Armor Penetration of Stalin Tanks?

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Darrin
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#16

Post by Darrin » 24 Dec 2003, 06:13

Paul Lakowski wrote:
Harri wrote:Christian:
Later model of JS-2 is actually rather similar to JS-3. Main differences are different turret and "reshaped" frontal hull.

Paul:
I have seen many kinds of figures so which one to rely on? I agree German main ammo was armour (and HEAT) shell. APCRs were reserved for smaller calibre guns (and later actually for "emergencies" only).

Only Soviet 100 mm L/54 gun could penetrate 155 mm (90/0 degrees, 500 m) and nothing more. Other guns were inferior to that. Do you have post war figures? JS-3 was used until 1970's and I'm sure their ammo was also improved a lot after the war.

Soviet 122 mm tank gun D-25M-1943 (used in JS-2 and 3) was based on A-19 gun (without muzzle break but barrel length L/45) but this new modification had L/43 barrel. Soviets didn't develop completely new guns during the war so the improvements in penetration could only be achieved in increasing the muzzle velocity significantly (in practise length of gun) or developing a new different type better piercing shell. The earlier mentioned gun was only slightly better.

Soviet armour shell weighted 25 kg and its muzzle velocity was 790 m/s. In smaller calibres Soviet subcalibre shot was only slighly better than their normal armour shell but I don't know if it was used or even developed during the war for 122 mm gun?

----

It is likely that also German armour steel became worse in quality during the last months of war but in 1944 the difference in quality was significant in favour of Germans. Not even Soviets couldn't produce equal steel without additional metals used for hardening the steel.
German armor quality started to decline about the same time soviet AP shot quality improved. Hetzer armor is 195BHN to 220BHN while Tiger-2 armor is around 220BHN...thats mid 1944. Jagd Panther Armor was supposed to be 285-345BHN but was tested with 260-310BHN, while the mantles ended up 230-260BHN . The panther armor was reported tobe 270 BHN , while the mantle cast hardness was reported to be 210-245 BHN.THese are low hardness.Source Jentz Panzertracks and several British firing trials. Resistance of plates was reported to vary widely at this time due to shortages of key alloying agents.

THe Russian tested their penetrators on RAS [Russian Armored Steel] thats has nominal hardness ~ 440BHN while their penetration criteria is 80% certified penetration...compared to german tests that were 50% ballistic limit tests on Plates around 300 BHN. THe difference in penetration is ~ 28-30% so that 155mm penetration at 500m range for the BR412 is infact ~ 200mm Vs german plate.

Russian armor piercing projectiles improved from late 1943 on because the general steel employed went up from 460 BHn steel to 550 BHN. German AP shot was generally around 600-620 BHN but started to decline to 580-590 due to the larger shots. Each 10 BHN points makes >1% difference in penetration...so early soviet penetrators were 20% below the norm...by late war this was improved to 90% due to improved steel quality. [Source: ARTCOM article AFVNEWS May-2003- Miles Krogfus],

The above mentioned source also reports that T-34 armor was 430-440BHN while turret casting was 444BHN. IS-II hardness was ~ 450 BHN cast turret and 440 BHN hull plates.While another doc puts the T-34/85 hardness @ 350-400BHN

Actually I think you or your source have it backwards. Hardness increases britleness which usually leads to easier breaking of armour. WWII gunnary and ballistics by lorin bird et al. Low hardness allows the armour to absorb most of the shells enegry resulting in little or no penetration. The ger often times covered thier soft armour with special face harded armour that caued dam to the AP nose decreasing max pen even more.

Also to compore the two different numbers bettween rus and ger test you just add together the 80% and 20% and divide by 2. That should compare directly the rus and ger pen numbers.

One of the major problems for the IS2 122 mm tank was its small space too large gun and heavy two piece shot. It meant its gun had a VERY low ROF maybe 3-5 times worse than the ger 88s.

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#17

Post by Paul Lakowski » 24 Dec 2003, 07:48

Darrin wrote:
Paul Lakowski wrote:
Harri wrote:Christian:


Actually I think you or your source have it backwards. Hardness increases britleness which usually leads to easier breaking of armour. WWII gunnary and ballistics by lorin bird et al. Low hardness allows the armour to absorb most of the shells enegry resulting in little or no penetration. The ger often times covered thier soft armour with special face harded armour that caued dam to the AP nose decreasing max pen even more.

