.50 / 20mm as AT

[JasonC]

Actually the types were API and HEI - armor piercing incendiary and HE incendiary. They were usually mixed with 1 API to 3 HEI in the same ammo clips. The I doubled as a tracer, which burned for 5 seconds. The HEI had about 6 grams of HE burster (1/27.5 as much as a German stick grenade, and about twice the charge of an M-80 firecracker - a "faster" detonating explosive to be sure), and was slightly lighter. Some sources I've seen put the actual high explosive at 3g (M-80 size), with the other 3g the incendiary tracer.

The Germans estimated it took 20 hits by 20mm to shoot down an American bomber. I also found this field report on their use against armor in Russia - "20mm auto-cannon: its rounds were useless against T-34s and of scarce use

even against light tanks: two light tanks managed to overrun two 20mm guns whose crews continued to fire until the tanks arrived at 10m range." The same report records good results with captured Russian 76mm firing either AP or HEAT against T-34 sides, and reports successful M-kills against T-34s with shots at the tracks with 105mm HE.

[Barleyman]

Gentlemen.

Not wishing to take a stance on the whole "there should be difference between brewed up and slightly broken!" issue, which is only really relevant as for how many weeks the tank will spend on yard before becoming operational or even if it'll be worthwhile to fix it if it's captured..

But come now, 20mm is NOT, repeat NOT a popgun! :eek:

Have you actually ever held a 23mm AA gun round? It's a big brute of a shell, I'd just plain HATE the idea of being anywhere near a crew compartment of any armored vehicle if 3-4 of those things were bouncing incide with a liberal helping of schrapnel!

Sure, it's not going to do such catastrophic damage to the tank equipment as a 76mm tungsten round. It's still going to break many things, beyond the obvious watery sacks of meat'n'bones..

[Michael Emrys]

<blockquote>quote:</font><hr>Originally posted by Barleyman:

Not wishing to take a stance on the whole "there should be difference between brewed up and slightly broken!" issue, which is only really relevant as for how many weeks the tank will spend on yard before becoming operational or even if it'll be worthwhile to fix it if it's captured...<hr></blockquote>

I think the relevance of that point to this discussion is in assigning varying points at the end of the game depending on the level of damage achieved.

Michael

[JasonC]

Yes, I've held 20mm shells. And 5.56, 7.62, 12.7, 37, 40, 105, 155, and 203. I've fired most of them too. I'm a former artilleryman, and to me the 20mm is a popgun. I'd much rather be behind the thin armor of a 'track or a M-109 SPA, than in the open or manning a towed gun, "armored" with a cloth field jacket, if one were shooting at me.

But in CM right now, 2 4-round bursts from a 20mm Flak are deadlier to thin armored vehicles than an 88L71 shell, which is just silly. What should they be like, instead? An individual penetration should have only a 5-10% chance of a KO, but a decent chance of a crew causalty, M-kill, or F-kill result - say 25-10-10. If the game only tracks the burst of four, assume 2-3 go in (toss a coin to see which). That is if the rounds can penetrate - if they can't, you'd just see 2-3% chances of gun or track damage.

In the penetrable cases, you'd see only about 1/6 KOs and the same number of no-significant-damage results. The majority of hits would do damage (immobilize or wreck the gun) or hurt crew. Several such bursts in succession would probably get several crew and the rest would bail after failing their "morale".

But you'd practically never see intact crew bail from a KO'ed vehicle, which was the anomoly that started the whole discussion. Somehow the folks arguing the other side can never seem to accept that, and must continually recur to their fantasies about crew causalties instead. If these light AP only made crews bail because they hit a couple of them, I'd have what I want. But it would not be the present system, it would be a change. Because right now, the vehicle gets knocked out 75% of the time by one burst, often without the crew having a scratch.

[Barleyman]

20mm AP is way too big for killing human beings, tho.

So the real beef here is that CM models tank/crew being disabled by small-bore gun bursts.. But it does not model crewmembers being decapitated/severely wounded by schrapnel resulting from said penetrations..

Neither is modelled "minor" damage to tank equipment which would make crew bail out but would probably allow tank to be restored in a week or so at the yard?

