Thursday, 10 April 2014

Spare Track Links

"In order to increase the protection of the T-VI (Tiger) tank, the Germans place spare track links in front of the hull, on the vertical armour plate.

In order to check if this is an effective method, in March of 1944, a T-34 upper front hull segment (part number 34.29.304) with track links attached was tested at the NIBT proving grounds.

The shooting was done with an armour piercing 75 mm shell fired from a German gun (PaK 40) with the muzzle velocity of 770 m/s.

Trials showed that the front of the hull protected by track links can be penetrated by the German gun from 800 meters, but not from 900 meters. The unprotected part of the hull can be penetrated from 1000 meters, but not from 1100 meters. Therefore, the tracks increase protection by 200 meters.

I deem it sensible to alter the existing spare track transport method on the T-34 and SU-85. I ask you to order the People's Commissariat of Tank Production to move the spare track link holders to the front of the T-34 and SU-85 hull starting on April 15th, 1944."

CAMD RF 38-11355-2548

Of course, not only the Tigers had such protection. Many vehicles had track links attached to them to the front for extra armour, including tracks from other vehicles.

This StuG, for example, is clearly covered in T-34 track links.


Those that could not find nice and wide T-34 tracks had to make do with less.


As is usually the case, no one waited for orders from the top to improvise. Pictures of T-34s using track links as additional armour way before 1944 are not uncommon. The most common way of using them was tucking them into the infantry rails to protect the turret.

55 comments:

  1. Very interesting, i was always wondering how much more resistent a armor plate with a track on it is.

    T(h)anks

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  2. A very important data point.

    Interesting that in the post war Yugoslavs tests the PaK 40 with Pzgr. 39 penetrated the front hull of the T-34/85 out to 1300m. So either the Yugoslav PaK 40 was using better ammo, had a higher muzzle velocity, or typically the Soviets nerfed the test results. Someone suggested a 4th possibility, the Soviets weren't able to calculate the ballistics of foreign guns correctly.

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    1. It's not very hard to calculate "we could penetrate at x meters but not at y meters", unless you are implying that the Red Army was not capable of accurately measuring distance.

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    2. This is far more complicated Peter :)

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    3. I don't know what the reason. If you compare the velocities of Russian tables for LL US guns 75mm M61, M72 and 37mm M51 you have posted here to the US tables of same guns you find the Russian measurement drops off much more with range. If the same kind of artificial velocity drop off is imposed on captured German guns that would explain the penetration difference.

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    4. Well, I don't see any table regarding the lend-lease guns on here at all, could you point me where are they? I've seen only penetration tests against actual tanks so far, in which the different methods and standards would only further differentiate the results.

      Back to the PaK 40, I believe it had to do more with fluctuating quality of both the ammunition and tank, a common occurrence during wartime.

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    5. Sorry, it was from another Russian site.

      http://i.imgur.com/WHkIKeF.png

      http://i.imgur.com/qbTcqd0.png

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    6. Thanks, but until Peter or someone else translate it, I could only say that it was a kind of table showing ballistic data (velocity drop, time and angle to reach desired distance, etc.) of US 37 mm and 75 mm guns, for two ammunition types each. Which is very good, I'd say.

      Still, until it is pointed out as being a largely calculated table, or you present me a similar US ballistic table, they are not enough to convince me to believe your point, unfortunately.

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    7. Anon, when the article explicitly talks about live-fire testing with a captured gun why ARE you going on about calculations anyway...?

      Anyways, going by what the Wiki sez about the mess that was the PaK 40 muzzle velocity (mainly due to changes in the propellant charge) the difference between these and the later Yugo tests probably comes down to the latter having been "hotter" loadings and probably also better shell metallurgy.

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    8. Well, Kellomies, sorry if you might misinterpreted me but I was discussing with another Anonymous who referred to the Yugoslavia test. He also claimed that the Soviet used artificial velocity drop via two links he replied to me, but I don't find them convincing enough, so I asked him for more proofs.

      By the way, I'm on your side about the fluctuation in shell quality.

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    9. My claim is real. But my job is not to convince anyone.

      Here is a source for US ballistic data.
      http://cgsc.cdmhost.com/cdm/singleitem/collection/p4013coll8/id/2327/rec/1
      You can convert meters to yards and m/s to ft/s on your own.

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    10. Now that's something, thanks, Anonymous.

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    12. OK, edited and back up.

