Yu guns vs armor tests of 1960s...

[jwduquette1]

to me -- the Yugoslavian Trials seem more consistant with the firing table penetration data than the RBF data. Is the upper RBF 57mm curve data supposed to be BR-271?

[Guest bojan]

Thanks.  I missed that the first time around.  Sounds like the test methodolgy was both careful and methodical.  That's good.  So we can draw realistic conclusions from the results.

405707[/snapback]

 

Those tests changed JNA look on the ammo loads (tanks lost most of the AP and HVAP ammo to HEAT), new ammo developement was started (that resulted in series of 76/85/90/100mm fin-stabilised HEAT ammo with all angle fuses), 57mm and 75mm ATGs were retired from the first-line and replaced with RCLs, older tanks got HEAT ammo etc... It was probably most important series of tank testing ever done in Yugoslavia.

[Mobius]

The 57mm penetration of the Sherman looks out of place.

Guns vs T-34/85:

Pak 40

M39 AP penetrates front turret @ 1000m

85mm ZiS-S-53

BR-365 AP penetrates front turret @ 1000m

57mm ZiS-2

BR-271 AP penetrates front turret @ 600m

 

Vs M4A3E4 Sherman:

Pak 40

M39 (PzGr.39?) AP penetrates front turret @ 1000m

85mm ZiS-S-53

BR-365 AP penetrates turret @ 1000m

57mm ZiS-2

BR-271 AP penetrates turret front turret @ 900m

Edited December 19, 2006 by Mobius

[jwduquette1]

The 57mm penetration of the Sherman looks out of place.

405837[/snapback]

 

Not sure what your beef is with the Yugoslavian 57mm tests. The numbers look OK to me.

Edited January 7, 2007 by jwduquette1

[f101]

Bojan, could you please provide me with the original titles of the reports you have quoted here ?

[Guest bojan]

I will check exactly this week, but those should be something like:

 

"Balisticki testovi xxx protiv oklopa tenka yyy" - "Balistic tests of xxx vs armor of yyy tank"

 

xxx is a weapon, yyy is a tank model.

 

EG:

"Balisticki testovi BsT 105mm M27A1 protiv oklopa tenka T-34/85 M-44" - "Balistic tests of RCL 105mm M27A1 vs armor of T-34/85 M-44 armor".

Edited March 9, 2007 by bojan

[f101]

It would be great. Im mostly interested in M20. Tests and penetration data that you have posted.

[Guest bojan]

Here it is:

 

Izvestaj br.****** - Pesadijsko protiv-oklopno oruzje **.**.****

BsT 75mm M20(A)

Deo 3.

Tenk T-34 M-44

 

Translates as:

 

Report no.****** - Infantry anti-armor weapons **.**.****

RCL 75mm M20(A)

Part 3.

Tank T-34 M-44 (that is T-34/85)

 

*** is censored part. Censored numbers at end are date, and last number is 5 or 6 - so it is most probably from either 1955 or 1956.

 

(A) is a country of origin, A being for "Američki" - "American".

Here is a list of codes:

A - US

Au - Austria

Al - Australia

B - Belgian

Č - Ch - Czechoslovakia

D - Denmark

E - UK

F - France

Fi - Finland

I - Italy

J - Japan

K - Canada

M - Hungary

N - Germany

P - Poland

R - Romania

S - USSR

Š - Sh - Swiss

 

Other weapons tested (but I have no results for most of them) were:

 

BsT 57mm M18A1 (A)

BsT 75mm M40 (N)

BsT 105mm M42 (N)

RBR 60mm M9A1 (A) - M9A1 Bazooka

RBR 89mm M20 (A) - Super Bazooka

RB 80mm Mk.1 PIAT (E)

RB PzF 60 M44 (N) - Panzerfaust 60

RBR PzS M43 (N) - Panzerschreck

Edited September 11, 2007 by bojan

[f101]

Thanks Bojan !

 

That "other weapons" list looks very interesting . Do you have any results for any handheld AT weapon from that list ?

[Guest bojan]

...Do you have any results for any handheld AT weapon from that list ?

 

Only 57mm M18A1 vs T-34/85, posted earlier.

[jwduquette1]

Thanks for the reference titles Bojan.

 

Regards

Jeff

[Mobius]

Say Bojan, have you ever thought about putting all your Yugo gun test data into a pdf?

Because it really is the Rosetta Stone of WWII penetration, unravelling east and west test data basis.

 

Nevermind. I did this myself and tablized the data.

Edited May 3, 2007 by Mobius

[jwduquette1]

There is something rather odd about many of the test values from the Yugoslavian Army armor penetration trials. Some of the values don't appear to be true limit ranges. Rather it appears that tests may represent “pass” or “fail” tests at various ranges. For example, consider the 57mm ZIS-2 BR-271 tests vs. both the Sherman M4A3E4 and T34/85.

 

Sherman M4A3E8 vs. BR-271

 

The results vs. the Glacis (Penetrates @ 900m) suggest a limit velocity that can be equated to a normal quality roll hardened armor plate (RHA), or an excellent quality cast armor vs. uncapped AP. I don't know off hand if the glacis is actually cast or RHA? This result seems to make sense physically if the glacis is constructed of good quality RHA.

