Wow, Panther destroyed Stuart and Sherman in one hit!

[phil stanbridge]

Talk about tough! These things are hard to kill. I've seen a few good shots and HE brewing up after it has been hit but nothing like this - one AP shell from a Panther seems to fly through the little Stuart, then impacts the Sherman behind it. The Stuart exploded, killing the crew instantly, and the remaining Sherman crew bailed. How unfortunate! I love this stuff. But would this sort of thing happen in reality?

[GreenAsJade]

No.

IMHO it's a bug: it seems that projectiles retain their speed after punching through things.

1) Shells either explode or deform when they hit something

2) They slow down.

GaJ

[phil stanbridge]

No.

IMHO it's a bug: it seems that projectiles retain their speed after punching through things.

1) Shells either explode or deform when they hit something

2) They slow down.

GaJ

Yeah that's what I was thinking. It doesn't happen all the time however. Just the odd shot, seems to get lucky.

[Boche]

well to not happen all the time we are seeing tonns of them on the forum xD

[womble]

I don't think it's unreasonable for more than one light armoured vehicle to be mangled by a single tank-killing KE round. Additional armour equal to one M5 though should make a Sherman pretty much invulnerable... If energy loss/deformation isn't modelled, punching its way out of the first target won't decrease its efficiency either...

[Glukx Ouglouk]

Not to mention that the AP round fired by a Panther is an APHE round, and should detonate and fragment after punching through an armor plate... Unless the game models some failure rate for the fuses, of course.

[bowlie]

i had this happen when a sherman took out two tank destroyers but they where literaly right next to each other so it was fair enough. it works because they made it so that rounds pass through dead tanks to stop you hiding behind a dead tank and letting the AI waste its ammo. as soon as the first round killed the first tank it became 'see-through' for the round and it carried on going. they could make it so that it dosnt happen, but that may cause problems when it dosnt kill the tank. there are some quite fun ricochets that might have to go to make it work

[YankeeDog]

Two armor plates separated by distance don't resist like one armor plate of the two combined. It's complex and depends a lot on the specific nature of the plates and the projectile. If the projectile substantially overmatches the first plate (e.g., the diameter of the projectile is more than 1.5x the thickness of the armor), the plate may not slow the projectile much at all.

However, IMHO, there is a bug here, or at least an element missing from the game model, because HE Burster charge that is part of the Panther AP shell doesn't seem to be taken into account.

Looking strictly at the kinetic energy of the projectile, a 75mm/L70 shot might well have enough power to through-and-through a Stuart, and then penetrate and KO a Sherman; especially if it hits the Sherman flank, as in this shot.

However, in the vast majority of situations, I would think that while the projectile easily overmatches the Stuart's armor from any aspect, the impact with the Stuart would nevertheless be enough to detonate the HE Burster fuse on the shell, which would mean that the shell would turn into shrapnel a few feet after impacting the first armor plate.

A secondary issue is what happens to the projectile shape and flight aspect after the first penetration. If the HE burster doesn't detonate, the projectile may easily penetrate the Stuart, and leave that vehicle with a substantial amount of KE. But the impacts with the Stuart (at least 2) will probably blunt the nose, and may also cause the projectile to yaw or tumble, which will substantially degrade the aerodynamics (meaning it will slow quickly as it continues to fly), and also reduce penetration on the next impact due to the degraded shape of the nose.

This is a difficult thing to test, but overall, it does seem that something is a little amiss here.

[argie]

4 HTs with one AP round

[flammenwerfer]

No.

IMHO it's a bug: it seems that projectiles retain their speed after punching through things.

1) Shells either explode or deform when they hit something

2) They slow down.

GaJ

3) Deflect/Change direction.

[dieseltaylor]

Tank Men records a Sherman commander who seeing an AA smartly retreated his tank behind a cottage only for the shot to come through the cottage and hit the tank rear side armour. He thought it made it through 5 walls - so I assume he counted.

[YankeeDog]

Well, yeah, but with the exceptions of really heavy construction like thick stone and rebar concrete, large caliber AP rounds go through most building materials like they're barely there. Even the relatively thin 29mm RHA plate on an M5A1 Stuart side provides far more resistance to a projectile than the wall of your typical modestly constructed cottage.

