How thick was the Jpz IV mantlet? Noticed it's vulnerable in game..

[Bulletpoint]

The ever-watchful bug eye has fallen on the Jpz IV

I noticed that in a recent game, a Jpz IV took a lot of 57mm AT-gun hits directly from the front at short range, and all shots bounced off, except for those that hit the mantlet straight on. 5 penetrations on the mantlet, none on the rest of the tank.

As the armour on the "snout" is extremely sloped against hits from the front, those penetrations seem odd to me, but I haven't been able to find any sources on the thickness of that armour piece.

Anyone has the info?

[wadepm]

If War Thunder is to be believed () the mantlet attached to the gun is 75 mm and the immovable part behind it is 80 mm.  Their effective thickness, taking in to account the angle from straight on, is 111 and 207 mm, respectively.  Take this for what it is... 

[JoMac]

Well, according to one of my Miniature War-games Rules the Jpz IV Short has 60mm sloped Hull @ 45-50 degrees-ish, and Mantlet has 80mm sloped @ 45 degrees-ish.

Keep this in perspective with the Jpz IV 70 Long, which has 80mm Sloped Hull @ 45-50 degrees-ish, and Mantlet about the same. 

I wonder if many hits in CM to the Mantlet are partial penetrations (in the sense that it penetrates the initial Outer Weapons Mount, but not the inner)...So, you may see penetrations listed, but in affect it's not penetrating fully into the Fighting Compartment, and Vehicle is still Ok.

Edited January 7, 2018 by JoMc67

[Bulletpoint]

Thanks. This is with the Jpz IV (late) 75mm L/48.

Another interesting thing was that the penetrations on the mantlet make a hole, but they don't give any penetration message! They all say "Hit: Weapon Mount"...

It's being shot at from 361m distance, and the enemy AT gun is placed straight in front, but at a lower elevation. This should further increase the angle of impact when hitting the top of the mantlet..

 

Edited January 7, 2018 by Bulletpoint

[JoMac]

9 minutes ago, Bulletpoint said:

Thanks. According to this website, the Jpz should be invulnerable from the front against US 57mm AP shot, at all ranges. My example takes place at 361 metres.

Another interesting thing was that the penetrations on the mantlet make a hole, but they don't give any penetration message! They all say "Hit: Weapon Mount"...

 

(This is with the Jpz IV (late) 75mm L/48)

Yeah, see what I wrote above, and that's my guess of what's happening...It's probably how the Mechanics work in CM.

Edited January 7, 2018 by JoMc67

[Bulletpoint]

11 minutes ago, JoMc67 said:

the Jpz IV Short has 60mm sloped Hull @ 45-50 degrees-ish, and Mantlet has 80mm sloped @ 45 degrees-ish.

So if the mantlet is thinker than the front hull, and both are angled about the same, the mantlet should be stronger than the hull (unless it's made of soft metal?). But in my tests that I'm looking at right now, the mantlet gets penetrated by every single shot, and the hull deflects every single hit.

And all these mantlet hits leave a hole, but NO penetration message. The tank is not damaged inside, only the gun was knocked out by the very first hit.

I can't remember ever seeing a tank get a visually represented hole anywhere without the penetration message, so something tells me there's a technical issue here.

Edited January 7, 2018 by Bulletpoint

[JoMac]

4 minutes ago, Bulletpoint said:

So if the mantlet is thinker than the front hull, and both are angled about the same, the mantlet should be stronger than the hull (unless it's made of soft metal?). But in my tests that I'm looking at right now, the mantlet gets penetrated by every single shot, and the hull deflects every single hit.

And all these mantlet hits leave a hole, but NO penetration message. The tank is not damaged inside, only the gun was knocked out by the very first hit.

I can't remember ever seeing a tank get a visually represented hole anywhere without the penetration message, so something tells me there's a technical issue here.

Hmm, Huston, I believe we might have a problem, then.

[Bulletpoint]

14 minutes ago, JoMc67 said:

Hmm, Huston, I believe we might have a problem, then.

Well, a savegame is available  if anybody more knowledable than I would like to take a look at it.

Update: Even more interesting.. Some of the hits that make holes still show the shot bounce off and fly away. So it penetrates and doesn't penetrate at the same time 

Edited January 7, 2018 by Bulletpoint

[Vanir Ausf B]

Send it to me.

[Sgt.Squarehead]

Just a thought, but could the rounds be penetrating and jamming the mantlet? 

This would KO the gun, but otherwise not harm the vehicle, as described by @Bulletpoint.

[Bulletpoint]

2 hours ago, Sgt.Squarehead said:

Just a thought, but could the rounds be penetrating and jamming the mantlet? 

