Hard shell: to improve survivability armoured fighting vehicles will get heavier before they get lighter. The US Army's claim that its 70-tonne M1 Abrams is the 'most survivable main battle tank in the world' is being tested each day in Iraq. Yet the army has suffered more armoured vehicle losses in the continuing 'stabilisation' phase of Operation Iraqi Freedom than in the six-week 'combat' phase.

The combination of lethality, mobility and protection provided by the M1 tank and M2/M3 Bradley fighting vehicle proved as decisive during the 2003 invasion of Iraq as it did during the 1991 Operation Desert Storm. Designed for classic armoured combat, these vehicles have the highest level of armour protection across the frontal arc. None of the 80 or so M1s 'knocked out' in Iraq has been penetrated through the frontal arc.

The threat to these and other coalition armoured fighting vehicles comes not from enemy tanks or sophisticated antitank missiles. The tactical initiative in Iraq is often with insurgents who choose when and where to strike. They use large improvised explosive devices (IED) and rocket propelled grenades (RPG) to attack the more vulnerable flanks and rear. Operations in former Yugoslavia, Somalia, Israel and Iraq have shown the need for all-round protection particularly when operating in urban environments.

Armour must offer protection against a range of threats, including medium and large-calibre kinetic energy rounds, shaped-charge warheads, explosively formed projectiles, high explosive squash head, shell fragments and small arms. All of these weapons are becoming more lethal.

The development of passive armour has long been focussed on using ceramics and other material that will provide the same or better protection levels than military-grade steel but with a much reduced weight penalty. Without exception these materials are more expensive: aluminium is twice the cost of steel, titanium about ten times as much and Kevlar at least 25 times the price. However, wider commercial applications could reduce cost. For example, the cost of producing titanium alloy armour is expected to fall as the material becomes more widely used in the civilian car industry.

Passive armour generally falls into two categories, the disruptor that uses a plate to upset the structure or motion of the projectile to render it harmless, and the absorber that uses a material to absorb the kinetic energy of the projectile or the behind-armour debris fragments. Wherever possible it is advantageous to use both types of armour. The glacis plate on a Russian T-72 main battle tank consists of a sandwich of hardened steel, toughened steel, a composite ceramic material, such as glass fibre, and a spall liner. The frontal armour on many M1A1 and M1A2 tanks incorporates depleted uranium rods in the armour sandwich.

In 2000 a British partnership that included Vickers Defence Systems (now BAE Systems Land & Armaments), the Defence Evaluation and Research Agency (now QuinetiQ) and Vosper Thornycroft completed the Advanced Composite Armoured Vehicle Platform (Acavp) demonstrator. This was the first armoured vehicle with a hull built of a plastic/fibreglass composite rather than steel or aluminium. The composite armour design is claimed to provide increased structural performance at equal ballistic protection levels to traditional materials and also eliminate the need for a spall liner. Other survivability features are inherent thermal and acoustic insulation. Applique armour would need to be fitted for protection against armour-piercing, fin-stabilised, discarding-sabot ammunition and shaped-charged attack.

At the same time United Defense (now BAE Systems Land & Armament Systems) developed the 22-tonne Composite Armored Vehicle Advanced Technology Demonstrator (Cav-ATD) for the US Army. Three types of plastic composites were used in its construction, The upper hull is a sandwich of aluminium oxide armour tiles between layers of fibreglass-reinforced epoxy, the lower hull was built of fibreglass and polyphenylene sulfide and the two-person crew capsule is made of fibreglass and phenolic resin. The materials used are claimed to offer the same ballistic protection for a weight saving of more than 35 per cent over a traditional metallic structure with armour. The recent acquisition of United Defense by BAE Systems thus concentrates considerable experience in the research of composite vehicles on both sides of the Atlantic.

Passive armour can be complemented by active armour technologies, of which the most mature and widely deployed is explosive reactive armour. This was developed by Rafael and other Israeli companies in response to the high tank losses suffered by the Israel Defence Force during the 1973 war. The Soviet Army fitted explosive reactive armour to many of its tanks to counter the threat from Nato antitank missiles during the Cold War.

