ERA Armour and related

[Rickshaw]

Bradley...

I don't think I'd like to be trying to provide close support to that if I was an infantry man.  It looks like it has enough ERA plastered all over it to make a very big hole in the ground if it all went off together...   


MOD edit: inserted quote for clarity's sake

[PR19_Kit]

Being totally ignorant about all things AFV related, what's 'ERA' and why would it go off?

[GTX_Admin]

Being totally ignorant about all things AFV related, what's 'ERA' and why would it go off?

ERA = explosive reactive armour.

Explosive Reactive Armour Explained

Going off would involve one of the panels exploding to defeat an incoming round.  However, given only single plates/panels would go off, having more on the vehicle should be no more dangerous than just a small quantity.  Mind you, I don't think any troop would want to be too close to an ERA equipped tank under fire.

[PR19_Kit]

VERY clever, thanks for the explanation.

Still got to be pretty loud inside the tank I bet!

[GTX_Admin]

Better than a round entering...

[Dr. YoKai]

I'd heard of the stuff, but didn't know the details - thanks, Greg. One question that wasn't answered in the Wiki, as far as I could tell - is there a minimum size round that will detonate ERA? Seems like a heavy MG would go a long way toward turning any AFV so
equiped into a very large Claymore...

[GTX_Admin]

I am not sure of the exact minimum round limit but I do know that most ERA is immune to detonation against small arms ammunition and artillery shell fragments.   The panels are also made so that there is no sympathetic detonation of neighbouring panels when one panel explodes.

[GTX_Admin]

Getting back to the Meng Models (in a round about way), how about one of the new Leopard 1s equipped with ERA?

[jcf]

Getting back to the Meng Models (in a round about way), how about one of the new Leopard 1s equipped with ERA?

Nah, ERA the Char 2C.   

[Volkodav]

I was thinking a Tiger I with ERA

[Rickshaw]

I am not sure of the exact minimum round limit but I do know that most ERA is immune to detonation against small arms ammunition and artillery shell fragments.   The panels are also made so that there is no sympathetic detonation of neighbouring panels when one panel explodes.

This is all dependent on how the internals of each tile are configured.  The external box is designed to ensure the correct standoff distance for a HEAT round, which is why they tend to be so bulky.  Inside each box is a smaller box containing the actual explosive element and inside that box, the explosive is sandwiched between two further plates of armour.*  An incoming round has to penetrate first the external box, then the internal one and finally the forward sandwich plate.   Most small arms or artillery fragments would be hard pressed to do all that and then set off the HE layer.   A 30+mm cannon firing APDS though, might have interesting and unfortunate results.


*this is actually the very clever bit of ERA.  Essentially these can be configured in different ways to provide the optimum protection to the armoured hull underneath the ERA tile.   Because this configuration is hidden, the anti-tank projectile designers find it impossible to optimise their weapon for maximum penetration.   The ERA explosive element can slope in any direction, be even a right angled element or nearly any other shape in between.   The only way to defeat ERA if you're firing HEAT is to either use a bigger warhead (not always reliable) or use a precursor warhead (essentially putting a mini-HEAT warhead in front of the main HEAT warhead - again, not always reliable) or use a top-attack profile (works only if there is no ERA on the top of the vehicle).

[Gingie]

  The only way to defeat ERA if you're firing HEAT..use a precursor warhead (essentially putting a mini-HEAT warhead in front of the main HEAT warhead -

aka TOW2A, RPG-29, Javelin...Tandem warheads fairly common these days.

[Rickshaw]

Obviously the designers think it works but I've always had my doubts about this does to the HEAT jet.  I suspect it must effect penetration but I've seen no research on it in the open sources.   It's also why the Russians put multiple layers on their vehicles but that seems to have stopped.  Perhaps they're just putting multiple layers now inside their tiles?

[GTX_Admin]

Obviously the designers think it works but I've always had my doubts about this does to the HEAT jet.  I suspect it must effect penetration but I've seen no research on it in the open sources.   

Can you please clarify?  Are you talking about what the ERA blast does to the Heat jet?

[GTX_Admin]

Folks a new thread dedicated to this discussion.  Split off from the original Meng Model kit one.

