Ramble on tanks, armor and other stuff...

[RiccardoTheBeAst]

Ok, just checked on Battlefield.ru, smoke is UD-354A (http://www.battlefield.ru/en/tank-a...ecification-penetration-soviet-tank-guns.html)

Now waiting for tests results, give us some news as soon as possible

EDIT:

Unfortunately the Russian infos are really confused (instead of the precise German infos), so, i've found lot of different values about the T-34 mod. 42's front turret armor. Someone says 45mm, other ones say 52mm and others more say 70mm (at least everyone is concorde on the sloping, luckily, @ 30

 

[LemoN]

Unfortunately the Russian infos are really confused (instead of the precise German infos), so, i've found lot of different values about the T-34 mod. 42's front turret armor. Someone says 45mm, other ones say 52mm and others more say 70mm (at least everyone is concorde on the sloping, luckily, @ 30

 

[RiccardoTheBeAst]

There were different factories producing the T-34 and there were a lot of differences, mainly the turret design and armour.

But generally, I think that we're looking at the standard Hex hard-edged turret, not the ChTZ turret, laminated turret or soft-edged turret. I'm actually rather suprised to see that they didn't include the M41/42 STZ variant which would probably be more common around Stalingrad. But I may be wrong here.

Seen here:

Cannot see the image, link it please

 

[Unus Offa Unus Nex]

Well, the definition of a penetration is quite clear, fully perforating the plate.

Now, the difference lies in the details. Each nation had different standards on how far the projectile had to go through the plate, (ie 50%, 80% or 100%), how often the plate had to be penetrated (50%, 80%, 100%).

I don't remember the exact numbers off the top of my head, so you're free to look them up.

The different criterias used to determine accepted penetration at specific ranges.

German criteria:
Complete penetration of plate by projectile (100% of projectile), by atleast 66.6% of the rounds fired. (50% for calibers below 5cm)

US criteria:
Partial penetration of plate by projectile (??% of projectile [not specified]), by 50% of the rounds fired. (All calibers)

British criteria:
Complete penetration of plate by projectile (100% of projectile), by atleast 50% of the rounds fired. (All calibers)

USSR criteria:
Partial penetration of plate by projectile (specifically 75% of projectile), by atleast 66.6% of projectiles fired. (All calibers)

Confusingly Battlefield.ru mentioned a "Certified Penetration" method used by the Soviets as-well, where CP indicated a 80% chance of a penetration, without going into further depth about wether this refers to the chance of achieving a complete or partial penetration. However this is in dispute with other sources, and the site's mistake on German criteria brings into question the validity of the information presented there.

As for the subject of the 7.5cm KwK40 L/43 versus the 45mm glacis of the T-34:

The 7.5cm KwK40 L/43 was, as all German guns, extensively tested and found capable of the following average performance against a 250-265 BHN RHA target plate tilted at an angle of 30 degrees from the vertical:

PzGr.39 (6.8 kg, APCBC-HE, 740 m/s):
100m = 99mm @ 30 deg
500m = 91mm @ 30 deg
1,000m = 81mm @ 30 deg
1,500m = 72mm @ 30 deg
2,000m = 63mm @ 30 deg

Total Projectile energy: 1,861 Kilo Joules
Cylinder plug projectile energy pr. sq.cm (Indicative of raw penetration power potential irrespective of projectile design): 42.2 KJ/sq.cm

In addition to this it is noted by Livingston & Bird, that the German test plates were of unusually high quality throughout the war, which would mean performance was even greater in practice versus Allied armour. (Worth keeping in mind) The quality & nose hardness of German AP projectiles were also higher than those of the other major countries.

T-34 front upper hull glacis specifications:
Actual thickness: 45mm
Slope/Tilt: 60 degrees from the vertical
Straight line relative thickness: 90mm
Type: Rolled Homogeneous Armour
Brinell Hardness Number: 420-430 BHN

With all this information in mind I would make an educated guess that straight on, with no lateral angle, the 7.5cm KwK40 L/43 was effective with the PzGr.39 against the T-34's 45mm glacis plate out to between 500 & 600 meters. However internal spalling could be expected to occur beyond even 1,000 meters.

