Cumulative jet: brief description, characteristics, features, interesting facts

Where is it used?

Actually, the cumulative effect itself was probably observed by all people without exception. It occurs, for example, when a drop falls into water. In this case, a funnel and a thin stream directed upward are formed on the surface of the latter.

The cumulative effect can be used, for example, for research purposes. By creating it artificially, scientists are looking for ways to achieve high speeds of substances - up to 90 km/s. This effect is also used in industry - mainly in mining. But it, of course, found its greatest application in military affairs. Ammunition operating on this principle has been used by various countries since the beginning of the last century.

Projectile design

How is this type of ammunition manufactured and used? A cumulative charge occurs in such projectiles due to their special structure. At the front of this type of ammunition there is a cone-shaped funnel, the walls of which are covered with a metal lining, the thickness of which can be less than 1 mm or several millimeters. On the side opposite to this recess there is a detonator.

After the latter is triggered, thanks to the presence of a funnel, a destructive cumulative effect occurs. The detonation wave begins to move along the charge axis into the funnel. As a result, the walls of the latter collapse. With a strong impact, the pressure in the funnel lining increases sharply, up to 1010 Pa. Such values ​​far exceed the yield strength of metals. Therefore, in this case it behaves like a liquid. As a result, the formation of a cumulative jet begins, which remains very hard and has great lethality.

The process of formation of a cumulative jet and its stability

When flowing through the surface of the cumulative recess, the detonation products will deviate from the initial trajectory so that the maximum action will have a direction almost perpendicular to this surface. There is a kind of refraction of the direction of movement of the explosion products and the shock wave front emerging in front of them. As a result of such movement of elementary jets, a flow of detonation products will be formed, converging along the axis of the cumulative recess and having an increased density and speed compared to detonation products scattering in other directions. The process of forming a cumulative jet is shown schematically in Figure 2.5.

Individual elementary jets will move perpendicular to the surface of the recess only in the immediate vicinity of the surface of the recess. In the future, the elementary jets will collide and form a single jet. In this jet, the detonation products, as they move away from the surface of the recess, will become more and more compacted until their density reaches a maximum value. The distance between the base of the charge and the cross section of the jet, in which the maximum density of detonation products is achieved, is called the cumulative focus.

The focal length for a given recess profile varies depending on the detonation speed of the explosive charge. The lower the detonation speed, the longer the focal length. This is one of the reasons for the significant drop in the cumulative effect when detonating explosive charges from low-blast explosives.

In the theory of cumulation, the concept of “active part of a shaped charge” is introduced; in fact, this is that part of the explosive charge that directly goes to the formation of a cumulative jet.

Action of a cylindrical charge with a cumulative recess lined with metal.

Many researchers see the difference between a gas jet and a metal jet primarily in the significantly greater compaction of the jet when using metal linings. The inertial factor is also significant, which determines the greater penetration of the target by a metal jet, despite the fact that the total initial energy of a jet of a shaped charge with a lined recess is no more, and even less than the energy of a gas jet of a charge without lining, due to the fact that part of the explosion energy is expended for compression of the cladding.

In this regard, the physical basis for the formation and subsequent movement of the jet after detonation of an explosive charge with a lined recess is as follows.

At the first stage according to F.A. Baum, K.P. Stanyukovich and B.I. Schechter and a number of other authors are rapidly compressing the cladding. Depending on the characteristics of the explosive, the compression speed of a steel cone with a wall thickness of 1-2 mm varies in the range of 1000 – 2500 m/s. Such a high compression speed turns the metal cladding into a compact formation - a pestle (Fig. No. 2.6, giving rise to the origin and subsequent development of the jet.

Here it must be said that after completion of the compression of the pestle, the metal inside it does not transform into a melt, but at the same time, the state of the metal in a certain internal region of the pestle undergoes a phase transition. Almost all researchers did not pay attention to the most important fact that the jet is formed precisely from a material that is no longer a solid body, but has not turned into a melt. It is this state of the material that determines many of the special properties of the cumulative jet. First of all, in a cumulative jet, as in a quantum mechanical system, due to the presence of metal particles in an excited state, energy from the entire jet is transferred to its head part, with a complete absence of energy dissipation in the radial direction. This predetermines high penetration ability with a relatively low jet mass. According to F.A. Baum, K.P. Stanyukovich and B.I. Shekhter, the jet is formed exclusively due to the flow of metal (but not melt) adjacent to the inner surface of the lining; the mass of metal passing into the cumulative jet does not exceed 11% of the mass of the lining.

For the normal process of compression of the cladding, according to the same researchers, high plasticity of its material is necessary. In the process of deformation of the lining, brittle destruction should not occur, since otherwise the coefficient of transition of the metal into the stream will significantly decrease and, accordingly, the penetrating ability of the shaped charge will decrease. When assessing the plasticity of a cladding material, it must be borne in mind that the physical and mechanical properties of materials under high-speed deformations can be fundamentally different from their properties at the usual deformation rates accepted in the practice of testing materials.

The pestle and the jet at the initial stages form a single whole, although they move at different speeds. The pestle speed is 500 – 1000m/s. The speed of the jet varies along its length. The head part can reach a speed of 10 km/s, while the speed of the tail part is close to the speed of the pestle. Table No. 2.4 shows the dependences of the speed of the head part of the cumulative jet on some factors.

Table No. 2.4

Dependence of the velocity of the head of the cumulative jet with steel cladding 1 mm thick on some factors.

Stability of cumulative jet.

Based on extensive experimental and theoretical studies, it has been established that partial or complete distortion of the cumulative jet occurs for the following reasons:

1. Getting into the cumulative recess of liquid;
2. The location of the obstacle is closer than the focal length;
3. Asymmetry of the detonation wave front approaching the surface of the lining of the cumulative recess;
4. Insufficient quality of the cumulative cladding used;
5. Partial decomposition of the charge under the influence of high temperature until it is triggered in the well.

Filling the cumulative recess with liquid makes the cumulative effect itself impossible. If the obstacle is close to the base of the charge, the jet will not be able to finally form.

The asymmetry of the detonation wave front will lead to a displacement of the jet axis relative to the geometric axis of the charge.

The cumulative lining should not have even the slightest difference in thickness and have special properties that ensure maximum transfer of the material into the stream.

The decomposition of a shaped charge under the influence of high temperatures reduces not only the energy reserve involved in the formation of the jet, but also High velocity gradients in the shaped jet cause the jet to stretch until it breaks into separate fragments. In Fig. No. 2.7 shows a diagram of the situation after stretching a cumulative jet in free flight to the maximum value of Lc. With further stretching, the jet will fragment.

The deformation of a cumulative jet with possible asymmetries of the explosive pulse and the lining was studied in detail by Crane. He showed that even with a slight asymmetry of the cumulative lining or explosive pulse, the center of jet formation shifts relative to the axis of the explosive charge. In this regard, as well as due to changes in time of the initial velocities and directions of the jet elements, its curvature occurs.

3

Theory

The appearance of a metal jet during the cumulative effect is caused not by the melting of the latter, but by its sharp plastic deformation. Like the liquid, the metal of the ammunition lining forms two zones when the funnel collapses:

• the actual thin metal jet moving at supersonic speed forward along the charge axis;
• pestle-tail, which is the “tail” of the jet, which accounts for up to 90% of the metal lining of the funnel.

The speed of the cumulative jet after the explosion of the detonator depends on two main factors:

• explosive detonation speed;
• funnel geometry.

What kind of ammunition can there be?

The smaller the projectile cone angle, the faster the jet moves. But when manufacturing ammunition in this case, special requirements are imposed on the lining of the funnel. If it is of poor quality, the jet moving at high speed may subsequently collapse prematurely.

Modern ammunition of this type can be manufactured with funnels whose angle is 30-60 degrees. The speed of the cumulative jets of such projectiles, arising after the collapse of the cone, reaches 10 km/s. Due to its greater mass, the tail section has a lower speed - about 2 km/s.

