Bizarre fluke or dodgy armour modelling?

[Tux]

I have recently had a PSW 234/1 heavy armoured car take a point-blank 75mm AP hit from a Sherman and was gratified (and more that a little surprised) to see it ricochet almost vertically into the air. The PSW was behind bocage but the Sherman's 75mm round definitely appears to hit the 'upper front hull' and then ricochet away causing zero damage. Was this a bizarre fluke resulting from a glancing blow to some obscure part of the car's armour or is something wrong here?

A save file is here for people who want to watch the replay: https://rapidshare.com/files/974096071/SPW_234_armour.zip

My laptop is very slow when running CMBN but I might try a few tests soon if I can get it to take less than an hour to set up...

[Battlefront.com]

Hmmm... I don't know! Definitely suspicious enough to take a look into, though often Charles comes back with an answer that is surprisingly supportive of the effect

Steve

[Dadekster88]

I haven't watched it but just the fact that you said the round went vertical implies a pretty hard ricochet which does sound odd.

[siffo998]

just took a look at...

i wish that had happened to me when i first played this campaign...

really seems a bit strange... especially that the shell did not penetrate and bounced of verticaly which indicates that it hit the armor directly and not just touched it at the edge.

the only thing i could think of is that the shell hit the heavily sloped 30mm upper frontal armor (not penetrated it because of the sloping) and then slided upwards towards the less sloped part under the turret and from there was catapulted towards the sky...

but this is just a guess from looking at the silouette from the psw 234...iam keen on what the designers have to say about this...

[StellarRat]

The Sherman had its cannon set on stun?

[Tux]

Yeah, it's the vertical deflection that got me too. Something put a hell of a lot of reactive force back into that shell. I thought maybe it clipped the upper rim of the armour plate or something, but then I imagine that would cause the shell to tumble straight onwards, beyond the car, or even deflect downwards into the car.

Is shell deformation after first impact modelled? Perhaps then siffo990's idea could be right - the shell could have hit the 30mm plate hard enough to deform but not to penetrate and then could have ricocheted off the lesser armour behind it?

Sorry, I forgot to mention: The impact takes place between the 34 and 33 second mark, for those who don't want to have to watch the turn and 'spot' it themselves.

Also, by way of an excuse to anyone who notices my horribly bunched-up infantry along the main road, they were hurriedly put there to be hidden from the Americans on the right flank, so no judging! Lol.

[Bruce Robert]

This might be a case where real world angles - armor, shell trajectory, vehicle angle do to the ground it is on - will cause a bounce. There are archival reports of large caliber weapons that should easily, according to a more "laboratory" based assesment, penetrate light armor, but didn't because of the actual angle that the shell hit (of course other reasons could have caused the ricochet as well). Conversely, smaller weapons penetrating armor that it should not have been able to. Battlefield angles can vary greatly and alter a more sanitized assessment.

Having said this, it would be interesting to know whether BF has coded something like this into the game. If so, thanks for the added "realism." The idea that a certain tank is immune from a certain weapon, or that a certain weapon is a certain kill, is not supported by the battlefield reports. So it should be an occasional (rare) occurence.

Bruce

[Amizaur]

Well, it may be a glitch, or we may imagine it was an abstraction of the shell hitting some massive metal object on PSW's hull - like towing hook or something .

I think it's not that important as long as it doesn't happen too often .

I may well accept an 75mm Sherman penetrating the front of my Tiger, or my Tiger NOT penetrating front of a Stuart or M20 car - if it's a really rare occurence, like once in 20-50 games. Such things just happen in real life, they are possible - so I do not care if they are technically "bug" or they are programmed.

Sure, it's good to report such incidents, as the programmers may want to take a look into the code, to check if there is a possible error. Or maybe they just smile and know that some rare occurence they had coded, was just triggered .

Personally I like to know what my code does and how some "strange" things happened, sometimes I can't go sleep before I fully understand what and how happend, looking from the code-side .

On the other hand, I do care for "not-right" things that happen often....

I'm not sure what are chaces of a Sherman taking 3 clean penetrations from a Tiger's gun and continue firing back, only 4th penetration knocking it out. Shouldn't the crew, even if still alive, be at least "shocked" like it often happened in CMx1 ? How often it could happen in real life for a Sherman to get 3 clean penetrations from 88mm or long 75mm gun and have a will to continue fighting ? Or weven being able to reverse back into safety, sometimes without casualities ? Like the tank was from paper and shells from potatos.