      Looking at the M61 seems that the Soviet version of the round even starts off at a significantly lower velocity (564 vs ~619 meters per second). Another way of putting it is that the Soviet's V0 is roughly equal to the American V700 (yards). Even if they tested off a M2 barrel, the rounds must be particularly shoddy or it was tested on a significantly colder day (which reduced the speed of chemical reactions and thus the velocity of the round).

      1000 yards (~900 meters) later, at 1700 yards, Americans claim their rounds have 1600fps = 487 m/s, while the Soviets claim 461m/s for +900m.

      I'm actually inclined to believe the Soviet data in this instance. All else being equal, if one source gives one result and another source gives a lower result by a few percent, it is not unreasonable to at suspect that the higher value was the theoretical one that failed to account for all the resistance factors. In fact, it seems from the chart that basically the Soviets retested the gun+shell and came to the conclusion that the gun doesn't fire quite as flat as the Americans thought it would when they painted the ranging reticules and drums, leading to Column 2 in the table where the designated sight settings are always higher than the American drum (at 1000m=~1100 yards, you are to use ~1200 yard sight setting) - you don't do that based on a theoretical calc.

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    13. Arkhangelsk, the Soviet is for a M2 gun while the US is a M3 gun. But, matching the velocity curve starting at 1850 f/s of the M3 should be very close as the rounds were the same.

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    14. Uh, I think I pointed out the possibility it was a M2 gun in my para 1. Even then, the Soviet round is a bit slow to start (a quick check of Wiki suggests the US figures the MV of a M2 gun to be around 2000fps rather than 1850).

      Anyway, I did as you suggested and the results are as per Para 2.

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    15. With all due respect, that is just ridiculous. That the Americans didn’t know the ballistics of their own shells. However, if one compares the US firing chart of their 37mm M74 shell to the Soviets firing table of the 37mm M51 they are similar. The M74 is a M51 without a ballistic cap. The US APHE shells like the M61 and M51 all had aluminum ballistic caps. If the Soviets were removing them and using the aluminum for aircraft or something else it would explain why the ballistics of the LL M51 and M61 was so poor.

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    16. It would have to be on another PDF then, because the source you chose only claims data on 37mm M51, M59 and M80 rounds, but no M74. I grant you it is theoretically possible, though one would seriously have to wonder whether the Soviets would be trying to recover the itty bit of aluminum that's on that shell. How many shells would have to be stripped for even one airplane ...

      Further, I don't find the idea the Americans are not fully *au fait* with the (at that time new) M61 that hard to believe - certainly no more than the "Soviets painstakingly stripped shells of their caps" theory. It was a new round being rushed to the battlefield and the M2 gun is an interim model even on the M3 Lee. I wouldn't put it pass them to just draw the range drums and reticules on theoretical calculations. Given FM23-95, which tells US gunners to just group the target range as being short (1-400 yd), medium (4-700yd) and long (7-1000yd), and the reticule so utterly lacking in lines (super-elevation lines at 500 yard intervals - the entire "common battle range" is covered by TWO lines!), would they be found out by the front-line soldier? (The Soviet manuals teach "measure-by-eye" methods of course but they also teach formulaic methods).

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    17. While the US used a chronograph to measure the terminal velocity of the shells fired by their guns it seems the Soviets used a jury-rigged formula to find it. Resulting in nerfed data. The difference between the limit velocity resulting in 51% penetration and 75% is only a few meters a second if it could even be measured. So comparisons with the Yugoslav data is a good indication of how much nerfing was going on.

      As to the M74 data, use the M59 shell instead.

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    18. The M59 must be a little less aerodynamic, then, according to you. Because starting at 2620 (~800m/s) at 100 yards, at 1,100 yards (+1000yd/900m) it descends to 1220fps (372m/s), which is over 100m/s slower than the Russian table at 900m range (506m/s) - thus, if you say the M59≒M74, then the Russians were probably measuring the M51 with cap.

      I find it cute that when you see a discrepancy, you automatically assume the Americans used a chronograph and the Russians misused a formula, even though it is the Russian table's application that is more verifiable. Further, you argued (in effect) that we should have faith in the American table because Americans know their rounds best, which has a prima facie logic, but when it comes to Russians, you say (in effect) we should trust the Yugoslavs!

