Defense Technology International - March 2008 - (Page 13)

TECH WATCH DAVID HAMBLING FORCE MULTIPLIER The U.S. Air Force’s BattleAxe munition will reportedly be the first operational weapon to use reactive materials in its warhead. The weapon will release shrapnel-like pieces of reactive materials that detonate on impact, generating heat, blast or a combination of both, depending on formulation. Reactive materials consist of two or more non-explosive components bound together into a solid, which is stable and safe in normal handling. Under a high level of dynamic stress, like the force of striking a target, the two components react together, creating an effect that’s determined by their composition. “The objective of the BattleAxe warhead program is to demonstrate a miniature warhead technology that defeats a broad spectrum of ground targets including soft-fixed, softmobile and heavy armor,” says Rex Swenson of the Air Force Research Laboratory’s Munitions Directorate. The weapon is claimed to pack more destructive power than similarly sized warheads with conventional explosives. Unlike cluster bombs, the use of reactive materials reduces the threat of injury to friendly troops or civilians from unexploded fragments. BattleAxe is sized to ﬁt the AGM114 Hellﬁre air-to-ground missile. There are several versions of the Hellfire for different missions— anti-tank, thermobaric blast and blast/fragmentation. A BattleAxe warhead can combine all three capabilities in one package. The weapon’s reactive fragments will be particularly lethal against soft targets like trucks. Since the fragments ignite on impact, they will release energy inside the target. Reactive materials, however, are not a replacement for explosives, notes Judah Goldwasser, program manager at the Ofﬁce of Naval Research (ONR). “They are a replacement for metal fragments.” Shrapnel has not changed much since its invention in 1784 by Henry Shrapnel. It relies on the kinetic energy of impact to inflict damage. But shrapnel made from reactive material combines kinetic effect with chemical energy release. Some AviationWeek.com/dti reactive materials release twice the energy as an equivalent weight of conventional explosive and are correspondingly more destructive. There are several types of reactive materials. ONR has put considerable work into mixtures of metal and polymer, in particular powdered aluminum in a polytetraﬂuoroethylene matrix. This produces a detonation-like energy release and blast. materials include a shaped charge, which transforms a concave metal liner (usually copper) into an aerodynamic shape that, moving at hyperspeed, can penetrate armor. The liner also creates a powerful jet of molten metal called plasma that devastates the interior of a target. If the copper is replaced with a reactive material, the kinetic effect of the jet is supplemented by additional energy release. British defense company Qinetiq has been U.S. DEFENSE DEPT. The destructive force of shrapnel-like fragments made of reactive materials is evident in this test strike. Since explosives are defined as chemically unstable materials, the mix, as with other reactive materials, is not technically an explosive, but an inﬂammable solid. Other versions are combinations of metals like aluminum and boron, or specially formulated thermites that combine aluminum powder with metal oxide. The difference between these and conventional thermites is that the energy release takes place in a fraction of a second. ATK won the contract late last year to be the single provider for the next phase of BattleAxe development. This should lead to final proof of principle of the warhead in 2010. Reactive fragments appear to be effective against targets such as aircraft and missiles. ONR estimates that reactive fragments may be up to 500% more lethal than inert fragments. Even small reactive fragments are effective in this role, so more fragments can be produced for a given warhead size with wider coverage. Other applications for reactive researching this technology for use in oil well perforators under the trade name Connex. “Such reactions are highly exothermic and therefore lead to the release of large amounts of energy, which is in addition to the kinetic energy within the jet,” says Qinetiq spokesman Douglas Millard. “An increase in the energy coupled into the target occurs and this results in greater damage.” A shaped charge made of reactive materials will not necessarily improve armor penetration, but it has the advantage of producing a much larger hole with greater destruction. The U.S. Army’s Armament Research, Development and Engineering Center (Ardec) at Picatinny Arsenal, N.J., has been researching demolition charges based on this principle for some time. Ardec’s tests against concrete targets show that varying the reactive materials mixture produces a range of effects, from deep fractures to cratering. Likely developments include improved wall-breaching tools and lightweight demolition charges. I 13 MARCH 2008 DEFENSE TECHNOLOGY INTERNATIONAL http://www.aviationweek.com/dti

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Defense Technology International - March 2008 Contents Sweden Cancels SEP; Israel Launches Imaging Satellite; Geotextiles Secure Ammo Dump U.S. Navy Taps Neural Architecture Software to Assure Job Satisfaction Shrapnel-Like Pieces of Reactive Materials Increase Explosive Force of Bombs Technology is Rapidly Closing the Gap Between Sensors and Shooters Italian Army Program Aims to Develop a Fully Networked Land Force Political and Military Uncertainties Plague U.S. Defense Budget Democrats Put Pentagon on Notice Over Spending and Policy at DTAR Conference Russian Combat Vehicle Protects Tank Formations from Anti-Armor Weapons European Battlelabs Use Simulation to Verify Technologies and Stretch Defense Funds Malaysia Accelerates Fleet Modernization to meet Long-Term Goals U.S. Navy Says Composite Raiding Boat May Reduce Injuries From Wave Shocks Seeing Isn’t Believing When it Comes to Deciphering Funds for Secret Projects Advances in Sensors and Propulsion Make Torpedoes Ever More Lethal FAA is in No Rush to Approve Rules that Let UAVs Fly in Civil Airspace USS Truman Carrier Strike Group Patrols a Rough Neighborhood 24/7 U.S. says Sino-Russian Space Disarmament Plan is Riddled with Pitfalls Hyperspeed Projectile; “Sound Cloak” Hides Subs; Improving Nuclear Forensics Dutch Air Commodore Theo ten Haaf Analyzes the Impact of Rotary-Wing Operations One Soldier’s War is a Behind-the-Headlines Look at Russia’s Campaigns in Chechnya Black Budgets are Huge and Growing, and Often Conceal Amazing Failures

Defense Technology International - March 2008

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