WWII German Ballistic Penetration Criteria

[jwduquette1]

I thought you asked if it was using t/d? And it does. I just qualified that the "t" is modified before being used in the equation by a factor. I mean if the armor thickness was 60" but made of cheese would it be 60/d?

 

I'm not trying to sell anyone on there validity. That's up to Nathan.

 

My goal was not to understand the equations as much as to be able to easily use them in my wargame design.

 

Steve:

 

I'm not trying to sell anyone on the idea that Okun's stuff is any more or any less reliable than any other penetration model floating around out there. Every such model has boundary conditions over which it will yield accurate information. Beyond the boundaries accuracy may degrade rapidly.

 

I have already provided you with a spreadsheet showing my own cross checks of the program output vs. a number of actual large caliber naval projectiles ballistic trials -- at low obliquity. The program seems to accurately predicate things in this realm. So yeah -- you wanna do Tsushima, or Jutland or Surigao your prolly good to go. If you wanna do Prokorovka than you're doing GIGO and you're kidding yourself that the bells and whistles are giving you something useful. But I doubt this was a consideration or even an interest on the part of Okun. He has mainly been interested in Battleships vs. Battleships. Think scale effects.

 

My questions regard use of the program with smaller caliber AP and higher obliquity hits. Is that what is motivating your questions here over the last few weeks -- i.e. why doesnt FACEHARD or M79 gimme the results from Jentz or the like? Or 57mm AP vs. the front of a Sherman? From what I have seen in side-by-side tests of program output vs. actual ballistic test information, the accuracy doesnt seem as good with smaller caliber AP at higher obliquities. I have already posted side-by-side ballistic trials for M79 AP vs. output from Nathan's M79 program. One would think a program called M79 would -- at the very least -- accurately model M79 penetration. It has reasonable accuracy at low obliquity -- poor accuracy at high obliquity.

 

I have talked about this before, your intent I presume is reasonable accuracy in predicting penetration\perforation. Thus the questions about whether or not normalizing German Penetration Data is required when comparing it to say USA or UK standards. Perhaps it is, perhaps it isn't. But the contrasts and potential error introduced between V50 and V80 limit velocities are minimal (i.e. 3% or 4% in contrast in velocity if you understand what your looking at) relative to the slope effects model which is introducing a an error source of 20% to 40%.

 

My point is simply that if you understand the alogrithim you can tweak it such that the program is more appicable to tank vs tank. Smaller caliber AP and high obliquity impacts.

 

Regards

Jeff

[Mobius]

My questions regard use of the program with smaller caliber AP and higher obliquity hits. Is that what is motivating your questions here over the last few weeks -- i.e. why doesnt FACEHARD or M79 gimme the results from Jentz or the like?

Maybe you're thinking I'm using Facehard for my questions on 88mm. I'm not I only use it to fill in gaps on information on naval penetrations. For the 88mm I was trying to organize the penetration data as there seems to be some misunderstanding or missing information there.

I think I now have solved the puzzle and unlike Lorin am not going to try to rationalize and normalize the Jentz tables to get the US/UK penetration data.

What I believe is that there were three 88mm AP shells used by the Flak 88mm gun.

 

nomenclature=8.8cm Pzgr.

weight=9.5 kg;

muzzle velocity=810 m/s;

penetration of homo plate at 30 deg from vert =

100m = 97mm;

500m = 93mm;

1000m = 87mm;

1500m = 80mm;

2000m = 72mm

 

nomenclature=8.8cm Pzgr.Patr. m. Bd. Z.

Weight = 9.39kg

muzzle velocity = 810 m/s;

penetration of homo plate at 30 deg from vert =

100m = 120mm;

500m = 110mm;

1000m = 100mm;

1500m = 91mm;

2000m = 84mm.

 

nomenclature=8.8cm Pzgr.39.

Weight = 10.2kg

muzzle velocity = 780-800 m/s; (not sure on this)

penetration of homo plate at 30 deg from vert =

 

100m = 127mm;

500m = 117mm;

1000m = 106mm;

1500m = 97mm;

2000m = 88mm.

