Fighting Fire With Fire…Kind Of

You may have seen photos or videos of Russian tanks in the news over the past several months and wondered why some of them were covered with weird boxes that kind of look like oversized bars of soap. This is explosive reactive armor (ERA), which protects the vehicle and its occupants. At least, that’s the theory.

You’ve likely seen these awkwardly placed blocks on the outside of some Russian tanks. This is Kontakt 1 armor, a first-generation Russian explosive reactive armor. Screenshot from YouTube and RedEffect

In the photo above, the blocks we see on the tank’s surface are Kontakt 1 ERA. Each block has two 4S20 plastic explosive charges wedged between two steel plates. The ERA is only effective against hollow charged munitions, also known as shaped charges or high explosive anti-tank (HEAT) rounds.

A cross-section of a Kontakt 1 block is about to be impacted by a HEAT round. Screenshot from YouTube and RedEffect.

The yellow plates in the image above are plastic explosives. We see the HEAT roundabout to impact the block at an angle.

A fraction of a second after impact. Screenshot from YouTube and Red Effect.

The yellow line above is the jet of focused energy from the shaped charge. It is about to detonate the plastic explosive.

Fragmented. Screenshot from YouTube and Red Effect.

The first 4S20 panel explodes, making the jet weaker. Next, we can see a steel plate (blue) and another 4S20 panel directly below that. When the jet hits the plate, it detonates the second plastic explosive panel forcing the blast away from the vehicle, as shown below.

The explosion of the second 4S20 panel forces the jet away from the vehicle and those inside. Screenshot from YouTube and Red Effect

Still with me? Good. This is basically how Kontakt 1 ERA protects the vehicle. If a second round were to impact the same area, there would be no such protection. It should be noted that the ERA will not detonate if the vehicle catches fire.

An example of a Russian tank utilizing Kontakt 5 ERA. Screenshot from YouTube and Red Effect

The larger, flatter blocks we see on the image of the tank in the picture above are Kontakt 5 ERA. On the turret, they are wedge-shaped. The blocks that makeup Kontakt 5 have more explosive TNT equivalency power as well…0.28 kg in Kontakt 1 versus 0.33 kg in the next generation. Kontakt 5 uses more substantial steel plating as well.

A cross-section of the Kontakt 5 ERA. Screenshot from YouTube and Red Effect

In the drawing above, the yellow squares are the 4S22 plastic explosive. The red block is the steel plate. As you can see, both are more substantial than in the first-generation ERA.