Hm, I'd rather take the "ignore soft targets" command for CMBB

[Tero]

What about such things as:

- deflection shooting using the open hatch to defelct the round downwards into the fighting compartment

- the crew becoming deaf or suffering injuries (possibly even going insane) after being subjected to repeated hits in rapid succession

- repeated hits in rapid succession resulting in a harmounious vibration that renders equipment inoperable

[JasonC]

Tero suggested "the open hatch to deflect the round downwards into the fighting compartment"

Exposed crew is already open to TC results. The rest is a rare weak point penetration.

"the crew becoming deaf"

Firing the gun is louder. A 1-2 million joules high caliber AP might exceed the noise of the gun, but not a 20mm AP bouncing off.

"(possibly even going insane)"

Where are all the insane bomber crews? It is documented that portions of exposed personnel exposed to carpet bombing, for hours, by strategic bombers dropping hundreds of tons of HE - or prolonged artillery fire, on the scale of weeks or months and totaling millions of shells - will succumb to "shell shock". (That is why it is called "shell shock"). Exposure to the ordinary risks of infantry fighting will do the same in 6 months. But scads of crazies in bomber and tank crews from the 20mm terror are not in evidence. (Combat fatigue did effect bomber crews, but mostly from the sense of helplessness flying through heavy Flak mission after mission, certainly not from the pinging noise of 20mm from fighters).

In the rare event it happens, it is just a -1 crew result, just like the far more common case of a 20mm penetration that goes through one of the crew.

"repeated hits in rapid succession resulting in a harmounious vibration"

Take a basic physics course and you will see why this is laughable.

[Jarmo]

A few notes off the top of my head.

Chance to kill. Way back there was this hot discussion of the .50cal killing power against light vehicles. A .50cal used to be able to kill almost any light vehicle with one burst. In the end, the kill chance was drastically reduced.

I believe it was this chance that brought up the problem of unkillable light vehicles. Like the german flak thingies. Any change in the "system" seems likely to screw up something else.

It's quite possible that the 20mm and such have too great killing power against lightly armored vehicles. Seems like that to me. But then, I don't really understand the "knockout mechanics" anyway. I'd need thorough explanations of wich pipe was broken and what doesn't function without that certain pipe.

Certainly the problem seems obvious. Let's take a high power rifle and shoot a car with it, not hitting the engine or gas tank, you can shoot pretty darn many times before the car actually dies. Hell, lots of things in the engine compartment could also be hit without the car immediately dying. With a random hit somewhere into the car, I wouldn't think the chance of knock-out would be too high.

But as already said, the chance of a knock-out is certainly higher for the larger calibre penetrations. Maybe not enough? One thing I've noted, is that it's almost impossible to get anything brew up with 50mm or lower calibre weapons.

Oh yeah, I've seen crew members get killed/wounded by spalling. I'd guess the chance is somewhere between 1/5 to 1/10. Probably around the same range as the chance with penetrating .50cal hit. No problems there.

The going insane&churchbell effect of hits.

I read a caption somewhere (almost certainly here) of a light calibre AA weapon shooting at some tanks (T-34's probably). The repeated hits did indeed cause such a horrible ding-dong that the crew was forced to abandon the tank. Right out there in the hostile territory, out to be killed by the AA gun and other stuff. Temporary insanity caused by ineffective hits.

But I'd classify that into the "odd things that happened in war" -category. Certainly wasn't the standard procedure. The same as the famous "shooting at tanks with white phosphorus, making them think their tank is on fire".

hmm hmm, where was I? Did I have an opinion? I'll go to sleep now...

[Puff the Magic Dragon]

The damage that ammo does to vehicles is known and can be verified with appropriate sources.

A good overview about ammo types, ways of penetrations and damages can be found here : Definitions of the Soviet Ammunition

The problem that Scipio and, as it seems, others have is indeed a game engine problem, and IMO it can be solved relative easy. All what would be necessary is a detailed description of the damage and what (ammo type) has caused it. Would this be realistic on the battlefield? Surely not. But I'm sure that some peoples could better sleep.

Now a personal issue:

Germanboy, personaly insulting someone as Arschloch(=asshole) on a public board is unacceptable, and to do it in a foreign language to avoid a warning from the moderators shows that you are a dishonorable coward. Maybe I will be excluded from this board for this sentence, but at least I accept the consequences of my words.