One drawback with explosive reactive armour is the risk of injury to friendly troops when the panel explodes. To avoid this problem Verseidag Indutex and Dynamit Nobel have collaborated to develop the Clara hybrid-reactive armour, claimed to be capable of stopping multiple hits from 30 mm AP rounds. The Clara has several layers of non-metal composite material and explosives that only create lightweight chaff to disrupt a shaped charge gas jet. Another solution is self-limiting explosive reactive armour (Slera) which uses smaller amounts of explosives to disrupt the gas jet. According to the Army Research Lab, the << Slera is inexpensive and easy to fabricate and can provide good multi-hit protection in a modular configuration, but is an unproven technology >>. Both approaches result in lighter explosive reactive armour.

The US Army's General Dynamics Land Systems 8 x 8 Stryker provides an interesting example of available armour technology and its performance in Iraq is being closely scrutinised. The hull is made of conventional hard steel armour, which will defeat 7.62 mm armour piercing rounds, and is augmented by lightweight applique panels of passive Modular Expandable Armor System (Mexas) II armour produced by a team led by IBD/Deisenroth Engineering of Germany. This ceramic composite armour provides all-round protection against 14.5 mm machine gun rounds, mortar and artillery fragments.

Strykers deployed to Iraq have been fitted with so-called 'slat armour', basically a steel cage intended to detonate RPGs before they reach the vehicle's hull. According to a US Army report, << Stryker crews report that slat armour successfully defeats the high explosive anti-tank (Heat) rocket propelled grenade round. The anti-personnel (AP) RPG and the anti-tank (AT) RPG round was not defeated by slat armour because of shrapnel passing through the slats, hitting exposed personnel, and the probability of the AT APG round penetrator not directly hitting the slat armour >>. The report notes that a Stryker survived nine RPG hits with only minor injuries to the crew. The 22,680-kg weight and the bulk of the slat armour affect the vehicle's manoeuvrability; therefore the Army now provides additional training for drivers.

Three of the six Stryker brigades will receive slat armour but this is only a temporary solution. In November 2002 United Defense received a contract to integrate and qualify explosive reactive add-on armour, developed by Israel's Rafael Armament Development Authority as the major subcontractor, that is intended to defeat RPGs. The kit weighs more than 4000 kg and increases the Stryker's width by 30 cm on each side. The package consists of 87 active boxes for the sides and some 20 passive boxes for the front. A slat armour skirt will be fitted to provide coverage above the wheel line. The kit completed live-fire testing and product qualification testing in 2004 leading to the award of a $ 30 million contract for 289 kits and spares. Deliveries are scheduled to begin in September 2005 and conclude in October 2006 to coincide with the fielding of the fourth brigade of Strykers. If options are exercised the contract could be worth up to $90.6 million.

In August 2004 a US General Accountability Office report on the Stryker notes, << [If] fitted with additional armour for increased protection against weapons such as rocket-propelled grenades, a Stryker vehicle would be unable to fit inside a C-130, and with added weight of the armor, the aircraft would be too heavy to take off. At the envisioned 38,000-pound maximum weight of the Future Combat System vehicles, the planned C-130 transport of those vehicles for the Army's Future Objective Force would present the same challenges >>.

Israeli Innovation

The US Department of Defense has bought both passive and reactive add-on armour systems designed and produced by Rafael. In its largest contract to date for passive armour Rafael produced Enhanced Applique Armor Kits for 1137 US Marine Corps AAV7A1 amphibious assault vehicles between 1991 and 1993. It has since received small contracts; the latest awarded this year for 75 kits. Each 1996-kg kit consists of 70 laminated steel plates that protect the vehicle's sides, slopes, top surfaces and hatches. The inner layer is 150 mm away from the vehicle's sides and the outer layer 175 mm away. The enhanced applique is required to provide 95 per cent probability of no penetration by 12.7 mm armour-piercing rounds at muzzle velocity, 95 per cent probability of no penetration by 14.5 mm armour-piercing rounds at 300 metres and 99 per cent probability of no penetration by 155 mm high explosive fragments at 15 metres overhead. The AAV7A1, seen on the cover of this issue, is expected to remain in service well into the next decade.

In 1995 General Dynamics received its first US Army contract to supply Bradley Reactive Armor Tile (Brat) vehicle sets based on Rafael's explosive reactive armour. The Army has bought more than 600 sets and further orders are expected. The present $ 84 million contract, awarded in November 2004, covers 168 Brat sets, with work evenly divided between Israel and the United States. The latest production standard consists of 96 tiles per vehicle: 18 M3 frontal, 8 M4 frontal wedge, 55 M5 side, 7 M6 turret front and 8 M7 turret wedge. In May 2004 GDLS opened a new reactive armour manufacturing facility in Stone County, Mississippi.

