What are HEAT Shells or How to Melt Armor?
With the advent of armored vehicles, a certain race arose between the shells and the thickness of the armor. The more protected the tanks became, the more powerful the shells were made to hit them, and vice versa. However, during the Second World War, this axiom ceased to exist, as they appeared that could pierce any armor, almost regardless of its thickness.
The high efficiency was due to the fact that the products of their explosion did not dissipate like conventional projectiles, but were concentrated and directed by a jet to one point. Such shells are called cumulative. Since they have a small radius of destruction, they are ineffective against infantry, but they can be used not only against armored vehicles but also against concrete fortifications. Next, we will analyze in more detail how this weapon works, how it works, and what types of protection against it exist
Cumulative projectile – the principle of operation
Unlike the classic projectile, the cumulative projectile contains a hollow cone instead of a blank. In the warhead of the charge, there is another funnel-shaped cavity with a wall thickness of 1-2 mm, which is called a cumulative recess. This recess is located with a wide edge towards the target, and an explosive is located around it.
At the moment of detonation of the explosive, under the influence of the blast wave, the walls of the funnel “collapse”, while the metal turns into a liquid, which bursts out towards the target with a powerful jet at a speed of several tens of kilometers per second. The pressure and temperature of the jet are so high that even the strongest armor cannot withstand it and melts.
For the greatest effectiveness of such projectiles, they use explosives with a high detonation velocity. These include RDX, various mixtures, and alloys with TNT. The effectiveness of projectiles, or armor penetration, depends on several factors, such as the material from which the walls of the cumulative recess are made, the size of the recess, the design of the detonator, and the size and mass of the charge itself.
What happens to the tank after being hit by a cumulative projectile? Inside, the pressure rises sharply, as a result of which the ammunition detonates. In this case, the crew receives injuries incompatible with life. For example, during the Second World War, there were cases when a cumulative jet literally cut tankers in half.
Dynamic protection of tanks from HEAT projectiles
A new type of shell required new protection systems from armored vehicles. Therefore, to increase the survivability of armored vehicles, external or active sources of protection were invented, which include dynamic protection (DZ). Surely you have noticed that modern tanks are hung with metal “bricks”. At the moment the projectile hits, they extinguish the energy of the cumulative jet.
Back in the years of the Second World War, it was noticed that when the products of the explosion are exposed to the cumulative jet, it loses the ability to “burn through” the armor. There were cases when tanks carrying explosives or ammunition on their armor generally remained intact after a direct hit.
In the USSR, many studies and tests were carried out in this area. As a result, it was proposed to use DZ as protection for tanks from a cumulative projectile. However, during development, engineers had to face a number of difficulties. The fact is that for reliable protection of armor from a shaped charge, a large amount of explosive is required, which in itself can pose a danger to the protected object. As a result, the first prototypes of dynamic protection appeared only in the 60s.
In order to reduce the volume of explosives in dynamic protection, it was decided to use it as an auxiliary element that shoots metal plates. That is, when the cumulative jet passes through the DZ, as a result of the detonation of the explosive, plates of solid, durable steel fly out towards the charge. They, together with the explosive, extinguish the energy of the projectile. Modern DZs are capable of reducing the armor penetration of HEAT projectiles by 50-80%. Accordingly, the hit of a cumulative projectile often does not become fatal for tanks.
Combining armor is a passive way to protect armored vehicles from HEAT rounds. The principle is quite simple, based on the use of several layers of armor in armored vehicles, with the laying of heat-resistant materials between them. In this case, the cumulative projectile destroys only the outer layers of the armor.
I must say that the development of combined armor began in the USSR and the USA back in the 1950s. However, for the first time, it was used in a series on the Soviet T-64 tanks, the production of which began in 1964. Other countries began to apply this technology on serial tanks only from the end of the 70s and the beginning of the 80s.
Tandem HEAT projectiles
We found out how dynamic protection works – it provides an obstacle in the way of a cumulative jet. However, weapon developers have created new types of cumulative projectiles that are able to overcome the DZ or the first layer of armor in the case of a combined booking.
Modern 125mm projectiles can have primary and secondary shaped charges. Such shells are called “tandem”. The primary charge is contained in the warhead and provides a premature response to dynamic protection. The secondary charge, which strikes the armor, is in a cylindrical body.
For example, the warhead of the Javelin missile of the American anti-missile system (ATGM) has a tandem cumulative design with an electronic delay in the detonation of the main charge. To protect the main charge from detonation as a result of the shock wave after the detonation of the primary charge, it is equipped with an explosion-absorbing screen made of composite materials.
must say that the instructions for the Javelin ATGM indicate that the ammunition overcomes all existing types of dynamic protection. However, the developers of the domestic DZ “Relic” argue that the use of special plates ensures the destruction of the funnel of the main shaped charge. That is, they are effective against any cumulative projectiles.
Tests in this regard were not carried out, however, there are videos of real hostilities, which filmed a direct hit of a Javelin missile on a tank equipped with a Relikt remote sensing system. The tank eventually remained intact and even continued to move.
Types of cumulative weapons
Artillery and tank shells, as well as aircraft missiles, naval anti-ship missiles, and even aircraft bombs are cumulative. Recently, tandem cumulative ammunition for anti-tank systems and hand grenade launchers, which are armed with infantry units, have become widespread. Thanks to such weapons, soldiers began to pose the main threat to armored vehicles.
One grenade launcher can destroy or disable a tank worth several million dollars. Moreover, in urban conditions, armored vehicles are especially vulnerable, since soldiers fire shots from the roofs of houses or high floors at those sections of tanks and infantry fighting vehicles that have the thinnest armor. Therefore, some military experts believe that the role of tanks in military conflicts will gradually decline. Drones are considered more promising weapons.
The most formidable Russian ATGM is currently the Kornet missile system, which can penetrate 1,300-1,400 mm armor or 3,000 mm thick concrete. In other words, it is capable of hitting any modern tank, but we will talk about it another time. Thus, cumulative munitions, which were created during the Second World War, remain relevant in the 21st century.
Finally, we suggest that you familiarize yourself with more modern weapons that can hit not only armored vehicles but also enemy shelters. We are talking about vacuum bombs and shells.
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