A little history

Thus, a cumulative jet is a long thin formation with a “tail”, liquid and at the same time dense and hard, moving forward with enormous speed. This effect was discovered quite a long time ago - back in the 18th century. The first to suggest that the energy of an explosion could be concentrated in the right way was the engineer Fratz von Baader. This scientist also conducted several experiments related to the cumulative effect. However, he failed to achieve any significant results at that time. The fact is that Franz von Baader used black powder in his research, which was unable to form detonation waves of the required strength.

For the first time, ammunition operating on the cumulative principle was created after the invention of high explosives. In those days, several people discovered the cumulative effect simultaneously and independently of each other:

• Russian military engineer M. Boriskov - in 1864;
• captain D. Andrievsky - in 1865;
• European Max von Forster - in 1883;
• American chemist C. Munro - in 1888

In the Soviet Union in the 20s, professor M. Sukharevsky studied the cumulative effect. In practice, the military encountered it for the first time during the Second World War. This happened at the very beginning of hostilities - in the summer of 1941. German cumulative shells left small melted holes in the armor of Soviet tanks. Therefore, they were originally called armor-burning.

Such BP-0350A shells were adopted by the Soviet army already in 1942. They were developed by domestic engineers and scientists based on captured German ammunition.

(meaning “concentration”) is the phenomenon of concentration of a blast wave during the detonation of a charge with a conical recess. The phenomenon is based on plastic deformation of the lining material of the cumulative recess under the influence of high pressure. High pressure occurs when the cumulative recess collapses on all sides with a blast wave, which is achieved due to the difference in the speed of propagation of longitudinal waves in a denser material (explosive relative to air).

For the first time, the cumulative effect was discovered and used in mining by military engineer M.M. Boreskov in 1864. An increase in the penetration ability of a bundle of pyroxylin blocks was noted when the central (containing the detonator) block was removed by half its length. A recess of decent depth formed under it. To enhance this effect, tin casings with a recess began to be molded, filled with explosives.

Independently, in 1883, Max Von Foerster noted the anomalous behavior of shaped charges of pressed pyroxylin. This happened when testing pressed pyroxylin blocks weighing 100 grams. on brisance and susceptibility to detonation at different humidity levels. The charge was placed on a steel plate and detonated by a detonator inserted on top. During one of the explosions, the tester noticed strange letters and symbols on the stove, in which he could read the date of manufacture of the checker. The date and place of manufacture were stamped on pyroxylin blocks of that time (since pyroxylin has a very limited shelf life). The researcher was interested in the mechanism of the appearance of the imprint. And soon, he found out that the depression on the surface of the charge adjacent to the surface causes the formation of a concentrated shock wave in this place. Which can even cause deformation of the flow of the target metal, even to the point of piercing it.

The first systematic studies of the effect of gas cumulation of explosion products were carried out in the Soviet Union by M.Ya. Sukharevsky in 1923-1926.

The first patent for the use of the cumulative effect in military affairs was received in 1932 in the USA. It was a ramrod grenade for shooting from an infantry repeating rifle. The first serial military product with a cumulative notch was a hemispherical charge for engineering troops, which was produced in Germany from 1938 to 1945. The charges were produced in two types: 8 and 12 kg. and were used to destroy fortifications. Soon, the cumulative effect began to be widely used to combat armored vehicles.

To understand the mechanism of formation of a cumulative jet, take a look at Figure 1. Figure 1 shows a simplified diagram of the processes in a cylindrical explosive block (shown in green) with end excitation of detonation (detonator shown in red). At the opposite end of the checker there is a conical recess lined with metal (metal is shown in blue). After the detonator is triggered, a detonation process occurs, accompanied by the expansion of explosion products (shown in yellow).

Picture 1.

Position 1 shows the beginning of detonation propagation around the detonator. Position 2 shows the exit of the detonation front into the section of the checker and its propagation throughout the material. In position 3, the blast wave approached the top of the metal lining cone, while the front of the explosive transformation was almost parallel to the section of the block. In position 4, the blast wave in the explosive material is overtaken relative to the one that propagates in the space of the conical funnel. In this case, the funnel is crushed from the entire surface with the formation of a high-pressure area. In position 5, further propagation of the blast wave occurs in the explosive block and the formation of a compressed area in place of the central axis of the funnel. At the same time, a stream of metal begins to be squeezed out from the high pressure area. Position 6 shows the full detonation of the explosive block, with part of the high-pressure area splashing out in the form of a needle in the direction of the target (the direction opposite to the direction of the detonator).

The black arrows show the impact of the high pressure front at the explosive transformation boundary, including on the metal lining material.

The temperature of the metal of the jet remains relatively low, about 600-1000oC. This is even lower than the temperature of explosive transformation in the explosive layers adjacent to the metal of the funnel (2000-5000oC). The cladding metal heats up only due to flow deformation and compression. The process of metal flow itself occurs under the influence of the pressure of the explosion products upon the collision of opposite edges of the lining.

Thus, the cumulative effect is the phenomenon of concentrating the action of a blast wave at a very specific point. The jet of ejected metal does not have the same speed; Figure 2 shows the speed gradient of the jet and pestle as they move. The speed of the jet tip reaches 10-12 km/sec. While the speed of movement of the base of the jet is close to 1-2 km/sec. The pestle (high pressure area, shown as an oval) moves after the jet at an almost constant speed, about 0.5-1 km/sec. The impact of the pestle on the metal causes the formation of a shallow crater or even traces of erosion around the hole from the cumulative jet.

Figure 2.

10-20% of the lining metal is consumed to form the jet, the rest is formed by pestle. Depending on the plasticity of the lining material and the characteristics of the explosive, at some distance from the point of detonation of the charge, the jet breaks into separate “drops”. Which is accompanied by a sharp decrease in penetration ability.

The use of highly elastic and at the same time hard lining materials makes it possible to increase the penetrating effect of the jet, which is maintained at a considerable distance from the point of detonation (up to 12-17 charge diameters). The greatest penetration effect is achieved by cladding made of tungsten powder (70-75%), copper (about 20%) and babbitt (about 5-8%). This composition, when used as explosive compositions such as “Okfol”, “Gekfol”, A-IX-2 or other high-energy compositions with a high detonation speed, makes it possible to achieve penetration of steel with a thickness of up to 12 charge calibers. This means that a grenade launcher with a caliber of 105 mm, with an explosive charge diameter of 90 mm, can penetrate a steel plate up to a meter thick. This is polygon data for a meeting angle of 90° and a monolithic slab made of St3 steel.

To ensure the impact of the jet on the target at the moment of its maximum speed, ballistic fairings, stands, polymer substrates, retractable stands and other devices are used to ensure the detonation of the charge at the optimal distance from the target.

In addition, to reduce the mass of the charge, a so-called “lens” is used, that is, a polymer insert along the detonation path between the detonator and the top of the cumulative funnel. This makes it possible to somewhat delay the movement of the blast wave along the axis of the checker, which reduces the required charge length and increases the efficiency of using the power of the available explosive mass. Typically, the lens is shaped like a flat disk.

Figure 3 shows a classic example of the cumulative warhead of the RPG-7 anti-tank rocket launcher. One of the best grenade launchers in the world for its time.

Figure 3.

In Figure 3, number 1 shows the piezoelectric element (giving an electrical impulse when it meets a target), number 2 – the lining of the cumulative recess, 3 – the fastening insert for centering the lens and the lining of the cumulative funnel, 4 – the lens, 5 – the bottom fuse. BB is shown in yellow. The main advantage of cumulative ammunition is its high penetration ability, which does not depend on the speed of the projectile.

Figure 4.

Figure 4 shows a cross-section of an elongated shaped charge for cutting metal. The charge is released in coils of at least 10 meters each. The polymer insulating shell (1) prevents the negative effects of water and other external factors on the charge. The load-bearing basis of the charge is the rubber shell (2). An explosive charge (3) is placed inside, usually: plastit, simtex or similar compositions PE-1 (2, 3, 4). The cladding is usually made of aluminum, less often copper (shown in red). The charge is covered from below with a microporous rubber gasket (shown in blue). The base of the charge may have an adhesive layer for sticking to the target, but more often the charge is secured with tape or tape.

On the right is an example of using a shaped charge to punch an oval hole in a steel sheet. At the same time, you can quickly punch a hole of any shape and size, or, for example, cut off a beam or pipe.

Figure 5.