Like the Bradley, the M1 will remain in US service until 2030. About 80 M1s have been knocked out in Iraq but most have been or will be returned to service after depot level repairs. According to the Army the few combat fatalities suffered in M1 attacks have been caused by IEDs. General Dynamics has recently developed the Tank Urban Survival Kit (Tusk), at the request of the Army's M1 project manager, to improve the tank's ability to operate in an urban environment. The package is based on feedback from M1 units that have served in Iraq. Survivability enhancements include Abrams Reactive Armor Tiles fitted to the sides of the hull, slat armour fitted to the hull rear, slat armour around the sides and rear of the turret and a Loader's Armored Gun Shield (Lags) to protect the loader when operating his machine gun. According to the army's project manager these upgrades use off-the-shelf technology to enable units to install the various elements in the field without returning the tanks to a depot for modification. The kits could be left behind for the next unit to deploy to a theatre, although some improvements are being considered for permanent installation. The first element to be introduced was the Lags, and about 130 shields were shipped to Iraq early this year. The complete Tusk package has yet to be funded.

Noting that many casualties are suffered by crew members when they are riding with their heads and shoulders outside of hatches United Defense developed the Transparent Armoured Gun Shield (Tags) for installation on M1s, Bradleys, Strykers and Humvees. This offers greatly improved situational awareness compared to other designs.

Following requests from senior commanders in Iraq the army is improving the protection of its widely deployed M113 series. This involves providing a complete suite of protection to 543 M113A3s including 'high hard steel applique sets' on sides, front and rear (to increase protection against IEDs), mine armour plates, Tags and slat armour. Upgrading an A3 to the new configuration costs less than $ 80,000. A further 191 vehicles will receive mine armour plates.

Concerned about the RPG threat the British Army has fitted bar armour, similar to the US Army's slat armour, to its Warriors and some other vehicles used in Iraq. The Warrior is already fitted with Chobham composite armour boxes on the sides and front glacis plate developed for the 1990-91 Gulf War. The bar armour adds 800 kg to the vehicle's weight. Bar armour has also been fitted to the sides of the Challenger Armoured Repair and Recovery Vehicle and on the rear of the Challenger 2 tank's hull and turret. Vehicles of the Combat Vehicle Reconnaissance, Tracked series have been fitted with additional armour protection. IMI and Rafael have briefed British Ministry of Defence officials about the scope of installing explosive reactive armour on the Warrior and Challenger. As the design authority for both vehicles BAE Systems will almost certainly be involved in any upgrade; its Royal Ordnance subsidiary produced the explosive reactive armour fitted to British vehicles during the 1990-91 Gulf War although further research was later halted.

The passive Mexas developed by Germany's IBD-Deisenroth is available in light, medium and heavy configurations for installation in new vehicles or as add-on kits. The Mexas package for the German Army's air-transportable Wiesel 1 weighs about 300 kg, while an installation on the larger M113 weighs about 600 kg. More than 12,500 packages have been built to date for the home and export markets. Phoenix-based Simula undertakes license production in America for the Stryker and the Cadillac Gage Textron Armored Security Vehicle. At Eurosatory 2004 IBD unveiled its Advanced Modular Armor Protection system that uses ultra-fine powers made from nano-particles to create thin, light ceramic modules. This armour is being used on the Hagglunds CV90 series and for Patria's 8 x 8 Armoured Modular Vehicle.

Although the CV90 series already boasts one of the highest protection levels of any IFV the Swedish Army upgraded 55 CV9040s to the C standard in 2001-02 by the installation of a passive armour package supplied by IBD. This provides additional protection to the front, sides and bottom of the hull and to the turret. Spall liners have also been fitted. These vehicles are allocated for international operations and have been deployed with the United Nations mission in Liberia.