Personally I believe such things happens much too often in my games... Unfortunately I have no statistical data on penetration effects in CMBN, maybe I'll generate them some day if I have some time.

What are the chances for BF to shed some light on penetration mechanics ? What happens in the game when a projectile penetrates the armor ?

What are possible consequences for the crew, for the vehicle, what parameters they depend on ? Is any "shock" effect for penetrated vehicle's crew programmed ? An effect that could prevent them from firing back for a moment, even if they were so lucky, than no one of the crew was killed or injured ?

Are APHE (or APCBC-HE) projectiles simulated somehow and their effect on the crew, it the fuse was working correctly ?

Anyone knows, if there any historical mentions about Shermans being penetrated 2-3 times from 88mm or 75mm guns, and still being able to fight on or withdraw, without being knocked out, or the crew mostly killed or injured ?

In game it's also true (to less extend) for German tanks, quite often they can take 2 penetrations from US tanks without damage and even one casuality. But especially the German ammo seem (for me) to have too little "damage" or "behind the armor" effect, undermodelled in this regard.

One of my buddies reported that in his game enemy M5A1 Stuart took 7 hits, 5 of which were penetrations, from a 75mm Stug, at distance of 50-100m, and just reversed into safety. How often should such thing happen ?

Try to kill a Tiger or Panther using German ammo. Possible in Blue on Blue scenario.

Usually several penetrations are needed to kill a cat, most of the (clean) penetrations even doesn't cause casualities !!! Does it sounds ok ?

Especially, taking into account the excess of kinetic energy the German shells have, and also the said-to-be-quite-reliable German fuses for said-to-be-effective burst charges.

I believe the external ballistics and modeling of accuracy of the guns are far better in CMBN than in CMx1. Also I belive, the penetration model in CMBN is better than in CMx1. I guess, it's refined and more detailed, especially the armor modeling.

But - unfortunately without any hard data to prove it - I believe the CMx1 (CMBB, CMAK) post-penetration damage model, effects on the crew, chances of crew being killed - was more "right" - to not say, more realistic.

[Battlefront.com]

We spent a lot of time trying to model what the effects of a penetration actually does to a vehicle. It's very difficult to do, surprisingly enough, because battlefield after action reports, first hand accounts, and theoretical physics often paint entirely different pictures. One thing that we have pretty firmly concluded, however, is that gamer perception of what should happen is often way off the mark. And by "gamer" I mean all our testers, myself, and even Charles sometimes

The amount of energy left over after a penetration is the most critical component. This determines the amount of possible damage that can be caused internally. The hit location takes into consideration what critical systems that damage might possibly cause. Based on vector, physics, and what's there the system assesses the chance that something might get damaged (including crew). Based on this result, and crew stats (Experience, Morale, etc), the TacAI decides whether the crew should bail, do evasive maneuvers, continue to engage, or sit there shocked.

There's two interesting issues which I don't think gamers fully appreciate. Solid shot AP that is completely overkill for it's target does have a chance of sailing through without causing significant damage because it doesn't break up. Just punches a clean hole and passes through. On the opposite extreme an AP shot can so barely penetrate that there's only a thin vector of damage caused. In other words, there is no such thing as one type of penetration.

Having said that, there could be something about a specific matchup that might skew the results in a bad way. The above cited example of a Stewart taking 5 penetrations and 2 other hits without brewing up does seem unbelievable. It also seems unbelievable to me that a Stuart would hang around at 50-100m long enough to be shot at that much This is why we really, really, really must stay away from anecdotal (especially 2nd and 3rd hand) examples. I'm not saying people deliberately make stuff up, but if I had a nickel for every time an anecdotal story turns out to be exaggerated or mis-remembered I could retire a rich guy. Well, at least until August 2nd

If someone has a save of something like the above mentioned StuG vs. Stewart matchup, we would be quite interested in seeing it.

Steve

[raz_atoth]

For what it's worth i had a Sherman in the Courage&Fortitude(second game) who took like 5-7 hits from a pak 40 and surviving.All hits were penetrations minus one which was a partial penetration.2 crew members got killed,the rest of the crew panicked but in the end-much to my pleasure-it managed to reverse to safety.It was played with 1.01.

[Battlefront.com]

The Pak40 vs. Sherman M4A3 was something we tested extensively (a huge understatement, actually!). The ability of the Pak40 to frontally penetrate (or oblique penetrate some areas) is really low. Therefore, it's ability to damage is not that great except when hitting square on the flanks or rear.