[Volkodav]

Now to derail the new thread, does anyone know much about NERA (Non-Explosive Reactive Armour)?  It actually sounds like an oxymoron but I cam across it when I was looking into ERA and some references to rubber, plastic and composites but no real detail on what it does or how it works.  Worsth thing is I can remember where I found this info so cant check it up again, I am actually starting to wonder if I mis-understood what I was listening to (I did have a fever at the time  )

[Rickshaw]

People have been talking about it for the last 20 odd years that I'm aware of.   No one has yet fielded any.   Most seem to work on the principle that you have something, let us for the moment say, unobtanium which is contained in tiles/blocks/spaced armour which when struck by an incoming warhead reacts in someway and defeats it.  I've seen mention of completely passive (water filled spaced armour - which would have interesting effects if the chemical warhead vaporises it [where/how does it vent?]) to quite active ("Electrical Armour" - where an anode and a diode are separated by a space and when a warhead bridges it, it completes the circuit and gets disrupted/vaporised).    Getting this sort of stuff to work is obviously harder than writing about it.

[Rickshaw]

Obviously the designers think it works but I've always had my doubts about this does to the HEAT jet.  I suspect it must effect penetration but I've seen no research on it in the open sources.   

Can you please clarify?  Are you talking about what the ERA blast does to the Heat jet?

I'm talking about the Pre-cursor explosion, setting off the ERA block.  The main jet has to cut through this.  If the ERA block has the ability to disrupt the HEAT jet by itself, having it explode before the jet arrives may reduce it's ability to do that but the jet still has to get through the ball of expanding gas.  While I doubt it stops it, it should still reduce it's velocity and hence it's penetration.   It may all be moot and only by a tiny fraction, I admit.

[Gingie]

The trick is to have the first charge put the hole in the ERA without it exploding, like SA and Arty fragments do. Then the second, larger cone, shoots the plasma down the same hole and all kinds of fluid dynamics take place.

[Old Wombat]

I've seen mention of completely passive (water filled spaced armour - which would have interesting effects if the chemical warhead vaporises it [where/how does it vent?])

IIRC, the water-filled passive armour was in blocks, similar to ERA, each block was built with weak points which would rupture if sufficient steam pressure built up inside the block without the block being penetrated. Alternatively, should a HEAT round hit, this would create an even weaker point & the steam would vent counter to the penetration jet.

My guess is that studies showed that the super-heated steam didn't have the disruptive power of ERA.

:)

Guy

[Volkodav]

If you've ever seen a toddler trying to eat a ginger nut biscuit I think we may have found the perfect NERO, tins of Ginger Nut Biscuits attached to the sides of armoured vehicles would be near invulnerable!

[Old Wombat]

If you've ever seen a toddler trying to eat a ginger nut biscuit I think we may have found the perfect NERO, tins of Ginger Nut Biscuits attached to the sides of armoured vehicles would be near invulnerable!

 

Or the old recipe Bush Biscuits, before Campbell's got their hands on Arnott's & "softened" them!

:)

Guy

[Rickshaw]

The trick is to have the first charge put the hole in the ERA without it exploding, like SA and Arty fragments do. Then the second, larger cone, shoots the plasma down the same hole and all kinds of fluid dynamics take place.

Yes, I'm aware of the theory but somehow the practicalities just feel wrong to me.    I suspect like HESH, the principle is understood while the mechanics still remain somewhat of a mystery and will remain so.  HESH some 60 years after it was developed is still largely a mystery.  I once had a lengthy discussion with a quite interesting defence scientist who was interested in AT warheads and HESH in particular.  Apparently the physics behind it are still theoretical, rather than practical.  No one has carried out proper scientific investigations of it unlike what they've done with HEAT and AP/APDS/APFSDS/etc. 

[Volkodav]

If you've ever seen a toddler trying to eat a ginger nut biscuit I think we may have found the perfect NERO, tins of Ginger Nut Biscuits attached to the sides of armoured vehicles would be near invulnerable!

 

Or the old recipe Bush Biscuits, before Campbell's got their hands on Arnott's & "softened" them!

:)

Guy

Just stow the army ration packs and hot boxes externally, the combination of harder than tungsten non-organic material and sloppy corrode through anything mushy stuff should stop any type of AT warhead, kinetic, chemical or explosive.

[Weaver]

Isn't that MEXAS armour a non-explosive reactive armour?

My understanding of NERA is that it's basically the same as ERA, but the explosive is replaced by a fast-reacting polymer whose volume inceases massively when subjected to heat. This has the effect of throwing the outer plate towards the HEAT warhead in the same way as ERA, thus spoiling it's stand-off distance (stand-off distance is critical for shaped charges to work properly)


EDIT : no, MEXAS is a ceramic composite, not a NERA. Must have been thinking of something else.....