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And which modern tank don't have NERA? I feel that NERA is like sloped armor in the second half of WW2, everybody use it.

 

 

Several of the modernized derivatives of old Soviet designs still use the old thermoset glass fiber matrix glacis plate, e.g. PT-91 and probably M-84 and T-84.  I don't believe that this behaves like NERA; purpose designed NERA arrays have many thin layers of steel and many thin layers of polymer/rubber, instead of a few big, inches-thick slabs of both.

 

How much of the Type 59 production equipment does the Al-Khalid re-use?  It might not have NERA either.

 

I'm also not particularly clear on the Leo 2's turret protection.

 

Abrams' upper hull isn't NERA either.  It appears to just be very sloped steel that is only a few inches thick (but not necessarily RHA, possibly a steel laminate).

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Russia thought of it first!

 

Several of the modernized derivatives of old Soviet designs still use the old thermoset glass fiber matrix glacis plate, e.g. PT-91 and probably M-84 and T-84.  I don't believe that this behaves like NERA; purpose designed NERA arrays have many thin layers of steel and many thin layers of polymer/rubber, instead of a few big, inches-thick slabs of both.

 

How much of the Type 59 production equipment does the Al-Khalid re-use?  It might not have NERA either.

 

I'm also not particularly clear on the Leo 2's turret protection.

 

Abrams' upper hull isn't NERA either.  It appears to just be very sloped steel that is only a few inches thick (but not necessarily RHA, possibly a steel laminate).

 

I dont think the Leo 2 is nearly as well protected as everyone makes it out to be, atleast the Abrams has DU armor and great ammo storage 

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A post from Overlord on the matter (found via Walters blog).

 

For those just getting here, it is my studied opinion from squinting at pictures of battle-damaged tanks that "Chobham" armor is most likely NERA.

 

NERA, or Non Explosive Reactive Armor, consists of layers of steel (or titanium) and layers of some polymer (usually rubber).  When the armor is penetrated by a threat, the rubber reacts, causing the steel to shift and bulge, feeding more steel into the path of the threat.  This effectively increases the thickness of the armor without making it heavier.  There is also supposed to be some sort of effect that screws up HEAT jets when they have to transition between perforating materials with very different densities, this may also be at play.

 

In addition to lots and lots and lots of pictures of damaged tank armor arrays that look like NERA:

 

T-72B3_Glacis%20Array%20Exposed_Lighter_

 

There are other reasons to think that the majority of "special armor" in tanks today is NERA.

 

 

1)  NERA works best when threats hit it obliquely.  Sloping conventional homogeneous steel armor does not improve its efficiency against HEAT threats, and actually makes it slightly less efficient against long rod penetrators.  Ceramic armors likewise do not work very well when hit obliquely.  Most modern tanks have sloped armor.

 

2)  NERA, being made of fairly prosaic materials, would be much cheaper than ceramic-heavy armor arrays.

 

3)  NERA, lacking anything brittle enough to degrade from normal operations, would have a very long shelf life.

 

4)  NERA, lacking explosive elements, would be easier to store safely, and does not generate additional shock and fragments when hit, making it safer for use on tanks around supporting infantry than explosive reactive armor (ERA).

 

5)  Unlike ERA, it is possible to stack multiple layers of NERA on top of each other.

 

Odds and ends:

 

Q:  What about the reports that boron carbide in some Soviet armor?  Wouldn't that be an example of non-NERA protection in a modern MBT?
A:  Boron carbide is an extremely hard, relatively light ceramic.  Theoretically, large pieces of it would provide excellent protection against both long rod penetrators and HEAT jets.  However, it would also be extremely expensive to make large, homogeneous pieces of boron carbide.  They would also be very brittle and likely need periodic replacement.  The most likely explanation is that reports of boron carbide armor are mistaken.  They are actually referring to a small amount of boron carbide mixed into a layer in the armor for shielding against fast neutrons from neutron bombs.  Enriched boron is an excellent neutron absorber.

 

Q:  What about the depleted uranium used in the armor of the most recent Abrams variants?
A:  Conjecture on my part, but battle-damaged M1A2s appear to show NERA.  I suspect that the "DU mesh" sit in front of the NERA, where it acts as perforated armor and degrades the effectiveness of long rod penetrators.

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You can have a single brick of ERA with multiple flyer plates inside, sure, the Russian designs appear to have been doing this for some time.  However, AIUI, you can't put multiple bricks of ERA on top of each other because the explosions from the first brick squishes or detonates the one underneath.

 

Unless the Russians have cooked up something new and clever, that is.

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Having grown up with the understanding that composite armour was some sort of amazing blend of high-tech ceramics, superalloys and advanced polymers; it has been supremely disappointing to learn how much of it is boring stuff like fibreglass sandwiches and NERA.

 

It's a bit like the discovery that the 'secret' to making a stradivarius was reasonable craftsmanship, a shit-ton of varnish and good marketing.

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Stillbrew was more crude than that. IIRC it was just a layer of cast steel with 3 or 4 hard rubber layers behind it.

That looks closer to Burlington's NERA.

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Stillbrew was more crude than that. IIRC it was just a layer of cast steel with 3 or 4 hard rubber layers behind it.

That looks closer to Burlington's NERA.

Looking at it again - it now reminds me Merkava 3BdD and Merk 4 turret sides armor.

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Indeed it does. Burlington inspired a lot of armour typs after it arrived.

Is there a good diagram of BDD out there? It looks to be like Burlington-esque NERA rather than the bulging NxRA (like on T-72B).

EDIT; NVM I forgot that it's just plates surrounded by a resin.

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What about it suggests that it's NERA?  If there's some clue I am missing it.

 

The majority of "special" armor does seem to be NERA though.  So many authoritative sources said that special armor was ceramic-based in the 1970s and 1980s, while polymer/steel composite structures have proven to be the most common.  I strongly suspect it was a deliberate misinformation campaign.

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Don't forget that a lot of NERA composites have the 'stereotypical' layered armour towards the rear. I suspect Burlington was just misindentified until it was shown to be NERA.

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