Destroying armour with HE

[Praxis]

I was playing an axis attack against the British with a 150mm Inf gun in tow. The attack bogged down on the edge of a town. I pushed my two tanks forward to wipe out the British armour, which consisted of 5 Crusader tanks.

Needless to say this rash descision ended with two dead German tanks. However it did enable me to bring my 150mm piece into action.

The Inf gun missed with its HC ammo and I ordered it to fire HE at the nearest tank which was 270-290m away.

Based on line of sight, the gun had NO chance of a kill.

I actuality what happended is that the gun engaged the tank and immobilised it. The second round saw the tank abandoned. The same occured for all of the other tanks. In one case the HE destroyed the tank on the first shot.

So heres the question:

Obviously the blast of a large calibre HE capable gun is able to destroy a tank? (Is this correct?) If this is the case, what size does the gun have to be to achieve this result? Will a 75mm or 105mm achieve the same result? Has anybody else had this experience?

Or is the destruction of the tank a morale effect of have a big shell blasted against the side of the tank?

I know i'd be pretty annoyed and shocked to have 5 to 10kg of HE go off next to my head.

Any thoughts?

[yacinator]

the first shot blew off tracks off of the tank. crews tend to abandon immobilised but otherwise unharmed tanks becausey they're sitting ducks.

hope this helps.

[Michael Emrys]

Originally posted by Praxis:

So heres the question:

Obviously the blast of a large calibre HE capable gun is able to destroy a tank?

Yes, in various ways. It can immobilize it through damage to the running gear. It can damage or destroy optics or radio equipment. It can cause crew casualties by interior armor spalling. It can also knock the engine off its motor mounts by shock.

If this is the case, what size does the gun have to be to achieve this result?

Depends on where it is hit and how well designed it is to tolerate such shock. Things like thickness of armor come into play.

Will a 75mm or 105mm achieve the same result?

Depends. Obviously the bigger the shell, the more likely it is to cause damage. Against mid- to late-war heavy tanks, you would need at least 150mm to be able to count on it, but against an early war light tank even 40mm HE has a chance. You can include halftracks and armored cars in that category as well.

Has anybody else had this experience?

Lots of real live soldiers.

Or is the destruction of the tank a morale effect of have a big shell blasted against the side of the tank?

Could be that too. If your bell gets rung hard enough, it will definitely make you start to wonder if hanging out in that neighborhood is really a good idea.

I know i'd be pretty annoyed and shocked to have 5 to 10kg of HE go off next to my head.

Heh, in that case you wouldn't have a care left in the world. Your next of kin, on the other hand...

Michael

[Hans]

In the late 1970s(?) during an exercise at Grafenwohr Germany a US M60 was hit by a US 155mm HE round. It was hit on the right side near the turret ring.

The armour was not penetrated but he results of explosion were: (as I recall)

Jammed turret

Ruptured hydraulic lines and fuel lines

Shattered optics

removal of all antennas

Activation of fire suppression system in engine compartment

The engine was killed but was able to restart. All commo gear, intercom and radio were damaged.

And the crew was left "stunned and silly" for an hour.

[Joachim]

You can even kill tanks by using area fire with HE chuckers. there is a thread where somebody asked whether this is gamey. He disabled a Tiger with lots of area fire from Soviet SUs. Works especially well vs. thin skinned TDs or ACs.

Once I could not target an armored car that stopped my infantry. An ATG bunker stopped my tanks. So I peppered the area next to the AC with 75mm HE. Next turn my inf casually strolled to the bunker and took it out.

Armor stops objects from getting thru. It can not stop shockwaves - only spread them across a big surface and thus decrease the effect on a given small space.

A crude description of the effect:

A 150mm blast will spread out in the air as a widening ball. Air is too thin to have a big effect. The whole energy will be absorbed by a huge area.

A 150mm round exploding deep in the ground will create energy. The enrgy will transfer into shockwaves and those will travel and may bury trenches once the shockwaves reach them.

A 150mm round exploding close to a tank will have a blast affecting a certain area of the tank. The thick and little elastic armor will absorb the waves in that area and spread the energy/shockwaves across the whole object (tank) - just like a hammer hitting a metal plate. The whole plate will vibrate. If the object is big enough in comparison to the blast, the blast will do nothing to the overall vehicle, except destroying some small/weak parts on the outside (antennas etc). Armor spalling is kind of the same effect as shockwaves burying trenches. If the blast is big enough (navy guns) the object (Tigers in Sicily) may even flip over.

Gruß

Joachim

[Sergei]

Originally posted by Hans:

In the late 1970s(?) during an exercise at Grafenwohr Germany a US M60 was hit by a US 155mm HE round.

How in the Underworld did they manage to do that??? :eek: I mean, I trust it wasn't intentional but what kind of commander was in charge of the maneuvers if 155mm guns could fire live ammunition at tanks with people inside...

