Paul Lakowski

Sooooo Kip what would it take to get a copy of this made? How much did you say [ouch]

<BLOCKQUOTE>quote:</font><HR>Originally posted by PzKpfw 1: Paul the Ausf.D was the standard model during Zitadelle. Both Pz.Abt 51 & 52 had Panther Ausf Ds. Ausf A's appeared later in 1943. Yes the Panther tested was captured during Zitadell, in fact another Ausf D from Pz.Abt 52 (Fgst,Nr.210055) is still on display in Russia. Regardless of model the armor protection of the glacis remained the same, 80mm @55^. <HR></BLOCKQUOTE> As usual I'm falling over my self again ...I'll have to check ,but as I recall the Panthers used at Kusrk had face hardened glacis and it was these that were used in the 122mm gun tests. As to D marre formula , I never use it I rely on ballistic formula from the Engineering journals modeled on lab test results .The formulas work for all modern KE projectiles and looks like it might just work on WW-II AP ...but we'll see about that... Kip in the monster archival document you found are there any 'S curve' charts or graphs for the various projectiles? ...cause that would help to shed light on this area.

John I was told the Panther was captured at Kursk , I thought all Panthers at Kursk were the old A models? Kip the Russians used blunter projectiles than the Germans and the 1.2 figure is optimistic , its closer to 1.1 making the LOS value maybe 154mm . The 122mm [bR 471B] 'calculated certififed penetration' figure is ~ 110mm @ 2.5 km , so the V-50 value should be about 121mm and the +/- range of results is 20%[over 90% of results] or 121 + 24mm = 145mm. Over 100% of results the value should be more. But this doesn't take into account bursting charges which british reports note can convert a 'partial penetration' into a 'kill'. So even if this is not a face hardened glacis its still possible, but that doesn't make it the norm.

<BLOCKQUOTE>quote:</font><HR>Originally posted by Rattus: I understand there are several different Brinell hardness scales - the common one using the little tungsten carbide ball under a 3000kg load giving the best range. Is there any chance that the Brinell hardness figures quoted from different nations use one of the alternative scales? Looking for an education here! <HR></BLOCKQUOTE> Who knows fro sure , I was talking with a russina 'expert' and he didn't know how to BHN scale at all.He said they used g/mm²I think [?].

Kip as I already pointed out to John last week the Panther that was tested was one of the batch captured at Kursk .... this first batch were all made with face hardened glacis. When a face hardened plate is struck by an over matching shell, it shatters resulting in a greatyly reduced resistance ...thats why all other Panthers had RHA glacis....I guess the germans read that report too Besides this gets to the question I asked earlier how is penetration calculated? cause a penetration of 100mm has a shot to shot variation of up to ±20% .Since the Russian 100mm value is the 'certified penetration value' which represents the 80% mark that means , to adjust it to 'normal V50 ballistic limit value' you need to increase this buy 10-20% . So in an extreme case the 122mm APC should be able to penetrate 140mm armor @ ~ 2.5kms [ maybe 1-10% of the time], but on a regular basis this should only be 110-120mm.

I think a better approach would be to identifiy 'weakened zones' and 'strong points'in all tanks ... set the bar around 150mm for Tiger-1 mantle and introduce a ± value [50mm for Tiger-1].

If you stick with the mostly 100mm value for the Tiger 1 Mantle, the JS-2 should ace Tiger tank at over 2.5km range and T-34/85 should get the same results at 1.0-1.5Km ....when Zaloga & Jentz puts the values at 500m @ 0m respectively.

OK if your going to use this notion of stong points you'd better be ready to change to some thing like 20% @ 100mm + 50% @ 140mm & 30%@ 200mm, cause those are the approximate resistance levels....and BTW you ought to do this to every tank cause they all have it to one extent or another. If you don't do this you'll end up with unrealistic penetration events ....unless the penetration system is also faulty. Does the penetration system take into account the fact that theres no such thing as a singular penetration value at any given range and angle? How does it distribute the probablity of X penetration or Y penetration? Is it a '± normal distribution' around a common value and if so which one ...the V50 'ballistic limit'?

