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RPG counters
I earlier posted ideas on IED detection. One of the comments brought up how a team had worked out a defense against RPGS -- basically a radar unit to detect incoming ones, then fire a shotgun blast at them, that disabled or detonated them. Check out the comment for details.
Yup, detonation would probably be halfway frequent: from what I understand, the fuze is a piezoelectric crystal that generates an electrical pulse. Anything that hits that fuze with sufficient force would detonate the round, even if the projectile itself is hardly slowed.
The other quirk at least the earlier models have is that the electrical pulse travels thru two metal layers, I believe the outer casing and an inner one. Anything that dents the casing shorts it out. Ordinary chain link fencing worked well in Vietnam, for a stationary vehicle. I wonder if that couldn't be upgraded. Say overlapping metal or cable circles, of almost the same diameter as the RPG, hanging loose so that they pivot upward when struck. Perhaps a few teeth on the inside of the ring at the lower end. A round that hits is unlikely to hit on the fuse, and thus may not detonate. The casing will be dented pretty badly as it spins. If it does go, with any luck it will be directed upward. The problem may be strength, as those things accelerate to (if I remember correctly) around 800-900 fps.
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The most serious threat now, provided by Iran, is not RPGs with piezoelectrically fuzed shaped charges, but EFPs. I don't know that detonating an EFP at a greater distance significantly reduces its penetration.
Many of our armored vehicles overseas already have screens installed to detonate RPGs. The ones I have seen in news photos were cages constructed of flat steel with the edge facing out, so they are much more sturdy than a chainlink fence.
The problem with this sort of ah-hoc solution (and particularly with all of the armor they are slapping onto HMMWVs) is the added weight beyond the design specs of the vehicles which causes the overloaded vehicles break down in bad places.
From the comfort of my air-conditioned office, it seems to me that the problem is not technological, rather it is a problem of our tactics. If our soldiers dismounted, spread out, and patrolled on foot, RPGs (and IEDs) would be ineffective against them... Maybe the solution to mounted patrols is not more armor, but rather a smaller one or two man vehicle that would allow our troops to spread out while still maintaining the extreme mobility that our current tactics require.
Hmmmm.
1. The armor used to defeat RPGs is called "slat armor".
2. Distance does attenuate the effectiveness of EFPs.
Basically the EFP is an explosive charge made with plastic explosives with a copper plate mounted on it that's facing the target. The explosive detonates and propels the copper plate towards the target while converting (self-forging) the copper into a molten spearhead.
3. Dismounted tactics is one way to ensure that losses from an RPG attack against a vehicle are minimal, but a lot of the firepower a mechanized infantry squad has is tied up in the vehicle.
4. The newest RPGs employ a tandem round where you've got two explosive warheads inside a single RPG. The first warhead is supposed to trigger the reactive armor while the second warhead punches through.
Reactive armor is basically explosive plates put on a vehicle that will detonate when struck by a shaped charge and thus disrupt the plasma gas flow of the warhead.
5. IMHO I wonder why nobody ever used Kevlar for this. Make something like a series of successive layers of netting (like the chain link fence idea) out of Kevlar. The idea being not to deal with the warhead but to guide the warhead into a position, between the gaps in the kevlar, where the warhead won't be triggered and won't come into contact with the vehicle.
The Israeli Merkava tanks already
have hanging metal chains to defeat
RPG's and other Anti-Tank rounds.
Though the Iranian's used Russian Anti-Tank
missiles
Merkavas are a pretty hardy tank design.
http://www.army-technology.com/projects/merkava/
Marc
The Trophy system is already on the Israeli Merkva IV tanks. The system uses radar to detect and aim an EFP at the incoming. It it very effective. The US (Navy) looked at (and evaluated) the Trophy system on a Styker and then an Army general shot down deployment on US vehicles, favoring instead a design by a US contractor that was only on the drawing board. Guess who the general is going to work for upon retirement...
There's an article in PopSci this month on an rpg defense for helicopters using rockets that trail steel and kevlar nets/parachutes that wrap up the rpg.
The Pentagon prefers LASERs instead.
http://www.popsci.com/popsci/technology/7bd4999bc5b82110vgnvcm1000004eecbccdrcrd.html
Just catching up to your latest posts... early in the occupation, when IEDs first became the weapon of choice, I read several articles that said the military had some were using jammers to disrupt IED detonation. The military did not want to discuss them for obvious reasons, but I believe these were essentially cell phone jammers, since cell phones, at that time, were the preferred device to command detonate IEDs.
Also, what you are suggesting to disrupt IED fuzes (altho I am not sure how you envision this being used) sounds a whole lot like what the military already uses to disrupt shaped-charge rounds (like RPGs), and has used since WWII. Any thing that gets the round to detonate prior to making contact with the actual vehicle helps reduce the damage. I think one of the problems nowadays is that the IEDs supplied by the Iranians are so large (as compared to an RPG round) that their kill range is greatly extended -- I have read of at least one M-1 Abrams being taken out. That is a big bomb.
elb