      While you were gone, I dug up FM23-80 which does include a table for the M51 shell. Amusingly, on P.15, it says the maximum ordinate when firing the M51 to 1000 yards is 8 feet (which is similar to the Russian table's 2.5m), while P.115 gives it as 6.5 feet (BTW, in FM23-81 it gives the exact same value, though the round's MV is now a whole 300fps faster). Further, according to the table, the velocity drop of the round is suspiciously unstable, with parts where it increases its rate of slowing down.

      As for the limit velocity, if the difference between 20-80% (in terms of milimeters penetrated) is 10-17%, it stands to reason that 50 v 75 (about half that range) would be about 5-8%. That would be about the difference between a German Pak 40 L/43 and a L/48, and the MV difference in that case would be 50m/s, so it doesn't seem likely a few m/s can do it.

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    19. You must be a gymnast because of the way you bend over backwards to try to find truth in the Bolshevik ministry data. Compare 37mm M51 Russian time-of-flight to 1500m is 2.8 secs. Look at FM23-80 table page 115. 792.5 m/s 37mm round at 1640 yds pro-rates time-of-flight to about 2.22 secs.

      Maybe you should read FM 23-80 a little more carefully. Page 15 elevation is 8 feet at 1000 yds for 2550 f.s, page 115 is 7.7 mils at 1000 yds for 2600 f.s.

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    20. For your Para 2, read the *top* of P.115, "102. Trajectory".

      For your Para 1, give me a bit of credit, Anonymous. I can see there is a discrepancy. I just find it amusing that when you find one, you automatically *assume* Russian incompetence to be the cause. Even if we must accept the "cap theory", the possibility that the Americans didn't supply them with caps didn't even pass your brain. No, somewhere, a never-identified Russian strafbat is slaving away, peeling off those little caps for their miniscule amounts of aluminum that may or may not be suitable for aircraft...

      Besides, if the Bolshies were as sneaky as you think they are, they won't have to implicate themselves by making a new table. Just hand out the American ones to the troops, and blame any discrepancies on the imperialists.

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    21. The missing cap is but one theory. The other is that the Russians used the same ballistic equation for the olgive shaped 2 PDR shot as they did for the aerodynamically shaped 37mm M51. Now if you look at the Russian tables on the 2 PDR you see that for the 782 m/s shot is 3m/s faster than the 37mm at 1000m.
      http://i.imgur.com/n0lZE1Q.png
      http://i.imgur.com/rfEB9ea.png

      The olgive shaped shell data of US 37mm M74 and M80 are fairly close to the Russian 37mm M51 data.

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  3. Yugoslavia used less strict "penetration" criteria.
    Bojan

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    1. Yes, but how much more strict? Yugoslavia criteria is at least 50% of mass behind armor. Soviet CP criteria is 80% chance of 75% of mass behind armor. 80% of 75% is 60%. So just comparing 50% of mass to 60% of mass.

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    2. Huh? You can't just compare by multiplying .75x.8 without knowing the dispersion of the results! Just for the sake of example, there might have been 1 hit at 74%, 3 hits with 75% and 1 at 76%. That would still be "80% chance of 75% of mass", but it'd be effectively a full 50% of mass vs 75%.

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    3. Your example is a rather unrealistic narrow dispersion. Known dispersion between 20%(IP) and 80%(CP)
      http://english.battlefield.ru/specification-and-armor-penetration.html
      are much larger to the tune of 10-17% at 0-degrees and more at 30-degrees.

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  4. does the PaK 40 had the same penetrating ability of the 75 mm l/48?

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  5. Tracks add protection only for sloped surfaces or oblique hits.

    PAK 40 ammunition for Yugo tests was German projectiles put together with US type powder and assembled with 'brass' primer etc. by Yugos. Supposedly to get teh same velocity as German. They also did this with 88mm.

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  6. Has it not occured to any of you nutters that these were done at the typical angle of 30 degrees?

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    1. Why do you think that? That's not a typical angle for the Soviets. Also a T-34 UFP at 30 degrees is 104 mm, I have a hard time believing that a KwK 40 could penetrate that at 1000 meters.

