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Defeating Era


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I come across this article How accurate is this it ?

Experimental, modified 3BM22 Szpilka APFSDS which was capable of penetrating Kontakt-5 ERA without initiating it.

 

 

The top of the rod looks like cylinder with a length of 50 mm and wchich cross section has a diameter of 13,8 mm. This way of defeating Explosive Reactive Armor uses the fact that Reactive Armor usually does not explode when hit by 20-30 mm rounds even if they perforate the cassette. The job of such a rod top design is to simulate a small caliber round and gradually increase the penetration channel without making the explosive elements inside the ERA explode

- See more at: http://m.liveleak.com/view?i=c47_1421699338#sthash.u7ZbiLv5.dpuf

 

 

 

EAT warheads vs ERA

 

 

In case of HEAT warheads (used mostly in RPGs and ATGMs) the main way of defeating ERA is using a precursor. Precursors are divided into initiating and non-initiating ones. The first ones are supposed to make the ERA explode before the cumulative jet from the main charge reaches the armor. The main disadvantage of this solution is a need to create a relatively large time interval between the explosion of the precursor and the main HEAT charge. It must be done in order to give time for ERA to blow up after being initiated by the precursor. In reality majority of modern ERA (Relikt, ERAWA-2, BLAZER, ARAT) have multiple layers of reactive elements between metal plates and the time each layer explodes is delayed thus initiating precursors are nowadays most likely outdated.

 

More effective are the non-initiating precursors used in PzF-3IT600, RPG-29, RPG-28 and Kornet ATGMs. Their job is to punch a hole in ERA layers without initiating them allowing the main HEAT charge to pass through. Publications presented below show results of tests of penetrating two ERA layers covered by 14 mm armor plate by a precursor without initiating any of them. This precursor type allows the main HEAT charge to blow up right after without any time delays and the use of different layers and heavy moving armor plates in ERA can bring little effect against it

- See more at: http://m.liveleak.com/view?i=c47_1421699338#sthash.u7ZbiLv5.dpuf

 

It sound very strange to me , are these part realistic ? I thought ERA doesn't explode when hit by small caliber bullet because these are not fast enough ? How can the tadem warhead and the long tip of APDS round penetrate ERA without make it explode?

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Guest Jason L

Impact initiation of high explosives is pretty complicated. If you generate sufficiently shock pressure on impact the interaction details don't really matter, it's going to DDT and detonate. Prompt initiation of HE by impact requires strong shocks being generated and so there are lots of impact conditions that don't generate sufficiently strong pressures to reliably initiate insensitive HEs.

 

If you're below those strong impact pressure (which you actually can be even at the high speeds involved here) tip shape, penetrator diameter and shock-shape make a substantial difference. I have no doubt that for some insensitive HEs there is a combination of impact velocity and tip geometry that can prevent prompt initiation of the ERA, whether that's possible at rod sizes and velocities of interest to effective KEPs is another matter.

 

Non-initiating precursor shaped charges are also absolutely a real thing.

 

All of these capabilities hinges on the fact that ERA explosives are using highly insensitive formulations specifically so that they don't go off against light caliber threats, frag/splinters etc. They are just a bitch to setoff and so counter weapons can exploit that.

 

In the long run I think ERA is going to be rolled in as the heavy/ultra-heavy element of vehicle active defense, with tiles being automatically fired based on radar threat detection instead of passive impact initiation. The passive impact initiation is attractive for ease of implementation, but if you're going active as a first defense layer any tway and reactive as your second layer you've already crossed the technical hurdle of the radars/fire control anyway.

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  • 3 years later...

 

Another option is to just put the ERA behind armor, and then you can use a sensitive filler.

In battle compartment?..

 

You could put it in the turret cavity in place of or after NERA, but before the final backing plate, and preferable in some accessible module like the Leopard II front turret applique module.

 

Edited by KV7
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Overally idea is good, but faces problem of too substantial growth of dimensions amd thus weight. Plus limiting freedom of flyer plate movement might limit its effectiveness.

Even on T-series tanks, the only real issue with extending the turret forward is clearing the driver's head. The simplest solution for T-90 would be to add eg. 10 mm HHS - 50mm textolite - 10 mm HHS array 20mm ahead of the the face plate of the Relikt modules, and then use a higher mass efficiency but same volume array within the turret cavity in order to compensate for the added mass.

