If the EDZ for "Contact-1" was not delivered: plexiglass instead of explosives
Explosives are the main component of domestic dynamic protection, thanks to which it works at all and resists attacking ammunition. But what happens if the explosives are replaced with simple plexiglass?
A little about the essence of the issue
This article will discuss the Kontakt-1 add-on anti-cumulative dynamic protection (DZ) system, which was adopted for service back in the 80s and has since become an essential attribute of many Soviet. It was actively used in many local and not very local conflicts of the late XNUMXth and early XNUMXst centuries, and is now being used in the area of the special military operation in Ukraine as a standard and home-made means of protection against drones, monoblock grenades, controlled missiles and cumulative projectiles.
In itself, "Contact-1" is as simple as a club. This applies to the method of its installation on танк, as well as the design of its units: a stamped container made of a bottom and a box-shaped lid, inside which two dynamic protection elements (DPE) are installed in a wedge shape, each of which consists of two thin plates and a layer of explosive between them. They act as the main destructive means, setting in motion due to the detonation of explosives and intersecting the cumulative jet at the moment of its passage through the DPE unit.
However, it is worth remembering that Kontakt-1, like any other dynamic protection, is first and foremost a consumable item - during active combat operations, several sets may be used up per week for one tank alone. Therefore, supplies, as always, play a primary role. But for one reason or another, their quality sometimes leaves much to be desired, which is why situations sometimes arise when there are containers for Kontakt-1, but there is simply nothing to equip them with - there are no ERA. This happened, for example, in the First Chechen Campaign - at that time, ERA was simply not issued at first.
In such cases, tank crews had to fill the containers with all sorts of junk, including rubber sheets, or go into battle with an empty Kontakt. And here, in general, nothing can be done, since the ERA is what the dynamic protection will not work without. Nevertheless, there is a meager and very difficult to implement home-made alternative. It consists of installing homemade non-explosive ERA, operating on the NERA principle, in the standard places of the Kontakt-1 containers.
NERA in "Contact-1"
Probably many people who have even a little interest in modern armored vehicles know what non-explosive reactive armor or NERA is. However, for those unfamiliar with the topic, we will explain: this is protection that works on a principle very similar to classic DZ. The difference is that instead of an explosive substance located between the thrown plates, an inert material is used - the same rubber, for example.
The principle of its operation is as follows:
At the moment of penetration of the cumulative jet, a powerful diverging shock wave is formed in the inert layer between the steel plates. During its propagation through the material, it quickly fades, but manages to cause local displacement (swelling) of the plates in the area of the hole. The image below clearly shows what is happening.
NERA action on a cumulative jet. 1 – cumulative charge, 2 – block of metal sheets and inert filler, 3 – damaged cumulative jet, 4 – metal plates, 5 – inert filler
This phenomenon in itself does not bring any benefit, since the cumulative jet interacts with the obstacle according to the laws of hydrodynamics, due to which the width of the formed hole is always greater than the diameter of the jet. Another matter if the "sandwich" of plates and interlayer is located at some angle to the attacking means. In this case, the resulting movement moves the unpierced sections of the plates to the trajectory of the cumulative jet, tearing it apart, which results in a significant decrease in its penetrating ability.
One of the most advantageous design options in terms of efficiency is a "sandwich" of 2 mm steel + 6 mm simple plexiglass + 2 mm steel. In the framework of the openly available study "Comparative study of the protective ability of dynamic protection elements" by I. F. Kobylkin and A. A. Gorbatenko, it showed the best results, reducing the armor penetration of the PG-7L anti-tank grenade (it penetrates 500 mm of steel armor by nominal value) by 87%.
Of course, not everyone has steel sheets of the required thickness at hand, much less plexiglass. However, if they are available and there is a possibility to cut out plates from them that correspond in size to the standard EDZ and place them in the containers of the "Kontakt-1", the results can be pleasing. Tests show that against grenades of the PG-9S and PG-9L type, the effectiveness of "Kontakt" with such homemade EDZ is only 29-30% lower than with standard EDZ with explosives.
X-ray of the state of the jet after overcoming the obstacle "steel + plexiglass + steel"
Of course, there are a number of disadvantages here, in addition to the complexity of production. The first is that the Kontakt-1 with homemade ERA will definitely not work against cannon cumulative projectiles - it works poorly against them even with standard ERA - and worse (relative to effectiveness against grenades) against guided single-block missiles.
The second drawback is an even greater dependence on the angle of impact with the ammunition than the regular Kontakt-1. If the "explosive" version of the DZ can at least slightly reduce penetration when hit by a grenade, including a drone, or a missile at a right angle (or close to it), then with homemade EZ - no. Nevertheless, such an alternative is in any case better than empty containers or "filler" in them in the form of rubber, sand, etc.
Information sources:
"Special issues of terminal ballistics" V.A. Grigoryan, A.N. Beloborodko, N.S. Dorokhov and others.
"Comparative study of the protective capacity of dynamic protection elements" I.F. Kobylkin, A.A. Gorbatenko.
Information