This would KO the gun, but otherwise not harm the vehicle, as described by @Bulletpoint.

In theory yes, but I f they penetrate, why is there no penetration message?

Also why is the tip of the snout mantlet the most vulnerable point - it seems to be the part that should be the strongest against fire from the front?

[Sgt.Squarehead]

1 hour ago, Bulletpoint said:

In theory yes, but I f they penetrate, why is there no penetration message?

Because the fighting compartment itself is not penetrated, just the mantlet.

1 hour ago, Bulletpoint said:

Also why is the tip of the snout mantlet the most vulnerable point - it seems to be the part that should be the strongest against fire from the front?

Not a Scooby.....Makes no sense to me either, just offering possibilities.

[Bulletpoint]

15 minutes ago, Sgt.Squarehead said:

1 hour ago, Bulletpoint said:

Also why is the tip of the snout mantlet the most vulnerable point - it seems to be the part that should be the strongest against fire from the front?

Not a Scooby.....Makes no sense to me either, just offering possibilities.

It's all good, I just forget to add a smiley sometimes

[Sgt.Squarehead]

I believe I've got a Spielberger text on the Jagdpanzer IV.....I'll take a look later for any known vulnerabilities, but I don't ever recall seeing it mentioned as a weak spot in the past (other than the shape of it in Dragon's kits, but that's a discussion for another forum). 

[Bulletpoint]

19 hours ago, Vanir Ausf B said:

Send it to me.

I sent you a savegame an a mail about the possible issues.

[Vanir Ausf B]

The JPz IV mantlet has two sections and there is an air gap between at least the outer edge of the first section and the second. At least some of the apparent penetrations are penetrating the outer plate and then getting stopped by the inner plate. You can sometimes see the two hit decals if you ghost the camera through the vehicle. When a shell strikes two plates in rapid succession only the hit text for the second impact is displayed.

The problem is that everything that get past that first section is knocking out the main cannon. That seems hard to justify so I have logged it as a bug.

[Bulletpoint]

6 hours ago, Vanir Ausf B said:

The JPz IV mantlet has two sections and there is an air gap between at least the outer edge of the first section and the second. At least some of the apparent penetrations are penetrating the outer plate and then getting stopped by the inner plate. You can sometimes see the two hit decals if you ghost the camera through the vehicle. When a shell strikes two plates in rapid succession only the hit text for the second impact is displayed.

The problem is that everything that get past that first section is knocking out the main cannon. That seems hard to justify so I have logged it as a bug.

Thanks for taking a look.

You find the penetrations of the mantlet to be in line with what can be expected of this plate and angle of impact?

Again, I'm no expert, but that part seems awfully thick and well angled against hits coming in head on.

[Vanir Ausf B]

5 hours ago, Bulletpoint said:

You find the penetrations of the mantlet to be in line with what can be expected of this plate and angle of impact?

I don't think any of those hits should make it into the interior of the vehicle. Since they don't appear to be making it that far I don't see a problem there. The gun damage is another matter.

Edited January 9, 2018 by Vanir Ausf B

[Sgt.Squarehead]

The damage to the mantlet might plausibly take the gun out of battery, even if the mantlet stops the round it's still absorbing a lot of energy.....Haven't had a chance to look at Spielberger or similar yet (up to my neck in Shermans), but I will. 

[General Jack Ripper]

We could be seeing something related to the old 'King Tiger Mantlet' bug, where the armor of tubular shaped mantlets wasn't being counted.

 

[Sgt.Squarehead]

Had a look in the obvious places and the only notable comments are the usual ones about the vehicle being front heavy, there's a comment about a number of prototype designs before the Saukopf was settled on and a picture of a type I'd never noticed before (which I can't currently find online), but nothing about any notable weakness. 

In a fair few pictures of KOed JgPz.IVs the mantlet has gone missing:

But equally often it's often the last thing to go:

Found these in a WT forum, possibly of interest, relevance:

[Bulletpoint]

1 hour ago, Sgt.Squarehead said:

Found these in a WT forum, possibly of interest, relevance:

This picture shows the mantlet to be much thicker and more sloped than the frontal armour. In my test, shots go through the mantlet all the time, but in no cases penetrate the front hull.

Edited January 9, 2018 by Bulletpoint

[Sgt.Squarehead]

That's not an armour thickness diagram, it's showing a profile of the mantlet rather than a section through it, the saukopf is a complex thing but the other diagram summarises its thickness at 80mm approx. with 30mm of armour behind it.  The main gun mount surrounding the aperture looks to be 80mm approx. too, which IIRC matches the frontal armour figure for a late L48 or a L70.

Edited January 9, 2018 by Sgt.Squarehead