 

The other advantage here is that the ERA will be somewhat more effective if the jet is already partially particulated by the now quite substantial face plate armor. In APFSDS with an expendable tip or narrow tip designed to defeat ERA, the armored face plate may be sufficient to sufficiently ablate the tip before hitting the ERA element, such that a solid rod is encountered by the ERA.

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You're making it sound easier than it is)

Strapping armor on top of ERA will make it totally ineffective due to no space for flyer plate to, well, fly. And dimensions are not the only problem - such installation will weight much more than couple hundred kg.

Yes, perhaps closer to 1 ton or even more. Thought there is not much standoff required as the flyer plate of eg. Relikt is already constrained by the face plate (which of course does not fly off the tank), though it may well undertake some significant deformation, though in this case a 25 mm air gap would be ample.

 

Here is a quick sketch suggesting how it could be done: (using K5 layout).

 

wjR37vG.png

Edited by KV7
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It is my understanding that the fracturing of the rod tip and inducing yaw, and in the case of HEAT rounds the degradation of the jet tip especially is accomplished very quickly, i.e. before the plates have moved 50mm or so. Apparently on Relikt the inner plate does move all the way back to the face armor which stops it's motion, which would not be interrupted by armor ahead of the module. I am not sure about the front flyer plate, though on all other Russian ERA there are not plates exiting the ERA container.

In any case increasing the air gap to even 100mm or so to facilitate flyer plate movement is hardly going to be prohibitive.

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It is my understanding that the fracturing of the rod tip and inducing yaw, and in the case of HEAT rounds the degradation of the jet tip especially is accomplished very quickly, i.e. before the plates have moved 50mm or so. Apparently on Relikt the inner plate does move all the way back to the face armor which stops it's motion, which would not be interrupted by armor ahead of the module. I am not sure about the front flyer plate, though on all other Russian ERA there are not plates exiting the ERA container.

 

In any case increasing the air gap to even 100mm or so to facilitate flyer plate movement is hardly going to be prohibitive.

The front plate of Relikt is a flyer plate. There is no containment.

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It is my understanding that the fracturing of the rod tip and inducing yaw, and in the case of HEAT rounds the degradation of the jet tip especially is accomplished very quickly, i.e. before the plates have moved 50mm or so. Apparently on Relikt the inner plate does move all the way back to the face armor which stops it's motion, which would not be interrupted by armor ahead of the module. I am not sure about the front flyer plate, though on all other Russian ERA there are not plates exiting the ERA container.

 

In any case increasing the air gap to even 100mm or so to facilitate flyer plate movement is hardly going to be prohibitive.

The front plate of Relikt is a flyer plate. There is no containment.

 

Ok. that is interesting, though completely expected given the design.

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Ok. that is interesting, though completely expected given the design.

Well, it's nothing special. Relikt is a conventional ERA with two flyer plates, flying in both directions. Its design features no real innovations except in the impact sensing technology which is based on the 4S23 explosive element.

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So, how does Relikt achieves the claimed degradation of tandem warheads?

Against tandem warheads that work on the principle of detonating the ERA with the precursor charge and then detonating the primary charge after a delay, Relikt works simply by throwing the front flyer plate into the path of the primary shaped charge jet. Kontakt-5 should also be capable of doing this in theory.

 

Against tandem warheads that work on the principle of creating a gap in the ERA with the precursor charge without detonating the ERA, Relikt relies on the increased sensitivity of the 4S23 explosive element to detonate despite the low shock energy delivered by this type of precursor charge which would otherwise be insufficient to detonate other insensitive explosive compounds.

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So, how does Relikt achieves the claimed degradation of tandem warheads?

Against tandem warheads that work on the principle of detonating the ERA with the precursor charge and then detonating the primary charge after a delay, Relikt works simply by throwing the front flyer plate into the path of the primary shaped charge jet. Kontakt-5 should also be capable of doing this in theory.

 

Against tandem warheads that work on the principle of creating a gap in the ERA with the precursor charge without detonating the ERA, Relikt relies on the increased sensitivity of the 4S23 explosive element to detonate despite the low shock energy delivered by this type of precursor charge which would otherwise be insufficient to detonate other insensitive explosive compounds.

 

On K-5 the flyer plate is restricted in movement though, and will have collided with the static front plate before the primary shaped charge jet appears. And so on Relikt the multi-charge capability seems to require giving up on flyer plate containment (something I did not realise previously as per my error above). But if the precursor can be defeated either by ERA or NERA, then presumably a more compact design could be utilised.