 

[Unus Offa Unus Nex]

For Lemon and Oldih... yes, correct, Pzgr.39 is capped. However, the Soviet rounds were also heavily shaped - hence the comments on the ogive. The cap helps vs. standard AP shot - but the Soviet BR-354A/B are better. Their external ballistics may not be as good, but the ogive shape lends a turning moment that will tend to rotate the round in towards normal. The cap on the German rounds will do so initially but, as the main body of the steel round makes contact, the ogive shape generates a turning moment in the wrong direction, leading to deflection.

Another classic case, by the way, of both sides designing ammunition to counter their own armor, not the enemy's!

So, standard AP shot < German Pzgr.39 < Soviet BR354A/B. But, of course, the Soviets had other issues around production quality earlier in the war. I'm just talking about the deisgn of the round's ogive here (NOT the cap on it). The German rounds cope will with angles out to 30-odd degrees off normal - but the Soviet (assume they get there AND don't fall apart), operate well out to much steeper angles.

Hi Wilsonam,

Owning Livingston & Bird's work myself I am afraid that what you mention above is all theory and not fact. The problem here being that L&B base a lot of their assumptions on old school armour penetration formulas, such as the DeMarre overmatch theory which no longer is in use.

Furthermore actual testing of different shape projectile disproves that the unusual Russian nose shape was any better at penetrating sloped armour than the regular capped ogive shaped penetrators then in use. Infact US tests indicate the direct opposite, which in the end led the US to adopt ballistic capped solid shot projectiles with an ogive shaped penetrator, such as the 90mm T33, as their std. AP round. These rounds proved much better against sloped armour than any APC or APCR projectile. Interestingly the shape of the T33 penetrator closely resembles that of the German PzGr.39 penetrator, only lacking the bursting charge and soft metal guiding cap on top.

It is good to keep this in mind.

 

[Hans_klempner]

Recently I bought the game Steel Fury Kharkov, and this discussion was in my head one day, so after a battle i decided to do a little testing.

Using the L/43 75mm gun, with PzGr. 39 I put some test shots on a few T 34/76 from 750, 550 and 390 meters away.


750 meter, only managed to penetrate in the turret ring, twice, ricochet's or partial penetration on turret and side armor
YouTube - 750 meters

550 meter, much better results

YouTube - 550 meters

390 meters, different results as the T-34 hull was on an upward slope, no full penetration on front glacis, however the turret was no issue

YouTube - 390 meters

 

[Unus Offa Unus Nex]

Thanks for the pictures and videos Hans, seems to correspond well with reality as a full penetration of the glacis at 550 meters seems quite realistic.

PS: Is it a good game?

 

[RiccardoTheBeAst]

The different criterias used to determine accepted penetration at specific ranges.

German criteria:
Complete penetration of plate by projectile (100% of projectile), by atleast 66.6% of the rounds fired. (50% for calibers below 5cm)

US criteria:
Partial penetration of plate by projectile (??% of projectile [not specified]), by 50% of the rounds fired. (All calibers)

British criteria:
Complete penetration of plate by projectile (100% of projectile), by atleast 50% of the rounds fired. (All calibers)

USSR criteria:
Partial penetration of plate by projectile (specifically 75% of projectile), by atleast 66.6% of projectiles fired. (All calibers)

Confusingly Battlefield.ru mentioned a "Certified Penetration" method used by the Soviets as-well, where CP indicated a 80% chance of a penetration, without going into further depth about wether this refers to the chance of achieving a complete or partial penetration. However this is in dispute with other sources, and the site's mistake on German criteria brings into question the validity of the information presented there.

As for the subject of the 7.5cm KwK40 L/43 versus the 45mm glacis of the T-34:

The 7.5cm KwK40 L/43 was, as all German guns, extensively tested and found capable of the following average performance against a 250-265 BHN RHA target plate tilted at an angle of 30 degrees from the vertical:

PzGr.39 (6.8 kg, APCBC-HE, 740 m/s):
100m = 99mm @ 30 deg
500m = 91mm @ 30 deg
1,000m = 81mm @ 30 deg
1,500m = 72mm @ 30 deg
2,000m = 63mm @ 30 deg

Total Projectile energy: 1,861 Kilo Joules
Cylinder plug projectile energy pr. sq.cm (Indicative of raw penetration power potential irrespective of projectile design): 42.2 KJ/sq.cm

In addition to this it is noted by Livingston & Bird, that the German test plates were of unusually high quality throughout the war, which would mean performance was even greater in practice versus Allied armour. (Worth keeping in mind) The quality & nose hardness of German AP projectiles were also higher than those of the other major countries.