 

The results vs. the Front Turret (penetrates @ 900m) suggests a limit velocity that would normally be associated with extremely high quality face hardened armor plate (FHA) vs. uncapped AP. I assume this is actually a cast armor turret? This doesn't seem to make sense, and I am wondering if the true limit range is much greater than 900m -- or if side angle to the shot line played a part in this very poor shot performance (or extremely excellent armor performance). Was the true limit range actually bracketed?

 

T34/85 vs. BR-271

 

The results vs. the Glacis (Penetrates @ 700m) suggest a limit velocity that would normally be equated to a low quality RHA plate vs. uncapped AP, or a good quality cast plate vs. uncapped shot. The plate is actually rolled high hardness armor. This result seems to make sense.

 

The results vs. the upper side hull (Penetrates @ 1500m) suggest a limit velocity that is off the charts as far as armor quality -- i.e. the T34/85’s side plate is performing much better than the best quality FHA plate vs. uncapped shot. The plate should be rolled high hardness armor. This result seems very odd given the above result vs. the glacis -- i.e. either the shot is very bad quality or the plate is extremely good quality, or some side angle to shot placement is at work, or the actual limit range was not bracketed.

 

The results vs. the upper side turret (Penetrates @ 1500m) suggest a limit velocity that is off the charts for cast armor. The turret side is performing as well as the best quality FHA plate vs. uncapped shot. Doesn't make sense -- is this a true limit range or are we seeing extremely poor shot quality -- or extremely good cast armor quality -- or some side angle to the shot line -- or the actual limit range was not truely bracketed?

 

There are a couple of possible explanations -- shot quality, plate quality, side angle not accounted for, vehicle on unlevel ground resulting in higher obliquity of plate, etc. However, I am wondering how bracketing of the limit range was conducted or how actual limit velocity of a specific plate and projectile combination was actually conducted by the Yu Army? Or; was bracketing not conducted. Moreover, were various ranges of vulnerability estimated, than ballistic tests conducted at the range in question as a pass fail event -- i.e. the projectile either penetrates at the estimated vulnerability range, or it doesn't penetrate. In which case some of the max ranges suggested don't represent true limit ranges of the plate\projectile combination.

Edited March 7, 2008 by jwduquette1

[Guest bojan]

...Rather it appears that tests may represent “pass” or “fail” tests at various ranges...

 

I think that it is obvious from purposes of testing - establish real distances where selected gun can hole selected tank.

 

I don't know off hand if the glacis is actually cast or RHA? This result seems to make sense physically if the glacis is constructed of good quality RHA.

RHA, but IIRc (data was posted earlier) relatively soft.

 

I assume this is actually a cast armor turret?

 

Yes.

 

...This doesn't seem to make sense, and I am wondering if the true limit range is much greater than 900m -- or if side angle to the shot line played a part in this very poor shot performance (or extremely excellent armor performance). Was the true limit range actually bracketed?

 

Considering that we don't realy know where on the front turret shots hit it could happen (but is unlikely) that most hit where armor is more sloped and were deflected... Also note that front turret is ~90mm at places and also mantle overlaps parts of the front turret, so there are weaker and stronger parts of turret...

http://elektron.tmf.bg.ac.yu/bojan/armor/t..._sherman_06.jpg

[jwduquette1]

Hi Bojan:

 

Thanks for the reply.

 

Are the various limit ranges based upon single shot tests? Or; is each limit range established by a minimum of two hits -- a penetrating hit at one range, and a non penetrating hit at a greater range?

 

Best regards

Jeff

[binder001]

I belatedly read the whole post. Quite fascinating material - thanks for posting. This rates right up there with the famous tests done by the US First Army against captured Panthers at Isgny, France in August of 1944.

[Guest bojan]

...Are the various limit ranges based upon single shot tests?...

 

No, multiple shots, IIRC 10 in case of tests vs T-54A.

I have no data for other tests but note that in tests of 90mm guns vs T-34/85 it is noted that "plate criticaly failed after Nth shot", indicating that there were more then one shot fired.

[jwduquette1]

No, multiple shots, IIRC 10 in case of tests vs T-54A.

I have no data for other tests but note that in tests of 90mm guns vs T-34/85 it is noted that "plate criticaly failed after Nth shot", indicating that there were more then one shot fired.

 

Ok...thanks.

[Guest bojan]

Minor addition, from other sources:

57mm M1 ATG, firing AP round penetrates T-34/85 front (no clarification if it is hull or turret) @ 320m and M4A3E4 Sherman front (no clarification if it is hull or turret) @ 400m.. For both results I guess it is vs front hull.

It penetrates Tip-A (local T-34 derivate) front (again not specified if it is turret or hull) @ 250m (hull - 50 or 60mm @60deg rolled, turret - 100mm cast) @250m.

 

Edit: Typed from a memory made a mistake...

Edited March 10, 2008 by bojan

[Guest bojan]

BTT

[Mobius]

Bojan, was there any data on the muzzle velocity of any of the guns?

I'm looking for the data of the Pak 40 75mm/L46.

The Yugo tests shows the 75mm/L46 to be superior to the US 76mm with the M79 round @ 792m/s.

According to this article http://en.wikipedia.org/wiki/7.5_cm_PaK_40

the Pak 40 was reduced to 750 m/s.

 

This is a little hard to reconcile.

[Przezdzieblo]

Any idea where is bojan?

[kNiks]

I was about to ask the same thing - why is he in 'guests'?

[bojan]

Alive and well, it was just my account that died...

[Przezdzieblo]

Welcome back