Figure 5 shows cumulative rotary hammers produced by FKP Chapaevsky Mechanical Plant, the main manufacturer of similar products on the Russian market. Cumulative hammer drills are widely used for punching holes in metal plates and other obstacles, as well as for purging oil wells, breaking large pieces of rock, careful demolition of buildings and structures, and many other applications. Such devices are of particular value in hard-to-reach areas (for example, in mines, oil platforms, polar stations, construction sites far from large cities, etc.).

The shape of cumulative perforators already vaguely demonstrates the shape of a cumulative notch. At the top of the oval or oval-conical structures, the mounting points for the detonator are visible. The characteristic color of the copper lining of the cumulative funnels is visible in two perforators.

Thus, the cumulative effect is quite widely used in ammunition for various purposes and industrial devices for a wide range of uses.

Why it penetrates armor: the principle of operation of a cumulative jet

During the Second World War, the features of the “work” of such shells had not yet been well studied. That is why the name “armor-burning” was used in relation to them. Later, already in 1949, the cumulation effect was taken seriously in our country. In 1949, the Russian scientist M. Lavrentyev created the theory of cumulative jets and received the Stalin Prize for this.

Ultimately, the researchers were able to find out that the high penetration ability of projectiles of this type has absolutely nothing to do with high temperatures. When the detonator explodes, a cumulative jet is formed, which, upon contact with the armor of the tank, creates enormous pressure on its surface of several tons per square centimeter. Such indicators also exceed the yield strength of the metal. As a result, a hole several centimeters in diameter is formed in the armor.

Jets of modern ammunition of this type are capable of piercing tanks and other armored vehicles literally right through. The pressure they exert on the armor is truly enormous. The temperature of the cumulative projectile jet is usually low and does not exceed 400-600 °C. That is, it cannot actually burn through armor or melt it.

The cumulative projectile itself does not come into direct contact with the material of the tank walls. It explodes at some distance. After its release, parts of the cumulative jet move at unequal speeds. Therefore, during the flight it begins to stretch. When the distance reaches 10-12 funnel diameters, the jet disintegrates. Accordingly, it can have the greatest destructive effect on the armor of a tank when it reaches its maximum length, but does not yet begin to collapse.

Impact core (Phenomena of cumulative effect and impact core)

Currently, everyone who is even slightly interested in military affairs knows about the existence of so-called cumulative projectiles, which are designed to penetrate armor. The high penetration ability of such projectiles is well known. Even a grenade from the RPG-7 hand grenade launcher is capable of penetrating 100 mm. armor. The missiles of the ATGM complexes are capable of penetrating up to 500 m of armor. It would seem that the eternal dispute between armor and projectile was finally won by the projectile. After all, it is almost impossible to create a tank with armor of such thickness. But as always, for every action there is a reaction. They quickly found out that if the explosion of a shell is caused prematurely, i.e. at some distance from the armor, the cumulative effect disappears. The hot jet dissipates. The sides of the tanks began to be protected with thin sheets of metal and even rubber, placed at some distance from the main armor. The main thing is to make the fuse work. To counteract this, so-called tandem projectiles were invented, i.e. one projectile contains two projectiles one after the other. The first penetrates the screen, the second the main armor. A worthy answer to this treachery was found - active armor. When a tank's hull is exposed to a cumulative jet, containers with explosives placed on the armor explode, the shock wave of which neutralizes the impact of the cumulative jet. The dispute between the shell and the armor continues.

About 15 years ago, both the term “shock core” itself and ammunition, the armor-piercing effect of which is based on the principle of the so-called “shock core,” appeared. The author is not yet aware of artillery shells that operate on this principle, but engineering ammunition, namely anti-tank mines of this type, have existed for a long time. So back in 1983, the TM-83 anti-tank anti-aircraft mine entered service with the Soviet Army. Sweden has a similar Type-14 mine (See photo). There are analogues of these mines in other countries. These mines are placed at a distance of several meters from the road along which the tank is walking. When a mine explodes, an impact core is formed, which retains its penetrating ability at a distance of up to 30-40 meters from the explosion site. When testing the T-72 tank for armor resistance to the TM-83 mine, it was discovered that the impact core pierced the side screen, the side, the opposite side, the opposite side screen. The tank was at a distance of 15 meters from the mine. The hole had a diameter of 3-3.5 cm.

The most curious thing about the impact core is that the explosion should occur at a distance of more than 1-1.5 meters from the armor. The impact core is formed precisely at a distance of about 1-2 meters from the site of the explosion of the ammunition and then flies unchanged for about 30-40 meters, after which, due to friction with the air, it loses its kinetic energy, high temperature and dissipates.

The phenomenon of the cumulative effect was accidentally discovered by the English explosive scientist Forster in 1883, while studying the explosive characteristics of the then fashionable explosive dynamite. Practical application of the cumulative effect was found by German ammunition designers in 1938. For the first time, German artillerymen used cumulative shells against Soviet tanks at the end of 1941, when the complete inability of the German 37 mm was revealed. and 47 mm. anti-tank guns to penetrate the armor of the T-34 and KV. The picture shows a finned over-caliber armor-piercing cumulative projectile for the German 37 mm. anti-tank gun

The physics of the impact core, however, like the physics of the cumulative effect itself, has not been fully elucidated. There is also no clear answer as to what a cumulative jet or impact core is. A number of experts believe that under the influence of high pressure and temperature in the area of ​​the explosion, matter transforms into a plasma state, which explains its high kinetic energy. Others rightly object that energy does not come from anywhere, but can only pass from one type to another. And the potential energy of this amount of explosive is clearly not enough for the transition of matter into the plasma state. However, the phenomenon exists! However, according to all the laws of aerodynamics, even the cockchafer cannot fly, but he still flies, the scoundrel!

There is one small theory that, if it does not completely explain the phenomenon of cumulation and the impact core, then quite clearly illustrates these phenomena. Everyone has seen rain quite often in their lives, seen raindrops falling into puddles. We saw how a stream of water jumped up from a puddle where a drop fell, and how a droplet broke away from it and continued its upward movement. Such a droplet has a fairly high speed. In any case, it hits your bare feet sensitively. It would seem that when a drop of rain falls into a puddle, this drop should simply go into the depths of the water and dissolve in its native environment.

Researcher F. Killing, filming with a high-speed movie camera the phenomena that occur when a drop of water hits a water surface, discovered the same phenomenon of cumulation as during the explosion of cumulative ammunition, only with the opposite sign. It is impossible to study what happens when a projectile explodes for a number of technical reasons. But water allows you to track all phases of this process. Let us consider in a very simplified way the processes that occur when a drop falls into water. We cannot consider in detail and in all intermediate phases, being limited by the size of the article. In Killing, the development of the process of falling a drop and the formation of a cumulative jet and impact core is monitored in more than 100 photographs.

The first stage is not interesting for us. The drop approaches the surface. However, it is interesting here that a drop in flight does not have the shape that everyone thinks, but the appearance of a thickened disk. A drop has a “drop-shaped shape” only at the moment of its separation from the tap.

Stage two. The drop penetrates the surface of the water. It still retains its integrity and behaves like a stone. The funnel formation process begins.

We omit the intermediate stages, because they are of no interest to us and only describe in detail the change in the behavior of a drop from behaving like a stone to its complete destruction.

Third stage. We see a parabola-shaped funnel. The water pressure in the area surrounding the funnel significantly exceeds the water pressure as a whole in this aquatic environment. This moment can be equated to the moment the process of explosive detonation begins. Those. from this moment on, the phenomena occurring in the ammunition and in the water are identical.

Stage four. Microdroplets of water under the influence of pressure rush to the geometric center of the parabola. This is the focus of cumulation. When ammunition explodes, this is the point of maximum pressure.

Stage five. The droplets merge into a single stream, moving upward at high speed. This is a cumulative jet. When ammunition explodes, such a jet penetrates the armor. Anyone who saw the holes from cumulative shells could not help but notice that the hole in the armor from such a shell was much smaller than its caliber. Naturally. The thickness of the jet is much smaller than the diameter of the funnel.

Stage six. Those microdroplets that find themselves in the leading part of the jet receive quite a large kinetic energy and rush far upward. An impact core is formed. Watching a drop fall into the water, at this moment we see a drop jumping quite far upward from the place where the raindrop fell.

