Paul Lakowski

As I recall , Glantz reports that priority was give to fire support weapons at the expence of line troops or 'trench strenght'. This was a diliberate policy to increase the ratio of Arty, mortars ATGs per soldier as a means of more effectively dealing with german attacks. If the division staffing was 7000, then full fire support weapons and two platoons per line company max! Even they would be a reduced strenght. 1:50,000 scale maps are available in the UBC map library here in Vancouver [b.C.], so terrain detail is not a problem for those who live in the Seattle area ....come to think of it I have some of these maps photo copied! In the Book "OStFront", the Pz Divisions are reported to field only ~ 20 tanks and face 100-300 SOviet tanks/SP at a time so 10:1 sounds about right. [ August 03, 2002, 05:52 AM: Message edited by: Paul Lakowski ]

As I recall , Glantz reports that priority was give to fire support weapons at the expence of line troops or 'trench strenght'. This was a diliberate policy to increase the ratio of Arty, mortars ATGs per soldier as a means of more effectively dealing with german attacks. If the division staffing was 7000, then full fire support weapons and two platoons per line company max! Even they would be a reduced strenght. 1:50,000 scale maps are available in the UBC map library here in Vancouver [b.C.], so terrain detail is not a problem for those who live in the Seattle area ....come to think of it I have some of these maps photo copied! In the Book "OStFront", the Pz Divisions are reported to field only ~ 20 tanks and face 100-300 SOviet tanks/SP at a time so 10:1 sounds about right. [ August 03, 2002, 05:52 AM: Message edited by: Paul Lakowski ]

As a rule post war studies of relation between penetration and kill are disturbing. The fact is that you need to overmatch the targets effective resistance by atleast 1.7 times to get a 75% kill chance per shot and overmatch by 2:1 to get 80% kill.The breakdown looks as follows... 2:1= 80% 1.75= 75% 1.5= 67% 1.34= 50% 1.2 = 30% 1.15 = 20% 1:1 = 10% 0.85 = 1% So if the penetration of the round equals armor resistance you only have a 10% chance of a kill. So what this means if you have a 200mm penetration at a given range and the target armor is 100mm you only have a 67% chance of a kill per shot. If that same target had 200mm of armor your kill chance would be only 10% With modern studies the situation is worse. In one case studied when the penetration was twice the armor resistance level, the kill probablity was ~ 50% and if the overmatch was 3:1 the kill chance was 60%. Modern liners can dramtically reduce these kill % [by ~ 20% or 1/2 , which ever is higher]. Most wargames don't model this aspect of combat accurately. Its true in some circumstances kill% can appear to be 80% , but these targets usually have fatal flaws like carring exposed ammo in the turret ....like ever russian tank up to the present day! [sOURCE: Applied Operations Research pp59 & Int.J.Impact Engng Vol 26 , pp 21-32. [ June 27, 2002, 10:15 PM: Message edited by: Paul Lakowski ]

Not really. Real life differed from CM in (mostly) one thing: At the tactical level, when attacking, you tried to have 3:1 or even 5:1, not just 1,5:1. And this allows for less subtle tactics, because with such an amount of superiority, you can attack with tanks only, for example, and still overrun a defence. CM only simulates relatively balanced engagements, for obvious reasons. But balanced engagements, at the tactical level, were unusual, because irl you try to attack with overwhelming force.</font>

So they would lose most CMBO games? Tanks first is (usually) a no no, as I have found to my cost.</font>

Well, it probably depends on how you count. The autoloader rate is constant, but the human one has "bursts" versus continued. Some of the very low numbers for Soviet tanks include an assumption that the gunner takes longer to aim (Conscript, no practice etc.). In any case, the autoloader does not raise the ROF.</font>

Ehh ROF of Russian tanks is about 1/2 to 1/3 that of comparable western models.

while ROF in tanks can be slow 3-4 RPM on most russian tanks and ~ 6-8 RPM on other tanks, the rate determining step is the loader. But with most ATG there where 2 or more loaders so I'd expect they would get much higher ROF. This probably explains why Soviet ATG accounted for most german tanks. Burst fire is every thing in fighting cause most units [tanks or ATG] don't last before there suppressed or destroyed.

