I’d like to see the raw numbers

Alternatives to Slat Armor (03/25/2005 entry)

Strategy Page:

The special “slat armor” on the U.S. Army’s new Stryker wheeled armored vehicle was supposed to stop 73 percent of RPG attacks. But actual experience has shown that only 50 percent of RPGs were stopped.

That’s quite interesting. First of all, I’m only aware of three Strykers lost to enemy action: One to an IED when the resulting fire could not be put out, one to an RPG which ignited a fuel can stored outside the hull, and possibly one to RPG fire in the big August 4th fight in Mosul. I’ve read various accounts that talk of scores of RPG hits on Strykers.

I’m wondering what “stopped” means when they say that the slat armor has only stopped 50% of the RPGs. Does that mean penetration of the Stryker hull by the warhead jet? Full penetration? How big of a hole?

For the record, the way that the slat armor is supposed to function is: The RPG warhead hits the “bird cage”-like slat armor and detonates at a distance from the armored hull rather than against the hull armor. This means that the jet of molten metal from the RPG’s HEAT shaped-charge warhead must travel the distance from the slat armor to the hull armor and is then turned aside by the hull armor.

As far as I’ve been able to gather, the slat armor has worked splendidly. The official story concerning the first Stryker lost to RPG fire is that the slat armor defeated the warhead, but that an external fuel can was ignited by the debris and the fire could not be extinguished in time to save the vehicle. The second incident, in the August 4th Mosul night fight, had a large number of RPG hits on the same vehicle in a short period of time. It isn’t very clear if that Stryker was indeed lost, though, and I haven’t been able to confirm either way.

Other defensive options are being looked at, including explosive reactive armor and guns, missiles, or lasers to shoot down incoming warheads.


  1. I think the Mosul one took several in the hatch area. The bitching is because the armor has to be replaced after an attack, and it probably isn’t much fun. My guess is that any plate showing damage must be replaced, even though some may still be safe for use. And, the plates may show more damage than was planned originally. The first plates failed testing and many were replaced before deployment. Bad ceramic science at the factory in Germany.

  2. By the way, I believe this concept was invented by the Germans during WW2. (Possibly by someone else sooner but I know it was being used by them). They put flat mesh screens along the sides of their Tank Destroyers (jagdpanzers) and possibly other AFVs to help protect the thinner side armour and running gear from weapons like Bazookas, PIATs, etc. I don’t know about ‘alternatives’. You can beef up the armour itself somehow but it’s still better to trigger the HEAT warhead early, no matter how good your armour. After all, better armour can be defeated with bigger HEAT warheads, and detonating them early will still reduce the effectiveness. Interestingly, it may be possible to produce a HEAT warhead specifically designed to defeat mesh/slat armour. By ‘focusing’ the penetration jet differently, it can be made to converge later. It will probably still lose some energy before it hits the armour but will likely still be somewhat effectively. Luckily nuts running around with RPGs won’t be able to get this advantage easily. It may also be possible to do something like what was done to defeat ERA (placing a precursor warhead before the main warhead). This warhead could blow a hole throught the mesh/slat armour. It would require some development effort as I doubt the anti-ERA precursors would work well on mesh/slats.

  3. Interestingly, I’m not sure, but the original reason for the mesh may have been so that branches could be threaded through it to provide camouflage and the benefits vs. shaped charges may have been a bonus. The book I read this in mentions both advantages for the mesh and doesn’t explain which was the original reason for its attachment.

  4. doc, by now you’ve probably seen this explanation for the % number: ‘Soldiers and commanders said the 50 percent figure was highly misleading because it characterized shrapnel sprayed by RPGs detonating on the slats as a failure. But soldiers said that in such instances, most of the Stryker’s occupants remain safe. Gunners exposed from three hatches are still vulnerable, but not because of any shortcoming in the vehicle, they contended.’

  5. HAHAHA…..good one chuck…..the Nazi’s did it….hahahaha maybe next time read what you write before clicking on Post