Some facts for you to chew on.... Both zaloga and Jentz report the Russian 76mm Gun was incapable of penetrating Tiger -1 frontally. Even the American 76mm is only rated at 100m @ 30° while the T-34/85 was rated at 0m range. Zaloga reports "However , by this time , the new BR-350P APDS round ,which could penetrate 92mm of armor at 500m , was introduced. The T-34 76.2mm gun was far less effective against the new tanks introduced by the Wehrmacht in 1943. The Tiger first appeared on the Leningrad Front in January 1943 , and could not be defeated frontally by the T-34." Every weapon tested against the Tiger 1 front armor show a difference in penetration against the mantle area compared to the hull @ 500m [122mm] 300m [uS 76mm] > 200m [85mm]. The hull is rated at 100mm@ 25°@ 30° which is about 127mm effective LOS armor .Thus the difference is the penetration for those guns .... <PRE> 122mm = 500m ;12-15mm + 127mm= 139-143mm 76mm& 85mm = 300m ;10-12mm + 127mm= 137-139mm </PRE> sounds like it should be ~ 14cm to me [This message has been edited by Paul Lakowski (edited 08-08-2000).]

<BLOCKQUOTE>quote:</font><HR>Originally posted by kipanderson: Hi, Lets take a situation in which two American 76mm gunned vehicles are firing at a hull down Tiger at 1000m. Once they got the range they would have a very good chance of a kill, assuming 2/3 of the mantlet is 100mm thick and 1/3 200mm thick.However if you made the mantlet 110mm thick there would be a chance of six, seven or more strikes before there was a kill. If you have a situation in which there is an armour plate that is 2/3 100mm thick and 1/3 200mm taking an average does not give you a representation of reality in terms of the tactical situation. If you make the mantlet 110mm thick you halve the effective range of the American 76mm guns against it from around 1200m to around 600m. The real world figure having been 1200m given that around 2/3 of the mantlet was 100mm thick. When it comes to CM2 you have similar problems. The effective range of the Soviet 76.2mm gun, firing the tungsten core BR350P round, against the mantlet was 400m-500m. If you increase the thickness to 110mm that decreases to around 200m, not a representation of the real tactical situation as it was. <HR></BLOCKQUOTE> The unfortunate problem here is that you can't use american penetration figures as a yard stick cause they used a completely different penetration criteria than the Brits Germans or Russians. If you quote which ammo does what penetration maybe we can sort this out more clearly.

BTT so 'Tiger' can contribute

Below is info from the game and my 1950 Ordnance Board report on penetration. <PRE> CM US 57mm 500m 1000 0' 91mm 70mm 30' 78mm 63mm Cm Br 6pdr 0' 91mm 70mm 30' 78mm 63mm CM Tung 0' 141mm 112mm 30' 112mm 90mm Ordnance Board 6 lb APCBC 500yards 1000 yards 0' 115mm 92mm 30' 106mm 85mm Ordnance Board 6 lb APDS 0' 165mm 146mm 30' 132mm 116mm 17lb APCBC 0' 165mm 146mm 30' 132mm 116mm 17lb APDS 0' 250mm 232mm 30' 208mm 191mm 60' ? 148mm </PRE> [This message has been edited by Paul Lakowski (edited 08-07-2000).]

<BLOCKQUOTE>quote:</font><HR>Originally posted by PzKpfw 1: Paul you sure the glacis was 220BHN? I have seen it listed as both 265BHN & 285BHN. why would we flame ?. <HR></BLOCKQUOTE> No it was a bit of a joke I made the same point on another board and was almost excommunicated for violating the 'sacred Tiger 2 tank' Here's Clause Bonnesen great site with alot of Roberts data and research work, check the Tiger-2 entry. http://www.mobilixnet.dk/~mob75281/ga/apen/bhn/bhn.htm

Take a deep breath.... In theory the 122mm APC shot should be able to penetrate the Tiger -2 glacis at very short range with a lucky shot.The reason this MAY be possible is three fold. Firstly; the Front armor of the Tiger-2 was only 220BHN ..not much better than mild steel [ 180 bhn]. Now with modern long rod penetration tests going from a 270 to 220 BHN would result in 50 x 0.00156 or 8% lower resistance.But actual resistance may be lower. The angle is 50° but the effective armor is 1.45[RL data] x 1.56 [50°]= 2.24 x 150mm RHA = 337mm effective armor x 92% = 310mm . Robert reported the glacis plate was 'flawed' and according to David honner thats 95% resistance reducing the armor to 294mm . Second; the free edge effect in and around the main gun embrassure and MG ports in the turret and glacis. In long rod penetration studies this should generate roughly 0.7 @ 2 projectile diameter. Which means around the MG port it offers 0.7 x 294mm= 206mm resistance[ 5inch radius around MG port] . If we assume the M-G ports are as thick as the glacis , then hits on the MG port would be 336mm x 0.6 or 202mm. Third; the penetration of the 122mm APC @ 300m range is ....161mm @ 0°, but this is a russian test so its the 'certified penetration' which is 80% penetration. This increases the Russian penetration values by 10% and apply ± 20% due to normal distribution , we get 1.1+ 0.2 x 161mm or 209mm maximum penetration @ 300m range . Put more clearly the penetration should be 177mm ± 32mm @ 300 meters range. So the 122mm should have a marginal capablity against the Tiger-2 glacis from straight on at short range. Alright flame on boys