Edited January 1, 2007 by Mobius

[DB]

Maybe you're thinking I'm using Facehard for my questions on 88mm. I'm not I only use it to fill in gaps on information on naval penetrations. For the 88mm I was trying to organize the penetration data as there seems to be some misunderstanding or missing information there.

I think I now have solved the puzzle and unlike Lorin am not going to try to rationalize and normalize the Jentz tables to get the US/UK penetration data.

What I believe is that there were three 88mm AP shells used by the Flak 88mm gun.

 

nomenclature=8.8cm Pzgr.

weight=9.5 kg;

muzzle velocity=810 m/s;

penetration of homo plate at 30 deg from vert =

100m = 97mm;

500m = 93mm;

1000m = 87mm;

1500m = 80mm;

2000m = 72mm

 

nomenclature=8.8cm Pzgr.Patr. m. Bd. Z.

Weight = 9.39kg

muzzle velocity = 810 m/s;

penetration of homo plate at 30 deg from vert =

100m = 120mm;

500m = 110mm;

1000m = 100mm;

1500m = 91mm;

2000m = 84mm.

 

nomenclature=8.8cm Pzgr.39.

Weight = 10.2kg

muzzle velocity = 780-800 m/s; (not sure on this)

penetration of homo plate at 30 deg from vert =

 

100m = 127mm;

500m = 117mm;

1000m = 106mm;

1500m = 97mm;

2000m = 88mm.

Doesn't "m. B. Z" merely mean "base fuzed"?

 

There do seem to be some superficial differences between the fig 429 and fig 436 projectiles, but they're no larger than some of the other differences shown for otherwise identically named rounds - could be as simple as early versus late fuze versions being less likely to premature on near-limit penetrations.

 

There doesn't seem to be enough information on the pages you show to indicate that they count as three distinct rounds, [edit: rather than the obvious two] at least to me.

 

David

Edited January 1, 2007 by DB

[jwduquette1]

Maybe you're thinking I'm using Facehard for my questions on 88mm. I'm not I only use it to fill in gaps on information on naval penetrations. For the 88mm I was trying to organize the penetration data as there seems to be some misunderstanding or missing information there.

 

I don't presume anything. I don't take you for an idiot. If I did I wouldn't waste my time even posting to this thread or scanning my own reference materials and providing them to you for review. You have stated on another thread that you are using M79 to model AP vs. RHA. Why should I think you’re doing anything different now?

 

But you are asking questions that are being answered, but than you are arguing about the answers. Your subsequent arguments suggest you are not really understanding your original questions let alone the answers being provided. I’m not trying to be an ass here. I’d be very interested in seeing you expand NAaB into something usable for WWII tank sims. But you're delving into the esoteric without having a handle on some of the basics. Open the door, look at the bowling ball. You want to have a meaningful discussion about whether the ball is red or whether the ball is scarlet. But you want to have this question resolved before you have accepted that the ball is actually there. Crawl – Walk – Than Run.

[C.G.Erickson]

I don't presume anything. I don't take you for an idiot. If I did I wouldn't waste my time even posting to this thread or scanning my own reference materials and providing them to you for review. You have stated on another thread that you are using M79 to model AP vs. RHA. Why should I think you’re doing anything different now?

 

But you are asking questions that are being answered, but than you are arguing about the answers. Your subsequent arguments suggest you are not really understanding your original questions let alone the answers being provided. I’m not trying to be an ass here. I’d be very interested in seeing you expand NAaB into something usable for WWII tank sims. But you're delving into the esoteric without having a handle on some of the basics. Open the door, look at the bowling ball. You want to have a meaningful discussion about whether the ball is red or whether the ball is scarlet. But you want to have this question resolved before you have accepted that the ball is actually there. Crawl – Walk – Than Run.

The problem I have in comparing test results between one nation to another is the prerequisites of each nation is different. For example, Russian tempering of projectiles to the same hardness as their armor plate. If the projectile is as hard as the armor plate, then it has to do some kind of damage. Worst case is the test of U.S tests of M61 AP versus German 75mm APBCHE versus 3 inch thick Face Hardened Armor plate. US M61 was fired at 0 obliquity while German 75 was fired at high obliquity. Not mentioned in the text of the report findings, but very evident in the test photos. Conspiracy?

