T-44 vesrus Panther

[WotS]

U guys take this too much as 1tank VS 1 tank!
In that point the mobility and production numbers,easy maintence,low weight dont matter much.
The optics,gun and ammo and front armor plate are most important.

Still T-44 had diesel engine.

I wonder what German vehicle costs same as T-44?

[cbo]

If we assume all the projectiles are of the same design and metal quality, then velocity, weight and Diameter are the only things that count.

Yes, but the projectiles for the guns you referred came in many different shapes and sizes and even those who are superficially similar have different properties like nose shape, different nose and body hardness, some where shot and some were shell, some had greater body cavities than others etc.

Also i would agree that De Marre's formula "T/D ratio effect" is long obselete for WW2 AP projectiles, as many of them relied on the normalizing effect against sloped armor.

I'm not sure what you mean by this?

Claus B

[Timber]

Yes, but the projectiles for the guns you referred came in many different shapes and sizes and even those who are superficially similar have different properties like nose shape, different nose and body hardness, some where shot and some were shell, some had greater body cavities than others etc.

Offcourse, but i was just qouting the principles, later comes the side effect's, such as the hardness of the shell and the shape both inside and outside the ballistic cap.

I'm not sure what you mean by this?

What i mean is, sadly alot of individuals rely on "bird and livingston's" penetration formula "T/D effect", wich is long obselete for WW2 projectiles. This has led to some wild penetration farrytales, mostly because "Bird and livingston" rely on Soviet penetration data, wich doesnt coinsist with Allied or German penetration data.

Example: English tests say Panther glacis will resist a 17pdr APCBC shell at up to 800m, while according to the Soviets the German 8.8cm Kwk43 would only penetrate the Panther glacis at 650m with a APCBC shell, this is offcourse bollocks. The energy transplanted into the target-plate from these two guns, are so different that it is impossible. By looking at the Official penetration data for the 8.8cm Kwk43 and 17pdr, this is offcourse obvious.

Regards.

[Timber]

To give an example on the difference in hardness of projectiles from the U.S., Germany and USSR. I qoute the resluts of a British test result against homogeneous armor at 610 m/s impact velocity.

102mm penetration for German 75mm APCBC
90mm penetration for U.S. 76mm APCBC
75mm penetration for Russian 76mm APBC


If you couple this with the Kinetic energy table i qouted, then i see a very prominant advantage for the German guns over the others.

Regards.

[WotS]

Think on that how many T-44 elements have been used on later tanks.

I can count few of them: diesel engine,turret is located at center,well sloped armour,RWD,good layout of transmission and engine.

How many elements have Panther what have been used on later tanks?

Im not sure but i assume gun and optics and communication system stuff.

[cbo]

What i mean is, sadly alot of individuals rely on "bird and livingston's" penetration formula "T/D effect", wich is long obselete for WW2 projectiles. This has led to some wild penetration farrytales, mostly because "Bird and livingston" rely on Soviet penetration data, wich doesnt coinsist with Allied or German penetration data.

Example: English tests say Panther glacis will resist a 17pdr APCBC shell at up to 800m, while according to the Soviets the German 8.8cm Kwk43 would only penetrate the Panther glacis at 650m with a APCBC shell, this is offcourse bollocks. The energy transplanted into the target-plate from these two guns, are so different that it is impossible. By looking at the Official penetration data for the 8.8cm Kwk43 and 17pdr, this is offcourse obvious.

I still dont see what you mean when you talk about "normalzing effects" etc.

Also, it is rather pointless to refer to "english" tests and "soviet" tests unless you go into the nature of the said tests.
In any case, the "english" tests stating the 17pdr APCBC could penetrate the Panther glacis at any range appears to be without any foundation in reality. AFAIK, tests against captured Panthers in Normandy clearly showed this to be possible only with APDS (at short ranges if you could actually hit the tank!).

Using Bird & Livingstons formulae, the 17pdr APCBC will not penetrate the Panthers glacis at any range while the 8,8cm will penetrate up to about 1000 meters. So what exactly is the problem?

I can understand you have some kind of beef with Bird & Livingston, but could you please explain why T/D ratio does not have any bearing on WW2 projectiles and what you mean by "normalizing effect".

Claus B

[Ultramagnus]

102mm penetration for German 75mm APCBC
90mm penetration for U.S. 76mm APCBC

As I remember,Livingstone had also pointed out this,the advantage of german APCBC over american APCBC at the same velocity due some factors like inert cavity size and nose hardness,especially by the 75-76mm.

Russians measured the Panther glacis as 85mm,not 80.

[Timber]

I still dont see what you mean when you talk about "normalzing effects" etc.

