Tank explosion

[Unus Offa Unus Nex]

Yeah, interesting... I just re-watched that old favorite again. The second round hit (looks like right at the base of the turret) is more than just some sparks. I'm guessing that shot didn't penetrate, but I can't be sure. It also shows how bright (and therefore visible) the tracer in the base of the 90mm round is. We may yet have to tweak the hit effects

Also please take into consideration the extra behind armour effects of the bursting charges. I'm not sure exactly how thick the armour had to be for the fuze to ignite the bursting charge in the PzGr.39's fired by the 75mm KwK40, but it would naturally be less at all ranges than for the 75mm KwK42, 88mm KwK36 & 43.

Seeing that 30mm of armour sloped at 30 deg would reliably ignite the fuze on a 88mm PzGr.39 fired by the FlaK18 at a range of 500 meters, I'd assume that 20mm would be enough for the PzGr.39 fired by 75mm KwK40 at the same range.

Thanks.

 

[Nylle]

I'd like to see tank crews bailing out of the tank. But thats probably out of te question, becouse you need to be alive to bail the tank, and if a player is alive that means the tank is still functional.

 

[[TW]Wilsonam]

Sure it would be irrelevant if ignited, but a direct hit, or even being hit by fragments could make a difference on where they're stowed. I would think rounds stored in the floor would be less likely to be hit, while rounds in the turret, the most visible part of the tank would be more likely to be hit (assuming penetration).

The bulk of the T-34's rounds are stored on the hull floor (not in it, obviously). Fairly hard to hit - but not impossible. Just made the loader's life hell

 

[Unus Offa Unus Nex]

The bulk of the T-34's rounds are stored on the hull floor (not in it, obviously). Fairly hard to hit - but not impossible. Just made the loader's life hell

But it also made him strong!

 

[wokelly]

Also let's not forget the deadly effects of overpressure a bursting charge will inflict if it goes off inside the confined space of a tank, where the opening or closing of hatches suddenly becomes a large factor. Heck the effects were severe enough in a buttoned up tank hit by solid shots without any form of bursting charge.

It is my understanding that the burster charge was actually quite minor, not near enough to actually cause any kind of overpressure or whatnot. Ian Hoggs 'German Artillery' shows the 7.5cm Pzgr Patr 39 to have the explosive charge of cyclonite/wax of 16 grams or .56 ounces. The burster charge was meant to break up the AP round into several chunks to increase the shrapnel effect (spall) after a penetration and hopefully light up the ammo. But on its own I don't see 16 grams of explosive causing an overpressure effect.

Well, like I said, on the western front German tank crews observed pretty much just flame ups from struck Allied tanks, and very rarely explosions. It was apparently a very different deal on the eastern front though, where the mention of enemy tanks exploding immediately after having been hit are common.

Dmitriy Loza in his book on Red Army Shermans mentions this difference. According to him it was an ammunition issue, the T-34s fuzes would go off when the ammunition burned, thus causing the HE shells to blow up. In comparison US shells burned but the fuzes did not ignite the explosives. This saved him at one point because when his crew bailed out of their sherman, they had to hide under it due to enemy fire while it burned. It got quite hot but the ammo didn't blow up, something he felt would certainly happen on a T-34.

I think that may account for the difference.

It's an interesting debate, but you need to be careful about "instant" fire and detonations.

Take a look at British tank losses and crew casualties in Normandy. The average was 1-2 crewmen "permanently lost" for each tank destroyed, which rather ruins the idea of "instant" detonations. All the accounts I've read of crew bailing out indicates there are a few seconds between impact and destruction. The same applies to the Russian experiences I've read.

I have personally come to question this statistic recently. In the book "South Albertas: A Canadian Regiment at War", Donald Graves examine the regiments casualties. From August 1944 to May 1945, the regiment lost about 200 tanks to all causes, and suffered 100 deaths. Of those, only 10 actually died in the tanks. The rest were cut down while bailing out and/or retreating their lines on foot, killed while caught outside their tanks during a German barrage, were commanders who were killed while unbuttoned, or died due to flu and accidents. Doesnt include wounded so I imagine total casualties per tank lost were probably at least 1 per lost Sherman.

