too. I know I laugh at my self when I do that kind of thing. It certainly applies to many of us. My point simply is that when any one of us decides to right all the wrongs we have a big job on our hands. And we should all have a laugh at ourselves from time to time.

Now just wait I'll discover that you were joking too...

[JonS]

Way too many people only want to understand things by the way they see it. It is just how people are. (myself and Jason included)

FTFY

HTH

[JasonC]

ian - my thought on the cartoon - which I have seen before - was "precisely. That is it, precisely". Must fix, or do somefink...

[Thomm]

Now that sounds interesting. Are you saying you have a system that can simulate the plasticity of the round and the armour to determine the final ricochet path (if there is one)?

Not exactly me, but the company I work for. I downloaded a couple of recent papers on ballistic simulation and they used the same general-purpose code.

Since the geometries are so easy, I was able to set up a basic shell versus armor plate simulation within 20 minutes, but with generic (i.e., fantasy) material properties.

I stopped for the time being when I could not get the remeshing algorithm to work, which is supposed to prevent finite elements from collapsing due to localized deformation, but I intend to pick it up again at some point, most likely in the Christmas holidays when more resources are available.

Best regards,

Thomm

[John Kettler]

Vanir Ausf B,

If you go look at the actual firing trials I cited in the stuff from The Chieftain's Hatch, the 76mm, supposedly a hot gun, failed to penetrate the Panther (and a beat up one at that) frontally at 200 yards, causing Ike to come unstuck. Given that was live fire, why should we believe that you can penetrate in the game at four times the range where the real 76mm, firing against a real Panther frontally, failed miserably?

That is a very big (15") APCBC shell you provide as an exemplar, and full marks for the inadvertent drollery of using "perpetrator" instead of "penetrator." The M62A1 cutaway is on page 504 of this. Simply put the scribd commercial header on the front end.

doc/13810984/Standard-Ordnance-Items-Catalog-1944-Vol-3

Thomm,

The Handbook of Ballistic and Engineering Data for Ammunition, Volume II (July 1950) is full of exactly the kind of information you'll need to run the projectile end of things. Please be sure you go find and read the results at The Chieftains Hatch of no less than four separate tests against the Panther (Shoeburyness, Isigny 1 and 2, Balleroy). They make fascinating, and most useful, reading.

http://www.dtic.mil/dtic/tr/fulltext/u2/a955369.pdf

Regards,

John Kettler

[Vanir Ausf B]

Vanir Ausf B,

If you go look at the actual firing trials I cited in the stuff from The Chieftain's Hatch, the 76mm, supposedly a hot gun, failed to penetrate the Panther (and a beat up one at that) frontally at 200 yards, causing Ike to come unstuck. Given that was live fire, why should we believe that you can penetrate in the game at four times the range where the real 76mm, firing against a real Panther frontally, failed miserably?

The reason that you should believe you can is because I said you can, and I have confirmed it through testing on multiple occasions. Set up your own test if you don't believe me.

The M62A1 cutaway is on page 504 of this.

Ironically, I was looking through that very same document last night for Bazooka information. I should've kept scrolling.

BTW, here is the full link. It's on page 71 in the viewer.

http://www.scribd.com/doc/13810984/Standard-Ordnance-Items-Catalog-1944-Vol-3

[JasonC]

JK - you are failing to distinguish the turret from the glacis. The US 76 has no chance against the glacis, and that was news to people who did not fully appreciate the full power of it being so sloped. But it did in practice as well as in tests routinely penetrate the mantlet at 400 yards, and a lot farther than that with APCR. The round suffered shatter gap failure between 400 and 1000 yards, where the naval penetration equations said it had sufficient power to penetrate the mantlet (not the glacis). That too was news, because it depended on material failure of the round before the plate, not on insufficient kinetic energy to bore through it. That, the US 76 did have at those medium ranges with plain AP. But the round couldn't take it. APCR was the fix for that problem, as soon as it was understood.