A 5 man crew being degraded by 2 men and Panicking, however, is not barely surviving. The vehicle is now seriously degraded in terms of capabilities and is just one hit away from being abandoned (i.e. if another crew member becomes a casualty).

BTW, there's a pretty big difference between 4 Penetrations + 1 Partial Penetration and 6 Penetrations + 1 Partial Penetration. Both, however, are within the outside range of a British post battle study of penetrations.

Steve

[Amizaur]

Thanks for the reply, Steve. If I have a save with such strange things happening, for sure I'll make it available.

In the described PAK40 vs Sherman case, those were probably penetrations with marginal energy excess. Also it was against sloped front hull, and it is known that German APCBC-HE fuses could be damaged by side-acceleration or just broken away, while penetrating highly-sloped armor. Just like against T-34's or Sherman's front hull. I would say it was reasonable outcome, low energy penetrations with HE bursters possibly not going off, some crew injured but able to withdraw.

On the other hand, many of the penetrations I have observed to not make any harm in CMBN, were high-energy penetrations, with huge amounts of kinetic energy left, also against non-sloped armor (so the burst charge fuses should work ok). For example trying to kill (just to observe game mechanics) a Tiger from a Panther. The Panther can very easily penetrate Tigers's side of even front armor, there is no slope so the (simulated or not) fuses should work ok, there are lot's of kinetic energy left and a lot's of armor splinters thrown into the tank, from the thick armor penetrated. And very often - no effect at all on crew and vehicle. Just like it was a penetration by 37mm AP that didn't hit anyone.

It's true an AP shot could fly trough the tank interior and fly out, without doing any damage if it doesn't hit anything. But such high-energy high-speed penetration also almost certainly have to throw few kilograms of metal from the penetrated armour, it would fly along the path of the projectile itself, in some 30degree cone. Faster the projectile, more fragmented the armor that was thrown inside. Something like a shotgun blast. If the fragments hits someone, he will likely be injured or even killed. Also, a tank interior is a cramped place, filled with 5 human bodies, huge amounts of ammo, sometimes fuel tanks. What are really the chances, such AP shot will fly trough not hitting directly any human body or any ammo box, or vital mechanism ? There are such chances of course, maybe even 50%, but I wonder how they can be estimated.

For sure the kinetic energy of the penetration is very important - the size of the shell, the velocity, the thickness of armor that was penetrated, the location and flight path trough the vehicle. But personally it's hard to imagine for me an energetic front gun mantlet penetration, that doesn't kill or injure either the gunner, loader or commander. Where the shell and all the splinters flew trough, and where they ended ?

I was inside few tank turrets (T-34, IS-2), always then tried to imagine what would happen to me, if the front was penetrated... The conclusion was, I'm in the direct path of the penetrator and all the splinters...

On the other hand - is the energy of the He burster and it's effect taken into account ?

The energy of HE burster in Joules is usually lower, or even much lower, than the left-off kinetic energy of the projectile itself. But it's a detonation of 30 or 50g of hexogene in thick, metal case in a confined, closed space. Sometimes closer than a meter from people's bodies, heads, faces. Small explosion that breaks the shell and throws large splinters to the sides (and not, like in case of AP shot, only flying close to the path of the projectile itself). The explosion causes an overpressure tip, that rips the eardrums or even make one to loose his consciousness, it can blind, make burns to faces and hands. Are we sure that after such penetration, people usually are able to continue fight, like nothing happened, and not just leave the vehicle, if they survived ? They know for sure that one penetration will be most likely followed by next one, fes seconds later...

From all the soldier's memoirs and written accounts I have read, it seem that the usual crew reaction to a penetration which caused an explosion, burns, many injures, smokre filling the inside, was to evacuate as fast as they could, to save their lives, to get out of this metal coffin. All above effects seem characteristic for penetration of APHE projectile with burster going-off, or AP causing internal explosion or fire (hitting ammo or something). Tankers feared fire, feared smoke, feared next rounds coming that would kill them. If the penetration was not very spectacular, didn't cause smoke, fire, much "boom", if the tank was still operational, and they felt still relatively safe (didn't expect it to happen again soon), then they could stay in tank and continue fighting, even if one of the crewmembers lost a whole arm from the projectile itself or armor splinter, and was bleeding badly.

So from the historical accounts I know, seems that much was depending on crew morale, their motivation, if they felt save in their tank (Tiger crews felt quite safe, Sherman crews don't), and how much shock and noise and smoke, burns and bleeding ears, the penetration has caused.