 

As for 88 rounds, there was a variety of different AP rounds.

 

Early war base detonated APBCHE. All APHE in German use was base detonated, while HE was point fused. Hint.

1942 APBCHE "39"

APBCHE "39/41"

HVAP tungsten cored

Heat rounds

 

Keep searching, Do some research. Or are you data mining for your lack of resource material?

 

C.G.

 

The US only tested captured rounds

[Mobius]

I don't presume anything. I don't take you for an idiot. If I did I wouldn't waste my time even posting to this thread or scanning my own reference materials and providing them to you for review. You have stated on another thread that you are using M79 to model AP vs. RHA. Why should I think you’re doing anything different now?

What in the world are you talking about NaaB or Okun for? This is about German penetration criteria of their tanks shells compared that used by British and US. The other thread was about a question of 60° impacts or something.

 

Jeff, I don't use Nathan's equations or my Naab on anything I do with WWII tanks. It is all from sources like data from Salt's pdf, Speilbergers books, Hunnicuts books, Encyclopedia of German tanks, Russian Battle Field site, and TM 9 1907.

 

The thread here is of why if it was that the UK/US penetration data on the 88 was so different than German on the lighter AP shell. The first thought was that they used much different criteria. Now my idea is that there were two lighter 88mm AP shells.

[Mobius]

Doesn't "m. B. Z" merely mean "base fuzed"?

But Black doesn't mean Black with red markings if I be so bold.

[jwduquette1]

What in the world are you talking about NaaB or Okun for? This is about German penetration criteria of their tanks shells compared that used by British and US. The other thread was about a question of 60° impacts or something.

 

Jeff, I don't use Nathan's equations or my Naab on anything I do with WWII tanks. It is all from sources like data from Salt's pdf, Speilbergers books, Hunnicuts books, Encyclopedia of German tanks, Russian Battle Field site, and TM 9 1907.

 

The thread here is of why if it was that the UK/US penetration data on the 88 was so different than German on the lighter AP shell. The first thought was that they used much different criteria. Now my idea is that there were two lighter 88mm AP shells.

 

Well that's good to hear. Your rather frugal in describing what it is your doing and why your asking questions.

 

To understand the potential sources of error or sources of contrast -- specifically those apparent from 1943 TM E9-369A -- you need to know the differences between plate specific ballistic limits and projectile specific ballistic limits. To that end are you up to speed on W/R limits, CV limits, Army Ballistic Limit and Navy Ballistic Limit?

[Mobius]

Well that's good to hear. Your rather frugal in describing what it is your doing and why your asking questions.

 

To understand the potential sources of error or sources of contrast -- specifically those apparent from 1943 TM E9-369A -- you need to know the differences between plate specific ballistic limits and projectile specific ballistic limits. To that end are you up to speed on W/R limits, CV limits, Army Ballistic Limit and Navy Ballistic Limit?

Well since I don't have the plate specific its not going to do me any good being up to speed.

I can't even confirm if the data in 1943 TM E9-369A is of US or British origin or just the German data redistributed in inches.

(As the same figures (except in millimeters) are listed in the Bovington data booklet.)

I can program the equations if need be, but first things first.

You are good at researching these types of things. Jentz indicates there are two velocities given Pzgr. 39. Can this be verified?

[jwduquette1]

Well since I don't have the plate specific its not going to do me any good being up to speed.

I can't even confirm if the data in 1943 TM E9-369A is of US or British origin or just the German data redistributed in inches.

(As the same figures (except in millimeters) are listed in the Bovington data booklet.)

I can program the equations if need be, but first things first.

You are good at researching these types of things. Jentz indicates there are two velocities given Pzgr. 39. Can this be verified?

 

I think they are traceable back to British guesstimates prepared in late 1942. But I am still collating information. Jentz’s numbers (see: "Tank Battles in N. Africa" & "Dreaded Threat") are – as you are probably aware -- consistent (identical) with Chamberlain’s numbers ("Encyclopedia of German Tanks of WWII") – weight, Vo and penetration. See “Encyclopedia of German Tanks of WWII”. I take Jentz’s numbers to be German in origin. Vo =810m/s and M = 9.5kg.