Stage seven, final. The impact core continues its movement, and the remaining water droplets, having spent their energy, begin to return back to the aquatic environment.

Here it is quite clearly clear that the cumulative jet exists for a rather short time and inevitably collapses. Therefore, if there is a screen in the path of the projectile, then the cumulative jet, having formed when the projectile meets the screen, has already reached the armor and is destroyed, and there is not enough space for the formation of the impact core. If the ammunition is detonated at a sufficient distance from the screen, then the formed impact core, having high kinetic energy, easily penetrates both the screen and the armor.

Notes in the margins.

Maybe one of the readers will inform me about artillery shells that use the impact cannonball effect? Calibers, brands, in which guns they are used. A method of ensuring the detonation of a projectile at a strictly measured distance from the armor. Sources of information. Just please do not refer to literary sources. There's so-a-a-who they can write to!

Veremeev Yu.G.

Crew defeat

A cumulative jet that has pierced the armor penetrates the interior of the tank at high speed and can also hit the crew members. At the moment it passes through the armor, pieces of metal and its liquefied drops come off. Such fragments, of course, also have a strong damaging effect.

A jet that penetrates inside the tank, as well as pieces of metal flying at great speed, can also end up in the vehicle’s combat reserves. In this case, the latter will ignite and an explosion will occur. This is exactly how cumulative projectiles operate.

Literature

• Andreev S. G., Babkin A. V., Baum F. A. and others.
  Chapter 17. Cumulation // Physics of explosion / Edited by L. P. Orlenko. — 3rd edition, revised and expanded. - M.: Fizmatlit, 2004. - T. 2. - P. 193-350. — 656 p. — ISBN 5-9221-0220-6.
• Lavrentyev M.A., Shabat B.V.
  Chapter VII. Jets. § 29. Cumulative jets // [libgen.org/book/index.php?md5=28C44CC9634910E3ED50BAEE0906269B Problems of hydrodynamics and their mathematical models]. - M.: Nauka, 1973. - P. 257-269. — 416 p.
• Balankin A. S., Lyubomudrov A. A., Sevryukov I. T.
  Kinetic theory of cumulative armor penetration. - M.: Publishing House of the USSR Ministry of Defense. — 271 p.

Advantages and disadvantages

What are the advantages of cumulative projectiles? First of all, the military considers their advantages to be that, unlike sub-caliber ones, their ability to penetrate armor does not depend on their speed. Such shells can also be fired from light guns. Also, such charges are quite convenient to use in reactive grants. For example, this is how the RPG-7 hand-held anti-tank grenade launcher is used. The cumulative jet of such weapons armors tanks with high efficiency. The Russian RPG-7 grenade launcher is still in service today.

The armor effect of a cumulative jet can be very destructive. Very often it kills one or two crew members and causes the ammunition stockpile to explode.

The main disadvantage of such weapons is considered to be the inconvenience of using them in an “artillery” manner. In most cases, projectiles are stabilized by rotation during flight. In cumulative ammunition, it can cause destruction of the jet. Therefore, military engineers are trying in every possible way to reduce the rotation of such projectiles in flight. A variety of methods can be used for this.

For example, such ammunition may use a special lining texture. Also, projectiles of this type are often supplemented with a rotating body. In any case, it is more convenient to use such charges in low-velocity ammunition or generally stationary ones. These could be, for example, rocket-propelled grenades, light gun shells, mines, and ATGMs.

Cumulative ammunition and their damaging factors

H 50 (Hohlladung 50 kg) - one of the first serial shaped charges.
Used to destroy defensive fortifications during World War II. Despite the relatively weak armor protection, a cumulative grenade, when it hits a turret, usually kills one or more crew members of an armored vehicle, can disable weapons, and detonate ammunition. A hit in the engine compartment made the car a stationary target, and if fuel lines were encountered along the path of the cumulative jet, ignition occurred.

Viktor Murakhovsky notes that there is a widespread myth that shaped charges cause excess pressure and temperature, but this is not true. The defeat of a protected target is achieved by the action of a short cumulative jet of small diameter, creating a pressure of several tons per square centimeter (which exceeds the yield strength of metals) and piercing a small hole of about 80 mm in the armor. The entire visually observed explosion of a shaped charge occurs before the armor and excess pressure and temperature cannot penetrate through a small hole and are not the main damaging factors. Pressure and temperature sensors installed inside tanks do not detect significant high-explosive or thermal effects after penetration of armor by a cumulative jet.[8] The main damaging factor of a shaped charge is the torn off fragments and drops of armor. If fragments and drops from pierced armor come into contact with the tank's ammunition, it may ignite and detonate, resulting in the destruction of the armored vehicle. If the cumulative jet and drops of armor do not hit people and fire/explosive equipment of the tank, then in general a direct hit from even a powerful cumulative charge may not damage the tank.[8]

Heavy ATGMs (type 9M120 “Attack”, “Hellfire”), when hitting light armored vehicles with bulletproof protection, with their synergistic effect, can destroy not only the crew, but also partially or completely destroy the vehicles. On the other hand, the impact of most wearable PTS on AFVs (in the absence of detonation of AFV ammunition) is not so critical - here the usual effect of the armor effect of a cumulative jet is observed, and the crew is not damaged by excess pressure.

see also

Cumulative fragmentation projectile

Passive protection

Of course, immediately after shaped charges appeared in armies, means began to be developed to prevent them from hitting tanks and other heavy military equipment. For protection, special remote screens were developed, installed at some distance from the armor. Such products are made of steel gratings and metal mesh. The effect of a cumulative jet on a tank's armor, if present, is nullified.

Since when a projectile hits a screen it explodes at a considerable distance from the armor, the jet has time to collapse before it reaches it. In addition, some types of such screens are capable of destroying the contacts of the detonator of cumulative ammunition, as a result of which the latter simply does not explode at all.

Detail of a standard cumulative projectile

The cumulative projectile consists of:

• Fuse and head;
• notches and rings;
• charge and detonator;
• retainer and tracer;
• stabilizer, housing, blade.

The concept of cumulative effect

The effect invented by Bereskov means an instant strengthening of ongoing processes due to the coherence of joint efforts.

A small recess is made in one of the parts of the charge, which is covered with a layer of metal with a total thickness of 1-3 mm. This recess is always turned towards the goal.

The explosion occurring at the edge of the crater causes the blast wave to pass along the side walls, thereby flattening them towards the axis of the projectile. During the explosion, a large pressure is created, which transmutes the crater lining into a quasi-liquid, then moves it along the axis of the ammunition. These actions form a jet that reaches speeds of up to (10 km/s).

IMPORTANT! The lining does not melt, but is deformed into a liquid under the influence of high pressure on it.

If the cumulative jet hits the target, then the strength of the armor does not matter. All that matters is the density and thickness of the metal. The penetration ability of a metal jet depends on:

• length;
• cladding density;
• target armor material.

IMPORTANT! The most effective action (focal) occurs when a projectile explodes at a short distance from an armored target.

The armor and the shaped charge interact with each other, i.e. the pressure created from the explosion of the projectile’s components is so high that the strongest armor will behave like a liquid. Standard ammunition penetrates armor with a thickness of 5 to 8 calibers.

Note! If the crater lining is made of depleted uranium, the armor-piercing power of the projectile increases to 10 calibers.

Advantages and disadvantages

HEAT ammunition has positive and negative sides. The absolute advantages of such shells:

• Penetrating almost any layer of armor;
• The jet penetrates armor regardless of the initial speed of the projectile;
• Powerful action after hitting the target.

But cumulative ammunition also has its disadvantages:

1. Difficulties in mass production due to the complexity of the design;
2. Great difficulties in using MLRS ammunition;
3. Vulnerabilities in penetrating reactive armor.

A warhead with a cumulative effect, used in the production of ammunition for RPGs, anti-tank guns and mines. When a projectile filled with “liquid metal” hits a target, it will most likely cause an explosion of ammunition. In this case, the crew will die.

Interesting fact! Modern ATGMs are capable of penetrating armor plates 10 cm thick.

What can protection be made of?

