Wednesday, 9 May 2018

Soviet Schurzen

I posted some information on Soviet protection research before, which included experiments spaced armour. Here is another such experiment, performed in the summer of 1943 at factory #112.


A drawing of the extra armour includes armour for the turret, but the prototype does not have it. Only the sides of the hull are equipped with additional armour.



The armour did not enter production. However, "everything old is new again" rang as true then as it does now, since the idea of skirt armour returned in 1945, this time to combat Panzerfausts. The additional armour was 6-8 mm thick and positioned 600 mm away from the main armour. A hit from a Panzerfaust created a 30 mm breach in the screen, but did not penetrate the main armour.

17 comments:

  1. Any specific reason why the first one doesn't add plating to the main glacis? Was the greater slope and (slightly) thicker plate felt to be sufficient protection as-is?

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    1. Panzerfausts almost always hit the side of the tank, very rarely the front or the rear.

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    2. That certainly makes sense for the second design, but were the 'Fausts enough of a headache already in early '43 to merit the first one? Or is that a continuation or variant of the additional armour devised against the 50 mm guns?

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    3. The biggest headache of the day was subcaliber ammunition, so it's probably to protect from that.

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  2. I would guess any extra spaced armor on the front slope would block the driver's vision.

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    1. I rather doubt the necessary cut-outs for his hatch and vision devices would have represented a significant engineering challenge... Especially as the designed add-on plating for the turret has the appropriate openings for the side vision slits and pistol ports.

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  3. skirts work best against high density, high velocity, small calibre impact. The glacis was proof against such thread in it´s original state.
    Against slower moving, larger calibre impact, which the glacis was very vulnerable against, a double, parallel layer might actually even increase vulnerability due to the normalizing effects of the too thin first layer and due to the inhibition of ricochet.

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    1. Ie. the 5 cm and 7,5 cm guns respectively. Makes sense if the first design was intented to protect against the former.

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    2. I´d agree partially with that observation.
      50mm hits were the largest cause of T34 losses in 1942, and the vertical sides and turret plating were particularely vulnerable (out to beyond max range >2000m when striking perpendicular under favourable obliquities).

      The 6-8mm screens, even if made from mild steel could be expected to be just thick enough to decap an ordinary medium calibre APC with the HHA vertical side armor taking care of the uncapped projectile afterwards, sharply reducing the vulnerability range. Also the interspace gap between screen and side plate is sufficiently large to support decapping. Notice, this might not be true for turret and upper side screening plates which were too close.
      However, the type of extra high strength solder used to cap the 5cm Pzgr.39 m.K. would render the decapping effect of the screens marginal at best (except at very acute obliquity, but then again, the side armor of the T34 was sufficiently thick to take care even of a capped 5cm pzgr39 at >45°). Somehow thicker screens would be required.

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    3. American research found that "one twelveth caliber plates remove the caps of APC projectiles at service velocities, irrespective of hardness of cap, closeness of fitting, or, within wide limits, of cap design", so 6-8 mm would be fine for 75-88 mm shells.

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    4. that´s american research, not german and only true for type 1 caps. The US didn´t use the extra strong solder which was employed in Germany. By the way, You are quoting information from Okun´s initial article on decapping plate thickness. I was involved in provided the primary prooving ground sources to Okun, which caused a review and reassessment of the initial decapping article.

      [url]http://www.navweaps.com/index_tech/tech-085.php[/url]

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    5. American research designed to protect against German shells, which straight up says that "The lack of success in the above attempts to make caps resist the penetration of 1/8" plate, together with the reports that make thin plates also decap German projectiles, make it seem likely that if our armored vehicles are equipped with 1/12th caliber decapping plate, the enemy will not, in the near future, perfect his porojectiles as to defeat the purpose of such plates."

      And by the way, I'm doing no such thing. I can read primary documents too, you know.

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    6. Obviously You can´t as demonstrated by your free interpretation of soviet TIGER trials, which were in contradiction to what was written in the source. This has been demonstrated multiple times.
      US Research was conducted with US APC shells, capped by US methods not with german APCBC and not with US shells capped by german methods. They therefore are suited only to give information about how US caps behave. 1/12 was ok for US APC as demonstrated by these trials. German research with large 38cm APCBC-HE and british post war trials with german actual 8.8cm Pzgr39/43 showed the same: 1/5 cal. minimum to decap, with 1/4 cal thickness required to ensure decapping under all conditions. Quite a difference.

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    7. My "free interpretation" is what's written in the document. Meanwhile, since you cannot read Russian, you mixed up the 6-pounder and ZIS-2 trials because both were labelled "57 mm" in the picture.

      And again, the American document is explicitly talking about protection from German shells. If you have this amazing evidence, you're welcome to post it.

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    8. You are wrong twofolds, Peter.

      A) I refer to the previous comments of You about 76mm AAA trials on the TIGER, which You claimed were sufficiently robust because they could defeat the side armor incorrectly citing a hit with clear EDGE EFFECTS.

      Actual source states instead:

      a) Бронебойный снаряд с дистанцин 500 метров не оте пробивает бортовую броню корпуса.
      b) Металл Бронебойного снаряда имеет невысокие механические свойства.

      Please enlighten me where my (or anybodys) reading of russian supports Your interpretation here, which is the exact OPPOSITE of what the primary source and I stated...

      And 2nd, US trials (WAL710/607-3 is dated June 1944) don´t even use german shells. THATS A PLAIN FACT. You think the US shells behave like german, and it is true that even the US believed that.

      But the fact remains that neither the german nor the british decapping trials with actual APCBC-HE support that they behaved like US test projectiles. Therefore You made a mistake. Mistakes can be made by everyone but I pointed out the mistake of You several times now and You are unable to admit mistakes and instead choose to keep repeating already disprooven points. YES, I CALL YOU ON THIS MISTAKE OF YOURS.
      The US had no information about german extra high strength solder until after the war.

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    9. It says right in the report that German shells are reported as being decapped by relatively thin plates. This "extra high strength solder" isn't magic.

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  4. No doubt the T-34 76 could manage with the extra weight of the extra armor. But what it needed more was a large 3 man turret and the 85mm gun.

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