Strange finding about HEAT

[murhis]

I just made few tests in a training server and I must say I'm a very confused.

I basically tried to find the range where 75 mm HEAT and 50 mm would have roughly the same penetration. Then something strange occured.

As example M3A3 Stuart(http://afvdb.50megs.com/usa/m3stuart.html) which is having 25 mm frontal glacis plate @ 48° from vertical. Which mean line of sight thickness: 25 mm / cos(48°) = 37.36 mm. (http://en.wikipedia.org/wiki/Sloped_armour)

Then I'm trying first range of 500 m. HEAT will go through it without a problem and killing the driver. But 50 mm fails to penetrate the glacis plate everytime. Though it managed to penetrate the turret armour which is 38 mm @ 10°. Which is ironically more (LoS)thick than the glacis plate.

qIxS8UovtxA

Penetration occured at 350 m range

Then I took something which is having a 90 deg armour and big surface to shoot at. Char was perfect for it. It's having 55-60? mm armour at sides(http://www.wwiivehicles.com/france/tanks_medium/b1.asp). But now something funny happened. This time 50 mm went through like a knife through a butter and 75mm HEAT couldn't penetrate at all. Expect the grill at other side.

So I'm just thinking that does the HEAT in this game ignore the angle completely or what's the explanation for this phenomenon?

[mrcheapydd]

quite odd

[chiapet]

well the 75mm heat round tends to be "lobbed' at the target, thus its angle of impact on a sloping face will tend to be more towards a 90 degree impact then say a 50mm ap round.

the 50mm AP round is high velocity so it will be hitting more horizontal to the ground and therefor hitting more of a slope then the 75 will.

my guess is the 50 will deflect while the 75 will not.

[jester]

HEAT has same penetration at all ranges...

Also HEAT effects certain armor more than others (not exactly sure on the details, I'm sure somebody can clarify)

[murhis]

HEAT has same penetration at all ranges...

Also HEAT effects certain armor more than others (not exactly sure on the details, I'm sure somebody can clarify)

I am very aware of that the HEAT has the same penetration at all ranges, but tell me if 50 mm is capable of penetrating 55-60 mm straight plate at 500 m, why it's not capable of penetrating Stuarts much thinner armour? Whereas with 75 mm HEAT it's exactly vice versa. It can't be about deflecting either, because in that case the 75 mm HEAT which penetrating the less should get deflected as well. And as far as I've understood WW2OL doesn't have shatter gap implemented(aka. high velocity rounds tend to get shattered more often).

well the 75mm heat round tends to be "lobbed' at the target, thus its angle of impact on a sloping face will tend to be more towards a 90 degree impact then say a 50mm ap round.

the 50mm AP round is high velocity so it will be hitting more horizontal to the ground and therefor hitting more of a slope then the 75 will.

my guess is the 50 will deflect while the 75 will not.

We've discussed about this earlier on a different topic. It's actually a visual distortion. Besides even if you would have like 5 degree difference(which it's not, not even close) it wouldn't mean anything significant. 25 mm / cos(48-5) = 34.18 mm vs. 37.36 mm. 3 mm difference...

Besides if you subract HEAT from the discussion there's something wrong on the penetrating model if your gun is able to penetrate 55-60 mm straight plate, but unable to penetrate 25 mm 48 degree plate(37 mm LoS thick).

For perspective here's a chart from http://www.wwiiequipment.com/pencalc

And no I'm not speaking only about PzIIIH being unable to penetrate Stuarts glacis plate. I'm speaking about every tank.

Edited September 3, 2011 by murhis

[monsjoex]

Need to be moved to testing bugs etc forums.

[jwilly]

1. As noted, angle of impact is not based on line of sight geometry.

2. The (realistic) variation in shot to shot performance due to aggregated minor shot variables is relatively large. Performance conclusions are not valid if based on one shot, or too few shots to not sufficiently average the shot performance.

3. Driver kill can occur due to spalling with an incomplete penetration, but this is a further variable.

4. Evaluating penetration according to kill of driver means of course that the test is dependent on exactly where the impact occurred. Thus both round dispersion and the limitations of calculated impact point vs. displayed impact point become relevant.

[murhis]

2. The (realistic) variation in shot to shot performance due to aggregated minor shot variables is relatively large. Performance conclusions are not valid if based on one shot, or too few shots to not sufficiently average the shot performance.

FYI I shot hundreds of shells. Would I upload video of hundreds of shots? Not.

3. Driver kill can occur due to spalling with an incomplete penetration' date=' but this is a further variable.[/quote']

With 75 mm HEAT it kills the driver everytime when hitting right of the glacis plate. With 50 mm not a single time at 500 m range.

4. Evaluating penetration according to kill of driver means of course that the test is dependent on exactly where the impact occurred. Thus both round dispersion and the limitations of calculated impact point vs. displayed impact point become relevant.

Same as point 2. I frapsed every shot watched them frame by frame with magnified view. So I damn sure know where the shells impacted.

