UK IFV Warrior, new infomation.

[PlasmaKrab]

OK, don't think I gto it wrong about what WAS slat armor!

I still don't see why an ATGM would have a better effect against it. A LOS-flying classical ATGM like any TOW or HOT or Konkurs or anything is contact-detonated, so in many cases the fuse has as many chances to get caught in the cage and not detonate as with a RPG rocket.

As I told you, I don't think weight will matter that much since the velocity of the thing is fixed and generally subsonic, better as fast as most AT rockets. Though the cage looks frail, it is built to withstand the sheer kinetic blow, as well as small arms fire, collisions, road vibrations and so on. I don't think the weight of an ATGM will make such a difference.

Maybe if you are talking Shturm, Krizantema or Maverick, but in many cases I bet the missile will either detonate prematuredly, get crushed out of order by the grid or even bounce off and THEN detonate. Don't forget the incidence angle!

Anyway in the cases where the warhead does detonate on the cage, a bigger shaped-charge will have more penetration and be less affected by the standoff. This is where you have to calculate how much steel it is worth!
Any data about this, lest you force me to dig out my thermodynamics printouts and bring back painful memories from the times I did study something?

On the other side, I must agree about thank rounds . That is where you have kinetic energy!

[JaM]

The only thing i want to point was that modern warheads will be more succesfull against SLAT. RPG-29 has for example thin precursor that will go thru the cage.Heavy ATGM weights around 10-25Kg so it will have much bigger punch,Mavericks, Hellfires, Sthurm Krisantemas or Kornets will be imune, they are quite big to be catched in the cage, Maverick has for example high explosive warhead and not HEAT, so it will be dangerous even for heavy armored tanks

[Pergite]

JaM said:
The only thing i want to point was that modern warheads will be more succesfull against SLAT. RPG-29 has for example thin precursor that will go thru the cage.Heavy ATGM weights around 10-25Kg so it will have much bigger punch,Mavericks, Hellfires, Sthurm Krisantemas or Kornets will be imune, they are quite big to be catched in the cage, Maverick has for example high explosive warhead and not HEAT, so it will be dangerous even for heavy armored tanks

The hellfire is also top-hitting as well as most other modern ATGM�s. The cage is good for disrupting the effect of shaped charges, makes them go of earlier and losing their penetration. That is why most modern HEAT rounds have tandem warheads, mostly to defeat reactive armour but that would probably counter this ugly SLAT thing as well.

[Backis]

PlasmaKrab said:
the whole concept derived from the RPG fences used in Vietnam.

Its older than that. Russians used to tie bed-springs to the outside of their tanks to interfere with HEAT warheads.

Back then the penetrator stream lost coherence pretty fast so the standoff distance affected the effectiveness of the penetrator. Everything from sandbags to logs were used like this in WW2 by most sides, so I would not attribute this to the Vietnam era.

[PlasmaKrab]

Alright, I didn't know about these, WW2 is not quite my forte. Was that meant to fence off German hand-held rockets like the Panzerfaust? I thought there weren't that any tank HEAT rounds at the time.

Vietnam RPG fences were just the older example I knew of, and I wanted to point out that spaced grill armor wasn't a new idea.

Anyway any old material was fitted onto armor in conflicts all over the world, since WW2 propulsed HEAT warheads and steel armor have been employed on many occasions.

So sandbags, planks, tyres, etc. can be used to some extent. What would be useful to know is the precise efficiency of these things in terms of armouring.

[Backis]

Regarding the slat armour, this is how I have understood the matter.

The main intention with the armour is probably not just to increase standoff distance as the methods I mentioned in my earlier post. Most modern HEAT rounds retain coherence of their penetrator stream long enough to penetrate most AFV through both sides from a flanking shot, thereby pretty evidently proving that a few decimeters more standoff will make no difference for initial penetration.