The Normalizing effect is something the Russians called it, i do not remember how its specified in english, it was normally an APCBC feature when it hit sloped armor. Anyway the Normalizing effect is when the projectile meets with the sloped armor surface, the tip starts to impede the projectile. This resulting to change its trajectory so the angle between projectile's axle and the armor surface becomes 90 degree's.

Also, it is rather pointless to refer to "english" tests and "soviet" tests unless you go into the nature of the said tests.

Sorry i was just trying to compare two tests, i got the information about these tests from the book "Tank versus Tank". (And i myself found some of the data in that book to be wrong)

In any case, the "english" tests stating the 17pdr APCBC could penetrate the Panther glacis at any range appears to be without any foundation in reality. AFAIK, tests against captured Panthers in Normandy clearly showed this to be possible only with APDS (at short ranges if you could actually hit the tank!).

If you would show them, i would really like to read about them.

Using Bird & Livingstons formulae, the 17pdr APCBC will not penetrate the Panthers glacis at any range while the 8,8cm will penetrate up to about 1000 meters. So what exactly is the problem?

As far as i remember Bird and livingston only qoutes the 8.8cm Kwk43 being able at 750m !.

I can understand you have some kind of beef with Bird & Livingston

Not at all !. But i find the whole T/D ratio thing abit out of hand, and not really usable for WW2 projectiles.

but could you please explain why T/D ratio does not have any bearing on WW2 projectiles

Because De Marre's equation doesnt take into considderation the Normalizing effect of WW2 APCBC.

Regards.

[cbo]

The Normalizing effect is something the Russians called it, i do not remember how its specified in english, it was normally an APCBC feature when it hit sloped armor. Anyway the Normalizing effect is when the projectile meets with the sloped armor surface, the tip starts to impede the projectile. This resulting to change its trajectory so the angle between projectile's axle and the armor surface becomes 90 degree's.

I think that is incorrect as a general rule. That effect depends a lot on the design of the round. For example, the flat-nosed APBC round would be much more inclined to "dig in" than a pointed-nosed, uncapped AP round, which would be more likely to bounce off. If there was indeed a general normalizing effect, you would never see a round bounce off sloped armour, it would always dig in and just get stuck, if it didn't penetrate. So I'd say that except for the "normalizing effect" of the radically blunt APBC round, the effect is a very small factor in penetration.

Sorry i was just trying to compare two tests, i got the information about these tests from the book "Tank versus Tank". (And i myself found some of the data in that book to be wrong)

I wouldn't put much faith in the figures in that book. I have it myself and IIRC the tables are unreferenced and does clearly not take into account any differences between the various tests. Also, I suspect that some of the data is actually based on calculated data rather than actual tests like the sometimes quoted WaPrüf comparision figures.

As far as i remember Bird and livingston only qoutes the 8.8cm Kwk43 being able at 750m !.

If you take the equations in their book for the resistance of 80mm@55 degrees vs a 88mm projectile, I get a resistance of 198mm vs the 0 degree RHA penetration of the 8,8cm KwK 43 of 204mm at 1000m. If you assume a 30 degree impact angle, the resistance raises to 241mm and the 8,8cm will not penetrate at all.
They did have some kind of Panther flawed glacis plate theory which may change these figures, but the validity of that theory has been questioned quite a lot.

Not at all !. But i find the whole T/D ratio thing abit out of hand, and not really usable for WW2 projectiles.

Because De Marre's equation doesnt take into considderation the Normalizing effect of WW2 APCBC.

I think the T/D ratio thing explains a lot of things which would be difficult to explain otherwise - furthermore, AFAIK, ballistics experts in the 1950ies, working with WWII projectiles used the T/D ratio in their equations, so it is by no means a Bird & Livingston "invention".
The so-called "normalizing effect" is only applicable to certain projectiles and only pronounced in those with a radically blunted nose and to a lesser extent with capped rounds.
Furthermore, the Bird & Livingston equations takes into account this effect for APBC and capped rounds which can clearly be seen in the results of their equations.

Claus B

[Ultramagnus]

As far as i remember Bird and livingston only qoutes the 8.8cm Kwk43 being able at 750m !.

85mm thick glacis,all the difference:)

[Timber]

I think that is incorrect as a general rule. That effect depends a lot on the design of the round. For example, the flat-nosed APBC round would be much more inclined to "dig in" than a pointed-nosed, uncapped AP round, which would be more likely to bounce off. If there was indeed a general normalizing effect, you would never see a round bounce off sloped armour, it would always dig in and just get stuck, if it didn't penetrate. So I'd say that except for the "normalizing effect" of the radically blunt APBC round, the effect is a very small factor in penetration.