[bowlie]

Well, yeah, but with the exceptions of really heavy construction like thick stone and rebar concrete, large caliber AP rounds go through most building materials like they're barely there. Even the relatively thin 29mm RHA plate on an M5A1 Stuart side provides far more resistance to a projectile than the wall of your typical modestly constructed cottage.

yeah but to me 'cottage in Normandy' sets an image of large thick stone walls. if it went through 5 of those.... wow

[ClarkWGriswold]

I wonder if this behavior has something to do with the way vehicles are treated when knocked out? The way the game works, KO'd vehicles are basically "ghosts" that can be shot through with no effects. This was done to address problems with the TacAI firing round after round into a dead vehicle, trying to hit a live vehicle behind it. To fix the problem, BFC made dead vehicles so that AFVs can shoot through them as though they aren't there. This is why we see, for example, the Panther in Barkmann's Corner shooting through three dead Shermans and killing the live one behind them. I get the feeling that perhaps this behavior is having unintended consequences in these situations as well:

The AP round hits vehicle #1 and kills it.

Vehicle #1 is now dead, so the game treats it as though it's not even there.

The AP round continues out the back of the vehicle, not impacting anything on its way out.

The AP round hits vehicle #2.

If vehicle #2 is immediately KO'd, then the whole thing starts over and the round continues out the back of the 2nd vehicle.

If any of the vehicles in the sequence aren't immediately KO'd (just crew casualties or whatever), then the round may be contained inside that vehicle since the game is not treating it as a dead "ghost" vehicle.

No idea if this is actually what's happening, but it seems like a plausible possibility. At the very least, it seems as though explosive AP rounds are being treated like solid, kinetic energy rounds. There doesn't seem to be any fragmenting once a round hits an object. Even if the "invisible" dead vehicle behavior isn't what's causing this problem, it should probably be changed anyway.

[YankeeDog]

This is actually the image that convinced me something isnt' right here:

I mean, sure, an 88mm round easily penetrates a Stuart. But that round goes right through the front upper hull plate (29mm @ 48 degrees), through the body of the vehicle (where it virtually has to run into a bunch of chunky stuff, including part of the engine), and out the rear plate (25 @ 0 _)degrees), and then plows on to the next Stuart with virtually no deflection.

Unless the game is modeling the occasional failure of the HE burster to detonate (and, from what I understand, the German APHE fuses were very reliable), I just don't see this happening.

[akd]

I wonder if this behavior has something to do with the way vehicles are treated when knocked out? The way the game works, KO'd vehicles are basically "ghosts" that can be shot through with no effects. This was done to address problems with the TacAI firing round after round into a dead vehicle, trying to hit a live vehicle behind it. To fix the problem, BFC made dead vehicles so that AFVs can shoot through them as though they aren't there. This is why we see, for example, the Panther in Barkmann's Corner shooting through three dead Shermans and killing the live one behind them. I get the feeling that perhaps this behavior is having unintended consequences in these situations as well:

The AP round hits vehicle #1 and kills it.

Vehicle #1 is now dead, so the game treats it as though it's not even there.

The AP round continues out the back of the vehicle, not impacting anything on its way out.

The AP round hits vehicle #2.

If vehicle #2 is immediately KO'd, then the whole thing starts over and the round continues out the back of the 2nd vehicle.

If any of the vehicles in the sequence aren't immediately KO'd (just crew casualties or whatever), then the round may be contained inside that vehicle since the game is not treating it as a dead "ghost" vehicle.

No, if you see multiple penetrations it is due to a through and through penetration of the target.

[ClarkWGriswold]

No, if you see multiple penetrations it is due to a through and through penetration of the target.

My point is that through and through penetration of the target would be nigh impossible in most of the situations we're seeing it. Explosive AP shells would fragment long before making it completely through two armored vehicles. Even solid kinetic rounds would be unlikely to go completely through a tank and continue out the other side with NO deflection at all.

Something isn't right. Vehicles becoming "invisible" to the shell might explain it. Shells not modeling explosive detonations might explain it. There are lots of things that could be the cause, but I really don't think this behavior is realistic.

[bowlie]

I wonder if this behavior has something to do with the way vehicles are treated when knocked out? The way the game works, KO'd vehicles are basically "ghosts" that can be shot through with no effects. This was done to address problems with the TacAI firing round after round into a dead vehicle, trying to hit a live vehicle behind it. To fix the problem, BFC made dead vehicles so that AFVs can shoot through them as though they aren't there. This is why we see, for example, the Panther in Barkmann's Corner shooting through three dead Shermans and killing the live one behind them. I get the feeling that perhaps this behavior is having unintended consequences in these situations as well:

The AP round hits vehicle #1 and kills it.

Vehicle #1 is now dead, so the game treats it as though it's not even there.

The AP round continues out the back of the vehicle, not impacting anything on its way out.

The AP round hits vehicle #2.

If vehicle #2 is immediately KO'd, then the whole thing starts over and the round continues out the back of the 2nd vehicle.

If any of the vehicles in the sequence aren't immediately KO'd (just crew casualties or whatever), then the round may be contained inside that vehicle since the game is not treating it as a dead "ghost" vehicle.