[flamingknives]

Technically, the shockwave of the blast will travel through a material until it reaces a free surface - i.e. a boundary between the material and another materials that has a significantly lower resistivity or density (the two are related)

At this point, the shockwave will reflect from the boundary as a release wave. Spalling occurs when release waves superpose to the extent that the forces in that area exceed the bulk yield modulus for that material. The effect of this is anything from a void being created within the plate (you'll see a bulge on the interior face of the armour) to sections of the plate being torn free and flying about the inside of the tank.

It is the superposition of release waves that causes spalling, be it in an armour plate or a trench, the mechanics is the same.

However, the transfer of an air to plate shockwave is inefficient. As HE shells are designed to explode out, most of the energy is transmitted to the air rather than the tank. This is why HESH (HE Squash Head) munitions were developed. The explosive hits, conforms to the plate it has hit before a base fuse detonates it. The HE is actually in contanct with the target plate, so the shockwave is transmitted much more effectively.

In addition to the above effects, HE shells can get to the parts of a tank other shells can't reach. In British tests against a Conqueror heavy gun tank, a 120mm HE shell striking the turret front managed to blow open the drivers hatch, exposing this location to blast and fragmentation.

[Oddball_E8]

There are instances where direct hits from HE shells have actually caused the turret of tanks to dislodge, and completely leave the tank body (not to mention what havoc that played on the commander, gunner and loader)

the russian battlefield site had some pictures of tigers knocked out by ISU152 in this way IIRC...

[GoofyStance]

As far as CMAK goes, I've played a QB where an immobilized Panther G with a crack crew fired off all its AP ammo at an advancing mass of (early) Shermans and then started using HE. Two Shermans, IIRC, were first immobilized, then abandoned, after the Panther put 5-7 rounds of HE on each of them. The Panther happened to be keyholed when it was immobilized (by an air strike), so it was able to pick off the Shermans one by one, and to spend more time chucking HE at each of them.

[EDIT - The Sherman crews were a mix of Regular and Veteran, btw]

[Mr. Tittles]

I think that HE has to be either in contact with the armor or inches away. The effect rapidly falls off with distance.

Even when in contact, the HE largely blasts its energy out sideways. So when a HE shell squarely lands on a vertical surface, the blast energy is not directed into the armor but to the sides.

A HE shell lucky enough to land under the tank would be as effective as a landmine with its blast energy trapped underneath.

Top deck armor like the Panthers driver/RO station is vulnerable to hits against the turret front. The blast/fragments directed downward could defeat this area. later versions uparmored this area.

A blast that could dislodge the internal engine from its mounts would be quite powerful and would kill any crewman and damage the tank dramatically.

Theres a long thread about HE against armor around. Maybe in the CMBB threads. For small caliber HE of around 90mm and less, I would contend that it would have to be set on delay (the fuse) and most of its antiarmor effect comes from a typical AP type model. That is, it needs velocity/hardness/etc. The explosive contributing very little 'AP' power. Larger HE in the 105mm class may have damaging effects but would need to hit a shell trap area or beneath the tank to really get a mobility kill. A knock out kill being rare.

The real question is the after armor effects of these large HE payload shells like the 155 and greater class. Bones and brains can be KO'd beyond armor and perhaps fuel lines and ammo also.

Aerial bombs should have been tank killers but the fact is that WWII dumb bombs could not get close enough to get these kills. The CEP negated the kill area.

[Jack Carr]

This is a good post/observation. Looking at this from the Axis point of view, the German big cats, Tiger and Panther, have HE that is also high velocity. Does the high velocity of the HE round equate to a penetration or is it, as so many have already pointed out in this thread, outer structural damage?

[Joachim]

@Jack

Depends on how you set the fuse - see Mr. Tittles post:

For small caliber HE of around 90mm and less, I would contend that it would have to be set on delay (the fuse) and most of its antiarmor effect comes from a typical AP type model. That is, it needs velocity/hardness/etc. The explosive contributing very little 'AP' power. Larger HE in the 105mm class may have damaging effects but would need to hit a shell trap area or beneath the tank to really get a mobility kill. A knock out kill being rare.

Gruß

Joachim

[MikeyD]

At least in Tiger IIs in CMBB (I haven't tried this with CMAK Nashorns) The 88's HE round is thick-walled enough to retain some penetration ability as well as the HE effects. I learned this to my regret in one scenario where i was positive I had run a distant KT out of AP rounds but his HE could still penetrate my T-34 sides.

[YankeeDog]

While you certainly can KO or damage tanks with HE in CM, IMHO CM presently somewhat undermodels the effect of nearby large HE explosions and light HE direct hits on AFVs because the resuls of minor damage isn't modeled.