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    2. That is not correct. The T-34 has an effective armor thickness of 93mm on the glacis when you take into account the slope multiplier and the BHN. Vs a 75mm gun, armor thickess is 122mm, but when you add the effect of the overly hard armor, you get 93mm. Tons of soviet tests, just like everyone elses, were done at 30 degrees. And in the case of this test, its the only way it makes sense

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    3. To be even more clear: The default slope multiplier for 45mm plate sloped at 60 degrees would be about 3.13, making that armor about 140mm thick. Once we add in the T/D ratio, we get 122mm. Add in BHN (460 Brinell was standard on soviet 45mm plates) and we get 93mm. These numbers are not in dispute, are published in great detail in WW2 Ballistics: Armor and Gunnery by Lorrin Rexford and Robert Livingston

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    4. PzG 39 out of the KwK 48 penetrated 97mm of RHA at 1500M, meaning that assuming a Normal angle of impact, the T-34 was vulnerable past 1500 from the front. PzG 39 penetrated 85mm at 30 degress at 1000m. Given that it is likely that the Soviet fired a statistically inconsequential number of rounds in this test (at the very least it is not detailed so far as I can see) it is perfectly reasonable to assume that PzG 39 penetrated at 1000m at 30 degrees. A similar example is the US 76mm, which achieved 93mm at 30 with 50% criteria, but at shoeburyness penetrated 100mm at 30 on at least two occasions. In short, its is simply impossible that the T-34 Glacis was proof against PzG 39 over 1000m at angles less than 30 degrees using average penetration criteria at 50% success.

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    5. "Tons of tests"? From what I've read and definitely from every test I posted here, firing is done at 0 degrees against the front and 90 degrees against the side, unless explicitly stated otherwise. You can quote WW2 Ballistics all you want, practice beats theory.

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    6. Its not theory, as all of the data in those books is based on testing. You cant just assume normal in the absense of being stated otherwise. This tests doesnt state the angle of shot, and therefore you opinion is based totally on assumption. I also dont have any proof per se that it was done at 30, but the AP performance is so far off normal that its physically impossible to be at normal. Practice = Theory. The Math never lies, period. A P-51 doesnt out turn a Bf109 simply because loads of pilots said it did. This test does not state that his was a normal, which mean you cannot matter of factly state that its was. Its possible that this particular T-34 came off the factory with slightly more than normal armor, which occasionally happened. But it is a matter of fact that your typical T-34 was vulnerable from 1500m or more. If you took every test out there at face value, we'd be here all day spewing contradictory reports at each other.

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    7. We could start with the numerous German reports of T-34s being knocked out "from any angle" at ranges of 1200m. Heck, take the Tiger for instance. There are tests showing 76mm guns on the T-34 penetrating the upper side at 500m, but there also ones that dont. So what? Does reality change itself at random? Nope. Its simply a matter of some rounds penetrating more than the 50% success average or perhaps a poorly built tiger. The "real world" is not different from the math, real world reports just have more variable to them. Given equal conditions, the "real world" is the same.

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    8. Here's what I see, Joystick. A person that even bothers to read WW2 Ballistics, Armor and Gunnery is no noob and must know that the standard Soviet test is done at 0 (it is a source of great mirth to Germanophiles, who can claim based on this at least a 15% advantage, just from simplistic trigonometrical considerations, over any Soviet penetration stat).

      Your main justification for insisting it is 30 is that after you added the normative "shaft" for 460BHN (hopefully it is from W2BAaG), the Soviet armor loses 25% of its resistance, and thus should not be able to resist the German shell at the specified range. However, there is another explanation for this - that the shaft ratio is not perfectly in line with reality.

      Because here's a thought. Why would *anyone* choose to use a hardness that's non-machineable (much harder to make) and loses 25% of its resistance? One would think any fringe advantages will not compensate for these two factors. Yet the Soviets choose this hardness. Since the actual durability of steel depends on its fine composition and production process (how the loss of certain elements caused German steel to degrade is a well known story), perhaps the shaft ratio is not as high as the West (who quickly decided to go for soft armor) believed.

      Just my two cents.

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    9. Hows this for food for thought? If the Soviets were so smart in using such high hardness (and highly brittle steel) then one does have to wonder why everyone else in the world was so foolish. Weird how everyone else seemed to find mid-200 BHN the most effective middle. Fancy That. Fancy that a book written by two highly respected historians, Lorrin Rexford and Robert Livingston to boot, completely agrees with what I just stated. Doing AP values without calculating BHN or ignoring it because it doesnt jive with your fantasy is pretty laughable. If the armor quality didnt matter, then the cast armor on he M4A1 Sherman would be worth 121mm. Put it this way, if we take off the BHN factor, then you get 122mm for the T-34, which would make penetration dead on impossible except at ranges under 500m. I dont even think you'd try to claim that nonsense. Fact is, you cant work out the armor resistance by conveniently leaving out factors you dont like, which your probably doing because your just now hearing this is a thing.