Giat is developing two new vehicles for the French Army as well as improving the protection of armoured vehicles already in service. Giat is now working on the first production examples of the 26-tonne 8 x 8 Vdhicule Blinde de Combat d' Infanterie (VBCI). The vehicle has a welded aluminium alloy hull to which modular titanium plates are fitted. According to Giat this will provide protection against 14.5 mm armour-piercing attack through a full 360[degrees]. The VBCI design has been optimised to provide protection against mines and additional armour can be fitted for protection against top-attack weapons. This is planned to be followed into service in the next decade by the EBXX (formerly known as the Engin Blinde a Roues de Contact [EBRC]) wheeled or tracked armoured reconnaissance vehicle which is expected to feature a hull and turret made of titanium. To bridge the gap until these new vehicles arrive Giat is upgrading 300 AMX-10RC reconnaissance vehicles and a yet-to-be-finalised number of AMX-10Ps. This includes the installation of new passive armour. The company earlier produced 100 kits of steel armour for possible deployment on AMX-10Ps in Kosovo, although these were not fitted. In the only production order for Giat's Brenus explosive reactive armour the company has installed kits on two battalions of AMX30 B2 tanks. The company claims the system provides protection equivalent to 400 mm of steel armour at an angle of 60[degrees]. Giat developed a modular armour concept for the Leclerc so the present modules can be replaced with new technology. About 2015 the French Army plans to field a layered solution to the Leclerc's survivability expected to include stealth measures, soft and hard kill systems and new armour modules that include titanium.

Not constrained by the need to keep its next-generation vehicles light enough to be carried by the C-130, the German Army has decided to take no risks with the protection of its new Puma. Designed to be carried by the Airbus Military A400M, the Puma will have a baseline weight of 31.45 tonnes at Protection Level A (Air-transportable) making it the heaviest purpose-built IFV in the world. This will protect it against 14.5 mm attack and at least a ten-kg landmine blast. If the threat warrants, additional protection armour modules can be added to the hull and turret to provide Protection Level C (Combat) to defeat handheld anti-tank weapons, 30 mm ammunition and top attack bomblets. With this armour fitted the Puma will weigh about 43 tonnes. Four A400Ms will be required to transport three Pumas, Protection Level C armour and their crews.

Israeli Projects

Following on from the first generation Blazer explosive reactive armour developed after the 1973 war, Rafael and Israeli Military Industries (IMI) jointly market Super Blazer, which can be tailored for any main battle tank. Applications include the Merkava Mk 2 and Mk 3 and the Magach-7 and Magach-8 upgrade packages for the M60 tank. Up to four tonnes of additional protection can be fitted to the M60 although this can only be done if the tracks are replaced with new tracks. The Sabra II M60 upgrade package includes active and passive armour and forms the basis of the comprehensive Sabra III modernisation programme for 170 Turkish M60s.

With more than 5000 M113s in Israeli service local companies have had plenty of incentive to develop armour packages. Rafael's Toga passive armour was fitted to some Israeli M113s in the early 1980s and was followed in the mid-1990s by the company's explosive reactive armour package. Urdan Industries developed a passive, all-metal armour kit for the M113 that includes Kevlar spall liners. The kits were acquired by both the Danish and Swiss armies.

The Israeli Ministry of Defense awarded IMI, working with Rafael, a contract in mid-2004 to install the Light-Vehicle Armour System (L-vas) on 50 M113s. The work will be split evenly between the two companies. Each L-Vas module consists of layers of steel, rubber, ceramics and explosive reactive armour that, according to the manufacturers, can withstand multiple direct or lateral hits by explosive warheads or 14.5 mm and 20 mm armourpiercing rounds. The full suite weighs about two tonnes. Hard pressed for funding it remains to be seen how many M113s the IDF can afford to up-armour. IMI is developing similar modification packages for the wheeled Renault Vab and the tracked BMP 1 and BMP 2.

The vulnerability of the M113 to RPGs was demonstrated on 11 May 2004 when an RPG destroyed an IDF M113 killing six soldiers, and again the following day when another M113 was destroyed with the loss of five men. Threatened by IEDs, RPGs and anti-tank missiles Israel has stopped using its M113s on the Gaza Strip, relying instead on its heavy vehicles converted from tank chassis such as the Achzarit (based on the T-55), Magmachon (M60) and Puma (Centurion). The IDF has long used such vehicles in the APC and engineer roles. The IDF is planning to convert an undisclosed number of Merkava Mk 1 tanks into Nemera heavy armoured personnel carriers. As with the M113 upgrade funding will limit the number of conversions that take place.

Revolution

The US Army wants the eight-man vehicles of the FCS family to be less than a third the weight of the M1--no more than 20 tonnes--and yet still be as lethal and survivable. The GAO noted in a March 2005 report, << ... at least 53 technologies that are considered critical to achieving FCS' critical performance capabilities will need to be matured and integrated>>.

