Defense Technology International - January/February 2008 - (Page 44) WARFARE ASYMMETRIC ISRAEL DEFENSE FORCES killing or severely injuring the crew. As a result, the U.S. and other nations are spending billions on heavily armored vehicle programs like MRAP (Mine Resistant Ambush Protected vehicle) to counter these devices (DTI October 2007, p. 46). A favorite weapon is an IED equipped with a shaped charge. A shaped charge, sometimes known as an EFP, is gaining greater use, especially in Iraq. In these devices, a concave shape, often machined of copper, covers an explosive charge, creating a hollow space in front of and along the axis of the charge. When it detonates, the copper is transformed into an aerodynamic shape, creating a powerful jet of molten metal known as plasma. The shaped plasma jet travels at up to 8,000 meters (26,248 ft.)/sec., and can penetrate armor 1-6 times the diameter of the original concave shape. The e ect inside the target is catastrophic. To be most e ective, the shaped charge has to be detonated at the right distance from a target. If it detonates too close, an optimal plasma jet cannot form, dissipating the penetration e ect. If detonated too far from the armor, the plasma jet begins to break up. Israel Defense Forces bomb disposal crews have uncovered what they call Kela (catapult)-type IEDs in Lebanon and in Gaza. These are explosives launched from a metal sling. Activated by a triggering device, the weapon has a chemical shaped charge, weighing 10-50 kg. (22-110 lb.), launched by remote control or by an electrical fuze, from several meters distance. The initial types have been ine ective against armored vehicles, but heavier versions have caused catastrophic results in lightly armored vehicles. IEDs containing a heavy metallic slug for added destruction can also be used in roadside ambushes, detonating at a stando distance from the target and inflicting significant damage on light armored vehicles. Insurgents have recently started using “mega-IEDs” weighing hundreds of pounds to attack heavy armored vehicles, including tanks. Some improvised “belly charges,” designed to penetrate the hulls of armored fighting vehicles from the bottom, are made from cylindrical containers like water tanks filled with explosives. The cylindrical shape and explosive design create a directional e ect, focusing most of the blast up at a target. The barrel shape is, moreover, easy to handle. A small team can roll it into position and rapidly dig a hole for it. The e ect of such a device was demonstrated six years ago in the Gaza Strip. Hamas insurgents buried 100 kg. of explosives packed in a discarded water boiler, giving it the e ect of a hollow charge. It was activated by remote control from a hidden position within sight of a narrow pass along a dirt road used by IDF tanks. The mix of C-4 CTP plastic explosive and detonating charges exploded under the right side of a Merkava tank. The blast dented the belly floor, forcing the lower hull upward. As result, the front power pack was blown up toward the gun barrel, which flipped the 22-ton turret o its ring hinges, killing the two crewmembers. Iraqi insurgents used a similar technique in 2003, when an M1A2 Abrams tank from the 4th Mechanized Infantry Div. was destroyed by a mega-IED belly bomb. One type of explosive that has been generally overlooked in Iraq are house-borne IEDs—entire buildings or blocks of houses rigged to explode. As recently as Jan. 9, six Army soldiers were killed by a house-borne IED. During the fight for Fallujah in 2004, house-borne IEDs were a particular threat. David Bellavia, then an Army sta sergeant with Task Force 2/2, learned to detect the threat by looking for piles of bricks in front of houses that signaled to insurgents a house was wired. If that tip-o wasn’t there, U.S. 44 Captured Hezbollah command and control center in Lebanon. Equipment includes VRC-12 FM receiver and modified transceivers. forces kept an eye out for “grouped up, bright-colored cables with electrical tape” that weren’t coated with dirt and dust. “One day, two hit,” he says. “We knew these were buildingcontained IEDs. As soon as a tank fired into them . . . it would chain [explode] the entire neighborhood. It wasn’t that they were wiring one house to blow, they were wiring the streets around it.” Bellavia says the insurgents almost always use propane as an igniter, and most of the house-borne IEDs contained P4 plastic explosive, a version of C4 used by the old Soviet Union, that was placed on stress-bearing walls to make the building a combat multiplier. “It wasn’t so much about exploding the house as it was collapsing it on you,” he says. “I believe they were command detonated, and because of that they wanted to protect the cables that led to the blasting cap. So they started to tunnel these things through walls and, if you found bricks missing at the bottom of walls, that was the first flag. But for the most part it was looking for anomaly wires that were clean or brightcolored in the midst of all that chaos.” During Operation Marne Torch II in Iraq’s Arab Jabour region last year, Army Col. Terry Ferrell, who commands the 2nd Brigade Combat Team (BCT), 3rd Infantry Div., said in a conference call with reporters that his soldiers uncovered three house-borne IEDs. In Operation Arrowhead Ripper in Diyala Province last summer, the house-borne IED threat was “unlike anywhere else in Iraq,” Col. Steve Townsend, commander of the 3rd Stryker BCT, 2nd Infantry Div., stated in a release from the Multinational Force-Iraq. “We . . . encountered 24 house-borne IEDs in . . . 11 days.” But Ferrell also pointed out that overall, the insurgents’ supply of explosives seems to have diminished. Many of the IEDs his troops now find are made of homemade explosives, and are hastily laid along roads and footpaths. In this respect it’s back to the basics for the Iraqi insurgency, to the early days of the war before shaped charges, mega-IEDs and EFPs were common. The bombs may be cruder, but they’re still just as deadly. And they show that the insurgent continues to adapt his tactics, using whatever tools are at hand. I With David Eshel in Tel Aviv. Read McLeary’s posts on DTI’s weblog, Ares, updated daily: aviationweek.com/ares www.aviationweek.com/dti DEFENSE TECHNOLOGY INTERNATIONAL JANUARY/FEBRUARY 2008 http://www.nxtbook.com/nxtbooks/aw/dti1007/index.php?startpage=46 http://aviationweek.com/ares http://www.aviationweek.com/dti
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