 

 

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So, how does Relikt achieves the claimed degradation of tandem warheads?

Against tandem warheads that work on the principle of detonating the ERA with the precursor charge and then detonating the primary charge after a delay, Relikt works simply by throwing the front flyer plate into the path of the primary shaped charge jet. Kontakt-5 should also be capable of doing this in theory.

 

Against tandem warheads that work on the principle of creating a gap in the ERA with the precursor charge without detonating the ERA, Relikt relies on the increased sensitivity of the 4S23 explosive element to detonate despite the low shock energy delivered by this type of precursor charge which would otherwise be insufficient to detonate other insensitive explosive compounds.

On K-5 the flyer plate is restricted in movement though, and will have collided with the static front plate before the primary shaped charge jet appears. And so on Relikt the multi-charge capability seems to require giving up on flyer plate containment (something I did not realise previously as per my error above). But if the precursor can be defeated either by ERA or NERA, then presumably a more compact design could be utilised.

 

Huh? The front plate of Kontakt-5 is a flyer plate. It's not static.

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So, how does Relikt achieves the claimed degradation of tandem warheads?

Against tandem warheads that work on the principle of detonating the ERA with the precursor charge and then detonating the primary charge after a delay, Relikt works simply by throwing the front flyer plate into the path of the primary shaped charge jet. Kontakt-5 should also be capable of doing this in theory.

 

Against tandem warheads that work on the principle of creating a gap in the ERA with the precursor charge without detonating the ERA, Relikt relies on the increased sensitivity of the 4S23 explosive element to detonate despite the low shock energy delivered by this type of precursor charge which would otherwise be insufficient to detonate other insensitive explosive compounds.

On K-5 the flyer plate is restricted in movement though, and will have collided with the static front plate before the primary shaped charge jet appears. And so on Relikt the multi-charge capability seems to require giving up on flyer plate containment (something I did not realise previously as per my error above). But if the precursor can be defeated either by ERA or NERA, then presumably a more compact design could be utilised.

 

Huh? The front plate of Kontakt-5 is a flyer plate. It's not static.

 

The front case plate is not ejected:

 

 

 

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The front case plate is not ejected:

 

 

 

The photo shows undetonated panels.

 

Kontakt-5 definitely uses its front plate as a flyer plate. It is the main reason why each panel covers a large surface area and is packed with so much explosive mass; to propel the 15-20mm front plate. I'm not sure what other evidence is needed to prove this, because it seems rather obvious to me.

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I agree that is the most obvious conclusion and I may have been fed bullshit. Last time I looked into it the available sources seemed to be adamant that the thick outer plate undergoes no more than elastic and probably also some plastic deformation.

Here is the text associated with the picture above:

'It is very important to note that while light ERA containers are completely destroyed in the process of detonation, Kontakt-5 sections are not, as their detonation is contained by the outside armor plates. Therefore even after detonation Kontakt-5 sections continue to provide some applique protection.'

'The second section from the right is spent. Notice lack of damage to the Kontakt-5 outer shell'


Now it does actually look like there has been a detonation here, as the side plate of the element has been ejected.


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I agree that is the most obvious conclusion and I may have been fed bullshit. Last time I looked into it the available sources seemed to be adamant that the thick outer plate undergoes no more than elastic and probably also some plastic deformation.

 

Here is the text associated with the picture above:

 

'It is very important to note that while light ERA containers are completely destroyed in the process of detonation, Kontakt-5 sections are not, as their detonation is contained by the outside armor plates. Therefore even after detonation Kontakt-5 sections continue to provide some applique protection.'

 

'The second section from the right is spent. Notice lack of damage to the Kontakt-5 outer shell'

 

Now it does actually look like there has been a detonation here, as the side plate of the element has been ejected.

 

 

 

10 years ago, Fofanov's site was better than nothing, but there is much, much more accurate information about this sort of stuff in the English part of the Internet nowadays.

 

The "side panel" here is just for inserting and removing the 4S22 explosive elements.

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Now it does actually look like there has been a detonation here, as the side plate of the element has been ejected.

All that is missing is the lid for the lower ERA element. No detonation has occurred. The lid is for arming the ERA by loading the explosive charge.

 

As interlinked it said.

Edited by Stefan Kotsch
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