Hmm... As far as i remember it was for APCBC, and not blunt nosed APBC, but there's no doubt blunt nosed APBC would be more effective against sloped armor. I do know that APCBC did have some of this normalizing effect, because of the the second cap in the Pzgr.39, the blunt one, designed for ballistic performance, takes over and avoids the projectile from ricocheting off inclined armor.

I wouldn't put much faith in the figures in that book. I have it myself and IIRC the tables are unreferenced and does clearly not take into account any differences between the various tests. Also, I suspect that some of the data is actually based on calculated data rather than actual tests like the sometimes quoted WaPrüf comparision figures.

The same conclusion has struck me a few times to.

If you take the equations in their book for the resistance of 80mm@55 degrees vs a 88mm projectile, I get a resistance of 198mm vs the 0 degree RHA penetration of the 8,8cm KwK 43 of 204mm at 1000m. If you assume a 30 degree impact angle, the resistance raises to 241mm and the 8,8cm will not penetrate at all.

Well wasnt the panther glacis 85mm ?? At least the Soviets said it was.

They did have some kind of Panther flawed glacis plate theory which may change these figures, but the validity of that theory has been questioned quite a lot.

And why is that ?? According to Bird and Livingstone the glacis plate on early panther's were flawed.

I think the T/D ratio thing explains a lot of things which would be difficult to explain otherwise - furthermore, AFAIK, ballistics experts in the 1950ies, working with WWII projectiles used the T/D ratio in their equations, so it is by no means a Bird & Livingston "invention".
The so-called "normalizing effect" is only applicable to certain projectiles and only pronounced in those with a radically blunted nose and to a lesser extent with capped rounds.
Furthermore, the Bird & Livingston equations takes into account this effect for APBC and capped rounds which can clearly be seen in the results of their equations.

Well i think there are some things they are forgetting, such as the fact that German AP projectiles were harder than Allied AP projectiles.

If you look at the Kinetic energy table i qouted, then youll see how the Panther's 7.5cm Kwk42 actually has an advantage over the 12.2cm D25T.
The stresses inflicted to the target-plate pr mm^2, are greater with the 7.5cm Kwk42 projectile than with the 12.2cm D25T projectile. (This offcourse changes with a small margin when the range is increased.) Now if you take that into account, then take into account that German AP projectiles also were harder !.

Regards.

[Ultramagnus]

Well i think there are some things they are forgetting, such as the fact that German AP projectiles were harder than Allied AP projectiles

They didn't forget it,the question rather should be,does this higher BH hardness influence sloped armor facing effects?

It's confusing to read references that 90mm M77 AP penetrated more homogenous sloped armor than APCBC at the same velocity.

[cbo]

Hmm... As far as i remember it was for APCBC, and not blunt nosed APBC, but there's no doubt blunt nosed APBC would be more effective against sloped armor. I do know that APCBC did have some of this normalizing effect, because of the the second cap in the Pzgr.39, the blunt one, designed for ballistic performance, takes over and avoids the projectile from ricocheting off inclined armor.

The original reason for having the cap on the AP projectile was not to deal with sloping armour but to deal with face-hardened armour. When plain AP rounds without a cap hit hard armour, they tended to brake up. Adding a cap had several advantages

- The forces of the impact would be transferred to the shoulders of the AP round, reducing the stress on the projectile and keep it intact after the initial impact.
- The cap would shatter and brake apart upon impact, but it would also make a partial penetration through the face-hardened part of the armour, allowing the AP round to penetrate the softer armour behind.

The cap on the PzGr. 39 (and any other round) did not prevent the projectile from ricocheting nor would it "normalize" the impact to 90 degrees, that is an exaggeration. The cap, and that goes for any such cap in principle, would probably reduced ricocheting and, if it was sufficiently blunt, give some degree of "normalization" by making a partial penetration and then brake off due to the richocheting forces. That would reduce the ricocheting forces on the the main projectile and leave it with a partial penetration which would help it to "dig" into the armour.

But again, this effect is shown in the Bird & Livingston formulae.

Well wasnt the panther glacis 85mm ?? At least the Soviets said it was.

Nominally it was 80mm but some measured examples were thicker (82mm, 85mm)

Well i think there are some things they are forgetting, such as the fact that German AP projectiles were harder than Allied AP projectiles.