Ultimately, with the new engine I would like to see some additional damage possibilities for AFVs, such as "Antenna Blown Off -- Radio contact lost", "Optics Damaged -- Accuracy Reduced", "Minor Running Gear Damage -- Speed Reduced", etc. Among other things, I think such minor damage modeling would would realistically increase the effectiveness of artillery barrages against concentrated armor formations without unrealistically making HE shells uber armor-killers.

A related question for those with real world armor experience:

It's well doumented that large explosions temporarily eliminate the oxygen in a limited area around the explosion - among other things, we all saw this effect on TV during the first Gulf War when oil well firefighters often used explosives to put out fires on Kuwati wells.

I have often wondered whether a large (155mm+) explosion close to an AFV, but not close enough to actually cause serious damage, might stall the engine due by temporarily starving it of oxygen. I do know from personal tinkering experience that if you cut of the air supply to an internal combustion engine for even just a second or two, the engine will stall.

Of course the engine could just be restarted, but in a tactical situation even a brief immobilization could be a very bad thing, especially if said immobilization takes place in the middle of an artillery barrage.

Does anybody know whether such an effect on vehicle engines is actually likely enough to make modeling it in CM worthwhile? IOW, if minor damage modeling is included in CMX2, should it be fairly common for large HE near misses to cause a "Engine Stalled - Temporarily Immobilized" result? And, if so, how long would it usually take for a WWII tank crew to restart the engine?

I imagine that WWII tank engines weren't as simple to start as modern passenger car engines. The closest experience I have to the kind of engine on a WWII tank would be the diesel engines on modern construction equipment and the large gasoline engines on general aviation propeller-driven aircraft. While the starting procedure for both these types of modern engines is all-electronic, it still usually takes 10-15 seconds to get the engine going, and if you're not careful, it's pretty easy to screw it up and flood the engine or cause vapor lock (especially when you're restarting a hot engine), in which case you usually have to wait a minute or two before you can try again. I have always conjectured that this also might be true for WWII AFVs - anybody know for sure?

Cheers,

YD

[Hans]

Sergei, as I recall it was a firing battery (gun crew) error dealing with green bag propellent vs white bag..ie the shell went way to far over the artillery impact area and hit a tank firing range.

[Hans]

YankeeDog, yes we do need a greater range of 'critical hits".

[Mr. Tittles]

Originally posted by Hans:

Sergei, as I recall it was a firing battery (gun crew) error dealing with green bag propellent vs white bag..ie the shell went way to far over the artillery impact area and hit a tank firing range.

I would imagine it came down at an angle and struck the top or rear part of the tank.

I think CM overstates the AP rating of most HE. But I agree that softer effects of HE should be modeled.

It would be cool to see radios KO'd for awhile (tubes changed, etc) or the tank being 'stunned' till the crewmen shook off the effects. Having reduced accuracy could be more from the gun falling out of alignment.

Tanks and AFVs carried extra sights, vision blocks, so the effects may not be as bad as thought.

I am glad dust is at least modeled. Arty makes tanks move for a number of reasons. One of which is the amount of dirt and black smoke TNT throws up.

[Dandelion]

A sidenote here - as the thread is about penetration or other critical hull damage I guess - is sound of HE.

I read in a study of StuGs that the sound of 20mm shells hitting the armour (harmlessly) was the decibel equivalent of standing next to a jet aircraft starting its engines. Machinegun fire hitting it was in the vicinity of human pain threshold for noise.

Been wondering about that ever since I read it really. The (German) "ape ears" headphones weren't efficient at all in closing sound out.

Cheerio

Dandelion

[Mr. Tittles]

I cant believe MG fire could be that bad. If it was, then concentrated MG fire against a tank would cripple it.

Sound falls off quickly so if it was hitting directly outside the armor that a crewman was stationed at, perhaps it could discomfort that crewman.

Studies show that even in the open against infantry, HE is not THAT deadly.

[General Bolt]

Originally posted by Joachim:

A 150mm round exploding deep in the ground will create energy. The enrgy will transfer into shockwaves and those will travel and may bury trenches once the shockwaves reach them.

Do trenches ever collapse in CM?

[Michael Emrys]

Originally posted by General Colt:

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

A 150mm round exploding deep in the ground will create energy. The enrgy will transfer into shockwaves and those will travel and may bury trenches once the shockwaves reach them.

Do trenches ever collapse in CM? </font>

[Dandelion]

Originally posted by Mr. Tittles:

I cant believe MG fire could be that bad. If it was, then concentrated MG fire against a tank would cripple it.

Well, not really. Painful but not crippling in terms of activity.

Decibel levels of pain threshold were commonplace in factories by the early 20th century. Today, it is equally common at any normal pop/rock concert. In fact some city cores around the world also have a daytime noise level close to human pain threshold. Yet people, even dogs live there and thrive.