Edited September 3, 2011 by murhis

[chiapet]

I am very aware of that the HEAT has the same penetration at all ranges, but tell me if 50 mm is capable of penetrating 55-60 mm straight plate at 500 m, why it's not capable of penetrating Stuarts much thinner armour? Whereas with 75 mm HEAT it's exactly vice versa. It can't be about deflecting either, because in that case the 75 mm HEAT which penetrating the less should get deflected as well. And as far as I've understood WW2OL doesn't have shatter gap implemented(aka. high velocity rounds tend to get shattered more often).

We've discussed about this earlier on a different topic. It's actually a visual distortion. Besides even if you would have like 5 degree difference(which it's not, not even close) it wouldn't mean anything significant. 25 mm / cos(48-5) = 34.18 mm vs. 37.36 mm. 3 mm difference...

Besides if you subract HEAT from the discussion there's something wrong on the penetrating model if your gun is able to penetrate 55-60 mm straight plate, but unable to penetrate 25 mm 48 degree plate(37 mm LoS thick).

For perspective here's a chart from http://www.wwiiequipment.com/pencalc

And no I'm not speaking only about PzIIIH being unable to penetrate Stuarts glacis plate. I'm speaking about every tank.

its got nothing to do with thickness, its deflection, its why bullets ricochet of angled plates and if at the right ange even skulls.

the 75mm doesnt actually push throw a plate at angle, it burns through it, and itll possibly have defelection too, just not as much.

[murhis]

its got nothing to do with thickness, its deflection, its why bullets ricochet of angled plates and if at the right ange even skulls.

the 75mm doesnt actually push throw a plate at angle, it burns through it, and itll possibly have defelection too, just not as much.

Nothing?

http://en.wikipedia.org/wiki/Sloped_armour (Read the deflection part)

This is though above my math ability...

But yeah if you read the text it's suggesting that sloping has a little effect with HEAT: "The situation of the penetrating metal jet caused by the explosion of the shaped charge of HEAT ammunition, forms a good approximation of this ideal. Therefore, if the angle is not too extreme, and the projectile is very dense and fast, sloping has little effect and no relevant deflection takes place."

Yet I would believe KwK38 should penetrate Stuart's glacis plate with ease on that distance. Like the data available suggesting. Like the site: http://www.wwiivehicles.com/germany/guns/50-mm.asp

43 mm @ 30 degree plate at 500 m equals 49.65 mm flat penetration. Which is ironically less than Char's side armour. Really odd...

[bronco69]

I am very aware of that the HEAT has the same penetration at all ranges, but tell me if 50 mm is capable of penetrating 55-60 mm straight plate at 500 m, why it's not capable of penetrating Stuarts much thinner armour? Whereas with 75 mm HEAT it's exactly vice versa. It can't be about deflecting either, because in that case the 75 mm HEAT which penetrating the less should get deflected as well. And as far as I've understood WW2OL doesn't have shatter gap implemented(aka. high velocity rounds tend to get shattered more often).

We've discussed about this earlier on a different topic. It's actually a visual distortion. Besides even if you would have like 5 degree difference(which it's not, not even close) it wouldn't mean anything significant. 25 mm / cos(48-5) = 34.18 mm vs. 37.36 mm. 3 mm difference...

Besides if you subract HEAT from the discussion there's something wrong on the penetrating model if your gun is able to penetrate 55-60 mm straight plate, but unable to penetrate 25 mm 48 degree plate(37 mm LoS thick).

For perspective here's a chart from http://www.wwiiequipment.com/pencalc

And no I'm not speaking only about PzIIIH being unable to penetrate Stuarts glacis plate. I'm speaking about every tank.

Lol

Never use these charts

That would be way too realistic. Ingame is mostly complete different

Just check M1 ATG vs. Tiger frontal

Or try 20mm rounds vs. other targets

We have to play with the DM CRS gives us. Enough said

[timmy41]

Lol

Never use these charts

That would be way too realistic. Ingame is mostly complete different

Just check M1 ATG vs. Tiger frontal

Or try 20mm rounds vs. other targets

We have to play with the DM CRS gives us. Enough said

looks accurate to me

[murhis]

Lol

Never use these charts

That would be way too realistic. Ingame is mostly complete different

Just check M1 ATG vs. Tiger frontal

Or try 20mm rounds vs. other targets

We have to play with the DM CRS gives us. Enough said

Perspective...

[stankyus]

Perspective...

Murhis - good catch and it is very odd indeed. I would suggest you check out the Stu's 37mm vrs the pzh frontally. I have found some oddities there but in know way can I do the math ^^^.... I wont poison you, with what I see but however check it out and if you find anything post it.

[Scotsman]

HEAT is yet another form of HE-based ammunition...all of which needs work..

[AHWULF]

There were some changes made to how HEAT impact is modeled in 1.34. Once there is open beta try it out.

Remember this is a model not reality - your subscription does not support molecular and quantum effects :-)

[GOPHUR]

HEAT rounds do not take into account angular thickness. There is a ticket to add this but I do not know when it will get done. Now that we have non-penetration effects for HEAT rounds it might be closer to reality.