<BLOCKQUOTE>quote:</font><HR>Originally posted by Olle Petersson: To penetrate or not to penetrate... What does it mean? As noted there were, and still is, great variations in what it means when it's stated that a round can penetrate X mm of armour... Suppose a round penetrates, then what? *If* there's any energy left in the round, it might cause some damage, otherwise it just drops dead on the floor. In the American standard it seems like those few shots that penetrate the given armour have so little energy left that they're pretty harmless... If there's no armour penetration, that doesn't mean the target is unharmed. There are several vulnerable spots on tanks; vision blocks/slits, external weapon parts (gun barrels, aiming and ranging devices), antennae, suspension and in some cases external fuel tanks. All of these are vulnerable to hits from light ATGs, small arms or shrapnel and will degrade the tanks ability to fight. It is impossible to compute and correctly take into account every parameter that determines the outcome of a shot. Therefore a large degree of randomness is necessary. What's the chance, in CM, of a 37mm AP disable a Tiger, given a straight frontal hit at 400m range? IMO it should be more than 1%. Cheers Olle<HR></BLOCKQUOTE> Hi Olle good to see you here . I have long wondered why the American standard is different. I first encountered this in modern armor and penetration and I'm not 100% sure the WW-II armor was rated the same , but Robert reported it was, sooo. In Jentzs book in notes the Americans mounted a captured German 75mm shell to one of there 75mm rounds and test fired it to find out how much difference their 'bursting charge' [APHE] made in the penetration.They found that even a incomplete projectile penetration would convert into a 'kill' due to the bursting out of the 'bursting charge'.

<BLOCKQUOTE>quote:</font><HR>Originally posted by Jeff Heidman: Wow, what a great discussion. Nothing like something like this to keep me humble. What is meant by the term "overmatching"? Jeff Heidman<HR></BLOCKQUOTE> Overmatch means the target armor plate is thinner than the projectile diameter. Armored steel has been shon to resist differently depending on wether the projectile is larger than the plate thickness.This is part of the 'confinement issue'. Modern long rod penetration studies are always done into targets 1.6 times the maximum penetration possible to avoid this problem in measurement. In the case of hard steel they seem to suffer more and result in plate shattering and less resistance than simple RHA.

First off if I new my Tiger scan was going to end up here I'd have given our poor tiger tank a better tilt so it doesn't look like its sliding sideways into a gully On the previous page I showed how I arrived at the 140mm 160mm resistance figure for the 'Tiger 1 front turret profile'.The main effect is the ' Free edge effect' & T/d but a reduction for cast is also needed. The other way is to use those calculated penetration ranges , that appear in every Jentz book.In those books the 122mm AP shot has penetration value of 500m @ 30° angle Vs the Tiger -1 Mantle. According to info supplied by John Waters [ from Russian tests] the 122mm APC shot can do . <PRE> on the BP-460 SC rounds. Range 300ms - 500ms 1000ms 1500ms 0° 161mm - 157mm -147mm ? 30° ? 137mm - 129mm - 122mm </PRE> This implies the resistance is not more than 137mm Vs 122mm AP shot. But as I already mentioned the Russian test standard is about 10% higher than the common 50% 'ballistic limit' standard. thus the adjusted figures should be times 1.1 or .... <PRE> on the BP-460 SC rounds. Range 300ms - 500ms 1000ms 1500ms 0° 177mm - 173mm -162mm ? 30° ? 151mm -142mm - 134mm </PRE> See if the value was 120mm penetration would be over 1500m ,so what this suggest that against a 122mm AP shot the Tiger -1 front mantle armor should be less than 151mm but more than 142mm .15cm sounds about right. edited for clarity [This message has been edited by Paul Lakowski (edited 08-07-2000).]

<BLOCKQUOTE>quote:</font><HR>Originally posted by PzKpfw 1: 76mm AP Penetration from Game Data: [PRE] 500ms 1000ms @ 0^- 112mm - 101mm @ 30^ - 89mm - 82mm @ 60^ - 50mm - 46mm 75L48 AP Penetration from Game Data: 500ms 1000ms @ 0^ - 130mm - 112mm @ 30^ - 100mm - 90mm @ 60^ - 49mm - 46mm <HR></BLOCKQUOTE> John are these LOS values cause Jentz reports "Example : The penetrating ability of the 7.5cm Pzgr.39 fired from the Pak 40 at a range of 1000meters os 81mm at an impact angle 30°. Penetrating ability at this same range at 0°is 95mm ,45° is 50mm , and 60° is 32mm."...'Tank Combat in North Africa'. Rgds Paul & keep up the good work