My take on the slats as used today are that they are mainly intended to "disrupt" the warhead before they detonate. This is mainly effective against the older type or HEAT rounds such as those used by Iraq (main HEAT threat being the PG-7 and perhaps some PG-7V). This type of protection is effective since the piezoelectric fuze only covers the tip of the forward cone of the round. If this misses the slat the remainder of the warhead will strike them and break up, severely degrading its effectiveness. If the fuze strikes the slat the round will work and probably retain almost full effect regardless of the standoff distance.

However, modern HEAT rounds are usually fuzed over their entire front(f e the AT-4 is) and will detonate when striking the slat, negating any advantage other than the increased standoff (which I hold as rather insignificant).

Add to this that the rounds used in Iraq are mostly really old and crappy examples, having been stored a decade and half longer than they were ever intended to. Some AAR's report a quarter to a third failing to detonate at all, how well those that DO detonate actually work one can only speculate.

[Backis]

PlasmaKrab said:
Alright, I didn't know about these, WW2 is not quite my forte. Was that meant to fence off German hand-held rockets like the Panzerfaust? I thought there weren't that any tank HEAT rounds at the time.

Vietnam RPG fences were just the older example I knew of, and I wanted to point out that spaced grill armor wasn't a new idea.

Anyway any old material was fitted onto armor in conflicts all over the world, since WW2 propulsed HEAT warheads and steel armor have been employed on many occasions.

So sandbags, planks, tyres, etc. can be used to some extent. What would be useful to know is the precise efficiency of these things in terms of armouring.

I believe the main intention of the bedsprings were as a stopgap measure to protect against Panzerfaust and Panzershreck. The effect may have been mainly psychological though. But as early HEAT rounds had poor focus they lost coherence and efficiency very fast, so a decimeter of extra standoff could give the equivalent of welding on several centimeters of steel for a fraction of weight and cost.

[PlasmaKrab]

This is broadly what we have discussed above in this thread.

Many older warheads, plus probably some tandem HEATs, will have a fine enough fuze well that can slip between two bars, which will lead the warhead to be crushed against the bars without detonating.

About standoff, the question is: from what weapon up can the penetrator be considered untouched by one foot thick of cold air? That is, neglecting the incidence angle. Air won't spend and slow the penetrator jet down as steel would, but the metal will cool down anywauy. If the amount of energy spent is significant or not I must still calculate...

Additionally the bars in these systems seem to be thick enough, in the penetration direction, to deflect and maybe disrupt a penetrator coming at an angle.

Standoff plus a thin steel of hardened sheet seem effective enough against RPGs, since Tsahal has fielded a different kind of plated perforated spaced armor on their M113 "Zelda".

[JaM]

So you think that +33 heat armor will be not enough? Even if this type of armor was such perfect against missiles, tank HEAT rounds will crush it,so we need some value wich will represent SLAT.

[Backis]

PlasmaKrab said:

About standoff, the question is: from what weapon up can the penetrator be considered untouched by one foot thick of cold air? That is, neglecting the incidence angle. Air won't spend and slow the penetrator jet down as steel would, but the metal will cool down anywauy. If the amount of energy spent is significant or not I must still calculate...

I said nothing about it being "untouched, I said it the standoff distance practically possible on vehicles of reasonable size will be pretty insignificant.

Why are you talking about projectile temperature btw? Projectile temperature has nothing to do with its effectiveness.

The HEAT penetrator uses velocity and mass to penetrate. Due to its nature (being a liquid hyper-velocity penetrator formed by an explosion) makes it interact differently with armour, but it still works through kinetic energy.

The standoff gives the liquid stream time to disperse (f e turn into smaller droplets through friction) and loose coherence" and effectiveness. Modern warheads loose coherence slower than early types decreasing the effect of stand off armour.

Most "spaced" armour today has "something" in the space, f e small aluminum balls suspended in foam, that interacts with the penetrator stream rather more agressivley than atmosphere.

I think that the APC mods you refer to use spaced armour matixes more advanced than mere standoff plates. The chain skirt on the Merk is probably intended to prevent people lodging a bomb between the hull and turret overhang, but perhaps also to induce yaw on kinetic penetrators.