In the first few days of the Yom Kippur war in October 1973, Israeli armoured units were attacked by Egyptian forces armed with Soviet-made anti-tank missiles. The Israelis “suffered wholesale destruction”, according to an American Army manual written soon afterwards to help counter the weapon in question. There was not much that could be done. As the American guide noted, the missile system—called Sagger by Western forces—could be carried in a suitcase, launched and steered using a joystick to hit a target 3km (1.9 miles) away. It would then penetrate any vehicle armour in existence.
Tanks had been destroyed with weapons carried by foot soldiers before; America introduced its M1 Bazooka during the second world war. But never had infantry so decimated armoured vehicles. Of Israel’s roughly 2,120 tanks, about 840 were destroyed during the 20-day war. The era when “the tank was king” had ended, says Keith Brendley, head of Artis, an American firm that develops protection systems for military vehicles. Since then anti-tank munitions have become even more powerful, but steel armours have improved little. Now, however, aided with new materials and advanced sensors, a promising and eclectic array of alternative and often ingenious new forms of armour is emerging.
Anti-tank missiles and rocket-propelled grenades (RPGs) penetrate armour with a shaped charge. This explodes after the tip of the warhead has sunk into the target. The brunt of the blast is projected straight ahead, forcing a powerful spike of metal, usually copper, into and through the armour. Using steel alone, few vehicles today could carry enough armour to stop even an inexpensive RPG reliably.
To provide added protection, engineers have developed explosive-reactive armour. This involves covering parts of a vehicle with bricks of plastic explosives sandwiched between metal plates. When a warhead hits the outer metal plate, the explosives underneath (also specially shaped) detonate and force the sandwich to rapidly bulge as the plates move apart. This can shear the armour-piercing spike into bits, which are then less likely to pierce the underlying armour….
Does this mean armour is catching up with weapons technology? Hardly. Armour is getting better, but weapons are getting deadlier. Consider the Panzerfaust 3 (literally, “tankfist”), a shoulder-fired anti-tank guided missile that flies at more than 720kph (450mph). After striking its target, the exploding warhead shoots out a spike of copper at more than 7km a second (25,200kph) with enough energy to blast through a metre of steel, or any armoured vehicle used today, according to its manufacturer, Dynamit Nobel Defence. (Like many defence suppliers, it makes both weapons and anti-weapon systems.)
Moreover, some munitions can kill a tank crew without even penetrating the armour. A high-explosive munition known as “squash head”, fired by some British tanks, flattens a ball of plastic explosives against an armoured vehicle. It immediately explodes, transmitting a compression shock wave into the crew compartment, where it strips off “spall”—flakes of metal, some the size of a frisbee—that fly into occupants. Summing up the outlook for vehicle survivability, Stuart Wheeler, an armour expert at the Tank Museum in Bovington, England, says: “It looks grim.” Armour and vehicle designers, he says, are still looking for a comeback.
It may be on the way. On March 1st an RPG was fired at an Israeli tank patrolling near the Gaza Strip security barrier. A radar system on the tank tracked the incoming warhead, feeding data to a computerised gun that shot it down with a small burst of projectiles. Israel plans to deploy the system, called Trophy, more widely. Daniel Klein, an armaments official at the EDA, reckons that the foiled attack, probably the first of its kind, bodes well for defending military vehicles. An additional benefit, he believes, is that Trophy and other so-called “active protection” systems are lightweight. Some modern military vehicles have become so heavy with armour that their manoeuvrability is impaired and they are unable to use certain roads and bridges.
The new Iron CurtainIron Curtain, another active-protection system, has been developed for American forces by Artis. It uses radar and optical sensors to calculate the trajectory of an incoming warhead, and then intercepts it with a projectile fired from a roof-rack (pictured). The impact causes the warhead to combust before it hits the armour. Mr Lehniger, of Dynamit Nobel Defence, says that Iron Curtain and similar systems might be able to defeat his firm’s Panzerfaust 3 missile. If so, the achievement will be especially instructive to those who, decades ago, considered protecting vehicles to be a doomed endeavour.
Excerpt from The future of armour: The armour strikes back, Economist Technology Quartely, June 4, 2011, at 19