In order for dynamic protection to save the tank, you need to set it correctly
Today we will talk about the hinged "Contact". However, this material will not be a lengthy roll of text about why dynamic protection is needed, how it affects certain types of ammunition and other nuances that are important in theory, but not in practice. Everything is much more prosaic here. It’s just that the media and other sources of information have made such a contribution to the elimination of illiteracy of the broad masses that the opinion has become too strong that the very presence of reactive armor is already a panacea for all ills, well, or for most of them. Anyhow I stuck it on the car, and then at least the grass does not grow. Like, it will still work and protect. Work something - it will work, but it will not fully protect.
Yes, and among the military sometimes there is a misunderstanding, because it often happens that they do not pay attention to the marking of containers of dynamic protection, or it does not exist at all. Meanwhile, it is the correct installation of these "bricks" that affects their protective properties.
Tilt angles
Surely many of those who were interested in dynamic protection (DZ), in particular "Contact", at a level slightly higher than "some kind of exploding bricks on the armor", know that in the block (container) of this reactive armor on the struts there is a wedge-shaped two items installed. They consist of projectile steel plates and an explosive that detonates when a cumulative jet penetrates. At the same time, both the energy of the explosion and the plates flying and crossing its trajectory have an impact on this very cumulative jet.
As a result, those parts of the jet that interact with dynamic protection are subjected to powerful deformation and rupture, losing their integrity and penetrating ability. On this, in fact, the principle of explosive reactive armor is based.
Marking on blocks of dynamic protection "Contact"
By the way, in order not to languish for a long time, you need to put the Contact containers as it is signed on the photo attached below. Parallel to axis tank. Often they are marked with a letter and an arrow indicating the direction of installation.
"Polarity" of the dynamic protection unit
Why - let's talk further. Including why there are two explosive elements in the block.
It seems that the answer to this question about the number of elements of dynamic protection in the block is extremely simple and can only be that two elements are better than one. Two layers of explosives, more throwable plates - stronger and the impact on the attacking cumulative jet. So right? That's right, there can be no disputes in this regard, but such a design has other functionality. And the angles of inclination under which you need to put the DZ are to blame for everything.
The bottom line is that any serial domestic complex of dynamic protection, be it the "Contact" that we are talking about, or the universal "Contact-5", and even more so the modern "Relic" - gizmos that are very reluctant to work at right angles to offensive ammunition. A very hypothetical example can be given.
If you fix the block of the same “Contact” on a strictly vertical surface and shoot it at a right angle from some kind of grenade launcher with a monoblock grenade penetrating 500 mm, then the DZ will be able to reduce its penetrating ability by a maximum of half or so, and then with a successful combination circumstances. This is due to the small contact area of the missile plates acting on the cumulative jet under such conditions.
"Sixty-four" with a good location of dynamic protection "Contact"
But the dynamic protection installed at an angle of 60–70 degrees for the same projectile can already “shave off” about 90% of penetration due to the larger area of \u72b\u1bcontact between the plates and the cumulative jet, which essentially make a side impact on it. That is why on the frontal parts of the Kontakt tanks they are placed at a large angle from the vertical: on the forehead of the hull this is obvious, since it itself has the desired slope, but on the forehead of the tower it is wedge-shaped with the help of metal structures. A kind of anti-example here can only be the T-1985B / BXNUMX model of XNUMX, in which the tower is plastered with DZ anyhow.
T-72B1 with an unfortunate location of dynamic protection on the frontal part of the tower
Edge effect and gaps
Why this passage with angles of inclination and how is it connected with two elements of dynamic protection in blocks?
Firstly, there are gaps within 40 millimeters between the blocks located at an angle anyway. If they had only one horizontally mounted element with missile plates, these gaps could serve as an excellent lure for a cumulative jet if the projectile hit the edge of the cover located below the block. Therefore, the second - standing at an angle - element overlaps the weakened zones, excluding such a possibility as much as possible. That is why "Contact" cannot be placed "upside down" or in any other way - the efficiency will immediately drop significantly.
The trajectories of cumulative jets, which, with the correct installation of the blocks of dynamic protection "Contact", at an angle and one after another, cross at least two elements of dynamic protection. The probability of getting into the gaps is minimal
Secondly, the Contact block itself, standing alone on the armor, albeit at the desired effective angle (60 degrees, for example), is far from uniform in terms of protective ability over its entire area. This is called the edge effect in the scientific literature on armored vehicles. Back in the 80s, D. A. Rototaev described such a contraption with colleagues - the man thanks to whom dynamic protection appeared on our tanks in general.
Conventionally, the upper and lower parts of the block of dynamic protection "Contact"
The essence of this effect is that when a cumulative projectile hits not in the center of the block, but closer to the edges, the effectiveness of reactive armor decreases sharply. Hitting the lower parts of the block leads to the fact that a very small area of the thrown plates and their fragments interacts with the cumulative jet. In the event of a projectile hitting the upper part of the block, only one explosive element of dynamic protection is in contact with the jet, while the second, lower, is actually inactive.
The test results are shown below. They used a dynamic protection unit at an angle of 60 degrees from the vertical and a combat cumulative part of an anti-tank grenade of 93 mm caliber.
Points of fire of the block of dynamic protection. Residual penetration of the cumulative jet when it hits the upper part of the block: C - 274 mm, F - 376 mm. Residual penetration when hit in the middle part of the block: B - 37 mm, E - 86 mm. Residual penetration when hitting the bottom of the block: A - 241 mm, D - 292 mm
Here, in general, the “Contact” design again proves its usefulness precisely with the correct installation - as in the case of gaps, the lower parts of the “superior” neighbors overlap, due to which the edge effect is partially leveled. In such conditions, the cumulative jet in any case passes through at least two elements of dynamic protection, or even three, with a corresponding decrease in penetration.
All of the above about the gaps and the edge effect applies to the sides of the combat vehicle: you need to put "Contact" on the side screens according to the same rules. It is then that reactive armor will most fully work against attacking ammunition in the heading angles of the tank's maneuvering. Correctly set - increased the chances of survival in combat conditions, both for the crew and for the equipment itself.
In fact, these are common truths that, in theory, any employee of the repair units, as well as the tank crew, should know. But in the current conditions, when there are simply no clear rules for handling dynamic protection (sometimes there is information that in disputes about the correct installation of remote sensing sometimes it comes to a massacre), knowledge seems to be not entirely useless. Moreover, handicraft flourishes with might and main, when reactive armor is molded anyhow, and even sometimes it or its components are made to order by volunteers ... Whether there is marking or not ... In short, what is written can come in handy.
Information sources:
"Influence of the edge effect on the dynamic protection of the tank". A. I. Anisko, S. V. Bodrov and others.
Tank Defense. V. A. Grigoryan, E. G. Yudin and others.
"Means of destruction and ammunition". A. V. Babkin, V. A. Veldanov and others.
Information