I do not think much percentage of the crews would stay inside after APHE penetration with burster going off inside, but it's my personal opinion .

An AP penetration, pure kinetic, well it seems for me that the outcome depends on how much damage and injures and noise/shock it caused, depends on crew morale and their feelings about their safety (is next penetration probable soon or not) and so on.

Some of my tests - a Sherman front turret or mantled was penetrated by Tiger's 88mm. No effect on the crew. In fact, 2 seconds later they returnet the gun fire against the Tiger. Not a simple instance, it happened many times during tests I did.

Even if the crew in the turret was so lucky to be unharmed (it happens), shouldn't they be a bit "rattled" if a 75mm or 88mm shell with lot's of armor fragments fly just by their heads and hits the rear of the turret, rumbling inside ?

Well, sometimes they are displayed as "rattled" after front turret penetration, but anyway they come on fighting, without any break, like nothing happened.

Such outcome wasn't too frequent considering total number of penetrations in tests, but it was noticeable considering limited number of front turret penetrations.

I understand you may still treat it as "anegdotical". Everytning I describe, are single isolated instances. I hope somene with more free time could collect hard statistical data on penetration effects in CMBN. On the other hand, taking into account how short the game is available, the number of such strange instances I have observed myself personally, makes me to worry about the model.

[Battlefront.com]

Bursting charges are simulated, directly.

I think you'll find many people that support the notion that a decent penetration should cause the crew to bail out more often than not. We had a huge round of testing about this very thing before the game shipped. We made significant improvements to several areas, however I personally feel that there's some instances where the crews are simply too brave.

I'll see what can be done about this.

Steve

[Amizaur]

Thanks again!

The game is in early 1.01 version so it's absolutely no problem than not everything is working perfectly at this stage, as long as there is producer's will to analyse and improve things over time .

[dieseltaylor]

If someone has a save of something like the above mentioned StuG vs. Stewart matchup, we would be quite interested in seeing it.

Steve

My groggery is shocked Sir shocked I tell you!!!

[dieseltaylor]

I had previously in V1.00 complained that I had decapitated the TC and the loader of a Sherman within the same minute and yet the gunner proceeded to nail the 88 mm Flak about 12 seconds later.

Whilst admiring the incredible sangfroid of the gunner I have problems with two extra bodies lying around the turret compartment spurting blood. From my readings I understand it is very cramped inside the turret, and ignoring the glancing turret hit as inconsequential, I still think BF has not modelled the effect of surplus bodies impeding a tank firing - and especially firing accurately.

Anyway with the advent of V1.01 we re-ran the prior turn and then generated the following turn orders and film. No difference whatsoever in the result. Should there have been?

[Battlefront.com]

When you say "reran", do you mean it recalculated the entire turn, the shot still hit, still penetrated, and still caused casualties BUT there was no ill effect on the rest of the crew?

Steve

[dieseltaylor]

ERROR Yep. Well I say yes because I sent Turn 47 version 1 and got back turn 48 version1.01. Film ran the same result. Two dead crew one dead 88mm. I was a bit surprised. Dang it! The shot penetrated neither time as far as I know as I got a top turret hit for the second shot when I nailed the loader who had taken over from the deceased TC. I took it to be a glancing hit both times. Lat newsI apologise for not making it clear that the loader was standing in the turret when he died. Actually if he were throwing the TC's body out of the turret it would have made some sense to be standing there.

ERROR OVER

LATE NEWS

I was looking at the wrong version. My apologies. On the correct V1.01 reply my crack 88mm crew missed and despite the +2 commander were all dead meat by the end of the minute. My apologies. I was impressed how quickly they recovered their morale though as with two dead and two wounded they dropped backed to nervous before they all died. Seemd to mostly die to the co-ax MG.

This is possibly due to my oppo not placing it in entirely the same place

[dieseltaylor]

Filler posts amalgamated above: (

Stewart Huh! : )

[Battlefront.com]

Hmmm... well, I don't trust PBEM games that had version switches. We're never even completely sure it will work. So I don't know for sure if v1.01 should behave differently or not. I presume it should if your opponent had Turn 48 compile on his end before coming back to you.

In any case, we are looking at this again. The tests we were using right before shipping showed major improvements to the behavior, but obviously the tests didn't represent a wide enough range of circumstances because we felt the need to tweak for v1.01 and I personally think there's still more room for improvement.

To be clear, the primary problem we see is about Crew behavior rather than ballistics/armor behavior. The latter seems to be working fine, it's the results of hits/pens on the crew that seem to still need some work.

Steve