      I am not a Germanophile or a Wehraboo or whatever you want to insinuate. But im not going to assume things into tests because it fits some simplistic understanding of the data. As I mentioned before, there are numerous German accounts of KwK48 being credited with being able to knock out T-34s "at any angle" at ranges of 1200m. The ratio I used is based on German and American test firings, IE: its hard fact based in real life test data. It isnt up for dispute. But of course, continue to propagate your soviet meta-metal theories. How the russians got right what everyones supposedly got wrong.

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    11. There simply isnt any way this was done at 0 degrees, no matter how you slice the numbers. If you go only be LOS, you get 90mm of armor. Without BHN factored in, you get 122mm. I think we'd both agree that LOS alone is not valid, and it would closely agree with 93mm anyhow. 122mm is obviously too high, as no combination of angles reconciles this test or the German combat accounts on this site or elsewhere.

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    12. Also note that Shermans in Korea reported penetrations of T-34s at ranges of 1500m as well, front the front, without HVAP.

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    13. 1) Do we really have to resort to bringing in tales about a different gun? I must wonder who was so diligent as to log in the heat of combat that a) it was definitely 1500m (surely they meant yards, a 10% difference) and b) they categorically did not use HVAP.

      2) I did not start bringing in the complexity, you did. I suppose you did that at least partially because you realize that just using the Cosine Formula is not going to beat a test. What you are not noticing is that you have to be *very careful* when you take the decision to squelch (which in turning the tank 30 degrees is effectively what you are doing) a new observation due to its failure to mesh with your existing theory.

      3) For that matter, I did not go so far as to say the "shaft" coefficient derived in the West was totally wrong, and Soviet armor is completely exempt from the laws and trends of metallurgy. I just propose, in light of observation, that the coefficient is imperfectly applicable since it's implausible for that coefficient to be equally valid for all the possible metallurgical permutations that would obtain 460BHN steel and its AP projectile counterparts anyway. Of your coefficients, it is probably the least universal so my blades are on it first.

      In fact, we can refine it pretty well here. At 1500m, the Pak40 penetrates 97mm at 0. If you are using a "85mm/30@1000" table (Jentz's table), then it is "74mm/30@1500". So a 14% improvement over 500m of range. Multiply that and we can extrapolate 111mm/0@1000.

      Divide that by 93 is 1.19. So, b/c the steel performed less than 20% better than predicted by a still relatively simple predictive formula we ignore observation? Can you see how that might be an uphill climb?

      4) For the German claims, since you can add 30 degrees where none is likely or necessary, given the data you provided, let me give you my first impression: "Maybe they meant the turret, which is often 50 or 70mm on T-34s. Even with a T-34/85 it is only 90mm on the front so there is still a chance at 1200m if you hit it square on."

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    14. Joystick, you make a lot of claims backed by "numerous" sources, but you fail to provide any. Take a look at literally any penetration test on this site. They are all done at 0 degrees. I can think of maybe two or three that include shots at another angle, but this angle is always explicitly stated in the test.

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  7. @ PS, alot of the stuff here does specify one way or another. And the things that do dont magically absolve this tests lack of specificity. Fact: The Russians didn't Specify. Fact: The Russians did do 30 degree tests. I do not have it here, but there is a 1942 test where they fully state its was at 30 degrees, 1000m, T-34 and KwK 43.

    @ARch- There is nothing wrong with the BHN multiplier. It is based on corroborating and separate tests, and any margin of error would be alot less than you propose. If you really want to argue this was at 0, then you should take note that T-34 armor could vary by as much a +/- 8mm, which would be a much better explanation---but would still main the average T-34 could be killed from over 1500m.

    Tales of a different gun that is very similar ballistically to the gun we are talking about. And I, apparently unlike you, cannot read minds.

    And your figuring hear is just plan silly. Clearly you need to sit down and actually READ Rexford and Livingston before you try to show me how the conversions are made. Reading you section on less than 20% or whatever makes me think you dont know what is being done here.