 

The British 1942 estimates have the projectile weight at 9.5Kg and Vo = 792m/s.

 

There is a conversion error in the US TM for projectile weight -- as the FTs in the same manual show it as both 9.65Kg and 20.75-lbs -- same projectile Another figure in the manual places the projectile weight at 20.71-lbs. 20.75-lbs is closest to the typically reported weight of 9.5kg

Edited January 3, 2007 by jwduquette1

[Mobius]

– as you are probably aware -- consistent (identical) with Chamberlain’s numbers ("Encyclopedia of German Tanks of WWII") – weight, Vo and penetration. See “Encyclopedia of German Tanks of WWII”. I take Jentz’s numbers to be German in origin.

Considering "Technical Editor: Thomas L. Jentz" I would hope so.

 

Seems you already got into this subject before.

Jeff Duquette posted a story some time ago where 88mm Flak units were having their shots shatter against KV and T34 armor at 2000+ meters, and it took 10 shots per kill.

 

If early 88mm Flak rounds were used, and there must have been a lot of them during 1942 and 1943, the penetration at 2000m would not be sufficient to get many penetrations against KV-I and T34 front hull, and KV-I turret front.

 

The data provided by Richard Simmie answers many questions, and he did a great job digging into the material.

 

This is a comparison of published 30° penetration for 88L56 APCBC and an explanation of what it seems to represent:

 

88L56 Early War Large HE Burster-88mm Flak (9.54kg projectile)

98mm at 100m, 93mm at 500m, 87mm at 1000m

 

88L56 Later War Large HE Burster-88mm Flak

(9.54 kg projectile)

120mm at 100m, 110mm at 500m, 100mm at 1000m

 

88L56 Later War Small HE Burster-Tiger and Flak

(10.2 kg projectile)

127mm at 100m, 117mm at 500m, 106mm at 1000m

 

88 ItK/37 RMB and 88 ItK/37 RMBK "Rämäpää"

"88 psakrv 54/65-K" (German made APHE-shell with 117 g of amatol and 31 g of penthrit, projectile weight 9.5 kg, muzzle velocity 820 m/sec)

"88 psakrv rj 54/65-K" (German made APHE-shell with 117 g of amatol and 31 g of penthrit, projectile weight 9.5 kg, muzzle velocity 820 m/sec)

"88 pshkrv 54/65-K" (German made APHE-shell with 64 g of RDX, projectile weight 10.2 kg, muzzle velocity 820 m/sec)

 

German designation:Pzgr. Patr. m Bd Z

for weapon: Flak 18, Flak 36, Flak 37

weight:9.44 kg.

charge weight:131 gm.

Color: Black

 

German designation:Pzgr. 8,8cm

for weapon: Flak 18, Flak 36, Flak 37, Flak 39( r)

weight:9.54 kg.

charge weight:150 gm.

Color: Black w/Red Markings

 

German designation:Pzgr. 39

for weapon: Flak 18, Flak 36, Flak 37, Flak 39®, Kwk 36

weight:10.0 kg.

charge weight:114 gm.

Color: Black w/Red Markings

There is a bar chart in Spielberger's Panther book "Der Panzer-Kampfwagen Panther und Seine Abarten" that has a bar chart showing the penetration of the Tiger at 100m to be about 120mm/30. It also has data for the the 88/L71 and 75/L70 for 30° which match Jentz's data for those two guns.

[jwduquette1]

So he did...I guess if you print the same thing over and over and over again it becomes the truth.

 

To be clear that's Lorrin's take on a set of German accounts detailed in "Dreaded Threat". I simply provided him scans of the accounts. Everything else is Lorrin's interpretation.

 

On the weights I'm thinking disconnects on fuzed and unfuzed weights.

 

As to the rest I scanned the 1943 TM numbers and posted them on Yahoo many many moons ago. Is the image you posted of the table in question from my original post way back when? If you actually have a copy of the manual you will see what it is I am referring to with the APC projectile weights.

 

As I recall Lorrin discounted the numbers in the TM outright. I don't recall his logic. Personally I think it is as simple as the difference between BL(A) and BL(N).

[Mobius]

So he did...I guess if you print the same thing over and over and over again it becomes the truth.