No idea if this is actually what's happening, but it seems like a plausible possibility. At the very least, it seems as though explosive AP rounds are being treated like solid, kinetic energy rounds. There doesn't seem to be any fragmenting once a round hits an object. Even if the "invisible" dead vehicle behavior isn't what's causing this problem, it should probably be changed anyway.

yeah thats what i thought. i already brought it up, sorry

[ClarkWGriswold]

Sorry, Bowlie. I somehow missed your comment. I think that regardless of whether or not the "see through" tanks are causing this problem, that behavior is going to have to be changed. I'd much rather have dead vehicles block LOF and LOS than have them block neither one. Just treat every dead vehicle as though it's smoking (blocks LOS) and keep dead vehicles "solid" (blocks LOF) and I think a lot of these strange issues and unrealistic results would go away. Sure, there would be some new strange things that would happen (tanks that look like they should have LOS not being able to see past a dead vehicle, for instance), but I think they would be less of an issue than the current situation, and would probably give more realistic results and be more intuitive at the same time.

[akd]

My point is that through and through penetration of the target would be nigh impossible in most of the situations we're seeing it. Explosive AP shells would fragment long before making it completely through two armored vehicles. Even solid kinetic rounds would be unlikely to go completely through a tank and continue out the other side with NO deflection at all.

Something isn't right. Vehicles becoming "invisible" to the shell might explain it. Shells not modeling explosive detonations might explain it. There are lots of things that could be the cause, but I really don't think this behavior is realistic.

I'm not commenting on whether APHE behaves correctly or whether shell deformation is modeled (we in fact went into an in depth discussion of this during beta testing), but these multiple penetrations are not because the target becomes invisible to the shell.

A through and through penetration is tracked through entry and exit and velocity is lost penetrating both plates. If entry is at a non-normal angle, the chance of exiting through the far plate is reduced.

[beatmasta]

It seems that the ammo that is modeled is more like an APFSDS than one of those WW2 ammo. Maybe the same piece of code calculating the penetrating hits in the BN as in the SF?

[ChrisND]

It seems that the ammo that is modeled is more like an APFSDS than one of those WW2 ammo. Maybe the same piece of code calculating the penetrating hits in the BN as in the SF?

I think it would be WAY more obvious if that was the case.

[Rokko]

But I have definately seen AP shells exploding after bouncing off for example, I even saw casualties occuring that way.

[GLynn41]

the charge in a APHE round is not large --it would shatter the thinner walls of the base of the shell but do nothing to the solid area of the front-- it would seem that this would destabilize the projectile and limit additional penetration--

[ShakyJake]

What Yankeedog says correct. When a shell is capable of significantly more penetration than what the armored plate represents, it won't lose a proportional amount of energy getting through it, but rather much less. There should also be some deformation of the nose in the shell as Yankeedog says, but I'll ignore it now out of convenience. Nathan Okun's published equations for single-plate equivalency of two spaced plates is expressed as:

Total Resistance = [(Resistance Plate1)^1.4 + (Resistance Plate2)^1.4]^(1/1.4)

With a little manipulation of the above equation, you can substitute a gun's penetration for the total resistance, and the plate you're examining for one, and the remaining plate will effectively become the remaining penetration potential of the shell. Rearranging the equation it could be expressed as:

Remaining Penetration = [(Gun Penetration)^1.4 - (Resistance Plate)^1.4]^(1/1.4)

In the OP's scenario, you have both a Stuart and Sherman being penetrated at about a 500m range. I can't see the Stuart's profile, but the Sherman is being struck at around a 30° angle, so we'll assume the same for the Stuart. The shell passes through both 29mm armor plates on the Stuart, and penetrates the 38mm side hull armor on the Sherman. At 500m, the 75mm L/70 can penetrate up to 168mm at 0°. So doing it step by step, we find that:

Stuart first side armor plate: 29mm@30° ~ 35mm, shell penetrates with 154mm of penetration remaining.

Stuart second side armor plate: 29mm@30° ~ 35mm, shell penetrates with 140mm of penetration remaining.

Sherman first side armor plate: 38mm@30° ~ 48mm, shell penetrates with 116mm of penetration remaining.

So from a pure penetration point of view, the OP's scenario is highly probable. Following the calculations through, it could even exit the second Sherman to go through a third Sherman completely before being stopped on the side armor of a fourth. It would even appear that some minor deflection of the shell may have happened in this case, as the two explosion sprites don't quite line up with the Panther's position in the back. So everything above is probably working as intended in the physics model. The only thing missing is the HE burster setting off the shell after the first penetration. The shell shouldn't have continued through so many penetrations without detonating, and if casualties are being determined with the HE burster calculated on each penetration as surmised in the half-track thread, that could be a problem.