Ok just to stir things up a bit, but that description could be applied to the Panthers inability to survive 100 & 122mm AP hits at those Kubinka test?Come to think of it , if US projectiles where low hardness [ compared to Germans] then that might also fit as "deforming projectiles". [ May 19, 2002, 01:27 PM: Message edited by: Paul Lakowski ]

If I remember right the quality of German armor that made it superior was the higher carbon content , while high silicon leads to more brittle armor [ as in the T-34]....but KV armor looks like its more in the german vane [higher carbon and lower Silicon]? [ May 18, 2002, 09:22 PM: Message edited by: Paul Lakowski ]

Ah. I assumed these refs were for open documents. I suppose it was too good to be true. By visiting the PRO on-line catalogue at www.pro.gov.uk, if you can stand the interface, you can tell the access status of records (and you don't even need a reader's ticket). All the records cited are noted as closed records with open descriptions, and carry the notation "Retained by Department under Section 3.4". Still, look on the bright side -- at least the records are shown as being stored at Kew, so they won't have been lost in the DERA split or when the folks moved out of Chertsey. So we might get to see them one day. All the best, John.</font>

[Paul obliges promptly, snipped] </font>

Could you oblige with the piece numbers of the relevant PRO documents, please? I'll give them a peek next time I'm at Kew. All the best, John.</font>

OK sorry didn't follow at first...yes so if the T-34 TC vision and poor ammo lay out hinder this process a realistic ROF of ~ 3-4 rpm is reasonable and would explain German troopers reports about realistic exchange rates... This in turn would skew any battle field exchanges since the Pz-III 50L60 had about the same chance of penetrating T-34 Front turret as 76mm had of penetrating the spaced armor of the front turret of the Pz-III L/M. So kill ratios should favor the Germans.

Sorry Jeff, I don't choose to ignor you its just that I seem to tire alot of the 'gay banter' or should I say 'battering matches ' that seem to happen on our much loved Yahoos group these days! Its kind of depressing! Tom Rodwell has happened upon what looks like some of the original Chobham armor studies by Dr Harvey etc [ credited with developing Chobham armor]....But these are available on @ 'PRO' and it may cost a pretty penny to get copies. I had high hopes of going to our Tankers group and saying 'guys these would be great finds if we could just pitch in to defray the costs'.... ah well the best laid plans of mice and men. BTW I agree with your last post...I'm not surprised that Russian sources claim that 50-80% of german tanks/SPguns were nailed by ATguns. Since they often could out shoot the panzers in ROF...and would probably have better sights and unlimited visibility / loaders etc etc. The source of those scale drawings was Gavin Kratz , who reports there from "UXO ID book US Amy /National ground Intelligence center".He wasn't more specific than that!

Huhh, not sure what that means? Jeff your refering to the cadance of the gun...how fast it can shoot max...by that standard M-1A2 has a ROF of >16 rpm. When they refer to ROF they mean the end result all factors considered. Many M-1 tankers told me they could chamber a round in 2-4 seconds. For Example T-72/80 is rated at 7-8 rpm but users indicate a round every 10-20 seconds depending on the ammo and FCS.

Jeff , several quotes and comments, Osprey Vol9 T-34/76 ; Steve Zaloga & Peter Sarson..pp40 " German tankers frequently commented that Soviet T-34s were very slow to find and engage targets. In the early years of the war,the Panzers could typically get off three rounds for every one fired by Soviet T-34s. This disparity in crew training was greatly reduced later in the war." Ospery Volume 20 T-34-85 Zaloga Kinnear & Sarson,pp19 " A trained crew could usually fire three to four rounds per minute". "Hitlers Panzers East". RH Stolfi,pp164" ....German tank crews were amazed that they would fire two,three, or four rounds against the T-34 to every round they recieved". I was asking David Glantz about this on the old RMF and he reported to me that in practice many early war Russian tanks where undermanned . He noted in the first few years of the Eastern Front,if a tank didn't actually have a radio, it was unlikely to have a radio operator. Thus the idea of radio operator shoving rounds to the loader is doubtful until mid war any way.

Jeff I'll buy 6 rounds a minute from a guards unit thats stationary...not more. Zaloga and many German reports note a that they could out shoot the Russians T-34s 3 to one.The max ROF for Pz-III & IV i've seen is 10-12 RPM.