Also to compore the two different numbers bettween rus and ger test you just add together the 80% and 20% and divide by 2. That should compare directly the rus and ger pen numbers.

One of the major problems for the IS2 122 mm tank was its small space too large gun and heavy two piece shot. It meant its gun had a VERY low ROF maybe 3-5 times worse than the ger 88s.
Thats laughable...on the one hand we have actual historical ballistic test results compared to ...what a computer game???

The RAS has a elongation of 10-12% [ductility] which puts it on par with RHA of 300BHN in terms of elasticity. GAS [German armored steel] has similar qualities at ~430 BHN.

What they are noting is that thin hard brittle plates struck by overmatching shells suffer shattering effects. In actual fact this is ABS [adabatic shear bands what happens in DU projectiles] and they depend on the projectile overmatching the plate[stretch it to the point of failure].

The mistake L&B make is that they don't know when to ascribe a quantity to either the armor ; the slope or the projectile. Each contributes differently to the penetration process.

If plate hardness didn't contribute to resistance all tanks would be made with mild steel....since is 1/4 of the price.


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Christian Ankerstjerne
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#18

Post by Christian Ankerstjerne » 24 Dec 2003, 14:25

In a tank vs. infantry battle, where the tank is without support, the infantry will almost always win. Tanks are great for long-distance fighting, but at short distances, vision becomes extremely poor, so even a very small group of infantry can take out a tank.

For example, all tanks will have 'dead angles' very close to them, unless they are packed with an absurd amount of gun ports. If you can get up next to the sid hull of a tank, you will most likely be able to destroy it. The only chance the tank commander will have is to open his hatch, and shoot at you with his sidearm, but then your comrades will take him out (if you are following standard practices).

Of course, the more machine guns, the better, but whereas the JS-2 had a rear machine gun, the German tanks had quite a large number of gun ports.

--

As for armour quality: The German armour was in some cases not up to the given standards, but as mentioned before, neither were the Russian armour. German armour, however, often exceeded the specified armour thicknesses, giving even better protection.
From the numbers I've seen, it appears that the German armour was almost never thinner than what was specified, whereas the Russian armour was more diffuse in armour thickness standards.

Furthermore, the German armour contained a lot of carbon. While this gave weaker weldings, it also gave harder armour...

Christian

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#19

Post by Darrin » 24 Dec 2003, 19:14

Paul Lakowski wrote:
Darrin wrote:
Paul Lakowski wrote:
Harri wrote:Christian:


Actually I think you or your source have it backwards. Hardness increases britleness which usually leads to easier breaking of armour. WWII gunnary and ballistics by lorin bird et al. Low hardness allows the armour to absorb most of the shells enegry resulting in little or no penetration. The ger often times covered thier soft armour with special face harded armour that caued dam to the AP nose decreasing max pen even more.
Thats laughable...on the one hand we have actual historical ballistic test results compared to ...what a computer game???

The RAS has a elongation of 10-12% [ductility] which puts it on par with RHA of 300BHN in terms of elasticity. GAS [German armored steel] has similar qualities at ~430 BHN.

What they are noting is that thin hard brittle plates struck by overmatching shells suffer shattering effects. In actual fact this is ABS [adabatic shear bands what happens in DU projectiles] and they depend on the projectile overmatching the plate[stretch it to the point of failure].

The mistake L&B make is that they don't know when to ascribe a quantity to either the armor ; the slope or the projectile. Each contributes differently to the penetration process.

If plate hardness didn't contribute to resistance all tanks would be made with mild steel....since is 1/4 of the price.

Well I heard that at least 1 game that is based on some of thier perhaps ealier work supposedly. I am refering to thier book which I read and seems very convincing. They take into acconut many different factors in thier book angle of arm lat angle shot type hard cast etc.... I think lorrin at least is an engineer and most of his statments apper to make sence to me a scientist. They provide much of the data they use in thier book and sorces as well.

Most light tanks had thin armour and sometimes kept it hard to provide protection aginst the smaller ammo on thebattlefield. When the rus first built the T34 it had 45mm arm thickess almost all around When hit with rounds simlar or less in dia the armour behaved as if it was ductile. This meant early in the war the 37mm and 50mm guns had little effect. As the war went on the ger guns all improved to 75 and even 88mm. This totally overmatched the rus 45 mm armour thickess resulting in perhaps a 20% decline in res and shatter.