The firing of a ordinary Mauser 98 also causes a noise beyond human pain threshold. If you actively listen to it as it discharges, your ears will immediately go uuUUUEEEEE and you will experience pain, with short or long term damage as consequence. Sadly, I have this experience with a G3 rifle, of about equal noiselevel. But damage was very temporary.

Its all about not listening.

Man, like all mammals, has selective hearing. If you listen carefully your brain amplifies faint sounds for you, enabling you to here a particular sound better and distinguish it from a general noise. Goes the other way too, extreme noise can be reduced in the transfer between ear and brain.

Of course, man's capacity for this "zooming" in and out is limited, especially compared to mammals like dogs and cats, and any damage caused by pressure (noise) would still be there, ignored or not.

Hardly any combat account mentions pain in the ears during combat, even though large numbers of weapons discharge, all of them individually capable of damaging your eardrums for life. Soldiers tend not to think of it, at least not as anything other than general deafening noise. It will be because they are too busy concentrating on other things. During combat, riflemen will by logical necessity have become deafened by massive stress on the eardrum, though only few mention that either (probably because they don't think of it, either). After the combat, they often mention "ringing" ears, i.e. traces of damage from the noise. Permanent and temporary damage manifests itself the same way. But as long as they remain active and focused (or panicked), they can push the extreme noise aside up to a rather impressive level.

If passive and inactive, man's ability decreases drastically. A little like a PC processor, the brain will not cease to operate simply because there is nothing useful to do (like moving the body), and there is no "waiting process" except counting sheep, so if not busy it translates all incoming sounds and if you start thinking about those sounds, it will amplify them for you as a matter of service.

That's the dripping tap phenonema. All you need to do to go to sleep is to make the brain too busy to transalte and amplify, e.g. by reading a book or counting sheep.

And for the same reasons, accounts of the horrible noise of incoming artillery hitting helplessly waiting infantry is rather common in literature from veterans.

If you like a sound, your listening will become active, wether you think of it or not. Stress will be reduced on the eardrum even if sounds are very high. That's the popconcert phenonema.

A StuG sprayed with MG fire would thus experience deafening noise inside, but the crew would still most probably be quite able to operate. They would be concentrating on their labourious tasks and too busy to think much of the noise. They would most probably not think of the pain in the ears either. At up to 20mm incoming hitting the hull, permanent hearing damage due to pressure is unlikely. But beyond that damage must, again by logic, have become a serious risk. And the level of noise of a 20mm shell is likely to seriously challenge any attempt at concentrating on anything. So at that point I also feel they must have been stunned, or at the very least dazed and slowed.

I am however not prepared to go through with an experiment to prove my point here.

Afterwards of course, for a StuG crew subjected to heavy MG fire hitting the hull, pain and headache must have been really horrible. It will have been difficult to go to sleep even if exhausted, because of hearing disorders and painful peEEep-sounds for quite a few hours. Easr will have been very sour indeed and echoing sounds will have pursued them for days.

Cheerio

Dandelion

[Mr. Tittles]

I corresponded with a WWII vet who described 50 cal range detail without hearing protection (guns to the left and right). He was deafened for hours after and ringing for days too. He said it was worse than any other loudness he encountered (and he had plenty). I think perhaps being on the firing end is as bad as the receiving end.

I fired a M16 without earplugs and it 'shfuzzed' my drums good. This was semi auto fire. Full auto would be damaging for sure. I asked a Nam vet what they did and he said some guys put paper from the cig filters in the ears. Many guys opened the mouth to relieve pressure also. Others just went deaf.

But back to the point of the thread; I believe unless a HE shell actuall strikes the armor itself, it is MUCH better than a poor infantry slob as far as effects. Of course, the fragments are nearly useless against most armor, the blast/debri/heat/etc are all reduced also. I would imagine the noise is attenuated too. The exception being the HE landing right on the armor that is protecting a crewmen. The shock/noise would be terrific.

I knew a tanker that had the misfortune of having a main weapon go off within feet of him. The concussion itself KO'd him for hours. He had horrible tinninitus that was permanant. Any closer and he may have died. The energy from the concussion would cream the brains and shatter all bones.

[Mr. Tittles]

The insides of afvs are very loud anyway. These headphones would offer some protection.

[MikeyD]

About noise in combat, I'm reminded of a decades old news report about something the Army came up with for crews of their M60(?) tanks. When the gunner pulled the trigger there'd be a fraction of a second delay during which time the tank crew's headsets would transmit a 'click' sound to prepare the ear drums to withstand the following "BOOM!". I don't think it was ever fielded (probably didn't like the idea of that hesitation). It does illustrate, though, the problem of coping with debilitating noise in combat.

I hear Churchills were grotesquely noisey beasties for the crews. Remember, the tracks are being dragged across the full length of the upper hull while moving! Yikes!

[ April 24, 2004, 09:16 PM: Message edited by: MikeyD ]