Since the first armored vehicles have been created, there has been a constant race between armor and anti-armor manufacturers to gain an edge over the other. Today we will have a look at some of the innovative solutions that they did come up with to increase the protection.
The definition for spaced armor is rather straightforward – it means two or more layers of armor that are spaced some distance apart. Its effectiveness comes from the fact that bullets and shells tend to deflect, deform or disintegrate as they pass through each layer, while explosive projectiles are set off prematurely, before reaching the main armor of the vehicle.
It is especially effective against single charge HEAT projectiles, which lose their penetrating power drastically over a short distance. Even a retrofitted light armor layer will cause shaped charges to detonate before the optimal distance from the main armor, thus rendering them relatively ineffective. (Modern HEAT projectiles overcome this problem by applying tandem / multiple charges that help to get through the spaced and/or reactive armor, and allow the main charge to be focused on the inner armor.)
It’s perhaps less known that spaced armor was used as early as World War One already, on the early tanks like the Schneider CA1 or the Saint Chamond. It really got popular by the Second World War however, as especially a lot of the German tanks (specifically Panzer III and IV versions) used often armored skirts (called Schürzen) to protect their weaker side armor. Contrary to popular belief these were applied to fight against the high powered anti-tank rifles used by the Soviet Army and not against shaped charges, though they deemed to be relatively effective against those as well.
We also have to mention improvised armor that came from the troops themselves desperately trying to increase their chances of survival. Sand bags and spare tank tracks were often fitted onto the tanks that acted also as a sort of additional spaced armor.
The next step in spaced armor technology was the integral spaced armor, introduced by the Leopard 1 series by the 1960s. Here the armor of the tank was created from the start with hollow spaces between the armor layers, greatly increasing its protection against shaped charges while keeping the same weight and thickness of the actual armor. (As an easy example, two 150mm layers spaced apart offer better protection than one solid 300mm thick block of armor.)
And finally for even better protection, they also started to use different types of layers. A great example is the Leopard 2 that uses 3 different layers. The first one is a sloped layer for deflection, followed by a hardened second stage for shattering and a third softer layer for containment.
Also known as bar armor, cage armor or standoff armor, this is basically a metal grid or mesh fitted onto key sections of the vehicle, that was developed for protection against RPG (rocket propelled grenade) attacks. It works two ways – firstly it can cause premature detonation just like regular spaced armor, but due to its design it can also damage the fusing mechanism, preventing detonation completely. It does not offer complete protection however, 30 to 50% of the missile impacts are unaffected by the slat design.
The first tanks to utilize this were once again the German Panzer III and IV-s, some of which used a wire mesh skirt instead of the usual steel plate skirt, and found it rather effective. With the Soviet developed RPG-s becoming widely used all over the word, it gained popularity later on, and was used in increasing numbers from the Vietnam Wars to today’s engagements – also being used by machines like the Russian T-62s or the American M1 Abrams tanks. Of course in the modern era the former steel or aluminum cage was replaced by composite variants, offering superior protection at reduced weight.
HE Shell Types – High Explosive Destruction