All the rus tanks had overly hard arm as ordered by the rus themselves and by the ger who got to study the tanks after they got thier. Except the kv1 frontal armour. The ger even built arm similar to the rus comp to test it and found the same thing. The problem was due to the war sit and could be changed... The rus built 1/4 the steel ger did so the ger could be a bit more selective in putting the steel on thier tanks. Esp when they had to build far fewer that lasted longer and had acess to many types of iron ore steeel type and minor elements to make stell with. With rus building so many tanks just to replace thier loses making hard steel used less workforce and waste discards.

It seems whofully illogical that you must consider ALL rus arm better quality then the ger one. But you can believe whatever you want...

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#20

Post by LAH Pz Grenadiere » 24 Dec 2003, 19:19

Thanks for the advice "Christian" Merry Christmas

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#21

Post by Paul Lakowski » 24 Dec 2003, 20:35

Darrin wrote:
Paul Lakowski wrote:
Darrin wrote:
Paul Lakowski wrote:
Harri wrote:Christian:


Actually I think you or your source have it backwards. Hardness increases britleness which usually leads to easier breaking of armour. WWII gunnary and ballistics by lorin bird et al. Low hardness allows the armour to absorb most of the shells enegry resulting in little or no penetration. The ger often times covered thier soft armour with special face harded armour that caued dam to the AP nose decreasing max pen even more.
Thats laughable...on the one hand we have actual historical ballistic test results compared to ...what a computer game???

The RAS has a elongation of 10-12% [ductility] which puts it on par with RHA of 300BHN in terms of elasticity. GAS [German armored steel] has similar qualities at ~430 BHN.

What they are noting is that thin hard brittle plates struck by overmatching shells suffer shattering effects. In actual fact this is ABS [adabatic shear bands what happens in DU projectiles] and they depend on the projectile overmatching the plate[stretch it to the point of failure].

The mistake L&B make is that they don't know when to ascribe a quantity to either the armor ; the slope or the projectile. Each contributes differently to the penetration process.

If plate hardness didn't contribute to resistance all tanks would be made with mild steel....since is 1/4 of the price.

Well I heard that at least 1 game that is based on some of thier perhaps ealier work supposedly. I am refering to thier book which I read and seems very convincing. They take into acconut many different factors in thier book angle of arm lat angle shot type hard cast etc.... I think lorrin at least is an engineer and most of his statments apper to make sence to me a scientist. They provide much of the data they use in thier book and sorces as well.

Most light tanks had thin armour and sometimes kept it hard to provide protection aginst the smaller ammo on thebattlefield. When the rus first built the T34 it had 45mm arm thickess almost all around When hit with rounds simlar or less in dia the armour behaved as if it was ductile. This meant early in the war the 37mm and 50mm guns had little effect. As the war went on the ger guns all improved to 75 and even 88mm. This totally overmatched the rus 45 mm armour thickess resulting in perhaps a 20% decline in res and shatter.

All the rus tanks had overly hard arm as ordered by the rus themselves and by the ger who got to study the tanks after they got thier. Except the kv1 frontal armour. The ger even built arm similar to the rus comp to test it and found the same thing. The problem was due to the war sit and could be changed... The rus built 1/4 the steel ger did so the ger could be a bit more selective in putting the steel on thier tanks. Esp when they had to build far fewer that lasted longer and had acess to many types of iron ore steeel type and minor elements to make stell with. With rus building so many tanks just to replace thier loses making hard steel used less workforce and waste discards.

It seems whofully illogical that you must consider ALL rus arm better quality then the ger one. But you can believe whatever you want...
Its not a question of believe...there are numerous papers where all this info comes from.Like Lorine I too study such works and come to a different conclusion....but your entitled to your believes too...have a happy and health holiday!

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Christoph Awender
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#22

Post by Christoph Awender » 24 Dec 2003, 20:53

LAH Pz Grenadiere wrote:Thanks for the advice "Christian" Merry Christmas
As I said to you on the other forum KGM. The blue pills in the morning and the red in the evening.

