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Did sandbags on Shermans do anything?


sevich
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They probably worked quite well against magnetic mines, but those were a fairly minor threat and weren't used that often.  The Germans, of course, were worried enough about magnetic mines that they developed zimmerit.

 

4Tyojoa.jpg

 

Against HE, the armor of most tanks was already adequate, the exceptions being the few lemons that made it out of the factory with poor quality welds or armor heat treatment.

 

Against HEAT, things get complicated.  Ceramic materials like sand often provide unusually high protection against HEAT rounds, but I doubt that loose sand in a canvas sack is ideal.  HEAT round fusing was pretty awful in WWII though, so hitting a (relatively) soft object like a sandbag could conceivably stop the HEAT round from fusing correctly in the first place.  Absent that though, I doubt it would do much.

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Pounding the front armour with HE is a losing proposition unless you have something really beefy like a 122 or 152 mm gun, the pro tip is to plant a round just above the tracks and knock out the floor of the sponson. If you do that to a German tank, congratulations, you just caused an ammunition fire.

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I don't remember where I read it, but supposedly the 3rd Army did testing on sandbags as well as concrete and other materials that were being put on tanks.  They found that these improvised types of armor actually made shaped charge weapons more effective since they improved the stand off distance of the warhead detonation, allowing the particle stream to form a little further out from the armor plate.  This is why Patton ordered all Third Army tanks to remove any extra armor other than actual armor plate.  

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12 hours ago, Walter_Sobchak said:

I don't remember where I read it, but supposedly the 3rd Army did testing on sandbags as well as concrete and other materials that were being put on tanks.  They found that these improvised types of armor actually made shaped charge weapons more effective since they improved the stand off distance of the warhead detonation, allowing the particle stream to form a little further out from the armor plate.  This is why Patton ordered all Third Army tanks to remove any extra armor other than actual armor plate.  

 

 

All true, as an interesting aside, there was another report, or the same one that concluded that sandbagging had a noticeable effect on crew morale, the book on the 731st mentions them as well, and assumes they helped, and it did make the crews feel safer. 

 

The add on armor plate Patton's 3rd Army adopted made the Shermans frontal armor significantly tougher, without having a major impact on the reliability.

 

Hey OP check out    www.theshermantank.com

 

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23 hours ago, Walter_Sobchak said:

I don't remember where I read it, but supposedly the 3rd Army did testing on sandbags as well as concrete and other materials that were being put on tanks.  They found that these improvised types of armor actually made shaped charge weapons more effective since they improved the stand off distance of the warhead detonation, allowing the particle stream to form a little further out from the armor plate.  This is why Patton ordered all Third Army tanks to remove any extra armor other than actual armor plate.  

 

Somewhere I have a just-right-after-WWII-era report on how to properly engineer spaced armor arrays that mentions that a small amount of stand-off applique armor will actually increase penetration by shaped charges.

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3 hours ago, EnsignExpendable said:

In that HEAT video I posted, a little bit of a standoff goes a long way. I think I also saw the same graph that you mention and the effectiveness starts dropping off again after a few cm of standoff, so I guess the trick was just more bags.

600mm for large caliber ATGMs if I remember correctly, anything less and penetration increases. 

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2 minutes ago, EnsignExpendable said:

It was definitely less than 600 mm for the curve I saw for the Panzerfaust.

 

3 minutes ago, Xoon said:

600mm for large caliber ATGMs if I remember correctly, anything less and penetration increases. 

 

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WWII-era shaped charges were poorly optimized in a number of ways.  They were fairly new and nobody knew what the hell they were doing, so they had some quirks.

 

WWII-era HEAT didn't have any built-in standoff, or at least not enough, so increasing the standoff distance by a small amount could actually increase the penetration of the rounds.  On the other hand, WWII-era HEAT was crudely constructed by modern standards, which meant that the jet didn't form very cleanly and started to disintegrate quickly.  This meant that a fair amount of standoff could allow for enough distance that the effectiveness of the jet was greatly diminished.

 

Modern HEAT is much more sophisticated.  A while back I read through a book on shaped charge design (because I LOOOOOVVVEEE being on watch lists) that mentions that details as small as the residual stresses in the liners after construction are taken into consideration.  Very sophisticated computer modeling and empirical testing methods are used to design shaped charges now.  As a result, they are much less sensitive to standoff because the jets are very clean and don't come apart rapidly.

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HOT is quite impressive in that test.  Not only do you need 3 meters of standoff to do any net good, but it seems to have the most consistent penetration of any of the warheads tested.

 

On 6/6/2017 at 2:53 PM, EnsignExpendable said:

Pounding the front armour with HE is a losing proposition unless you have something really beefy like a 122 or 152 mm gun, the pro tip is to plant a round just above the tracks and knock out the floor of the sponson. If you do that to a German tank, congratulations, you just caused an ammunition fire.

 

Are there battle reports of people doing this?  That sounds like a difficult shot.

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13 hours ago, Collimatrix said:

HOT is quite impressive in that test.  Not only do you need 3 meters of standoff to do any net good, but it seems to have the most consistent penetration of any of the warheads tested.

 

 

Are there battle reports of people doing this?  That sounds like a difficult shot.

 

No, but then again, I haven't seen battle reports specify where the tank was hit that much in general.

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A bit of quick searching finds a simpified penetration model and a few tests into frozen dirt:

 

Using the former and plugging in appropriate values using known penetration - a panzerfaust can penetrate something like 1.1m into dirt.

 

So a suitably thick sandbag might actually do a good job of eating up the penetration capacity of a primitive shaped charge - lowering penetration by anything from 25-50%. 

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One question I've always had is whether there's anything resembling a "focal point" with HEAT type warheads...

 

What I mean by this is can you engineer them with a sort of optimal penetrative depth to where the jet or EFP starts to spread out just as it's getting into the crew compartment of what you're intending to kill with a particular product?

 

If I wasn't on watch lists before... I am now, but I really want to know.

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30 minutes ago, Toxn said:

A bit of quick searching finds a simpified penetration model and a few tests into frozen dirt:

 

Using the former and plugging in appropriate values using known penetration - a panzerfaust can penetrate something like 1.1m into dirt.

 

So a suitably thick sandbag might actually do a good job of eating up the penetration capacity of a primitive shaped charge - lowering penetration by anything from 25-50%. 

https://ntrl.ntis.gov/NTRL/dashboard/searchResults/titleDetail/DE85011182.xhtml

 

Have fun.

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