T-34-76 had only two men in the turret and the ROF was very low, about 3-4 rpm . Experienced [Guards?] crews would get the radio operator to feed rounds to the gunner who loaded while the Tank commander fired spoted and tried to direct the tank???? no wonder they had poor spotting. German repeatly report getting 3-4 shots of in the time the T-34s took to fire one shot! T-34/85 is also reported to get only 3-4 RPM due to the large gun and ammo in such a confined turret. T-54/55 etc also reported 3-4 RPM and the T-62 droped to around 3 RPM, while Most NATO contemporaries report 3 shots in 15-20 seconds. Crews from the early versions of the T-64-72 also reported one shot in 20 seconds but later models report 1 shot in 10 seconds. Modern NATO tankers reportedly can also manage 3 rounds in 12-15 seconds or less. By far this is one of the main factors miss handled in most wargames.

Continued ... The APC shot can be shattered all the time if the mild steel skirting plate has a t/d ratio of 0.3 compared to the attacking projectiles,thus the 5mm skirting plates around the Pz-III/IV, should be effective at decapping and shattering projectiles 12-15mm diameter. This should result in 1.2 increase in the effectiveness of the over all armor arrangement. The armor as I recall is 30mm hull plate plus the skirting plate but the travel distance over which the damaged projectiles have to travel is much more than the 16 inches in the test[4-7 projectile diameters]. Holher and Stilp showed that at sub ordance velocity a gain of 10% on the ballistic limit of a spaced plate arrangement can be gained if the airgap is ~ 20 projectile diameters.So in the above case the overall resistance may be 1.3 times the plate thicknes or 30mm hull plate plus 5mm mild steel x 1.2-1.3 = 42-46mm effective resistance. Things get really interesting when the attacking projectile is tungsten carbide.Under the test conditions the 90mm M-304 HVAP shot shattered in almost every spaced plate impact condition resulting in enormous increases in the ballistic limits of the armor arrangement. Here are some examples... 90mm M-304 HVAP striking the following targets. 4 inch back plate -280BHN- plus 1/2 inch mild steel skirting plate set back at an angle of 30° was equivellent to 7 inches or armor at the same angle [ 1.56 times the LOS thickness]. 4 inch back plate -280BHN- plus 1/2 inch mild steel skirting plate set back at an angle of 45° was equivellent to 8 inches or armor at the same angle [ 1.78 times the LOS thickness]. 6 inch back plate -280BHN- plus 1/2 inch mild steel skirting plate set back at an angle of 30° was equivellent to 11.5 inches or armor at the same angle [ 1.77 times the LOS thickness] So in the Pz-III/IV case the effectiveness of the armor against HVAP shots @ 0° impact angle should be some where in the 1.4-1.5 times the LOS thickness or 49mm-52mm equivellent armor protection @ 0°.