T-34 front upper hull glacis specifications:
Actual thickness: 45mm
Slope/Tilt: 60 degrees from the vertical
Straight line relative thickness: 90mm
Type: Rolled Homogeneous Armour
Brinell Hardness Number: 420-430 BHN

With all this information in mind I would make an educated guess that straight on, with no lateral angle, the 7.5cm KwK40 L/43 was effective with the PzGr.39 against the T-34's 45mm glacis plate out to between 500 & 600 meters. However internal spalling could be expected to occur beyond even 1,000 meters.

Excellent stuff

The penetration data is also confirmed here [url]http://www.tarrif.net/cgi/production/all_vehicles_adv.php?op=getvehicles&vehiclesX=65[/URL]


Can you suggest me some interesting book about WWII and the one where you found these infos? Thx

 

[Unus Offa Unus Nex]

Hi Ricardo,

Much of the info comes from Livingston & Bird themselves, as-well as Thomas L. Jentz and in no small amount the original German documents from which much of the information is pulled, a Mr. Rausch has been most helpful on this issue.

I can recommend most of Jentz's works (L&B's single book too), but really even the expert books out there sometimes need to be taken with a tiny bit of skepticism, cause none are without fault. The sincerest information is that which is extensively backed up with original and/or reliable documentation, the rest is up for any skeptic to research.

 

[Oldih]

The problem here being that L&B base a lot of their assumptions on old school armour penetration formulas, such as the DeMarre overmatch theory which no longer is in use.

Correct me if I'm wrong but isn't the problem more related to the fact that most T\D related stuff is more dependant on both shell and armour quality than any hard written physics fundamental (besides basic kinetic energy stuff) ?

Trying to replicate (just for example) the effect known as shatter gap with some genuine success so to speak has been pretty much impossible, yet even though anecdotal field reports and some other tests under odd conditions would heavily imply something like that occured under certain odd circumstances, which were not present during other testings and in some other genuine combat situation may not have been present for some odd factor AFAIK. Same with the referred overmatching, I have not heard or read any major* spalling and fragmentation issues related to Shermans compared to T-34s with high velocity german guns during penetration or in cases where the shell richocheted, something which is commonly associated with stress and spalling caused by the presumed overmatching vs armour quality even when no physical penetration occurs.

Of course this might be due conflicting information avaible regarding field reports vs official statements and some other research, as it gets pretty messy at some point.

(*in this case referring to relatively severe\notable internal damage rather than the obvious fragments and such that always come around whenever something is broken)

 

[Unus Offa Unus Nex]

Well the theory of overmatch goes pretty much as follows:

If the diameter of the penetrator overmatches the thickness of the armour plate it strikes, the protection given by the inclination of the armour plate diminishes proportionally pr. the increase in the overmatch of the penetrator's diameter. So the theory goes that for example when a Tiger's 88mm gun hit a T-34's glacis plate, the 88mm diameter of the Tiger's round overmatched the 45 mm glacis plate of the T-34 by so much that it made no difference that the Russian tank's glacis was inclined at an angle of 60 degrees from vertical.

Problem is that the above is completely untrue. The 60 degree inclination of the T-34's armour certainly made a difference, and it wasn't because of a t/d overmatch that the 88mm round would penetrate. Looking past the metallurgic composition of the projectile itself, the Tiger's 88mm projectile was able to penetrate the T-34's glacis at great distances because of its' raw kinetic energy displaced over a small area. The more KE you can concentrate over as small an area as possible, the better the penetration performance (within a certain limit ofcourse), as was realized with the many subcaliber tungsten projectiles developed during the war. Today tanks almost exclusivel fire long & slender arrow like tungsten projectiles when opposed with enemy armour (safe from the Britisk who still use HESH rounds in the AT role).

 

[[TW]Wilsonam]

Well the theory of overmatch goes pretty much as follows:

If the diameter of the penetrator overmatches the thickness of the armour plate it strikes, the protection given by the inclination of the armour plate diminishes proportionally pr. the increase in the overmatch of the penetrator's diameter. So the theory goes that for example when a Tiger's 88mm gun hit a T-34's glacis plate, the 88mm diameter of the Tiger's round overmatched the 45 mm glacis plate of the T-34 by so much that it made no difference that the Russian tank's glacis was inclined at an angle of 60 degrees from vertical.