[John Kettler]

JasonC,

The firing results for the 3-Inch/76mm were:

"7) 3-inch Gun, M5, mounted on Motor Carriage, M10

a) APC M62, w/BDF M66A1 will not penetrate front glacis slope plate at 200 yards. Will penetrate gun mantlet at 200 yards and penetrate sides and rear of the 'Panther' Tank up to 1500 yards."

At this stage of the war, there was no HVAP for that gun in service, so the point's moot. I do see, though, the dangers of working from memory, in that I got only part of the critical information right regarding the test which set off Ike. APC M62 was the Standard round for the 3-Inch/76mm and was really APCBCHE, where AP Shot M72 was Substitute Standard until production could be ginned up and deliveries made on the"earlier" round. As a long discussion on the CMFI Forum eventually established, by the time Italy was invaded, the M62 was what the M10s were firing. From this, it's obvious that both the M10s and 76mm Shermans at Normandy were firing what in U.S. military shorthand was called the APC M62.

Regards,

John Kettler

[JasonC]

JK - first, penetrating the mantlet at 200 yards it not not penetrating from the front. Second, combat AARs from Normandy and Lorraine have US 76mm penetrating successfully out to 400 yards, not 200. (By the Bulge they have APCR so longer kills are commonplace). Third, still not getting the irrelevancy, so an operational odds explanation is in order.

This is the armor odds match up for Cobra, scaled down. The Germans start with 1 Panther, 1 Panzer IV, and 1 StuG on the map as their armor force component. They get a reinforcement of 1 additional Panther and 1 additional Panzer IV, together, early in the fight. A bit later they get a 2nd StuG too, doubling their original force. To deal with these beasties, the Americans get the following, all on map from the start -

2 76mm Shermans, model M4A1(76)

2 105mm Shermans

5 M10 tank destroyers

17 M4 (75) Shermans

12 M5A1 Stuarts

(They would also have 3 Priests but those would be off map...)

[Cuirassier]

And have the Germans attacking.

[John Kettler]

JasonC,

All the test said was that the 3-Inch/76mm would penetrate the Panther's mantlet from 200 yards, but there were no tests done then to ascertain the range from which the 76mm would no longer penetrate. I therefore have no quibble with the 400 yard ranges cited the AARs, which I'd love to read. Are any online? The operational case you present is downright scary for the Germans. I'd attempt to list the how they lasted as long as they did in Normandy, but I'd doubtless forget something significant.

As ever, you remain the Man on operational and war production matters. Again I request: Please write a book. You obviously thoroughly command and have mastery over your subject matter.

Regards,

John Kettler

[Cuirassier]

Yes they are online:

http://www.history.army.mil/html/bookshelves/resmat/ww2eamet.html

The Lorraine volume is quite good. However, it takes some combing through to find the specific actions involved, as the books cover lots of higher level operational stuff as well.

[JasonC]

"And have the Germans attacking."

LOL. Not quite, but close. The forces I gave are for the breakout and immediate reaction reserves, rather than the grandious counterattack. After most of the force I described is overrun, with maybe 1 Panzer IV left, give the Germans the following reinforcement to initiate their grand counterattack -

2 Panthers, 1 more Panzer IV, 1 Jagdpanzer IV, a Pz Gdr platoon riding them, and a second Pz Gdr platoon in SPWs trailing the newly arriving armor.

The Americans get 2 155mm and 4 105mm FOs the turn those arrive. (They have a whole infantry battalion from the outset, incidentally). Then at intervals give them air support from 5 Typhoons and 3 P-47s to supplement the on board armor. There is your Mortain counterattack, to scale.

FWIW.

[OrdeaL]

Sounds too scary to be a German to me!

[c3k]

Verdammt! If it weren't for that darn mantlet deflection problem, they would've succeeded!

[Redwolf]

There is a silver lining to this, which my testing of 76mm at 800 meters reminded me of. US 76mm will penetrate the Panther mantlet at ranges well over the 200 to 400 yard maximum that almost all sources give. Penetrations at 800 meters are not uncommon. It's similar to the extra vulnerability given to the Panther turret in CMx1, although in the case of CMx2 I don't think it is intentional.

I thought that the vulnerability given in CMx1 *was* the shot trap?