In addition to the effects on AP & APC shots the spaced armor also reduces the effect of shaped charges. From tests I've seen copper charges fall from 4.3 cone diameters [Cd] penetration @ 2CD standoff down to 2.8Cd penetration @ 6CD standoff..In the "Journal of Battlefield Technology" Vol 1-1 pp 1 a article was published on HEAT developement and standoff penetration chart was published for Steel,Copper and Aluminum cone shaped liners.....here are provisional figures taken from the chart. Standoff in cone diameters Liner----------1.0----2.0----3.0----4.0----5.0----6.0----8.0 Aluminum--1.0----1.5----2.0----2.4----2.5----2.5 Steel---------2.8----3.1----3.5----3.5----3.2----2.8 Steel---------3.0----3.5----3.5----3.1----2.6----2.1----1.9 Vs mild steel?* Copper-------3.1----4.1----4.8----5.0----4.3----3.8----2.5 Vs mild steel? Copper-------4.2----4.4----4.2----3.8----3.4----2.8----2.2 Vs 340BHN result is the expected average penetration in cone diameters * "Explosives with Lined Cavities"J of Applied Physiscs Vol-19 June 1948 pp 563. So against a M-9 [rifle grenade] at normal impact [2 Cd standoff ] that should be 2.3 Cd penetration into RHA [3.5 into mild steel] and @ 7.5Cd standoff about 1.2Cd penetration into RHA[1.9 into mild steel]. The M-9 warhead is a 1.76 inches diameter so by the above figures it should get 4 inches into RHA ,while the same penetration into a spaced armor arrangement with 4 additional Cd standoff should do 2.1 inches penetration… "The Vulnerability of Armored Vehicles to Ballistic Attack" , reports HEAT M-9A1 hollow charge to penetrate 4 inches of solid rolled plate but it was found that 1/2 inch RHA with a 14.5 inch air gap and a 1.5 inch RHA back plate defeated the warhead.Exactly what the above figures suggest! It also reported 105mm HEAT [M67] penetrate 5 inches of RHA plate @ 0° , but this was defeated by a spaced armor arrangement of two 1.5 inch RHA plates with a 10 inch airgap set @ 0°.Also two 1.5 inch RHA plates with 5 inches of air gap set back @ 45° defeated the M67 warhead 4.2 .Its reported in American Arsenal that the penetration is 4.5inches but this is probably the 30° penetration . This would be a 5.2inch LOS penetration but 105mm warheads have been known to penetrate Panther glacis in tests 80-85mm @ 55° =140-148mm [5.5-5.8inches].At first glance this doesn’t make sense , however the Rheinmetall Hand Book on Weaponry show the following relationship of HEAT warheads to slanted penetration. ------------10°-----30°------45°-----60° HEAT---1.02----1.14----1.37----1.96 LOS----1.02----1.15-----1.41----2.0 1982 Rheinmetall Hand book on Weaponary....[figure 1128]relative penetration of modern 105mm projectiles @ 1000m range...... So the penetration against sloped armor is more than vertical armor of the same LOS thickness. Now in the M-67 , 45° angle case is interesting because the solid thickness is 3 inches @ 45° or 4.3 inches LOS solid thickness suggesting that the spaced armor had little additional effect. The 1.7Cd additional standoff should have resulted in 12% drop in penetration [4.4 inches] when the actual solid LOS penetration @ 45° should have been about ~ 5.4inches. this suggests the effects of standoff on spinning warheads is more substantial than non spinning warheads or the spaced plate offers more advantage than the LOS thickness suggest...as is the case in the 1982 study [int.J.Engng. Sci Vol-20, pp 947-961[1982] "Effects of Hypervelocity jet on a layered target".

MOre from the book "The vulnerablity of Armored Vehicles to Ballistic attack" It reports that against slanted spaced armor Vs AP projectiles , the net resistance of the spaced plate arrangement was less than the resistance of the same over all thickness of solid plate [lower t/d in the spaced plate arrangement].However they conceeded that if the spaced plate is able to damage the penetrator in any serious way then spaced plate should be benifical as was the case in caped projectiles. For "D-capping" see Dr Elder's paper on Battle ship armor...another smashing good read! They state that HVAP would definatly suffer from slanted spaced armor impacts.90mm HVAP could penetrate 11 inches of homogeneous plate @ 30° while the same projectile was defeated by a 1/2 inch and 6 inch roled plates with a 12 inch airgap set back at 30°. HEAT M-9A1 hollow charge is reported to penetrate 4 inches of solid rolled plate but it was found that 1/2 inch RHA with a 14.5 inch air gap and a 1.5 inch RHA back plate defeated the warhead. It also reported the two 1.5 inch RHA plates with only 5 inches air gap set @ 45° could also defeat the warhead. 105mm HEAT [M67] penetrate 5 inches of RHA plate @ 0° , but this was defeated by a spaced armor arrangement of two 1.5 inch RHA plates with a 10 inch airgap set @ 0°.Also two 1.5 inch RHA plates with 5 inches of air gap set back @ 45° defeated the M67 warhead.

I've been given a 1950 Research paper into spaced armor that further explores the effects of spaced armor. Hurlich reports that in tests of 90mm APC fired through 'skirting plates '[ Heat treated T-33 & T-50 Vs 1/2 inch & 1 inch steel @ 30-60° ] , 21% [30/145 shots] of the T-50 APC shots shattered while 93%[26/28 shots] of the T-33 AP shots shattered.In the same series of tests 57mm AP& APC shots [M-70 & M86] were fired through the 1/2 inch skirting plates and the caps were removed from the APC shots but none of the 40 projectiles fired shattered . The poorer performance of the T-33 round could have been as a result of its heat treatment and shorter L/d. The results of impacts @ 40° suggest the penetrating projectiles 'picked up' a yaw of 5-7°. Int.J.Impact Engng Vol-22 p211 shows that penetration loss per degree yaw is about 0.5-0.7 % per degree yaw for a AP type shot, thus this should result in a drop of 3-4% in penetration. But it seems that yaw and deflection are interconnected and the penetrating projectiles struck the main armor at angles 5-7 ° , over a 16 inch travel distance. If these plates are parallel then this means less than the inital angle of impact , thus the over all penetration was increased by ~ 10%. But this outcome seemed to be controlled by the projectile. In the case of 57mm AP/APC the change in penetration was to reduce resistance 10-12%. However in the case of the T-50 90mm APC round , the spaced plates reduced penetration by 20-23% @ 30-40° impact.

