LINE-X spall liner

Spall testing - untreated steel...

...and treated steel

Hobson Industries Develop New Armouring Techniques to Meet Current Threat

Over the last 8 years Hobson Industries has been upgrading and re-armouring Land Rover steel armoured vehicles for the Police Service of Northern Ireland. Essentially this was a highly manoeuvrable vehicle suited to the streets of Belfast and other towns but with cross-country ability. It is a fully protected and fire-protected vehicle capable of withstanding high powered rifle round, fire-bombs and explosives. This work was carried out in a special build fabrication facility by welders holding the necessary welding qualifications in the special metals used. Testing and actual in-theatre targeting proved highly successful.

Through the experienced gained from this project we expanded our field to include less conspicuous vehicles such as Mitsubishi 4 by 4s and Skoda saloon cars. Hobsons has expanded this business to include the armouring of Land Rovers and other vehicles for UK police services and government offices.

Over the last few years we have been developing vehicle protection solutions suitable for the UK Ministry of Defence (MoD) Land Rover vehicles in theatre in Afghanistan and Iraq. Weight constraints of the Land Rover chassis have focused Hobson’s attentions on light weight protective armour for ballistic and mine blast situations. A strategic alliance was formed with Aigis who has developed a light weight energy absorbing material suitable to fix to the blast side of steel armour currently being tested to provide enhanced blast protection whilst allowing lighter steel to be used.

Line-X material has been subject to testing by the US Military where it provided the best anti spall properties of a batch of some 30 different products. Since those tests in the late1990’s Line-X have further developed their products to include fire retardant properties and are currently carrying out tests with the US Department of Justice to ascertain the improved capabilities of their products. Additionally the scientific branch of the UK MoD is currently carrying out tests on Line-X to determine defensive properties suitable for many applications.

Electro Magnetic Compatibility shielding quality and Infra Red Reflective protection is also being developed and tested for Line-X.

Through an agreement with Paxcom Line-X USA Hobson Industries have secured the UK rights for LINE-X for vehicle applications in defence.

Hobson Industries boasts a proud reputation of quality and reliability. Vehicle and power train remanufacturing have been carried out for the MoD and Land Rover UK for many years. Major parts supply contracts are in place with the UK MoD. Accreditation for Quality and Environmental Management Systems with the British Standards Institution are held and our thoroughly “Green” credentials can be assessed by viewing the attached press releases.

Spall Protection

Spalling, by definition, are flakes of a material that are broken off a larger solid body and can be produced by a variety of mechanisms, including as a result of projectile impact.

In anti-tank warfare, spalling through mechanical stress is an intended effect of high explosive squash head (HESH) anti-tank shells and many other munitions which may not be powerful enough to pierce the armour of a target. The relatively soft warhead, containing or made of plastic explosive, flattens against the armour plating on tanks and other armoured fighting vehicles (AFVs) and explodes, creating a shock wave that travels through the armour and breaks the softer metal on the inside. The resulting spall is dangerous to crew and equipment, and may result in a partial or complete disablement of a vehicle. Many AFVs are equipped with spall liners inside their armour for protection.

Spalling frequently occurs with bullets as well. The rounds fragment upon impact of equipment, breastplates, etc. The fragment can them travel into the bodies of nearby troops causing death and injuries.

Recently, there have been many polyurethane materials advertised for spall protection. The only company that offers certified testing is PAXCON by Line-X Corporation. Their product, PX-2100, has been tested and certified by H.P. White labs in Maryland, USA. The product was tested in accordance to STANAG 4569 III and NIJ III. The results showed that PX-2100 applied over armoured steel at a thickness of 6mm completely stopped any and all bullet spalling. On a test to failure at .30 caliber, the protected side application of PX-2100 stopped all spalling as well, even though the round passed through the steel. The results can be viewed by request at www.PAXCON.com. The company can also provide hi-speed digital photography of the events.

Application Methods

Along with the varied formulations, there are also different application methods. Hi-pressure spray, low-pressure spray, and casting are the most common forms of applications. Hi-pressure applications are the most common. Most are 1:1 ratios, mixed in the chamber of a triggered gun. Applications temperatures are around 65C (150F), pressures around 2500psi. The material is delivered in heated hose and the material sets up in seconds.

Low-pressure applications are generally mixed in a static mixing tube outside of the gun. The delivery temperatures are generally ambient. There are variable ratios available. The material will generally set up in 15-45 seconds.

Casting is a unique way to deliver the material. There are thousands of cast polyurethane applications in the world, from bumpers to roller skate wheels. Casting of urethane molds can provide different shapes, sizes, etc. Many casting formulations are used with polyurethanes that contain solvents. The curing of the materials is affected by the off-gassing of the solvents which can last minutes to hours. Non-solvented polyurethanes are also available and cure in minutes.

Castable polyurethanes are currently being used in armour panel applications in conjunction with different ceramic layups. The Polyurethane will not stop the projectiles, but are terrific in keeping the ceramic from braking apart. Many breastplates are coated in polyurethanes. If applied correctly, this can allow the plates to be hit multiple times and still maintain physical integrity.