    For one, we dont need to do any multiplying to get the actual @0 values. 1000m for KwK48 is 109mm. Let me spell this out for you. If we add in slope multiplier alone, we get 122m. Which would prevent the Pak 40 from penetrating except at less than 500, which I think youd agree is nonsense. Without slope, and just LOS, you get 90mm, which agrees with me.....but it should be obvious that you cant just dispense with slope multiplier. So the only way you get a reasonable number without dispensing with the facts is use Multiplier and BHN for the strength of the armor. The BHN multiplier is NOT up for dispute pal. It was determined from test firings, and is not a pure estimate. And I have other news for you. Whatever witchcraft you were trying to construct up there its kinda irrelevant if you dont take into account T/D ratio, since the BHN multiplier for high hardness steel is not one size fits all, and varies depending on round diameter.

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    1. Yes, they did do 30 degree tests. They then explicitly stated, even in summaries and conclusions, that these tests were at 30 degrees. If you have this test, I would very much like to look at it.

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  8. I dont have, it but I have seen it. If you want to seach for it, Rexford himself brought it up years ago on the CM forums.

    Sorry but I disagree that you can just assume normal when not stated otherwise. W'ell just have to agree to disagree.

    Perhaps we can find common ground on the fact that T-34 Armor thickness did vary. Most had 45mm of armor, but examples have been found with less than 45mm, and some with more, since soviet manufacturing was different at every factory. For example, Rexford stated that when they were going through a museum, they found a Su-85 with 60mm of frontal armor!

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    1. Ah, well that's awfully convenient. Why don't you find it and get back to me.

      Yes, there were variances, +2 to -1 was acceptable IIRC. Not +15. I've never read about a 60 mm armoured SU-85. Maybe it was a SU-85M?

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  9. Quoting Rexford: Medium hardness plate, 220 to 300 Brinell Hardness, is designed to have good ductility so it can take hard hits without cracking. Shermans used medium hardness armor.

    High hardness armor, 450 Brinell, has low impact resistance than good medium hardness plate.

    A 45mm medium hardness plate will resist like 45mm of medium hardness armor against 20mm and 90mm hits. A 45mm high hardness plate may resist 20mm hits like 53mm of medium hardness plate, but will resist 75mm hits like about 34mm medium hardness because it cannot take the impact with cracking.

    Russian tankers talk alot about how ricochets off the T34 could result in armor flakes flying off the armor interior, injuring or killing the crew. It's due to the brittle nature of the plate.

    Russian tankers who fought in Shermans noted that ricochets did not result in internal armor flaking, like the T34, because the plate was medium hardness and had high impact resistance.

    High hardness armor is like auto glass, it works really well against small objects but can't take large hits very well and when it is penetrated it can send shards flying off into the driver compartment.

    The good thing about high hardness armor is that it can be quicker to make than medium hardness armor, because one doesn't have to spend as much time reducing the hardness to a specific range and getting the correct temper that will assure high impact resistance. So high hardness armor may have allowed more T34 to be made, although they were not especially resistant to PzKpfw IV and StuG III 75mm hits.

    Prior to October 1943, the Americans made quite a bit of medium hardness cast armor that was very brittle due to the composition and heat treatment.

    German face-hardened armor uses a thin 500 to 600 Brinell hardness surface layer to break up the nose of projectiles, but the bulk of the armor thickness is around 350 Brinell Hardness area and provides good impact resistance.

    Face-hardened and high hardness armor is good when you have thin plates under attack by small rounds, and you wish to boost the resistance. Like an armored car or halftrack attacked by rifle or machine gun bullets. U-Boats supposedly had face-hardened conning tower walls to boost the resistance to 20mm aircraft cannon fire.

    The Russians noted during the Spanish Civil War that penetrations of the German tanks with high hardness Krupp armor usually resulted in severe crew casualties as the armor shattered and allowed pieces to fly inside the tank. Russian T26 tanks used medium hardness armor and unless a round directly hit a crew man it was common to suffer penetration without crew injury.

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  10. More from Rexford: Research over the years on the penetration range of 75mm L43 APCBC against the T34 front resulted in the following bits of info:

    1. T34 stands at 1235m and is "safe", outranging panzer guns, based on George Forty recounting of March 1943 report from Grossdeutschland Division experience. The 1235m "safe" range is consistent with figures presented in the next factoid.

    2. 75mm Pak 40 cannot penetrate T34 beyond 1000m, German instructions to units on Eastern Front for Combating T34, May 1942. T34 76.2mm gun noted to be superior to 75mm L43, which would be the case if T34 has 50mm to 55mm glacis armor at 60 degrees slope and PzKpfw IV carries 50mm near-vertical frontal protection. "In correctly recognizing his technical superiority in weapons, the T34 already opens fire on German panzers at ranges from 1200 to 1800 meters."