" The Vulnerability of Armored Vehicles to Ballistic Attack" On the section on spaced armor report that against a conventional AP shot spaced armor would have little effect. However later in the book a number of case are detailed where impacting projectiles shatter as a result of the angle of impact. These include pics of the shattered projectiles and these are almost always cut in half . The point is that if this happens on the outer plate , any penetration of the inner plates is going to be reduced by half. 20mm AP M-75 impact 3/4 inch 364 BHN plate [1:1 t/d] @ the following angles and results 0° Ballistic limit 1100f/s projectile intact 10° Ballistic limit 1150f/s projectile intact 20° Ballistic limit 1400f/s front 1/4 broke off 23° Ballistic limit 2000f/s broke into two into 1/3 and 2/3 30° Ballistic limit 2100f/s broke into 3x 1/3 parts 40° Ballistic limit 2220f/s broke into 7 parts 50° Ballistic limit 2580f/s broke into many 37mm APC M-51 impact 3/4 inch 364 BHN plate [t/d 0.5:1] @ the following angles and results 20° Ballistic limit 900f/s projectile intact 30° Ballistic limit 1150f/s projectile intact 40° Ballistic limit 1400f/s projectile intact 50° Ballistic limit 1850f/s projectile intact 60° Ballistic limit 2250f/s projectile intact tip more blunted 50 Cal APM2 impact 1/2 inch 494 BHN RHA plate [1:1 t/d] @ the following angles and results 0° Ballistic limit 1240f/s projectile intact 10° Ballistic limit 1380f/s projectile intact 15° Ballistic limit 2000f/s Projectile shattered 20° Ballistic limit 2180f/s Projectile shattered 30° Ballistic limit 2480f/s Projectile shattered 50 Cal APM2 impact 1/2 inch Face Hardened plate [1:1 t/d] @ the following angles and results 0° Ballistic limit 2180f/s Projectile shattered 10° Ballistic limit 2200f/s Projectile shattered 20° Ballistic limit 2340f/s Projectile shattered 30° Ballistic limit 2560f/s Projectile shattered 37mm APC M-51 impact 1 inch[0.7:1 t/d] Face Hardened plate 648 BHN front 437 BHN back , @ the following angles and results. 0° Ballistic limit 1180f/s Projectile shattered 10° Ballistic limit 1220f/s Projectile shattered 20° Ballistic limit 1280f/s Projectile shattered 30° Ballistic limit 1410f/s Projectile shattered 40° Ballistic limit 1690f/s Projectile shattered Last entry should read as follows 37mm APC M-51 impact 1 inch [0.7:1 t/d] Modified Face Hardened plate 481BHN front & 389bHN rear @ the following angles and results 0° Ballistic limit 800f/s Projectile Intact 10° Ballistic limit 830f/s Projectile Intact 20° Ballistic limit 960f/s Projectile shattered 30° Ballistic limit 1250f/s Projectile Intact 40° Ballistic limit 1680f/s Projectile shattered The exception @ 30° could be that this is a statistical event , they report that in the modified plate all the results were intact until the 40° angle was reached so the 20° event could be graphical error.especially when you compare to the regular face hardened plate at that angle 1410 f/s. The prior explaination for this behaviour was that the projectile had to turn on impact and thus the side of the projetile hit the side wall of the crater, thus shattering the projectile. [ 12-08-2001: Message edited by: Paul Lakowski ]</p>

I have a vague recollection of Rokossovsky, implmenting a tactic at Kursk , where by the bulk of the russian tanks were deployed inbetween the ridges that crossed the german advance. This way as the spearhead Tigers and Pz crested the ridges they were set apon by mass of T-34 [etc] that broke from cover and dashed at short range to clash. I even seem to remember that this was based on Wellingtons similar tactic at Waterloo...where he deployed his less capable troops between the folds in the ground to avoid exposing them to the fierce French artillery. Has any one else read this?