<BLOCKQUOTE>quote:</font><HR>Originally posted by :USERNAME:: The above is pretty good proof if based on foiring tests. I really get totally Missouri ('Show me state') about this AP stuff and only really believe either official range shoots or field tests where people record everything they can. I have seen Tigers I with extra tracks on the front hull but never on the front of the turret. Panzer IVs did this even to the extent of making cutouts so the turret MG and sights would work. A hull down Tiger I would be a nightmare from the front. Lewis <HR></BLOCKQUOTE> Here unfortunately is part of the problem Official figures and test reports are next to useless with out {A} all the data & {B} having a sound grounding in how penetration % works....this is not as easy as it sounds .Each country has different criteria for defining what constitute a'complete or partial penetration' and each countries test plates are different again. So we do need to improve our 'back ground knowledge' as well as better test reports.For example any penetration figure quoted is only a probability value, British and German tests use the 50% value while Soviet test use a 75% mark and American's use 20-25% mark. the difference between all these values is about ± 40% around the 50% value .... that means if a projectile has a penetration of 100mm what this means is that any given shot could achieve a actual penetration of 140-60mm. Now the 10% top part of top part and bottom 10% of these 'S' curves constitute about half this range, so 'truncating' the values to cover only the middle 80% makes allot of sense cause it cuts this range in half. So the range would be 120-80mm or 100mm±20mm in 4 out of 5 cases . But if the test is American what it means is the range of values should be 110-70mm, while if its a Russian test it means the range should be 130-90mm. And that assumes they all use the same test plate hardness . German test plate was against 280-300 plate while American test were on 240BHN plate and some sources suggest Russian figures are against upto 400BHN plate [but Robert Livingston reported to me that the actual resistance of these Russian plates was about the same as German test plate 250-300BHN] . So when you see that all the rounds [ with 100mm penetration] of a particular projectile fail to penetrate the Tiger 1 mantle ; all that tells you is the armor must be more than 120mm and maybe even more than 140mm. But when you see a value like 122mm APC @ 500 M range @ 30°, this can often tell you more cause it usually is a exact 50/50 split ; provided you adjust for the penetration criteria.

<BLOCKQUOTE>quote:</font><HR>Originally posted by RMC: CM models the hardness and slope of armor and takes into account the changes to these values from the angle of attack both vertically and horizontally. It's just that there aren't as many hit locations being represented as I had thought. <HR></BLOCKQUOTE> Out of curiosity, how did they model plate hardness and overmatching shells etc?

I've bee asked my opinion of the accuracy of the armor penetration system, while the armor question [related to Tiger-1 front armor ] is still open to debate, I'd like to examine the Armor penetration system. What is the game penetration value assigned the US 57mm APCBC ammo at 500-1000 yards and whats the value for the British 6lb APCBC round? Whats the same game value for the 76mm APCBC ammo and German 75L48 gun @ 500 M & 1000 M range? How did you deal with slanted penetration and the differing criteria for defining what is and is not a penetration?

<BLOCKQUOTE>quote:</font><HR>Originally posted by PzKpfw 1: Seeing as for all intents and purposes the mantlet is the front turret armor. As it covers the entire front turret & the FT armor is barely exposed, are these rounds defeating the mantlet or is the round hitting the FT armor & missing the mantlet?. <HR></BLOCKQUOTE> No there 'failed penetrations' ... thats whats refered to in the digram I posted on the Tank Net from Jentz's 'Germany's Tiger Tanks'.

If you only bump the armor from 110 to 120mm you are 'under estimating' the Tiger-1 front turret armor, cause its clearly much more than that even if you ignor the over hang.... BTW if you looked at my post you'd see the 'overhang' is the weakest spot due to the free edge effect. http://www.tanknet.org/ubb/Forum3/HTML/000033.html Heres the Tiger 1 front turret armor , the shaded area is ~ 140mm effective resistance Vs 100-122mm APC shot , while against 57-76mm APC shot the value is about 160mm. The side s are actually 210-270mm LOS , while the top is 26mm @ 81 ° over 170mm LOS. The reason for the variation in the Mantle area is due to the free edge effect.

<BLOCKQUOTE>quote:</font><HR>Originally posted by Fionn: Slightly after WW2. IIRC the British had developed them before the end of the war but didn't provide them to front-line troops until too late. HESH is great though. Any weapon which can cause crew kills irrespective of armour thickness would have really given the 75mm Shermans something to fight with.<HR></BLOCKQUOTE> Fionn have you ever seen any chart referencing penetration of armor for HESH?