\Christoph

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#23

Post by ChristopherPerrien » 24 Dec 2003, 21:27

In a tank vs. infantry battle, where the tank is without support, the infantry will almost always win. Tanks are great for long-distance fighting, but at short distances, vision becomes extremely poor, so even a very small group of infantry can take out a tank.


Exactly what kind of short distances are you talking about? 10 meters,
And past about 100m infantry carry no weapons that could hit and kill an average tank.

In any kind of open country, infantry don't stand a chance against tanks.

I will also note that a tank can also take out a small group of infantry at short range, SQUISH!!! It takes alot bravery or foolishness to be that close to a tank or unseen in a blind spot, even with a "friendly" tank.

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#24

Post by Christoph Awender » 24 Dec 2003, 22:15

Hello Christopher!

In this case I have to disagree with you. OK we are talking about tanks without infantry.
No infantry position is without cover, foxholes, trenches. If they are on the wide open the only help was run.

Infantry in positions are as good as invisible for a tank crew. if the infantry doesn´t panic they will let the tanks pass and attack the from the rear and side. Of course if a tank finds the foxhole he can make rounds on it and burry the soldier underneath. In this situation he is again vulnerable against attacks from the neighbouring infantry positions.
Also if a soldiers is close enough to the tank the weapons of the tank are ineffective because of the angle of fire.
It is easy to get closer to a tank when he concentrates on a target. Running soldiers are extremely hard to see and shoot at when at close range because of the limited visibility in a tank.
There are plenty of accounts of infantry units taking out several tanks in close combat when alone.
Usuall tactics were that a machinegun or another target draws the fire of the tank on itself while teams attack the tanks from two sides. Even if he sees one team the second team has the chance of placing a charge. One M.G. or MPi. provides cover if someone comes out of the tank.

You always have to think of the limited view they have through their slits especially in a range of under 50 meters. Smoke, fire, dirt, bullets clutching against the armor etc....

\Christoph

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#25

Post by ChristopherPerrien » 24 Dec 2003, 23:26

Ok Christoph, I see you have that true "ground pounder" mentality. :roll: :P :lol:

Excuse the off topic digression

Me myself, unless infantry are in heavy woods or a built up area , I might feel sorry for them if I was in a tank while I was running them over. :) A good tank driver is really going to seriously reduce your chances of surviving getting close to a mobile tank to hurt it. And it is true well dug in infantry are "safe" to an extent from tanks and many other weapons but,
if the infantry doesn´t panic
Believe me it would take alot of bravery or foolishness not to panic when a "fire and lead spitting armor plated 30-60 ton monster with 4 or 5 brains", is coming at you at speed.
The real panic is that you don't know IF!!!!! a tank crew sees you or not till it shoots you or runs you over, and that feeling is disconcerting to say the least.

Granted the few infantry in prepared positions I almost ran over once, I didn't see, i.e friendly troops, but they had the "big eyes" after the fact anyway 8O. I can only imagine how big those eyes would have been if I had seen them and was actually trying to run them over, 8O x 10. "Tank Terror, PanzerTerror" is a "real thing".
You always have to think of the limited view they have through their slits especially in a range of under 50 meters.
Having been a party to that limited view for a few years, I somewhat agree with you, but if you are in the front 120 degrees or so of that tank were the driver can see, you are pretty dam near dead in alot of situations. And none of the tanks I was on had a bow-mg gun position either.

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#26

Post by Harri » 25 Dec 2003, 00:22

I'm no expert in metallurgy so I can't say much about this case except that I agree with Darrin that the "hardness" of steel really has nothing to do with its "capability" to resist for example AP, HEAT or APCR ammo. Actually all these ammo types "behave" differently against same kind of armour plates. There are at least half dozen other factors in armour steel which are equally important if we talk about penetration of ammo. Cast steel is also weaker than rolled (and welded) steel but the first one could be "moulded" and that is a benefit. So, there are two basic factors: shape of the surface and the "quality" of armour steel. Then we have several basic characters of steel i.e. armour steel is a compromise between all these.

My figures are based on well known Finnish tank expert and his knowledge is based on Finnish, Soviet(/Russian) and western sources. Finland has used Soviet tanks since 1940 and we have had a change to compare our war booty (JSU-152, T-34 m/43, T-34/85) to their later designs (T-54, T-55, T-72) with our German tanks (StuG III G, PzKw IV J obtained in the summer 1944). I think big changes should have be seen? But for example our StuGs obtained in 1943 and 1944 were similar in quality.