- British 17-pr APCBC had a noose hardness of 710+ BHN
- US 76mm M62 APCBC had a noose hardness of 477-627 BHN
- Soviet 76mm BR350 B APBC had a noose hardness of 460-560 BHN
- German 75mm PzGr 39 APCBC had a noose hardness of 627+ BHN

So it was not "allied" projectiles per se that were "soft", it was primarily the Soviet and US rounds. And the softest of the German ones were on par with the hardest of the US rounds but below the British.
There were different versions of the PzGr. 39, the most advanced were two piece rounds, where the noose was treated to be very hard while the body was considerably softer. That ensured that the noose would penetrate while the body would be sufficiently ductile to remain intact as it passed through the target armour. That was important, because the body contained the small explosive charge that would go off after penetration. The Soviet and US projectiles also had a HE charge, but the cavity was larger and thus weakened the projectile more than in the German round. Furthermore, their comparatively soft nooses could cause the round to break up during penetration and thus render the HE charge ineffective.
The Germans, however, changed the design of the PzGr. 39 to a one-piece round during the war.
The British got around the problem by omitting the HE charge and cavity all together, which is why it turned out to be the most effective penetrator of the bunch, even if the post-penetration effect was reduced compared with the other rounds. To complete the numbers you gave before:

101mm penetration for German 75mm APCBC
90mm penetration for U.S. 76mm APCBC
75mm penetration for Russian 76mm APBC

107mm penetration for the British 76mm (17pdr) APCBC

But you also make the mistake of assuming that Bird & Livingstons figures does not take this into account. Their 0 degree vs RHA penetration figures are based on firing tests and these tests does of course show the different capabilities of the different rounds.

If you look at the Kinetic energy table i qouted, then youll see how the Panther's 7.5cm Kwk42 actually has an advantage over the 12.2cm D25T.
The stresses inflicted to the target-plate pr mm^2, are greater with the 7.5cm Kwk42 projectile than with the 12.2cm D25T projectile. (This offcourse changes with a small margin when the range is increased.) Now if you take that into account, then take into account that German AP projectiles also were harder !.

The difference in kinetic energy is only 4%, hardly significant?

If you look at Bird & Livingstons penetration figures, you should notice that they are quite similar for the two projectiles (depending on which one of the 122mm Soviet rounds you refer to) . So again, I dont really see your point?

Claus B

[Ultramagnus]

It took a while but I have found it. I'm not personally a wargamer (if chess doesn't count ),but I found it interesting.

http://www.battlefront.com/cgi-bin/bbs/ ... 220#000017

The British report on "German 75mm and 88mm APCBC Ammunition at Oblique Angle", Department of Tank Design Report No. M.6914A/4 No.1 provides test data at 45 and 55 degrees from vertical. Converting the data to performance against vertical armor provides some interesting insights into relative effectiveness.

A graph in the report presents the following penetration figures for 88mm APCBC, which are then converted to performance at the Tiger and Tiger II muzzle velocities (2558 and 3280 fps) against vertical plate using U.S. slope effect curves and the DeMarre equation:

=========================
88mm Large HE Capacity APCBC
65mm at 55 degrees & 2750 fps => 135mm at vertical and 2558 fps
58mm at 55 degrees & 2310 fps => 150mm at vertical and 2558 fps
62mm at 45 degrees & 2060 fps => 139mm at vertical and 2558 fps
Average = 141mm vertical at 2558 fps
=========================
88mm Small HE Capacity APCBC
81mm at 55 degrees & 2965 fps => 160mm at vertical and 2558 fps
76mm at 55 degrees & 2887 fps => 154mm at vertical and 2558 fps
57mm at 55 degrees & 2220 fps => 156mm at vertical and 2558 fps
Average = 157mm vertical at 2558 fps
=========================

Note that the small capacity 88mm round outpenetrates the large capacity ammo by about 11%.

Following converts small capacity data to 3280 fps muzzle velocity of 88L71 gun:
=========================
88mm Small HE Capacity APCBC
81mm at 55 degrees & 2965 fps => 228mm at vertical and 3280 fps
76mm at 55 degrees & 2887 fps => 220mm at vertical and 3280 fps
57mm at 55 degrees & 2220 fps => 223mm at vertical and 3280 fps
Average = 224mm vertical at 3280 fps
=========================

Curves are presented for 17 pdr APCBC penetration vs velocity against 45 and 55 degree plate (2900 fps is muzzle velocity of gun firing APCBC):

===================
17 pdr APCBC Solid Shot
82mm at 55 degrees and 2900 fps => 209mm at vertical and 2900 fps
100mm at 45 degrees and 2850 fps => 182mm at vertical and 2900 fps
===================
Notable that 17 pdr APCBC is not going to pierce the Panther glacis on other than an occasional hit at 100m and beyond, if hits take place on level ground and do not strike highly vulnerable spots (weld lines, MG mount and ball, driver visor area).

