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Comment by refurb | Hacker News Reader

I thought the slats were to provide stand off distance for explosively formed projectiles.

If the explosively formed jet forms more than a few inches from the armor, it's way less effective.

Nope, we had them in Iraq before EFPs were really a thing (Thanks Iranain Quds Force for that). They were specifically for RPGs, which was one of the few things that could take out a Stryker without it. They even tried those Soviet parachute anti-tank grenades, but the Stryker is much faster than a tank and just moved away in time. That being said, the I'm sure this slat (birdcage as we called it) armor would help with that as well.

I thought an RPG _was_ an EFP? The round is just a shaped charge with a copper liner that penetrates the armour. So the slatted armour stops both RPGs and EFP-based IEDs.

The usual RPG with a HEAT shaped charge doesn't destroy by forging a penetrator that then potentially travels some distance to the target, it produces an intense, narrow jet that'll cut through a lot of material.

Not really. EFPs (in Iraq) were more or less IEDv2 in that they were simply much more lethal than the original IEDs:

http://www.cbsnews.com/news/us-sees-new-weapon-in-iraq-irani...

The Vampir uses a tandem charge -- Two successive charges. The point of this is to counter reactive armor, which is designed to counter explosively formed projectiles.

The "cage" slats can be effective against both.

That's backwards. Explosively formed jets need space to form, so work better if they detonate a little distance from the target.

No, you're right. Explosively formed projectiles work best when formed a few inches from the armor. However, they have a sweet spot and if the distance is too far, they don't work. I figured that's what the cages were for.

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