Finns considered StuGs better than T-34/85 due to its better gun. 122 mm gun was not a big improvement over the smaller Soviet tank guns but enough to match the more and more rare German heavy tanks in combat. It would be nice to hear how Soviet ammunition improved during the last months of war. There actually was no need anymore because war was almost over by winter 1944/45.

----

I don't remember which metals Germans lacked of (I think Manganese was one of these) but for example Nickel they had for the next years because the mine in Finland had produced really large amounts of nickel in 1943 and 1944.

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#27

Post by LAH Pz Grenadiere » 25 Dec 2003, 02:27

Christoph Awender wrote:
LAH Pz Grenadiere wrote:Thanks for the advice "Christian" Merry Christmas
As I said to you on the other forum KGM. The blue pills in the morning and the red in the evening.

\Christoph
Christoph, I was not not talking to you. What forum is KGM, as I have never been there? And I don't take any pills. But Merry Christmas to you as well.

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#28

Post by Christoph Awender » 25 Dec 2003, 04:04

LAH Pz Grenadiere wrote:....And I don't take any pills....
:lol: And thats exactly your problem LHA Granzer Penadiere!

Christopher I didn´t know that you are a tankcrew man. I am definately not so experienced like you as I only sat in our austrian army tanks and a M-24 Chaffee on our training ground.
But I think that the visibility out of a T-34 was not as good as from a modern tank.

I just can talk from things I´ve read in manuals, veteran stories and war diaries.
Of course the "panic factor" is very high within green troops. But if you think of 1943 onwards at least a good percentage of a company and a even higher percentage of the NCO´s will have good experience in anti-tank actions. I know pamphlets and instruction sheets for NCO´s to tell their men that it is more dangerous to run away in front of a tank than to stay in the trench/foxhole.
But I think we both agree to the fact that everything depends on the situation. :)

\Christoph

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#29

Post by Paul Lakowski » 25 Dec 2003, 08:33

Harri wrote:I'm no expert in metallurgy so I can't say much about this case except that I agree with Darrin that the "hardness" of steel really has nothing to do with its "capability" to resist for example AP, HEAT or APCR ammo. Actually all these ammo types "behave" differently against same kind of armour plates. There are at least half dozen other factors in armour steel which are equally important if we talk about penetration of ammo. Cast steel is also weaker than rolled (and welded) steel but the first one could be "moulded" and that is a benefit. So, there are two basic factors: shape of the surface and the "quality" of armour steel. Then we have several basic characters of steel i.e. armour steel is a compromise between all these.

My figures are based on well known Finnish tank expert and his knowledge is based on Finnish, Soviet(/Russian) and western sources. Finland has used Soviet tanks since 1940 and we have had a change to compare our war booty (JSU-152, T-34 m/43, T-34/85) to their later designs (T-54, T-55, T-72) with our German tanks (StuG III G, PzKw IV J obtained in the summer 1944). I think big changes should have be seen? But for example our StuGs obtained in 1943 and 1944 were similar in quality.

Finns considered StuGs better than T-34/85 due to its better gun. 122 mm gun was not a big improvement over the smaller Soviet tank guns but enough to match the more and more rare German heavy tanks in combat. It would be nice to hear how Soviet ammunition improved during the last months of war. There actually was no need anymore because war was almost over by winter 1944/45.

----

I don't remember which metals Germans lacked of (I think Manganese was one of these) but for example Nickel they had for the next years because the mine in Finland had produced really large amounts of nickel in 1943 and 1944.
I don't have time to get into to this but most of my work is based on several hunderd engineering papers on ballistics and most of my estimates end up being very close to L&B anyway.

Any way its christmass not time for armor but scotch!

Have a great christmass every one!! :D

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Tanks vs Inf

#30

Post by Paul Timms » 25 Dec 2003, 10:53

Whilst one tank attacking infantry unsupported would be vunerable (my father in law claimed his unit destroyed a lone tiger) it would take balls of steel to get out of your foxhole to take them on hand to hand so to speak. The real problem would be multiple tanks. If 20 or 30 tanks are rolling over your position the could cover each other. As a rule Russian tanks tended to be in large groups.

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