Is is a form of armour in which explosive is sandwiched between two thin armour plates. The force of the penetrator hitting the front armour plate causes the explosive to detonate, reducing penetration. ERA is more effective against high-explosive anti-tank projectiles.

The most important aspect of explosive reactive armour (ERA) is that it can be used to enhance the protection of existing vehicles though it is likely to lie more effective if its characteristics are taken into account at the vehicle design stage. ERA armour consists of a series of individual panels installed onto the sloping surfaces of the tank hull and turret. Each panel is made up of a layer of explosive material sandwiched between two metal plates. These panels, which are attached at an oblique angle to the vulnerable areas of a tank's superstructure will on attack from a shaped charge warheard, explode, dispersing the high-explosive anti-tank warhead plasma jet generated on impact. A number of countries market ERA armour under various proprietary names. Claims for their effectiveness vary but a useful rule of thumb is that they can provide protection equivalent to ten times the weight of homogeneous rolled steel armour and that penetration of the charge jet can be reduced by more than 75%. Though designed primarily to protect against chemical energy warheads they provide some small additional protection against kinetic energy attack.

ERA can be easily and quickly applied to a wide range of vehicles. Even though each panel has only a 'one-shot' capability, their modular design and light weight enable them to be exchanged in the field. A simple fixing system also enables ERA to be retro-fitted to existing vehicles, giving an extremely cost-effective improvement in armoured protection. The need for high standards of safety has been taken into account in the design of the explosive material used between the plates. ERA represents a major departure for many armies in that explosive will be carried on the external surfaces of a tank and there are may be environmental objections in some countries to mounting ERA on tanks in peace. Special insensitive explosive has been developed to ensure that the panels can be handled, cut, drilled and welded without risk and that small arms fire and rough usage will not detonate them. When attacked by a hollow charge warhead the panels are so designed that there is no risk of sympathetic detonation of the other panels in close proximity.

Sergyi Way
16.11.2006

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