[Redwolf]

I think there is only one way to end this pseculation and come up with data worth putting into the engine. We have to investigate actual knocked out vehicles and count how many rounds they had taken before getting knocked out.

For starters:

http://www.armourarchive.co.uk/pgt2cont.htm states a Tiger with two 6 pdr rounds

The Panzermuseum Munster has a Jagdpanther with 2 (3?) penetrations, of which only the frontal 6pdr penetration (got hooked into the gun mantlet, hence didn't ricochet on the front plate) was fatal. The one in the engine compartment wasn't lethal and did not even immobilze it.

I know that this method is weak since guns would often continue to fire after a knockout because either they couldn't tell that the tank was dead and/or they wasnted to destroy it completely. But it's the best method I can think of.

[ 11-08-2001: Message edited by: redwolf ]</p>

[Andreas]

<blockquote>quote:</font><hr>Originally posted by Puff the Magic Dragon:

Now a personal issue:

Germanboy, personaly insulting someone as Arschloch(=asshole) on a public board is unacceptable, and to do it in a foreign language to avoid a warning from the moderators shows that you are a dishonorable coward. Maybe I will be excluded from this board for this sentence, but at least I accept the consequences of my words.<hr></blockquote>

There are German language moderators who can pick up on this. If there weren't, I would have said it in English. Since Scipio and I are German speakers, I thought it appropriate. On a more general note, I also thought it an appropriate reaction for being yelled at for no reason at all (you do know that caps indicate yelling, do you?) and insulted by him, since he obviously had not read my post. He did set the standards, and should not come whinging if people treat him accordingly.

Your point was?

[Puff the Magic Dragon]

<blockquote>quote:</font><hr>Originally posted by Germanboy:

There are German language moderators who can pick up on this. If there weren't, I would have said it in English. Since Scipio and I are German speakers, I thought it appropriate. On a more general note, I also thought it an appropriate reaction for being yelled at for no reason at all (you do know that caps indicate yelling, do you?) and insulted by him, since he obviously had not read my post. He did set the standards, and should not come whinging if people treat him accordingly.

Your point was?<hr></blockquote>

Scipio is (mental) a mad child. This is description of him, not an insult. I know him personally. Anyway, my point is: 'asshole' is not the kind of language that answers any questions. But please don't let us turn this into a discussion about correct discussions. Sent me a mail if you want to talk about this.

And to come back to the question: maybe the information helps that German AP rounds are always APHE, even if the German sources refer them as simple 'AP'. I don't know about the .50. And as I said, IMO the main problem is the lack of information we get from the program. I would like to hear your opinion about that.

[JasonC]

There is plenty of information about what 20mm rounds did to vehicles, and I've already mentioned it. It is just that the vehicles in question were not Hellcats, because the 20mm wasn't built to destroy Hellcats. It was built to destroy airplanes, and the Germans extensively tested what they did to airplanes.

They concluded it took 20 20mm hits, on average, to shoot down a US bomber. I don't say so, they said so. They also thought it was rather high, which is why they developed 30mm aircraft guns, which could do the job with 3-5 hits. Anyone used to air combat games or sims has extensive grognard knowledge of what 50 cal, 20mm, and similar weapons do to thin skinned (but sometimes sizable) vehicles.

As for 20mm bursters, as I've already mentioned they were the size of cherry bombs, 3 grams - only a few percent of the power of a hand grenade. Almost all of the energy of a hit was kinetic - on the order of 60,000 Joules per round.

Notice, 20 hits will deliver around 1 million Joules all told. So will 3-5 hits by larger cannon, or 1 hit by a short 75mm. Delivering 1 million Joules was about the threshold for reliable knock-out, if the armor was defeated.

[JasonC]

Double post, sorry...

[ 11-08-2001: Message edited by: JasonC ]</p>

[Puff the Magic Dragon]

Jason, if you answered to my last post : I assume you're right - I don't know much about AA - and I havn't contradicted? Have I?

What would be nice :

lower rear hull penetration (by APHE shell), engine critical damaged, tank immobile.

Or

front turret penetration (by 2cm(if known) APHE shell), critical internal damage, gunner dead ( or wounded), tank abandoned

or

side turret penetration, ammo shelter hit, tank knocked out

or

upper rear hull hit (by Molotov-Cocktail), engine burning, tank knocked out

Maybe not as pop-up message, but in the detailed unit description.