The penetration data at 55 degrees results in a vertical estimate which appears to be high, while the 45 degree figure is in line with published figures against vertical armor.

17 pdr APCBC appears to outpenetrate large capacity 88mm APCBC at 45 and 55 degrees by a considerable amount, which may be due to the following combination of factors:

1. solid shot vs HE burster yields greater penetration at all angles
2. British claim 17 pdr APCBC projectile nose is harder, increasing penetration

Data is also presented for German 75mm very small HE capacity APCBC:

=============================
75mm Very Small HE Capacity APCBC
58mm at 55 degrees and 2440 fps => 138mm at vertical & 2460 fps
62mm at 45 degrees and less than 2099 fps => above 130mm at vertical & 2460 fps

[Timber]

The original reason for having the cap on the AP projectile was not to deal with sloping armour but to deal with face-hardened armour. When plain AP rounds without a cap hit hard armour, they tended to brake up. Adding a cap had several advantages

- The forces of the impact would be transferred to the shoulders of the AP round, reducing the stress on the projectile and keep it intact after the initial impact.
- The cap would shatter and brake apart upon impact, but it would also make a partial penetration through the face-hardened part of the armour, allowing the AP round to penetrate the softer armour behind.

The cap on the PzGr. 39 (and any other round) did not prevent the projectile from ricocheting nor would it "normalize" the impact to 90 degrees, that is an exaggeration. The cap, and that goes for any such cap in principle, would probably reduced ricocheting and, if it was sufficiently blunt, give some degree of "normalization" by making a partial penetration and then brake off due to the richocheting forces. That would reduce the ricocheting forces on the the main projectile and leave it with a partial penetration which would help it to "dig" into the armour.

But again, this effect is shown in the Bird & Livingston formulae.

Well that is what i ment, the second cap doesnt provide full "Normalization" but it does however have a normalizing kind of effect.

Nominally it was 80mm but some measured examples were thicker (82mm, 85mm)

Yes, i know but i normally use 83-85mm as a standpoint.

- British 17-pr APCBC had a noose hardness of 710+ BHN
- US 76mm M62 APCBC had a noose hardness of 477-627 BHN
- Soviet 76mm BR350 B APBC had a noose hardness of 460-560 BHN
- German 75mm PzGr 39 APCBC had a noose hardness of 627+ BHN

So it was not "allied" projectiles per se that were "soft", it was primarily the Soviet and US rounds. And the softest of the German ones were on par with the hardest of the US rounds but below the British.
There were different versions of the PzGr. 39, the most advanced were two piece rounds, where the noose was treated to be very hard while the body was considerably softer. That ensured that the noose would penetrate while the body would be sufficiently ductile to remain intact as it passed through the target armour. That was important, because the body contained the small explosive charge that would go off after penetration. The Soviet and US projectiles also had a HE charge, but the cavity was larger and thus weakened the projectile more than in the German round. Furthermore, their comparatively soft nooses could cause the round to break up during penetration and thus render the HE charge ineffective.
The Germans, however, changed the design of the PzGr. 39 to a one-piece round during the war.
The British got around the problem by omitting the HE charge and cavity all together, which is why it turned out to be the most effective penetrator of the bunch, even if the post-penetration effect was reduced compared with the other rounds.

Well i do remember Lorrin talking about that because UK projectiles for the 17pdr were so hard, that also ment higher probabillity of shattering against FH armor. However i was mainly comparing US, USSR and German projectiles, not UK ones, but it doesnt matter.

To complete the numbers you gave before:

101mm penetration for German 75mm APCBC
90mm penetration for U.S. 76mm APCBC
75mm penetration for Russian 76mm APBC

107mm penetration for the British 76mm (17pdr) APCBC

Yes this is also against HA armor.

But you also make the mistake of assuming that Bird & Livingstons figures does not take this into account. Their 0 degree vs RHA penetration figures are based on firing tests and these tests does of course show the different capabilities of the different rounds.

Hmm.. firing tests from where ??

The difference in kinetic energy is only 4%, hardly significant?

If you look at Bird & Livingstons penetration figures, you should notice that they are quite similar for the two projectiles (depending on which one of the 122mm Soviet rounds you refer to) . So again, I dont really see your point?

I never said the difference was significant, and im not talking 0 degree penetration here(as in Bird and Livingstone's book), im talking the obligatory 30 degree penetration.

If im not mistaken then German tests were carried out against 300BHN plates wich is more than what the Soviets did. And the penetration data for the 7.5cm Kwk42 is 124mm at 500m, 111mm at 1000m at 30 degree's from vertical. Now how does Bird and Livingstone's penetration data against 240BHN plates par up with this ?

Regards.