Situational awareness, active defence systems, mobility and new armour technologies are the four factors that the army is seeking to combine to provide improved protection with minimum weight penalties for the FCS. The April 2003 after-action review of the US Army's Task Force 1-64 Armor described the RPG threat faced by the unit's M1A1 tanks and M2A2 Bradleys during its advance into Iraq: <<No degree of IPB [intelligence preparation of the battlefield] could compensate, alert or prepare for the massive numbers of RPGs stored in houses, shacks, lockers and cars. The only way to counter RPGs fired from covered and concealed positions was to absorb the hit, identify the source of the fire, and respond with massive overwhelming firepower.>>

BAE Systems announced in March 2005 that it had achieved an "industry first" by successfully defeating a shaped-charge threat during live-fire testing of an electro-magnetic armour (EMA) package at the Aberdeen Proving Ground in Maryland. The EMA is mounted over the baseline armour and connected to the vehicle's electric power system. The electrical circuit is complete when the round strikes the system and high voltages defeat shaped-charge warheads. Reliable power management and delivery at lower volumes is essential for the application of EMA.

The US Army is exploring a range of other technologies--smart armour, momentum transfer armour, non-energetic reactive armour and non-explosive reactive armour--to protect the FCS. Affordability will be a key issue as the army balances the immediate needs of the war on terrorism with investing in the development of the Future Force.

The then-United Defense entered into a co-operative agreement with the US Army's Research Lab in March 2005 in support of its Mantech (Manufacturing Technology) objectives for advanced structures and applique armour that could be incorporated into the FCS and other vehicles. The company will investigate, develop and demonstrate emerging technologies to reduce manufacturing costs and integration risks. The effort is initially funded at $ 1.4 million and will encompass 14 specific projects and technologies through 2008. Funding through the Department of Defense's Mantech programme could be increased to $ 46 million over a five-year period.

The Two Armour Options

Influenced by events in Iraq, armour projects are focussed on two areas:

Upgrades to the full spectrum, from light utility vehicles to main battle tanks, this to meet immediate operational needs. Depending on the platform these projects can add several tonnes of weight and usually have penalties such as reduced manoeuvrability and increased maintenance costs to both wheeled and tracked vehicles.

The development of new armour will provide better protection for next-generation vehicles at a reduced weight penalty. Much of this research is being driven by the US Army's determination to keep the weight of Future Combat System (FCS) vehicles to less that 20 tonnes so they can be carried by the C-130 Hercules tactical transport aircraft.

Aslav

The Australian Army has copied the US example and fitted bar armour on its Aslav vehicles deployed in Iraq. Developed by GDLS-Canada, the American continent's manufacturer of the Piranha series, the armour is similar to that fitted on the Stryker but extended to protect the turret on the Aslav-25. However, the base level protection of the Australian vehicles, based on the LAV II, is not as great as the Stryker that has been developed from LAV III. The Aslavs now in Iraq have also been fitted with a Kevlar spall liner provided by Armatec of Canada. To install such a contact spall liner all of the vehicle's internal fittings must be stripped out so that the liner can be glued to the armour plate. The army has earmarked AS 200 million to AS 250 million to improve the protection of its fleet of 270 Aslavs in the period between 2009 and 2011. Although a decision on the armour package is not scheduled until 2006 or 2007, fitting spall liners could cost up to one third of the budget.

Lighter Get it Too!

The Bosnian and Kosovan conflicts in particular quickly demonstrated the necessity to up-armour jeep-like vehicles. One of the pioneers in this respect was O'Gara-Hess & Eisenhardt, which provided the American forces with an up-armoured version of the Hummer (left). Another firm that has up-armoured the Hummer is Mowag, in this case to supply Eagle Scout vehicles to the Swiss Army. Plasan Sasa is now also playing with the AM General Hummer up-armouring band and has recently chalked up an order from a Nato nation.

According to the Israeli firm met by Armada staff at the Eurosatory 2004 exhibition (see Complete Guide to Mobility, issue 5/2004, page 14) the art has been pushed as far as armouring structural elements of the vehicle now known as the M-PAV2 (left centre). Ceradyne also provides modular elements to upgrade light vehicles, whilst firms such as Panhard with the new PVP (right centre), Krauss-Maffei Wegmann with the Dingo, Mowag with the Eagle IV and Auverland with the A4 (right) offer readily armoured solutions.