[Redwolf]

Jason, your model of energy inside vehicle (note to others: that is *after* penetration) has something for it and it would blend nicely with how HE damage to unarmoured targets is modeled now.

However, there are people on this forum who think that a small shell will often be more dangerous that the big one. One reason would be that the big one has a chance to go though the vehicle altogether, which could be modeled based on the remaining enegery and a probablity.

Then, some people say the smaller round bounces more often inside a compartment, thus it has -for the same energy- more chance to hit something vital that can be damaged with a fraction of the energy (humans amoung them).

[Scipio]

Heres some more oil for the 'tanks die to fast' fire.

Just today I read from the Poland war about a German tank - not sure which one, but I assume it was a III or IV.

One penetration through the driver hatch (by an AT Rifle) with only light damage. The drivers has reported it to the commander - the commander didn't noticed the hit. Then a 7.5 shell explodes under the tank and lifted it, with light damage on the undercarriage. The tank retreats now, and when they were out of action, the tank commander noticed that he couldn't move the turret anymore, and that another shell penetrated the rear hull into the motor, but didn't exploded.

From Janusz Piekalkiewicz 'War of tanks'.

Interesting for the 'the crews bails at the first penetration' and also for the 'a penetration is usually deadly' groups on this boards.

Puff, go back into cave. I'm not a mad child. I'm a childish paranoid

[ 11-09-2001: Message edited by: Scipio ]</p>

[Porajkl]

All this talking about energy and Joules... I wonder what would happen back in Forties if Germans have been pouring energy drinks over their 20mm shells. I guess the penetration would be much higher. Am I right? Can anybody make a test?

[Tero]

Originally posted by JasonC:

Exposed crew is already open to TC results. The rest is a rare weak point penetration.

Actually rare weak point penetration of top armour at 0º OR worse with a direct fire weapon potentially resulting in a critical hit which blows up the vehicle.

Firing the gun is louder. A 1-2 million joules high caliber AP might exceed the noise of the gun, but not a 20mm AP bouncing off.

What about a Flakvierling bouncing them off at high ROF ?

But scads of crazies in bomber and tank crews from the 20mm terror are not in evidence.

Can you direct me to a source on that ?

Insane was perhaps not the best choice of words.

Take a basic physics course and you will see why this is laughable.

So the energy of a sustained burst of 20mm fire can NOT make your aiming device vibrate the least bit ? Or vibrate the vision block loose ?

[JasonC]

Oh it might vibrate all right. Firing the gun and driving around also make parts of the tank vibrate. So does a pothole.

[Michael Emrys]

<blockquote>quote:</font><hr>Originally posted by tero:

Actually rare weak point penetration of top armour at 0º OR worse with a direct fire weapon potentially resulting in a critical hit which blows up the vehicle.<hr></blockquote>

Do you think you could rephrase this statement, tero? As it is, I find it confusing.

0° angle of incidence would be parallel to the face of the armor and wouldn't penetrate at all. Of course you do add "OR worse", and I suppose that could include anything up to 90°, which might have an excellent chance of penetrating, but other than a diving attack plane or a high-trajectory weapon, I don't know how you'd get it against the top armor.

:confused:

Michael

[Puff the Magic Dragon]

<blockquote>quote:</font><hr>Originally posted by tero:

So the energy of a sustained burst of 20mm fire can NOT make your aiming device vibrate the least bit ? Or vibrate the vision block loose ?<hr></blockquote>

No. Jason is right here. When you are in a tank with the engine on, you are nearly deaf. And when you drive through terrain, the whole tank is shaking like a ship in storm.

Look at Scipios last post. This is reality - the tankcrew often doesn't noticed that the tank was hit. The driver noticed a hit on his hatch - the commander 1 meter away already missed this.

Of course it's something else if a 76mm penetrates and explodes in the cabine.

[Tero]

Originally posted by Michael emrys:

Do you think you could rephrase this statement, tero? As it is, I find it confusing. I don't know how you'd get it against the top armor.

The case in point is Finnish 20mm ATR firing at a KV-1 which has its commander hatch open (a totally random example based on RL Finnish instructions given to the ATR gunners about engageing the KV-1). The open hatch stood up at a 90º angle from the turret roof and aiming at it you could get shots or molten metal and splinters deflecting into the turret.