During the Second World War, the Soviet army used fairly massive steel screens. Sometimes they could be made of 10 mm steel and extended 300-500 mm. During the war, the Germans everywhere used lighter steel mesh protection. At the moment, some durable screens are capable of protecting tanks even from high-explosive fragmentation shells. By causing detonation at a certain distance from the armor, they reduce the impact of the shock wave on the vehicle.

Sometimes multi-layer protective screens are now used for tanks. For example, a sheet of steel 8 mm thick can be carried 150 mm behind the vehicle, after which the space between it and the armor is filled with light material - expanded clay, glass wool, etc. Next, a steel mesh is also placed 300 mm on top of such a screen. Such devices are capable of protecting the vehicle from almost all types of explosive ammunition.

Notes

1. Slobodetsky I. Sh., Aslamazov I. G.
   [publ.lib.ru/ARCHIVES/B/%27%27Bibliotechka_%27%27Kvant%27%27/_%27%27Bibliotechka_%27%27Kvant%27%27.html Problems in physics]. — M.: Science. Main editorial office of physical and mathematical literature, 1980. - P. 55-59. — 176 p. — (Library “Quantum”). — 150,000 copies. — ISBN no, UDC S48 530.1, BBK 22.3 53.
2. Viktor Murakhovsky, reserve colonel.
   [otvaga2004.narod.ru/publ_w5/012_myth.htm Another cumulative myth]. [www.webcitation.org/688TMHk5z Archived from the original on June 3, 2012].
3. Walters WP, Zukas JA
   Fundamentals of Shaped Charges. - John Wiley & Sons Inc., 1989. - ISBN 0-471-62172-2.
4. Hubert Chardin.
   Über die Entwicklung der Hohlladung, in: Wehrtechnische Hefte. — 1954.
5. James E Mrazek.
   The fall of Eben Emael: prelude to Dunkerque. —Luce, 1971.
6. [www.inert-ord.net/ger03a/gerrg2/ggp40/index.html German GG/P 40 HEAT Rifle Grenade - Inert-Ord.net] (English). [www.webcitation.org/65V67rJDn Archived from the original on February 16, 2012].
7. Drabkin A.
   [militera.lib.ru/memo/russian/drabkin_ay4/ I fought with the Panzerwaffe. “Double salary - triple death!”]. - M.: Yauza, Eksmo, 2007. - (War and us). — 10,000 copies. — ISBN 978-5-699-20524-0.
8. [otvaga2004.ru/armiya-i-vpk/armiya-i-vpk-vzglyad/kumulyativnyj-mif/ ANOTHER CUMULATIVE MYTH]. Military-patriotic site "Courage". Retrieved February 29, 2020.

Dynamic protection

Such a screen is also called reactive armor. For the first time, the protection of this variety in the Soviet Union was tested in the 40s by engineer S. Smolensky. The first prototypes were developed in the USSR in the 60s. The production and use of such protective equipment in our country began only in the 80s of the last century. This delay in the development of reactive armor is explained by the fact that it was initially considered unpromising.

For a very long time, the Americans did not use this type of protection. The Israelis were the first to actively use reactive armor. Engineers in this country noticed that when ammunition stocks explode inside a tank, the cumulative jet does not pierce the vehicle through. That is, a counter-explosion is capable of containing it to some extent.

Israel began actively using dynamic protection against cumulative projectiles in the 70s of the last century. Such devices were called “Blazer”, were made in the form of removable containers and were placed on the outside of the tank’s armor. They used Semtex explosives based on hexogen as a bursting charge.

Later, dynamic protection of tanks against cumulative shells was gradually improved. At the moment, in Russia, for example, the Malachite systems are used, which are complexes with electronic detonation control. Such a screen is capable of not only effectively counteracting cumulative projectiles, but also destroying the most modern NATO sub-caliber DM53 and DM63, designed specifically for the destruction of Russian dynamic defenses of the previous generation.

On the cumulative effect of projectiles

The specifics of the cumulative action of an explosive charge are usually illustrated with the following examples. If a cylindrical block of high explosive is placed on an armor plate and detonated with a detonator in the middle of the block, then the energy of the explosion will spread equally in all directions, and only a small dent will form on the armor. But if in the same explosive charge the detonator is placed at the upper end of the block, then the effect of the explosion will be stronger in the direction of the plate, and accordingly the dent on it after the explosion will be of greater depth. However, in both cases, the dispersion of explosion products occurs in all directions. If the charge has a conical or spherical recess along its axis on the part facing the slab, then as a result of the explosion a deeper dent in the form of a crater is formed in the slab. The presence of a recess in the explosive charge leads to the fact that the direction of the flow of explosion products is concentrated along the axis of the recess, and does not disperse in all directions. A jet of explosive explosion products is formed in the form of a narrow beam of gases with a beam of light. The speed of the jet at the focus reaches 15 km/s. But the greatest impact on the plate is achieved when the wall of the recess in the charge is covered with a metal lining. When a charge is detonated while the recess is lined with a copper or steel funnel, an armor plate even of considerable thickness is pierced through. It happens this way. When the detonator located at the upper end of the block is triggered, a detonation wave propagates in the explosive in the direction of the recess. The detonation speed of explosives used in shaped charges is 7-9 km/s. A detonation wave at such a speed exerts enormous pressure on the metal lining - up to 800 thousand atmospheres. As a result, the lining metal collapses and is pulled along the axis of the recess in the form of a cumulative jet. The metal that makes up the cumulative jet does not melt, although it heats up to 400-600 degrees. Let us remember that the melting point of copper is about 1100 degrees, and steel – 1300-1400 degrees. A jet of metal with a diameter of 3-4 mm acquires a speed of up to 10 km/s and exerts pressure on the armor of the order of one million atmospheres. Science defines the state of the metal in a cumulative jet as an ideally incompressible liquid. With such enormous pressure, the barrier material is armor, concrete, etc. at the point of influence of the cumulative jet it “flows”, that is, just like the jet itself, it acquires the properties of an ideally incompressible liquid. A hole appears in the barrier, the edges of which have a melted appearance. This led at one time to the incorrect definition of cumulative shells as armor-piercing shells. Even after overcoming the obstacle, the high energy of the residual elements of the jet remains, causing destruction of equipment, detonation of ammunition, and injury to people.

Thus, the highly effective action of a cumulative projectile is the result of the fact that the energy of a charge with a recess and metal lining of its surface during an explosion propagates in one direction - along the axis of the recess, and not in all directions, as in the explosion of a conventional charge. This concentration of energy leads to the formation of a metal jet with a speed of up to 10 km/s - about 1st cosmic velocity - and creates pressure on the barrier of millions of atmospheres. This is where the name of the phenomenon came from – cumulation, from the Latin word “cumulatio” – accumulation, concentration.

The cumulative effect was discovered in 1864 by the Russian military engineer M.M. Boreskov. In 1865, Captain D.A. Andievsky used the cumulative effect in the design of the detonator capsule. Then for a long time they did not remember about the cumulation of the explosion, and only in 1914 a patent appeared for its use in military affairs. In 1923 - 1926, the Soviet scientist M.Ya. Sukharevsky conducted a study of the cumulative effect, then applied directed explosions in practice during the construction of the Dnieper dam. In 1942, Professor G.I. Pokrovsky published the work “Directed Action of an Explosion,” which contained theoretical and practical conclusions from his research. The theory of the cumulative effect was most fully developed by the Soviet academician M.A. Lavrentiev in 1945. There has been active research into the cumulative effect in a number of other countries.

Sequence of formation of a cumulative jet.

Modern anti-tank shells use shaped charges that provide armor penetration of 800-900 mm. The amount of penetration of durable barriers by cumulative projectiles depends on a number of factors: the diameter of their charge, the properties of the explosive charge and its mass, the shape of the recess and the properties of the metal of its lining, the distance from the charge to the barrier at the moment of the explosion.