Problem is that the above is completely untrue. The 60 degree inclination of the T-34's armour certainly made a difference, and it wasn't because of a t/d overmatch that the 88mm round would penetrate. Looking past the metallurgic composition of the projectile itself, the Tiger's 88mm projectile was able to penetrate the T-34's glacis at great distances because of its' raw kinetic energy displaced over a small area. The more KE you can concentrate over as small an area as possible, the better the penetration performance (within a certain limit ofcourse), as was realized with the many subcaliber tungsten projectiles developed during the war. Today tanks almost exclusivel fire long & slender arrow like tungsten projectiles when opposed with enemy armour (safe from the Britisk who still use HESH rounds in the AT role).

Errr... excuse me... who INVENTED APFSDS? And who still uses it today? THE BRITISH! Small detail that we have to rent DU rounds, dig them out and give them back to the Yanks after we've finished with them. Bloody Yanks forget to mention the teenie problem of ablation, though. So - we use HESH because it is cheaper than long-rod. Doesn't go well with rifled barrels, mind you

 

[Oldih]

@ Unas -- I know the basics of the overmatching theory and probably I just worded it in a silly manner, but thank you for clarifying it + the KE part anyway. I mostly pondered that would've armour quality vs shell quality played more role in the supposed idea more than was expected, which could possibly be the case when we apply current knowledge to something that was reported and implied back then.

 

[Unus Offa Unus Nex]

Errr... excuse me... who INVENTED APFSDS? And who still uses it today? THE BRITISH! Small detail that we have to rent DU rounds, dig them out and give them back to the Yanks after we've finished with them. Bloody Yanks forget to mention the teenie problem of ablation, though. So - we use HESH because it is cheaper than long-rod. Doesn't go well with rifled barrels, mind you

Well the British didn't exactly invent it (I believe the French were first actually), seeing as the discarding SABOT was a known technology and some forms of arrow shot was used by some other countries as-well. The British were the first to put rounds of APDS design into regular service however, that is true.

Also I merely pointed out that the British, while they certainly do use APFSDS in the AT role, still prefer HESH in many circumstances (Which I can understand btw). The British are pretty much the only big nation not to rely exclusively on APFSDS against enemy armour, and this probably wont change until they switch to smoothbores.


PS: I thought you were American ?

 

[[TW]Wilsonam]

PS: I thought you were American ?

Only in the sense that America was once British...

 

[Unus Offa Unus Nex]

Only in the sense that America was once British...

Ah I see, like that

 

[Hans_klempner]

Thanks for the pictures and videos Hans, seems to correspond well with reality as a full penetration of the glacis at 550 meters seems quite realistic.

PS: Is it a good game?

Any time, I was just kind of goofing around in my spare time, with interesting outcome.


I love the game as it is difficult and realistic, and the Soviet AT defense belt is very tricky.

The enemy AI tank's are also pretty good, as they shoot for the weakest spot possible.
Plus, there are several mods available.

Good game to waste time until RO2 comes out!

 

[Unus Offa Unus Nex]

Will have to check out then Hans, thanks again

Now on another more visual subject regarding tanks ingame:

I would really love to see a realistic environmental effect for when the main gun fires, like all the fine dust being kicked up around the tank, or even buildings right next to it (heck even snow kicks up). Add to this a nice chest thumping sound effect and you get the nice concussive effect of when a tank opens fire, which will look impressive and make most soldiers nearby flinch.

You can observe it happening in this video during the winter from 1:30 min and at 1:37 min especially:
YouTube - Panzer - SS Tiger tank batallion 502, 505 - Eastern front action

And here at 6:26min during the summer:
YouTube - The German Panzer & Tiger Tank In Action Pt 2-6

This effect is also faithfully replicated in the recent RTS game Men of War: Assault Squad, so its definitely possible to implement.

 

[Unus Offa Unus Nex]

Sorry about the double videos, but I have no idea why it does this or how to fix it.

 

[u-s-e-r]

Sorry about the double videos, but I have no idea why it does this or how to fix it.

If you write only the URL of the video it will embed it only once.

I.e. only

http://www.youtube.com/watch?v=5JIlYZ8ScYM

=

YouTube - Darkest Hour - Version 5.0 Release Trailer

Edit. And nice videos btw, it would be great if dust effects would be in RO2