 

To be clear that's Lorrin's take on a set of German accounts detailed in "Dreaded Threat". I simply provided him scans of the accounts. Everything else is Lorrin's interpretation.

 

On the weights I'm thinking disconnects on fuzed and unfuzed weights.

 

As to the rest I scanned the 1943 TM numbers and posted them on Yahoo many many moons ago. Is the image you posted of the table in question from my original post way back when? If you actually have a copy of the manual you will see what it is I am referring to with the APC projectile weights.

 

All the scans are my own.

The data on the 88mm Flak is from my TM E9-369A.

The data and pictures on the three 88mm shells are from a copy of 3/1953 TM 9-1985-3 German Explosive Ordinance (Projectiles and Projectile Fuses).

 

As I recall Lorrin discounted the numbers in the TM outright. I don't recall his logic. Personally I think it is as simple as the difference between BL(A) and BL(N).

I think Lorrin thought (like most everyone else) there was only one early shell and two late war shells. So he had to reconcile Jentz early shell data with that in TM E9-369A.

[jwduquette1]

All the scans are my own.

The data on the 88mm Flak is from my TM E9-369A.

The data and pictures on the three 88mm shells are from a copy of 3/1953 TM 9-1985-3 German Explosive Ordinance (Projectiles and Projectile Fuses).

 

I think Lorrin thought (like most everyone else) there was only one early shell and two late war shells. So he had to reconcile Jentz early shell data with that in TM E9-369A.

 

than the variety of weights described within the TM for the same projectile should be evident.

 

as to the rest...your memory is better than mine as this was some five or six years ago. i thought he said something to the effect that the TM numbers were wrong and probably based upon early war estimates --like DeMarre or Milne or the like. perhaps you can find his exact words. as I recall, i argued that they were probably based upon testing of captured equipment and ammunition. as to the actual origins, i still don't know for certain if they are equation based estimates or based upon real shooting trials. the british notes i have been looking at are not quite the same numbers, which may mean different origins for the penetration data. but the british specifically indicate that the estimates for german projectiles may be too high -- i.e. the document includes british AP and german AP penetration estimates. their words not mine. its in WO 185/178. if you get the entire document you will see how the penetration figures for the british AP rounds "evolve" through various drafts of the original report. like one dude felt Milne coefficients were too conservative, or not conservative enough -- my guess. so the numbers are changed for the next draft.

 

anyway if you can trace the actual source of the TM penetration numbers or the firing trial reports it would be rather simple to detemine limit velocity criteria employed, or if the numbers were generated using a penetration equation rather than ballistic tests. if you can find the test report than you might be able to develop a basis for normalizing german penetration data. without the true origins of these TM figures...hmmm...well you can derive whatever conclusions you like. if you find actual ballistic testing data and than side-by-side the data with actual German ballistic testing data for the same projectile than you might have something interesting to look at.

[Mobius]

I have a suspicion that they are anglicized German penetration numbers. Then the US borrowed them from the British and put in to their own TM. What makes me think this is that the appendix of the book has a table of 88mm data for each 100m from 100m to 4000m, time of flight, the elevation, velocity, drift, x,y 50% dispersion for AP. And has the same for HE out to 14,800m. HE table also has angle of impact and dispersion.

 

I don't think the British or Americans did that amount of testing. The US usually put their test data into the graph format or lists one value at say 1000 yards.

[jwduquette1]

I have a suspicion that they are anglicized German penetration numbers. Then the US borrowed them from the British and put in to their own TM. What makes me think this is that the appendix of the book has a table of 88mm data for each 100m from 100m to 4000m, time of flight, the elevation, velocity, drift, x,y 50% dispersion for AP. And has the same for HE out to 14,800m. HE table also has angle of impact and dispersion.

 

I don't think the British or Americans did that amount of testing. The US usually put their test data into the graph format or lists one value at say 1000 yards.

 

I am speaking specifically of the TM penetration tables. The firing tables are translated from captured schusstafeln. Allied firing tables and range tables are of the same sort of basic format -- i.e. I'm not sure where you're getting the idea about the graph thing or the bit about one value for 1000-yards.