The 0º degree refers to the turret roof when the ATR is at the same level as the turret roof. The "OR worse" bit refers to the ATR being at a lower level than the turret roof, say on the ground. The results of these shots deflecting were hoped to vary from crew casualties to at the extreme case brew up or catastrophic explosion of ammo. I do not know if this ever worked IRL but those were the instructions given to the ATR gunners.

I hope this was more accesible.

[Michael Emrys]

Okay, I think I have it now. Sounds like a real desperation measure to me, but then I guess there were a lot of those.

Michael

[JasonC]

A proposed energy-based system of determining post-penetration damage

First, I classify rounds into broad ranges of muzzle energy.

"Super" - 88L71, Russian 122mm and 152mm, German 128mm. These all have MEs in the range 5-10 mJ. If the armor can stop them, OK, but if they get in the vehicle is almost certainly toast. 90-95% of hits should result in KOs, and most of the rest will be M-kills. This is about how 88L71 works in CM today.

The first is really a class by itself. The next three all cover typical tank guns, meant to destroy second half of the war tanks.

"High powered" - 75L70, 17-bler, Russian 85mm, 88L56. These all have MEs around 3 mJ. They should have an improved chance of causing KO, 85% or so, and more of the KOs should be brew ups. High caliber HEAT (95mm and up) should be in this category too.

"Standard" - 75L48, US 76mm, Russian 76.2mm Long. All these have MEs around 2 mJ. They should have kill chances around 80%, and all other hits will cause substantial damage (M-kill, F-kill, or crew loss with shock and risk of bailout). Most HEAT should be in this category.

"Lower powered" - US and British short 75mm, Russian 76.2mm Short (as on T-34/76), 57mm and 6-lber. These have muzzle energies between 1 and 1.5 mJ. Which should be enough for high chances of KO after penetrating, around 75%, but somewhat less than the previous. Smaller heat, like 60mm bazookas, should be in this category.

The next broad range covers early war tank guns, and the more high powered guns meant for other missions. These should have reduced chances of KO against typical tanks, even if the armor is penetrated. But the KO chance should be on the order of half, and most other penetrating hits will still cause substantial damage.

Better mid-war - German 50L60, 40mm Bofors, US 37mm AT. All these have substantial MEs, around .75 mJ. Their KO chances on penetration should be on the order of 60%. A chance of no significant damage (NSF) appears for the first time, but only around 10%. The remaining 30% would be M-kill, crew loss, etc.

Average mid-war - German 50L42 and 75L24, French 47mm, Russian 45mm, British 2-lber. These have MEs around .5 mJ. Their KO chances should be around 50%, with NSD up to 1/8th of the time. This is more like what light AP does in CM today. Few targets will withstand 2-3 penetrations, but not every round can be counted on to KO the target, even if it penetrates. Rifle grenade HEAT might belong here, as well.

Weaker mid-war - German 37mm (including Czech and Flak), Russian 37mm, late war German 30mm. These have MEs around .25 mJ. Their KO chances should be only around 40%, with NSD results up to 20% of the time. Normally a second round will be needed, but few vehicles will withstand multiple hits.

The last broad category covers lighter weapons, generally meant to be used against planes or light armor. They have little chance of a KO with a single hit, and will generally disable a vehicle by accumulated damage, or multiple crew losses resulting in morale failure and bail-out. The shooters are often burst weapons as well, and those that are may "roll" damage twice.

Light AP - 20mm Flak, 15mm ATR, 50 cal HMG. These all have MEs under .1 mJ, and even remain under that level even with several rounds hitting. Each penetration should have only a 15% chance of a KO, and a 50% chance of NSF. The remaining 35% should be mostly 1 crew loss, shock, and morale check for bailout (25%), and 10% M-kill and the like. But remember, burst weapons get to roll twice and apply both results.

Which gives a 28% chance of knock-out, plus some bailouts on morale loss, and only a 25% chance of NSF from both. Several such bursts in succession will scrap most vehicles. E.g. 20 rounds of 20mm as 5 4-round bursts, if penetration is achieved each time, will produce 10 damage rolls all told. Leaving an 80% chance of knock out and only 1/1024 chance of NSF, with multiple damage results in the remaining 20% likely to destroy the vehicle as well.

I hope this is interesting.