Of the properties of an explosive charge, the most important is its detonation speed. The higher this speed, the higher the parameters of the cumulative jet will be - its speed, pressure, density. In the 60-70s, a mixture of TNT and hexogen (50% each) was used in shaped charges. The detonation speed of TNT is 7000 m/s, and that of RDX is 8100 m/s. Explosives have an even higher detonation speed, which began to be used in new types of anti-tank shells. This is the so-called okfol - a mixture of octogen with a phlegmatizer. Its detonation speed reaches 8700 m/s. It is clear that a large explosive mass provides, other things being equal, a greater penetration effect. This way of increasing the penetration of cumulative projectiles is limited by their mass and caliber.

The shape of the cumulative recess and the material of its coating have a significant influence on armor penetration. The shapes of the cumulative recess are selected in different ways: conical or spherical, depending on the purpose and caliber of the projectile. The dimensions of the recess - its diameter and depth - significantly influence the punching effect of the same shape. When the lining collapses, the initial length of the metal cumulative jet is equal to the forming recess; subsequently the jet stretches several times and provides a penetration depth of up to 10 diameters of the lining (until the density of the jet and the obstacles remain approximately the same). The lining material also affects the breakdown effect of the charge. The best effect is provided by copper cladding.

Shooting from an RPG-26.

The armor of a modern tank, pierced by cumulative grenades. On the left photo are the inlet holes, on the right photo are the outlet holes.

In the 1960s, another improvement to shaped charges was introduced, increasing their efficiency. A screen (an inert plastic lens) was placed in the charge between the detonator and the cumulative recess. In this case, the front of the detonation wave approaches the lining at an optimal angle. As a result, a cumulative jet with higher parameters is formed.

Penetrating an obstacle becomes less likely with the rapid rotation of cumulative projectiles. Therefore, to stabilize the flight of cumulative projectiles, their rapid rotation around the longitudinal axis is not used. When projectiles rotate at a speed of the order of several hundred revolutions per second, which is necessary to achieve their stabilized flight in the air, the cumulative jet is disrupted under the influence of centripetal forces, and its penetrating effect worsens. Modern cumulative projectiles are stabilized in flight by the tail, rather than by rapid rotation. The rotation imparted to some cumulative projectiles around its axis is intended to increase accuracy, while it has a speed of the order of several tens of revolutions per second.

In cumulative shells and grenades, the front part (fairing) is made in the form of an elongated tip made of a relatively weak material. When meeting an obstacle, the tip must collapse in such a way that the cumulative recess is not deformed, and the charge is detonated at a certain distance from the obstacle. The significance of just such a detonation was discussed earlier when we discussed the role of the piezoelectric fuse in achieving maximum efficiency of cumulative projectiles with relatively high flight speeds.

Let's add to this the features of the action of cumulative projectiles, which have a tandem warhead. In them, the front warhead is designed to undermine dynamic protection. The design of the fusing mechanism of tandem ammunition provides for the necessary time delay between the detonation of the front and main charges. This delay should eliminate the impact of flying fragments of dynamic protection on the cumulative jet formed by the main warhead.

The cumulative effect is widely used in the national economy. When constructing dams, with the help of high-power shaped charges, large masses of soil are moved in the desired direction and over a certain distance, and wells of the required size are punched in rocks. The cumulative action is used when cutting strong sheets of metal of large thickness, for crimping metal pipes, for strengthening metal, and for eliminating blockages in mines.

Research into the cumulative effect is ongoing. Based on them, shaped charges are improved.

Appendix 2

How does a jet behave underwater?

In some cases, the cumulative effect of ammunition may be reduced. For example, a cumulative jet underwater behaves in a special way. Under such conditions, it disintegrates already at a distance of 7 funnel diameters. The fact is that at high speeds it is about as difficult for a jet to penetrate water as it is to penetrate metal.

On Soviet cumulative ammunition for use under water, for example, special nozzles were installed that facilitated the formation of a jet and were equipped with weighting agents.

