StuG BS discussions

[Mobius]

Is that a European or African Paella?

[Ratzki]

Can we get some pictures of the tanks with the modification slathered on, I need a picture. Anyone know if this was ever done at the factory, or is this just a field fix?

[Jacko]

This has gone far enough, don't you think, guys? [;)] You've made your point now. Put your energy in more serious subjects and let's keep this forum civil and tolerant.

[Yoozername]

ORIGINAL: Mobius

ORIGINAL: Yoozername

The Soviet HVAP BR-350P
This arrow-head design 'featured' a follow-on slug of steel material. Evidently to save tungsten. Arrowhead designs were dropped by the Germans. The HVAP were not very effective vs. sloped armor since they would 'land' on the soft outer carrier material, typically aluminum, and destabilize. The Soviet round, with its steel 'follow-on' was unstabile even further. This design is best used against vertical armor. Actual penetrator is 27mm in diameter.

We don't call Soviet Arrowhead 'HVAP'. We call it APCR. As we have separate penetration adjustment tables for subcaliber shot of APCR, HVAP, APDS and now APCNR.

They are slightly different. US HVAP has the most deflection on sloped armor, APDS the a little less and APCR and APCNR the least. Though these all have much more deflection than the full sized rounds.

When the game starts up and you are waiting for it to load little tip bits of info are shown the player. Some of the messages are about things like APCR and its origins.

If we were to do a modern game mod (as some suggest) we would need a variable penetration table for APFSDS. It wouldn't have much deflection as instead of a sharp nose like APDS as it has a blunt nose like APBC. I guess you could even use the APBC table in a pinch.

This is somewhat confusing since you used deflection table in the last post. Is the deflection table some routine that checks for ricochet before it checks penetration?

In any case, the Soviet APCR round is just about the worst candidate for piercing highly sloped armor. And that can be sloped from the vertical or shots that have struck the side of a vehicle with vertical armor at an extreme angle. The design of the 350P shows the hard tungsten to have a length of approx 70mm and a diam of 27mm? It is usually overmatched by most armor as far as diam to thickness. The rear-steel slug would more than likely not follow a penetration and probably would break away on high angle impact.

Edit: concrete would actually help the APCR round.

[Mobius]

ORIGINAL: Yoozername
This is somewhat confusing since you used deflection table in the last post. Is the deflection table some routine that checks for ricochet before it checks penetration?

I think this is brought out in the rules.
Besides the classical penetration vs. armor values there is a modifier applied to the penetration number.
The modifier is dependent on both the type of shell and armor traits.
There are tables of the modifier for vertical armor, highly sloped armor, round armor and deflection angled armor.

[Yoozername]

Ricochet and armor penetration are two different things.  Ricochet, in some cases, does not depend on the surface material for example.  But you are attempting to abstract the dynamics.  I suppose that shooting from the sides will tell.

[Josh]

Nice find. "Kleeblatt" is german for "clover". So a T-34/76 could penetrate a Tiger I at three o'clock at 1500 mtr? That's a longer distance than I thought... but I'm no expert on this. Even at 2 o'clock the Tiger is safe at less than 500 mtr, then at 3 o'clock the 76 gun becomes dangerous at 1.500 mtr...
The leaflet advices the crew to turn the frontal armor to the enemy, and when faced with two opponents to turn the frontal armor to one opponent and kill the other one.

[Yoozername]

I think the intent is 'certainty' (sicher).  The Tiger may only be vulnerable in the lower side armor past the roadwheels.  A very small target to hit without striking roadwheels.  But the Germans are showing Tiger crews that IF they want to be certain THEN make sure no one is sitting to your immediate right or left for 1500 meters. Keep all enemys in 'front' of you to either the half-right or half-left and make sure they are 500+ meters away.

But it does illustrate the benefits of ricochets and the natural 'sloping' that even vertical armor recieves from shot landing at an angle.

[Mobius]

I've tried to run down the % chances of penetration for the early round of the T-34 gun.
The 8% chance at the longer ranges reflects the vulnerable lower hull past the road wheels.

