Frontal armour on the PzIIIH turret and mantlet...a bug?

[rexford]

CMAK tends to give the turret front armor thickness for tanks, cause all tanks have a turret front but a few don't have a big mantlet I guess, and the usen the mantlet thickness for the actual penetration calculations.

Tiger is one example, 100mm turret front "reinforced". The mantlet is much thicker than 100mm on almost all areas when backing plates are cranked in, and the CM games appear to use the mantlet armor when the "turret front" is hit..

With regard to turret armor in general, weight is a big limit and many turret fronts are significantly more vulnerable than the hull front due to weight limits: Panther, T34, T34/85, IS-2, Tiger II.

Tiger is an oddity because the mantlet is better protected than the hull front.

The exact calculations for 37mm/40 degrees are:

37mm armor at 40 degrees resists a 2 pdr AP hit like 59mm vertical, and 2 pdr AP penetrates 59mm of vertical face-hardened armor at 190m or 208 yards. Close to Jentz information.

Various discussions of PzKpfw III mantlets state that the 37mm armed models had an internal mantlet, and the 50mm armed tanks had an external mantlet. There may well be a splash guard between the external mantlet on PzKpfw IIIH and the turret interior to reduce the chance that HE shell fragments and bullets and mantlet flaking will injure the crew.

British records on PzKpfw III show a 37mm mantlet on the PzKpfw IIIH and 50mm mantlet on PzKpfw IIIJ-M, with a 57mm turret front on PzKpfw IIIL,M. The turret front on PzKpfw IIIJ is listed as 30mm.

Our book uses 35mm for PzKpfw IIIE-H mantlet but the British records show 37mm.

[rexford]

Originally posted by Little_Black_Devil:

Thanks Rexford.

I guess I should elaborate, that from the outset, I assumed the turret was as well armoured as the hull, with the exception that the mantlet would be rounded/curved, and that the way this has been conveyed in a myriad of sources was just never "detailed" enough - so as to explain the actual layout of the turret front (armour) and mantlet.

I assumed this, because it just seemed logical to up-armour the turret frontally, as with the hull, so as to be reistent to enemy fire from the front entirely. Leaving the turret so suceptable just didn't make much sense to me.

My fault for making an assumption.

I also meant, earlier - with reference to overlapping of armour, that I was wondering if the Mantlet (37mm curved - or partially curved) overlapped any part of, the front turret armour (30mm) which alone would have provided 67mm of armour (albeit probably spaced). Sorry if I confused this with overlapping the hull.

I didn't expect that the curved portion of the mantlet (37mm at 40°) would equate in resistance as if it were 60mm of Face Hardened Armour).

This obviously explains much.

I should have done some math before I started blabbing I guess.

To sum up - and make sure I undertand this correctly, you're saying that a portion of the PzIIIH mantlet, was 37mm thick and curved at 40° which gave it the equivilent protection of 60mm of Face Hardened Armour (accredited to the tests in Cairo you cited), though the non-sloped portion of the mantlet was only "just" 37mm thick(at 0°?) - which is why, this small (unsloped) area of the mantlet WAS penetrable by the 2 Pounder?

From here;

It appears that, the upper portion of the mantlet, is the part which is sloped at 40°. The lower portion appears to be sloped at roughly a 20° (inverse) angle, with the centre of the mantlet almost at 0°. From that, it would seem that from the centre down - that the mantlet armour would subsequently be less reistent.

Aside from the Mantlet, what little portion of the exposed turret armout there is - would only be 30mm thick at 15°.

Is all that on-track or have I botched it somewhere?

Thanks for the great drawing that brings several points into focus.

What is the source for the PzKpfw III drawing?

[Dinsdale]

I recognize that drawing from a 1943 report on the Vulnerability of German tanks to 20mm MKIII AP

I can send it to you if you like.

[ March 22, 2004, 11:22 AM: Message edited by: Dinsdale ]

[Little_Black_Devil]

What he said.

[MikeyD]

"Various discussions of PzKpfw III mantlets state that the 37mm armed models had an internal mantlet..."

Could it be that 'internal mantlet' in that sentence actually refer to VERY early initial production vehicles? I have vague recollections that 1939 PzIII mantlets looked quite different than the stand wartime type. I'd be awfully surprised to discover a post-invasion of France PzIII had anything heftier than a sheetmetal spall liner behind the mantlet.

[Dinsdale]

You are misunderstanding.

Look at this PIIIE

Compare to the IIIH which has a large External Mantlet.

[Rausch]

"That and the Viewport covers are 25mm-30 mm and vulnerable as well."

This is wrong. The original drawings of the Pz-III H viewport claps show a thickness of about 48 mm. Since it was measured on a curved screen, perhaps 3 or 4 mm less.

[Dinsdale]

This is wrong. The original drawings of the Pz-III H viewport claps show a thickness of about 48 mm. Since it was measured on a curved screen, perhaps 3 or 4 mm less.

That is all fine and dandy but as a Production tank has the following values, measured off the tank, I question the value of your 'original drwaing' until you find any production tanks with a values that corroborates your inforamation.

The covers over the sight openings at either side of the mantlet are 25 to 30mm thick and recess into the mantlet armor when closed.

[Rausch]

You can of course question all you want, basing on "your" "production" tank located in Bovington, which was a training tank upgraded to a hybrid of several variants.

The "production" tank in the collection of the WTS Koblenz has thicker viewport covers than your claimed 30 mm.

The value of the data of the original manual for the Pz-III H can imho be judged by the readers of this forum quite well.

[Dinsdale]

Funny how the III at the Patton Museum has the same values as the one at the Bovington museum.

I'll measure the one at Borden as well later in the Spring.

But of course, your "drawings" are more accurate.

[AC]

My guess: penetration at a weak point?

[Zulu]

Looks like to some over at the WWIIOL kiddie forums, neither Allied nor German equipment has any weak points.

I guess they want bigger clubs. The baby seals must be starting to gum their toes a little too hard.