An excerpt characterizing the Cumulative Effect

Natasha’s wound healed in the same way. She thought her life was over. But suddenly love for her mother showed her that the essence of her life - love - was still alive in her. Love woke up and life woke up. The last days of Prince Andrei connected Natasha with Princess Marya. The new misfortune brought them even closer together. Princess Marya postponed her departure and for the last three weeks, like a sick child, she looked after Natasha. The last weeks Natasha spent in her mother’s room had strained her physical strength. One day, Princess Marya, in the middle of the day, noticing that Natasha was trembling with a feverish chill, took her to her place and laid her on her bed. Natasha lay down, but when Princess Marya, lowering the curtains, wanted to go out, Natasha called her over. – I don’t want to sleep. Marie, sit with me. – You’re tired, try to sleep. - No no. Why did you take me away? She will ask. - She's much better. “She spoke so well today,” said Princess Marya. Natasha lay in bed and in the semi-darkness of the room looked at the face of Princess Marya. “Does she look like him? – thought Natasha. – Yes, similar and not similar. But she is special, alien, completely new, unknown. And she loves me. What's on her mind? All is good. But how? What does she think? How does she look at me? Yes, she is beautiful." “Masha,” she said, timidly pulling her hand towards her. - Masha, don’t think that I’m bad. No? Masha, my dear. I love you so much. We will be completely, completely friends. And Natasha, hugging and kissing the hands and face of Princess Marya. Princess Marya was ashamed and rejoiced at this expression of Natasha’s feelings. From that day on, that passionate and tender friendship that only happens between women was established between Princess Marya and Natasha. They kissed constantly, spoke tender words to each other and spent most of their time together. If one went out, then the other was restless and hurried to join her. The two of them felt greater agreement among themselves than apart, each with herself. A feeling stronger than friendship was established between them: it was an exceptional feeling of the possibility of life only in the presence of each other. Sometimes they were silent for hours; sometimes, already lying in bed, they began to talk and talked until the morning. They talked mostly about the distant past. Princess Marya talked about her childhood, about her mother, about her father, about her dreams; and Natasha, who had previously turned away with calm incomprehension from this life, devotion, humility, from the poetry of Christian self-sacrifice, now, feeling herself bound by love with Princess Marya, fell in love with Princess Marya’s past and understood a side of life that was previously incomprehensible to her. She did not think of applying humility and self-sacrifice to her life, because she was accustomed to looking for other joys, but she understood and fell in love with this previously incomprehensible virtue in another. For Princess Marya, listening to stories about Natasha’s childhood and early youth, a previously incomprehensible side of life, faith in life, in the pleasures of life, also opened up. They still never spoke about him in the same way, so as not to violate with words, as it seemed to them, the height of feeling that was in them, and this silence about him made them forget him little by little, not believing it. Natasha lost weight, turned pale and became so physically weak that everyone constantly talked about her health, and she was pleased with it. But sometimes she was suddenly overcome not only by the fear of death, but by the fear of illness, weakness, loss of beauty, and involuntarily she sometimes carefully examined her bare arm, surprised at its thinness, or looked in the mirror in the morning at her elongated, pitiful, as it seemed to her , face. It seemed to her that this was how it should be, and at the same time she became scared and sad. Once she quickly went upstairs and was out of breath. Immediately, involuntarily, she came up with something to do downstairs and from there she ran upstairs again, testing her strength and observing herself. Another time she called Dunyasha, and her voice trembled. She called her again, despite the fact that she heard her steps, called her in the chest voice with which she sang, and listened to him. She didn’t know this, she wouldn’t have believed it, but under the seemingly impenetrable layer of silt that covered her soul, thin, tender young needles of grass were already breaking through, which were supposed to take root and so cover with their life shoots the grief that had crushed her that it would soon not be visible and not noticeable. The wound was healing from the inside. At the end of January, Princess Marya left for Moscow, and the Count insisted that Natasha go with her in order to consult with doctors. After the clash at Vyazma, where Kutuzov could not restrain his troops from the desire to overturn, cut off, etc., the further movement of the fleeing French and the fleeing Russians behind them, to Krasnoye, took place without battles. The flight was so fast that the Russian army running after the French could not keep up with them, that the horses in the cavalry and artillery became weak and that information about the movement of the French was always incorrect. The people of the Russian army were so exhausted by this continuous movement of forty miles a day that they could not move faster. To understand the degree of exhaustion of the Russian army, you only need to clearly understand the significance of the fact that, having lost no more than five thousand people wounded and killed during the entire movement from Tarutino, without losing hundreds of people as prisoners, the Russian army, which left Tarutino numbering one hundred thousand, came to Red in the number of fifty thousand. The rapid movement of the Russians after the French had just as destructive an effect on the Russian army as the flight of the French. The only difference was that the Russian army moved arbitrarily, without the threat of death that hung over the French army, and that the backward sick of the French remained in the hands of the enemy, the backward Russians remained at home. The main reason for the decrease in Napoleon's army was the speed of movement, and the undoubted proof of this is the corresponding decrease in Russian troops. All of Kutuzov’s activities, as was the case near Tarutin and near Vyazma, were aimed only at ensuring, as far as was in his power, not to stop this movement disastrous for the French (as the Russian generals wanted in St. Petersburg and in the army), but assist him and facilitate the movement of his troops. But, in addition, since the fatigue and huge loss that occurred in the troops due to the speed of movement appeared in the troops, another reason seemed to Kutuzov to slow down the movement of the troops and to wait. The goal of the Russian troops was to follow the French. The path of the French was unknown, and therefore the closer our troops followed on the heels of the French, the greater the distance they covered. Only by following at a certain distance was it possible to cut the zigzags that the French were making along the shortest path. All the skillful maneuvers that the generals proposed were expressed in the movements of troops, in increasing the transitions, and the only reasonable goal was to reduce these transitions. And Kutuzov’s activity was directed towards this goal throughout the entire campaign, from Moscow to Vilna - not by chance, not temporarily, but so consistently that he never betrayed it. Kutuzov knew not with his mind or science, but with his whole Russian being, he knew and felt what every Russian soldier felt, that the French were defeated, that the enemies were fleeing and it was necessary to see them out; but at the same time, he felt, along with the soldiers, the full weight of this campaign, unheard of in its speed and time of year. But to the generals, especially not Russians, who wanted to distinguish themselves, to surprise someone, to take some duke or king prisoner for something - it seemed to the generals now, when every battle was disgusting and meaningless, it seemed to them that now was the time fight and defeat someone. Kutuzov only shrugged his shoulders when, one after another, he was presented with plans for maneuvers with those poorly shod, without sheepskin coats, half-starved soldiers, who in one month, without battles, had melted to half and with whom, under the best conditions of ongoing flight, it was necessary to go to the border the space is larger than that which was traversed. In particular, this desire to distinguish itself and maneuver, overturn and cut off was manifested when Russian troops encountered French troops. This is how it happened near Krasnoye, where they thought to find one of the three columns of the French and came across Napoleon himself with sixteen thousand. Despite all the means used by Kutuzov in order to get rid of this disastrous clash and in order to save his troops, for three days Krasny continued to finish off the defeated gatherings of the French with the exhausted people of the Russian army. Toll wrote the disposition: die erste Colonne marschiert [the first column will go there then], etc. And, as always, everything was done not according to the disposition. Prince Eugene of Wirtemberg shot at the fleeing crowds of Frenchmen from the mountain and demanded reinforcements, which did not come. The French, running around the Russians at night, scattered, hid in the forests and made their way further as best they could. Miloradovich, who said that he did not want to know anything about the economic affairs of the detachment, which could never be found when he was needed, “chevalier sans peur et sans reproche” [“knight without fear and reproach”], as he called himself , and eager to talk with the French, sent envoys demanding surrender, and lost time and did not do what he was ordered. “I give you guys this column,” he said, driving up to the troops and pointing to the cavalrymen at the French. And the cavalrymen on thin, tattered, barely moving horses, urging them on with spurs and sabers, at a trot, after great exertion, drove up to the donated column, that is, to a crowd of frostbitten, numb and hungry Frenchmen; and the donated column threw down its weapons and surrendered, which it had long wanted. At Krasnoe they took twenty-six thousand prisoners, hundreds of cannons, some kind of stick, which was called a marshal's baton, and they argued about who had distinguished himself there, and were pleased with that, but they very much regretted that they did not take Napoleon or at least some hero, Marshal, and reproached each other and especially Kutuzov for this. These people, carried away by their passions, were blind executors of only the saddest law of necessity; but they considered themselves heroes and imagined that what they did was the most worthy and noble thing. They accused Kutuzov and said that from the very beginning of the campaign he had prevented them from defeating Napoleon, that he only thought about satisfying his passions and did not want to leave the Linen Factories because he was at peace there; that he stopped the movement near Krasny only because, having learned about Napoleon’s presence, he was completely lost; that it can be assumed that he is in a conspiracy with Napoleon, that he is bribed by him, [Wilson's Notes. (Note by L.N. Tolstoy.) ], etc., etc. Not only did contemporaries, carried away by passions, say so, but posterity and history recognized Napoleon as grand, and Kutuzov: foreigners as cunning, depraved , a weak old court man; Russians - something vague - some kind of doll, useful only by its Russian name... In the 12th and 13th years, Kutuzov was directly blamed for mistakes. The Emperor was dissatisfied with him. And in history, written recently by order of the highest, it is said that Kutuzov was a cunning court liar who was afraid of the name of Napoleon and with his mistakes at Krasnoye and near Berezina deprived the Russian troops of glory - a complete victory over the French. [The history of Bogdanovich in 1812: characteristics of Kutuzov and reasoning about the unsatisfactory results of the Krasnensky battles. (Note by L.N. Tolstoy.)] This is not the fate of great people, not grand homme, whom the Russian mind does not recognize, but the fate of those rare, always lonely people who, comprehending the will of Providence, subordinate their personal will to it. The hatred and contempt of the crowd punish these people for their insight into higher laws. For Russian historians - it’s strange and scary to say - Napoleon is the most insignificant instrument of history - never and nowhere, even in exile, who did not show human dignity - Napoleon is an object of admiration and delight; he's grand. Kutuzov, the man who, from the beginning to the end of his activity in 1812, from Borodin to Vilna, without ever changing one action or word, shows an extraordinary example in history of self-sacrifice and consciousness in the present of the future significance of the event, – Kutuzov seems to them like something vague and pitiful, and when talking about Kutuzov and the 12th year, they always seem to be a little ashamed. Meanwhile, it is difficult to imagine a historical person whose activity would be so invariably and constantly directed towards the same goal. It is difficult to imagine a goal more worthy and more consistent with the will of the entire people. It is even more difficult to find another example in history where the goal that a historical figure set for himself would be so completely achieved as the goal towards which all of Kutuzov’s activities were directed in 1812.

Interesting Facts

Of course, Russia is currently working to improve, among other things, the cumulative weapons themselves. Modern domestic grenades of this variety, for example, are capable of penetrating a layer of metal more than a meter thick.

Weapons of this type have been used by different countries of the world for quite a long time. However, there are still all sorts of legends and myths about him. So, for example, sometimes on the Internet you can find information that cumulative jets, when entering the internal space of a tank, can cause such a sharp jump in pressure that it leads to the death of the crew. Horror stories are often told about this effect of cumulative waves on the Internet, including by the military themselves. There is even an opinion that Russian tank crews specially drive with their hatches open during combat operations in order to relieve pressure in the event of a hit from a cumulative projectile.

However, according to the laws of physics, a metal jet cannot cause such an effect. This type of projectile simply concentrates the energy of the explosion in a specific direction. To the question of whether a cumulative jet burns or pierces armor, there is thus a very simple answer. When it encounters the material of the tank walls, it slows down and really puts strong pressure on it. As a result, the metal begins to spread to the sides and is washed out in drops at high speed into the tank.

In this case, the material liquefies precisely because of pressure. The temperature of the cumulative jet is low. At the same time, it itself, of course, does not create any significant shock wave. The jet can penetrate right through the human body. Also, drops of liquid metal that come off the armor itself have serious destructive power. Even the shock wave from the explosion of the ammunition itself is not able to penetrate the hole made by the jet in the armor. Accordingly, no excess pressure arises inside the tank.

According to the laws of physics, the answer to the question of whether a cumulative jet pierces or burns through armor is thus obvious. When it comes into contact with metal, it simply liquefies it and passes into the car. It does not create excess pressure behind the armor. Therefore, of course, it is not worth opening the vehicle hatch when the enemy uses such ammunition. On top of everything else, this, on the contrary, increases the risk of shell shock or death of crew members. The blast wave from the projectile itself can penetrate into the open hatch.