Still casualties directly related to the penetration seem to be low. Many tank casualties would be a side effect of the tank being penetrated, mainly those being cut down as they bailed out and tried to retreat back to their own lines, at least in this regiment. I am not sure who or how people came to the oft quoted 1-2 casualties per KOed tank, but I wounder if it may simply have been dividing crew casualties by tanks reported lost.

 

[Unus Offa Unus Nex]

Well, it ofcourse depends on where the tank is struck as-well. For example, in the famous Cologne incident, the Panther which was caught unawares by the Pershing had 20min earlier or so hit a Sherman with a single shot to the front that immediately killed two of the crew members, whilst the commander's leg was cut off just below the knee. The commander was sadly unable to be saved and as such died outside the tank just a few minutes later. Two of the crew survived with fragmentation injuries. So thats 3 men for one tank, struck just once IIRC.

Another incident involves that of Pat Diaz, who's Cromwell tank also was hit with a single shot to the front, in this case by the 88mm KwK36 of Wittmann's Tiger. The bursting charge ignited and two of his crew were killed instantly, while he himself was blown out the top and was seriously hurt. The last two crew members were out of the war with serious injuries as far as I can remember.

 

[Unus Offa Unus Nex]

It is my understanding that the burster charge was actually quite minor, not near enough to actually cause any kind of overpressure or whatnot. Ian Hoggs 'German Artillery' shows the 7.5cm Pzgr Patr 39 to have the explosive charge of cyclonite/wax of 16 grams or .56 ounces. The burster charge was meant to break up the AP round into several chunks to increase the shrapnel effect (spall) after a penetration and hopefully light up the ammo. But on its own I don't see 16 grams of explosive causing an overpressure effect.

The bursting charge was small indeed, but it doesn't take a lot to create overpressure inside a buttoned up tank. Infact the penetration alone creates overpressure serious enough to cause ear drums to burst and even lung damage. There's an extensive report on this, examining the most common injuries to tank crews having had their tank punctured, with burst ear drums and collapsed lungs being the most common injuries. Those are the typical signs of exposure to sudden and violent increases in pressure.

 

[Schnurx]

The latter may cause a flash of sparks, but nothing like the heat of a modern round ablating...

True. But on the other hand the AP and APHE projectiles contained a tracer flare to facilitate tracing the projectile, so the crew was able to judge if they have scored a hit or not.
Maybe it's even possible that the energy of the impact caused the remaining flare to shatter/pulverise and burn up at once?

 

[Unus Offa Unus Nex]

True. But on the other hand the AP and APHE projectiles contained a tracer flare to facilitate tracing the projectile, so the crew was able to judge if they have scored a hit or not.
Maybe it's even possible that the energy of the impact caused the remaining flare to shatter/pulverise and burn up at once?

I'm sure that will have an effect too, as I mentioned earlier. But I do believe the flash mostly is generated by the enormous heat generated by the friction between the projectile and armor plate.

 

[wokelly]

The bursting charge was small indeed, but it doesn't take a lot to create overpressure inside a buttoned up tank. Infact the penetration alone creates overpressure serious enough to cause ear drums to burst and even lung damage. There's an extensive report on this, examining the most common injuries to tank crews having had their tank punctured, with burst ear drums and collapsed lungs being the most common injuries. Those are the typical signs of exposure to sudden and violent increases in pressure.

Is that report available online, would be interested in reading it through. Have a big interest in tanks and tank combat.

Another incident involves that of Pat Diaz, who's Cromwell tank also was hit with a single shot to the front, in this case by the 88mm KwK36 of Wittmann's Tiger. The bursting charge ignited and two of his crew were killed instantly, while he himself was blown out the top and was seriously hurt. The last two crew members were out of the war with serious injuries as far as I can remember.