 

As to your original question, and the TM penetration data being Anglicized German data, why do you think that? Clearly the Jentz numbers are derived from German sources and they are not the same as the TM data at any range. The 88mm 10.2Kg APC figures listed by Jentz in his numerous volumes are identical to the data presented on German figures contained in BIOS. So I know for certain that these are German in origin. BIOS doesn’t have the 9.5Kg pzgr projectiles penetration figures. But why should we think Jentz’s numbers for the 9.5Kg projectile are not German in origin?

 

The other bust in logic is; If the TM penetration numbers are ultimately from a German source -- as you are now suggesting -- than what exactly are you going on about. You were interested in whether German penetration figures needed modifying to bring them on par with Allied penetration figures -- you were going on about something to do with V50 and V80 percentiles. If the TM penetration figures are German in origin why bring them to the table?

 

Like I said back on page-1 of this thread you need to compare German testing data with Allied Testing Data for the same projectile. You need to understand both German and Allied success and failure criteria for the test data.

Edited January 5, 2007 by jwduquette1

[Mobius]

As to your original question, and the TM penetration data being Anglicized German data, why do you think that? Clearly the Jentz numbers are derived from German sources and they are not the same as the TM data at any range. The 88mm 10.2Kg APC figures listed by Jentz in his numerous volumes are identical to the data presented on German figures contained in BIOS. So I know for certain that these are German in origin. BIOS doesn’t have the 9.5Kg pzgr projectiles penetration figures. But why should we think Jentz’s numbers for the 9.5Kg projectile are not German in origin?

I'm only saying it may be possible. Or some set circumstances could happen so that

the data looks like it could have a common source. The US data also looks very similar

to that in the Bovington Fire and Movement booklet. Jentz 88/56 data seems very close.

Not so much for data on the 75/48 or 88/71. It's close but not that close.

Odviously Jentz's data is in meters while Bovington data is in yards. But converting yards to meters

and continuing the curve it could be the same curve (except for the last figure).

88/L56

yards..................500.......1000....1500...2000

TM.E9-369A........4.33.....3.97......3.62....3.30.

Converted.to.mm..110......101........92.......84

Bovington............110......101........93.......84

meters.................500.......1000....1500...2000

Jentz...................110.......100.........91......84

 

75/L48

yards/meters.......500.......1000....1500...2000

Bovington.............90.........79........70......62

Jentz....................91.........82........72......63

 

88/L71

yards/meters.......500.......1000....1500...2000

Bovington............182.......167.......153......139

Jentz..................185.......165........148......132

 

Edit erased last line.

Edited January 5, 2007 by Mobius

[jwduquette1]

I'm only saying it may be possible. Or some set circumstances could happen so that

the data looks like it could have a common source. The US data also looks very similar

to that in the Bovington Fire and Movement booklet. Jentz 88/56 data seems very close.

Not so much for data on the 75/48 or 88/71. It's close but not that close.

Odviously Jentz's data is in meters while Bovington data is in yards. But converting yards to meters

and continuing the curve it could be the same curve (except for the last figure).

88/L56

yards..................500.......1000....1500...2000

TM.E9-369A........4.33.....3.97......3.62....3.30.

Converted.to.mm..110......101........92.......84

Bovington............110......101........93.......84

meters.................500.......1000....1500...2000

Jentz...................110.......100.........91......84

 

75/L48

yards/meters.......500.......1000....1500...2000

Bovington.............90.........79........70......62

Jentz....................91.........82........72......63

 

88/L71

yards/meters.......500.......1000....1500...2000

Bovington............182.......167.......153......139

Jentz..................185.......165........148......132

 

There was a 'hot' 88mm AP ((40/43) shell for the 88/71. Maybe Jentz is assuming the two sets of values for the Tiger's 88mm AP is similar with a 'hot' pzgr39.

 

You’re startin' to worry me again Steve. You’re doin' the apples to oranges thing again. Jentz clearly distinguishes between pzgr39 and pzgr. The 1943 US Army TM is referring to pzgr -- not pzgr39. look at weights and Vo's reported in each of the sources.

 

These Jentz numbers you have quoted in your upper table:

...................110.......100.........91......84

 

are for pzgr.39 (10.2Kg, Vo=800m/s), not pzgr.