MILITARY REVIEW AND POLITICS

Introduction

There are practically no requests for “cumulative bomb” on the Internet and there seems to be no point in writing an article. But the authors, both online and on television, who are still BURNING through tank armor were so fed up that their hands reached for the keyboard. I will not delve into history to find out who was the very first. Many people guessed about the cumulative effect. But before the Second World War, the Germans and Americans were certainly ahead of the rest. They used the first samples of shells in Spain. To understand the principle of operation of a shaped charge, the Germans photographed the moment of the explosion in X-rays, which for that time was a very advanced research technology.

The principle of operation of a shaped charge

The principle of operation of a shaped charge is to direct part of the explosion energy in a certain direction. This is achieved using a special recess created in the explosive. A recess in the form of a cone with an angle of sixty degrees is considered close to ideal. The blast wave at each point is perpendicular to the surface of the charge and, meeting in the center of the recess, continues to move forward along the axis of symmetry of the cone. The result is a cumulative jet consisting of explosive combustion products flying at a speed of eight to twelve KILOMETERS per second. How does it act on an obstacle? The fact is that at high speeds and pressures, solids begin to behave like liquids. Therefore, the cumulative jet simply SPLASHES any obstacle. Naturally, traces of SPLASHING remain on the surface of the barrier, very similar to traces of melting. Our and American scientists came to the “splashing” theory almost simultaneously immediately after the war. But many authors, both on the Internet and on television, still burn through tank armor. Below are photographs that help to understand the process of jet formation, as well as the moments of armor penetration and their results.

Penetration depth of the cumulative jet

The depth of penetration, and accordingly the amount of armor penetrated, of a cumulative jet depends on its LENGTH, SPEED and WEIGHT. The length of the cumulative jet depends mainly on the height of the cone of the cumulative notch. And since this size grows with the caliber of the bomb or projectile, we can say that the thickness of the armor penetrated depends on the caliber of the cumulative bomb or projectile. The speed of the cumulative jet depends on the properties of the explosive. The most important characteristics of an explosive are the detonation speed and its specific gravity. The higher these parameters, the higher the pressure in the detonation front and, accordingly, the speed of the cumulative jet itself.

The third column shows the specific gravity of explosives. The fourth is the detonation speed. The fifth is the pressure at the front of the detonation wave.

By definition, the weight of a gas jet cannot be large. To increase it, add LINING of the cumulative recess. Any (even bread crumb) lining dramatically increases the thickness of the armor being penetrated. But the ideal material for cladding is a fairly plastic substance with a high specific gravity. A close to ideal material is copper.

Iron has lower values. An important factor is the thickness of the cladding. With thin cladding, the jet weight will not be sufficient. If thick, the jet speed will drop. With the correct thickness of the lining, it is not a gas jet that flies to the target, but a metal needle. The photographs show the difference in penetration depth of armor with and without lining.

The cumulative jet is formed in time and space, so the barrier being penetrated must be located outside of this space. The distance at which the jet has already formed and has maximum speed and minimum diameter is called focal. The focal length depends on the shape of the shaped charge and the caliber of the projectile or bomb and is usually a size slightly larger than the diameter of the charge. Modern, properly designed shaped charges penetrate armor up to six of their calibers thick.

Empire cumulative bomb

Although many cheering patriots consider Russia the homeland of elephants, we must admit honestly - before the war we had no idea about the theory of the production of cumulative bombs and shells. I had to copy everything from the Germans. The Germans themselves considered cumulative shells secret and had no intention of using them. But when they met our tanks, they immediately included these shells in the ammunition load of the T-4 tank, and the short seventy-five millimeter gun began to successfully hit the T-34. To be fair, it must be said that before the war we tested cumulative shells. But the focal length was not maintained, the fuse was slow and the results were disastrous. Having received samples of German shells, we began a new round of experiments. Moreover, our first shells were tested with German fuses.

As for our famous cumulative bomb, it was tested for a long time and tediously, but it turned out to be very unsuccessful. Everything was wrong - the shape of the funnel, the focal length, the thickness of the lining. Therefore, a cumulative bomb with a diameter of sixty-six millimeters penetrated only seventy millimeters of armor at an impact angle of ninety degrees. And according to the most conservative calculations, it should have penetrated at least one hundred and eighty millimeters of armor. But at that time, the fact that a tin cumulative bomb penetrated tank armor seemed like a miracle. And the top armor of even heavy tanks did not exceed thirty millimeters, and the cumulative bomb went into large production. Of course, this cumulative bomb increased the capabilities of IL-2 attack aircraft in the fight against German tanks, but its role in the Battle of Kursk is greatly exaggerated.

Modern cumulative bombs

The top armor of tanks has remained thin, so bombarding tank columns with small cumulative bombs is still relevant today. They are actually used not from bomb bays, but mainly from cluster bombs or special containers.

In the photo, a TORNADO plane fires cumulative bombs from a huge hanging container.

The cumulative combat element of the SMERCH multiple launch rocket system is very similar to a bomb. Instead of a stabilizer, it has a tape made of ordinary matter, which stabilizes the combat element and orients it with a cumulative funnel straight down.

Modern cumulative projectiles

The main difficulty in creating a cumulative projectile is that it flies and rotates quickly. High flight speed requires instantaneous operation of the fuse and leaves little time for the formation of a jet. The rotation of the projectile also prevents the correct formation of the jet. Instant fuses are designed as follows. There is a piezo crystal in the head of the projectile and from it there is a wiring to the electric fuse located at the bottom of the projectile or rocket. When hitting a target, the piezo crystal generates electricity (and the higher the speed of the projectile upon impact, the faster it generates it) and transmits it to the electric fuse. Rotation is more difficult. There are two main methods. In the first, the rotation is simply removed. There are also two options here. Install the charge on bearings in the projectile body (French version) or make the projectile non-rotating. A non-rotating projectile can be a feathered one fired from a smoothbore cannon. or fired from a rifled gun but also feathered. In the second case, a huge stabilizer of the projectile opens after the shot and this mill greatly reduces the rotation speed.

Shell for a 100mm tank gun. In the photo, the drop-down stabilizer is green.

Our ammunition is one hundred twenty-five millimeter caliber.

NATO caliber one hundred and twenty millimeters.

Our most advanced.

The second method of combating the influence of projectile rotation on the formation of a cumulative jet is to manufacture a lining of complex shape. What is written in the section about the formation of a cumulative jet is true, but the truth is simplified. In fact, when an explosive detonates, some kind of longitudinal - transverse - standing waves arise that must be fought with all our might. A person with an average-sized brain simply cannot understand this. Therefore, just look at the options for corrugated cladding and quietly melt with admiration.

It must be understood that both the cumulative bomb and the projectile direct only a small part of the energy forward, but in general they behave like an ordinary high-explosive charge. And if they wear a fragmentation shirt, then they get a universal bomb or shell.

You can read more about cumulative projectiles in this article

Protection against cumulative jet

I specifically did not write - protection from bombs and shells, in order to narrow the topic and not write about reactive armor. Our conditions are as follows: the cumulative jet has overcome all external obstacles and is left alone with the obstacle. Knowing that the jet sprays the obstacle, we just need to find a material that does not spray well. As it turned out, ceramics and organic glass are the worst to splash. For the latter, this is due to the size of the molecules - they are very large. These are the simplest options. But there is also cellular armor. Its cells are filled with polyethylene; when the jet passes, cross currents arise that deform and kill the jet.

Experiments with water and gelatin armor

If desired, you can recreate the cumulative effect even at home. To do this, you will need distilled water and a high-voltage spark gap. The latter can be made, for example, from a cable by soldering a copper washer to its braiding coaxially with the main core. Next, the central wire must be connected to the capacitor.

The role of a funnel in this experiment can be played by a meniscus formed in a thin paper tube. The discharger and the capillary must be connected with a thin elastic tube. Next, pour water into the tube using a syringe. After the formation of the meniscus at a distance of approximately 1 cm from the spark gap, you need to install a capacitor and close the circuit with a conductor attached to the insulating rod.

During such a home experiment, high pressure will develop in the breakdown region. The shock wave will run towards the meniscus and collapse it.