[Mad Russian]

Tiger and Panther crews were notorious for thinking they were invincible. Guderian told them, that cat fur didn't stop enemy tank shells. A clear warning to use good tactics all the time.

Good Hunting.

MR

[Lieste]

Why the higher rear penetration chance? I thought that the hull was 80mm upper hull side, turret curve and rear hull, with 60mm plus interleaved road wheels in the lower hull area, which is quite variable depending on how many (from 0-6) wheels are penetrated.

The side hull is vertical, the rear hull has a small underslope, and the turret is curved - somewhat flatter towards the mantlet area than over the rear curve, and not symmetrical left/right.

[Mobius]

ORIGINAL: Lieste

Why the higher rear penetration chance? I thought that the hull was 80mm upper hull side, turret curve and rear hull, with 60mm plus interleaved road wheels in the lower hull area, which is quite variable depending on how many (from 0-6) wheels are penetrated.

It's not higher, its lower. It is about 33% out to 270m. The sides have two ranges. 26% out to 270m and another 8% all the way to 1070m. (Note- I did some rounding).

[Lieste]

That is an odd presentation...   what you mean is 26+8 at 270m or 33/34% at 270?
It really isn't reading like that from your image... which looks much more like 26% or 18+8.

Anyway, so long as the engine combines them correctly... [;)]

[Yoozername]

I don't get it.  Why is there no rear 8% arc at the bottom somehwere?  Is the rear suddenly safe after the 33% is done?
 
It appears that these AP shells coming into the side armor at 750 meters, at about a 45-60 degree angle to the side armor, are doing very well.  Even without hitting wheel or tracks.
 
This modeling of side armor seems to go against the Soviets own findings and the reported armor penetration values they used. 
 
The clover-leaf is way to fat on the sides of Mobius' modeling. 
 
 

[Yoozername]

[Ratzki]

You have to use Russian penetration reports very carefully, 1st they purposely error on the conservative side, usually about 5-10% conservative values. Secondly, they require much higher test penetration levels in comparison to everyone else before before confirming armor vulnerability to the round in question.

[Prince of Eckmühl]

ORIGINAL: Ratzki

You have to use Russian penetration reports very carefully, 1st they purposely error on the conservative side, usually about 5-10% conservative values. Secondly, they require much higher test penetration levels in comparison to everyone else before before confirming armor vulnerability to the round in question.

Some published Russian values for F-34:

[Prince of Eckmühl]

I've not checked every entry, but the values in the following translation should be the same:

[Lieste]

CP is certified (80% chance of 50% mass passing the plate) and IP is ?expected? penetration (50% of 50% mass passing)?

[Yoozername]

No its supposedly all based on 75% of the shell's mass making it through.  So, IP or Initial penetration, is when 1 out of 5 (20%) make it (that is, 75% of shell mass is inside AFV), and CP or Certified Penetration is when 4 out of 5 'make it'.

A very odd way of reporting penetration indeed.  The variance is from a number of factors if the data is that skewed.

Other data is noted as being 'tabular' and is supposedly a calculated value. It is calculated from when a AP round can first break through (front/crack-bac)..

But most 76mm and larger Soviet AP weapons have CP or both CP and IP values.

The bad quality of this ammunition is documented.

To do a IP/CP test would require firing a minimum of 10 rounds at the same distance. More than likely, 30-some rounds would be fired.

The reason being is that this is a distribution. If we look at BR-350A, 500 meter target (assume good RHA), we see an IP of 70mm and a CP of 59mm. Its a good hunch the 50% point is about the average of those two. Lets say 65mm for the sake of discussion. Note that this is hitting armor sloped from the vertical by 30 degrees. I really doubt the IP or CP or the Pavg is going to be looking so good at a 45 degree slope. And that is 500 meters. And that is without it striking a track or multiple roadwheels.



Image shows the real 'naked' 60mm track area. The mud guards are off. I can't see many projectiles making it through without multiple roadwheel strikes.