    3. 75mm L43 penetrates T34 at 1200m at any angle, with 1600m max range, spring 1942. Report included in T. Jentz' Panzertruppen Volume I.

    4. 75mm L43 penetrates T34 front hull at 1000m with a 30 degree side angle during 1942 Russian firing tests, according to Valera Potapov notes from Russian report he reviewed. This result is consistent with 1600m maximum penetration range when gun is lined up with T34 hull direction.

    Whether the penetration range variations noted above are primarily due to changes in armor and projectile quality or T34 armor thickness are open to debate. Glacis thickness variations from 42mm to 53mm would certainly appear to support the above reports if all or most of the T34 in a group has similar armor thicknesses, which is possible if some factories aimed at greater thicknesses and others strove to meet the design spec as closely as possible.

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    1. Who is Valera Potapov? What report did he review? You keep referring to this mystical penetration test, and yet I have yet to see any kind of picture or citation or anything. Or any evidence of such wild glacis thickness variation.

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    2. Find it on your own if you want. You keep refering to mystical angles of penetration that I havent seen evident of.

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    3. Ah, that's rich. Find this evidence on your own, I don't care! Meanwhile, I already told you to find my evidence. It's conveniently assembled right here! Click the "penetration" tag and conveniently observe.

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    4. >For one, we dont need to do any multiplying to get the actual @0 values. 1000m for KwK48 is 109mm.

      For one thing, not everyone has a zero degree table w/i easy reach. For another, my table only has the 30 degrees, and I'm wary of mixing and matching tables from different sources. If you want to see why, perhaps this link would be a clue:
      https://de.wikipedia.org/wiki/7,5-cm-PaK_40

      In any case, 2mm. Gee, that's *really* worth a poke.

      >Let me spell this out for you. If we add in slope multiplier alone, we get 122m.

      Forget what's the truth, that's not even what you claimed. You said "The default slope multiplier for 45mm plate sloped at 60 degrees would be about 3.13, making that armor about 140mm thick. Once we add in the T/D ratio, we get 122mm." Not the same thing.

      >A 45mm medium hardness plate will resist like 45mm of medium hardness armor against 20mm and 90mm hits. A 45mm high hardness plate may resist 20mm hits like 53mm of medium hardness plate, but will resist 75mm hits like about 34mm medium hardness because it cannot take the impact with cracking.

      Oh, I see. And you took that and went: 34*3.13*(122/140)=93mm?

      I see the problem is *not* with what Rexford said, but with your comprehension of it. He ran the risk of putting numbers with his text, and it didn't work out for you. He *could* have said "High hardness armor tends to do better against smaller projectiles and worse against bigger ones", but that's not very satisfactory because it has no magnitude, so he threw two numbers in as a guide. He almost certainly did not mean for his readers to treat his examples as inviolable law, immune to any variation in the production of the armor, or the armor piercing projectile. Or to try to roll over observation based on it. But some people inevitably do, because numbers create an illusion of precision.

      >The 1235m "safe" range is consistent with figures presented in the next factoid.

      This neither supports nor denies Samsonov's example.

      >2. 75mm Pak 40 cannot penetrate T34 beyond 1000m

      Isn't that what Samsonov's example said? Though I must wonder. Not even the turret?

      >3. 75mm L43 penetrates T34 at 1200m at any angle, with 1600m max range, spring 1942. Report included in T. Jentz' Panzertruppen Volume I.

      I think in Spring 1942, T-34 turrets are about 50mm thick (or was it 45)?

      >75mm L43 penetrates T34 front hull at 1000m with a 30 degree side angle during 1942 Russian firing tests, according to Valera Potapov notes from Russian report he reviewed. This result is consistent with 1600m maximum penetration range when gun is lined up with T34 hull direction.

      It seems a bit mean of Samsonov to pretend to not even know Valeri Potapov, since he's Battlefield.ru's guy and that's famous enough.

      For all that, you might want to think twice before this one. The penetration of the L/43 is 82mm at 30 at 1000 (according to Jentz anyway). That's 11mm lower than your "divine law" estimate of 93mm - by your own estimate, this should not have worked and yet it did. Or is it only one direction for you? You will drink down anything lower, but not higher?

      BTW, the moment you have to rely on half-remembered tests you can't relink to should be a hint that 30 degrees is a real minority scenario for Russian tests.

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