I don't know if the explosion could be attributed to the burster charge, from my own understanding the entire tank went up when it was hit. I'm not sure what the burster charge for the 88mm was, but I doubt it was much more than the burster charge for the 75mm gun. My understanding is that he was the Cromwell commander, and that he was blown out of the tank was due to him being unbuttoned so I dont think any overpressure explination fits there. The tank went up due to a catastrophic explosion, most likely the ammunition was hit directly.

I don't think a buster charge of several grams really increased lethality that much more or cause tanks to blow up more often. It increased the shrapnel effect of the AP round by breaking it up post penetration, but I don't see it blowing people out of the turret.

 

[Unus Offa Unus Nex]

Is that report available online, would be interested in reading it through. Have a big interest in tanks and tank combat.

It is, I'll try to locate it for you.

I don't know if the explosion could be attributed to the burster charge, from my own understanding the entire tank went up when it was hit. I'm not sure what the burster charge for the 88mm was, but I doubt it was much more than the burster charge for the 75mm gun. My understanding is that he was the Cromwell commander, and that he was blown out of the tank was due to him being unbuttoned so I dont think any overpressure explination fits there. The tank went up due to a catastrophic explosion, most likely the ammunition was hit directly.

I don't think a buster charge of several grams really increased lethality that much more or cause tanks to blow up more often. It increased the shrapnel effect of the AP round by breaking it up post penetration, but I don't see it blowing people out of the turret.

Hehe I think you've misunderstood me. No, it certainly wasn't the explosive power of the bursting charge that sent him flying, it was the ammunition storage exploding which did that. But it was the bursting charge that actually set off the ammunition storage so quickly, otherwise the tank would've likely just burned.

We're talking about setting off an explosive in amongst loads of other explosives. The super hot shrapnel would fly around inside the tank to all sides, hitting the ammunition storage and setting it off.

 

[Unus Offa Unus Nex]

This is not the study I am talking about, but it looks like this one is referencing it: http://www.bordeninstitute.army.mil/other_pub/ews/Chp1WeaponsEffects.pdf

"Blast overpressure occurs from the explosion occurring
inside a confined space. One study from WWII showed 31%
of armored crewmen casualties had ear injury due to blast
overpressure, including ruptured tympanic membranes"

 

[wokelly]

Great, thanks for the link!

 

[samspade]

Another incident involves that of Pat Diaz, who's Cromwell tank also was hit with a single shot to the front, in this case by the 88mm KwK36 of Wittmann's Tiger. The bursting charge ignited and two of his crew were killed instantly, while he himself was blown out the top and was seriously hurt. The last two crew members were out of the war with serious injuries as far as I can remember.

One man killed not two. Earlier the tank of John Cloudsley-Thompson was hit by Wittmann and none of the crew were serously injured.

 

[Unus Offa Unus Nex]

One man killed not two. Earlier the tank of John Cloudsley-Thompson was hit by Wittmann and none of the crew were serously injured.

And your source for this is?

Pat Dias says himself that two of his crew were killed instantly, and that he himself was seriously injured, so I think I'll take his words over yours on this one

As for John Cloudsley and his fellow crewmembers, well it all depends upon where the round struck, if it hit the engine, well then most of the time the entire crew got out alive.

 

[samspade]

And your source for this is?

Pat Dias says himself that two of his crew were killed instantly, and that he himself was seriously injured, so I think I'll take his words over yours on this one

As for John Cloudsley and his fellow crewmembers, well it all depends upon where the round struck, if it hit the engine, well then most of the time the entire crew got out alive.

Fact is Cloudsley-Thompson's tank was fired at twice at close range by Wittmann. He was side-on to Wittmann for both shots and the crew compartment was penetrated.
The first shot missed but passed closed to C-T's head. The second penetrated but all the crew got out without serious injury.
Dya's lost a crew member to machine gun fire after he left the penetrated tank.
Total British tank crew dead were 12 from 25 tanks and not all were killed in the tanks.

The ability of an '88' to hit 'first-time' and to wipe out a tank crew is much overated.