 

if you are trying to imply there is a boo-boo on the part of the British and Americans in reporting pzgr.39 penetration figures for pzgr than you should say as much. otherwise one comes away with the impression -- after looking at your last post -- that you are inadvertently trying to compare two different projectiles. if you plot out the various numbers reported for pzgr. you should come away with two distinct sets of curves. one for the Jentz data -- one for the WO 185/178 & TM data. The WO data being slightly different than the TM data -- but I suppose close enough for government work.

[Mobius]

These Jentz numbers you have quoted in your upper table:

...................110.......100.........91......84

are for pzgr.39 (10.2Kg, Vo=800m/s), not pzgr.

The question is - are they?

 

if you are trying to imply there is a boo-boo on the part of the British and Americans in reporting pzgr.39 penetration figures for pzgr than you should say as much. otherwise one comes away with the impression -- after looking at your last post -- that you are inadvertently trying to compare two different projectiles.

Jeff, you're starting to worry me. Could Jentz be wrong in identifying the shell that gave those numbers?

Can you or anyone find two pzgr.39 (10.2Kg.) that have two different velocities? That is what I want to know?

I haven't found that anywhere.

Second question, is why did Jentz leave out the Pzgr. Patr. m. Bd. Z. round (which the US and UK apparently know all about) yet he includes two varieties of Pzgr 39?

[jwduquette1]

dude -- there are two sets of penetration data floating around out there for pzgr. why are you now mixing penetration data for pzgr39 in with pzgr?

[jwduquette1]

never mind

Edited January 5, 2007 by jwduquette1

[Mobius]

dude -- there are two sets of penetration data floating around out there for pzgr. why are you now mixing penetration data for pzgr39 in with pzgr?

I'm asking is what Jentz has identified as a Pzgr 39 (10.2kg, v=773ms) could possibly be Pzgr Patr. m. Bd Z? If not then can two Pzgr.39 exist?

Logic works this way:

Jentz lists 3 types of 88mm/56 APC. US TM Ordinance lists 3 types of 88mm/56 APC.

Two of the items are the same in both lists.

The difference being is that the TM has the item Pzgr Patr. m. Bd Z and Jentz has the item Pzgr 39 (10.2kg, v=773ms).

So either the TM is incomplete or is wrong about the types of German 88mm/56 APC or Jentz is. (or they both are)

The TM does include a picture of the item so its up to Jentz (or anyone else) to provide equally convincing proof of his item.

 

I guess I'm done with this subject until more information turns up.

Edited January 5, 2007 by Mobius

[jwduquette1]

 

I’m not here to defend Jentz, but in this instance all his poop looks fine -- all German based according to the datenblatt for Flak 18/36. Only one pzgr listed -- along with one set of penetration data for pzgr. Penetration data is pretty much what Jentz reports in "dreaded threat" as well as "Encyclopedia of German tanks". Note the fuze type indicated by the Germans for pzgr. Weights and such all jive. (Sorry – the red circles were in reference to the hollow charge round.)

 

Several different pzgr.39 projectiles listed. Penetration is pretty much what Jentz reports in “Dreaded Threat” as well as "Encyclopedia of German tanks" – off by a mm or so.

 

I would “guess” that there may be some subtle aspects of “pzgr.” that may have been changed. Drive bands etc. But going from a bimetal driving band to an iron driving band doesn’t seem a likely source for a 30% boost in penetration capability.

[Mobius]

Several different pzgr.39 projectiles listed. Penetration is pretty much what Jentz reports in “Dreaded Threat” as well as "Encyclopedia of German tanks" – off by a mm or so.

 

I would “guess” that there may be some subtle aspects of “pzgr.” that may have been changed. Drive bands etc. But going from a bimetal driving band to an iron driving band doesn’t seem a likely source for a 30% boost in penetration capability.

Could be one or more different sub-species was left off the lists. I found one site that says there was a pzgr. 39/1 type round for this weapon.

That document does indicate the v0=800m/sek or 820m/sek (can't tell which they mean). Don't see a 773m/sek.

Edited January 5, 2007 by Mobius

[jwduquette1]

773m/s is specific to kwk, so why would it appear on a datenblatte for Flak 18/36?