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Showing content with the highest reputation since 05/27/2020 in Posts

  1. 4 points
    SH_MM

    Polish Armoured Vehicles

  2. 3 points
    3-8 Cav got some SEPv3 yesterday, although they are slightly different again.
  3. 2 points
    TWMSR

    Tanks guns and ammunition.

    Hard to tell. L28 used WC core with WHA cap/nose and steel cup in-between. The cup would not be seen without disassembly, but core and cap material should differ in look. At this picture WC cores of older APDS looks darker than supposed WHA cores of newer APDS. Probably L52, not L28.
  4. 2 points
    And here is unknown model of T-80 that was adopted for service - T-80B2. Main difference between T-80B2 and T-80B was GL-ATGM - instead of Kobra T-80B2 model was armed with 9M128 Agona GL-ATGM. In 1985, when development of Agona was reaching it's goal, Svir and Reflex GL-ATGMs were already adopted for service, making Agona irrelevant in eyes of Soviet Army. But tank was adopted for service before army made final decision, and that decision was not to produce T-80B2. Agona ATGM reached state trials in 1986 and was adopted for service in 1988. It had tandem HEAT warhead, ~600-650 mm RHA penetration. Guidance system was similar or same as with Kobra - radiocommand.
  5. 2 points
    Laser Shark

    CV-90, why so much love ?

    https://www.regjeringen.no/no/aktuelt/fremskynder-forsvarsplaner/id2704271/?utm_source=www.regjeringen.no&utm_medium=rss&utm_campaign=RSS-2581966-ownerid380 It looks like Norway is going to acquire another 20 CV90. There is no info on what variants this order will include, but if it’s a direct purchase from the Norwegian industry, I suspect there will be more of the turretless support variants based on Mk I hulls. It was the Norwegian industry that was responsible for rebuild of these vehicles the last time, and Norway should still have more hulls available as out of the original 104 CV9030N (Mk I), 16 hulls have been upgraded to CV90RWS STING (combat engineer vehicle), 16 to CV90RWS Multi-BK (multi-role mortar carrier), 37 have been sold to Estonia and a few have also been used in mine/IED tests. In any case, as suggested by the wording in the second to last sentence of the quoted paragraph, Norway will probably have to order more CV90s than that (and of the turreted variants as well if those aren't included in this order) if it wishes to realize the army structure mentioned in this post.
  6. 2 points
    Beer

    Get Away, Damnit. (The Camping Thread)

    Few more pics from my hiking. Only one or two from each. It would be way too many of them... Vltava river, south of Prague Sázava river, just few kilometers away Pastviny dam, eastern Bohemia A tourist path over the Lužnice river near Tábor, south Bohemia. Once there was one of the main Hussite fortresses near this tunnel but close to nothing is left of it (Příběnice), it's some 10 km from the Hussite capital city Tábor. Countryside near Česká Lípa, Northern Bohemia Now something cultural, Kutná Hora without the crowds of tourists. This city was once one of the richest in Europe thanks to its silver mines which were the deepest medieaval mines in the world (around 450 meters under the ground at the end of 15th century). This fantastic place is also famous for its bone church which is decorated by bones of 40 thousand victims of plague and Hussite wars (and which is by some funny coincidence lcated just next to a factory of Philip Morris). Jizera mountains, north-eastern Bohemia, view towards Liberec city (hidden behind the hills) and its Ještěd mountain with a tower which won the 1969 Prix Auguste Perret architectural prize as the only building in our country. A very local rain shower at the Sedlo mountain, northern Bohemia View towards the German Saxony border, Lužice mountains, northern Bohemia (the boxy cliffs at the far distance are already in Saxony).
  7. 2 points
    Today made a trip with a friend back to abandoned buildings from my post above. Apparenly they were supposed to be water treatment facilities. This time 80% more of parkour was used to get to new places. Moving to biggest of unfinished buildings in this area. Will try to get inside of it. Back to underground level of that building, but walked deeper. In order to get there we had to do 3 jumps from concrete pieces that were surrounded by water on top pillar base. Next is small building. We got in it and explored 2 floors and a roof. Roof was uninteresting, no photos of it. Few other guys were there, firing BB gun somewhere. Small building away from main group of structures. Big hangar-like structure. Hangar itself you could see in pics from my previous trip, this time me and friend explored smaller rooms. And friend's photos of building that is like 70% flooded from my previous post.
  8. 2 points
    SH_MM

    Turkish touch

    New design of the Turkish Leopard 2 armor upgrade offered by Roketsan: I wonder if they took a look at Aselsan's Leopard 2 NG with AMAP armor... Seems to be an evolution of their earlier prototype design:
  9. 2 points
    https://thedeaddistrict.blogspot.com/2020/03/analisys-of-combat-damage-of-ukrainian.html
  10. 2 points
    From 2017 Belarussian OJSC “2566 electronic weapons repair plant” is working on putting Osa AA system combat module on wheeled chassis (MAZ-6317).
  11. 2 points
    Model of Sosna AA system combat module on BTR-82A chassis
  12. 2 points
    VPZ

    Israeli AFVs

  13. 1 point
    Linked to the above - Lance turret for Boxer CRV Block 1 vehicles being test-fired from a KF31 hull in Germany.
  14. 1 point
    https://andrei-bt.livejournal.com/1648707.html Puny capitalist mortar shells.
  15. 1 point
  16. 1 point
    This is what Valve was developing all those years after Episode 2...
  17. 1 point
    Karamazov

    Polish Armoured Vehicles

  18. 1 point
    Beer

    Czechoslovak interwar bits

    Some footage of the only LT vz.35 tank in running condition. In fact it's Pz.35(t) - naturally - as can be seen from the fact that it has four men crew instead of original three (the German modification of original Czechoslovak tanks added fourth crew member) including some shooting. You can see a lot of machine gun scars on the tank. It was originally captured by US Army and displayed in Aberdeen before getting back to Czechia some ten years ago or so. More of LT-35 driving. Here preserved and running original LT-38. Praga AH-IV tankette driving, this tankette was exported to Sweden, Iran and other countries before WW2. It was never used by Czechoslovak army. You can see that it was pretty fast and nimble machine (although its engine is a bit more powerful today when it runs on modern petrol). Nicely done replica of tankette vz.33 running. This rather useless thing (modification of Carden Lloyed Mk.VI tankette) was actually fielded with the border units and even saw some combat with Sudettendeutsche Freikorps before the WW2. In this reanectment event you can see running an armoured car Austin from Czechoslovak legion (1919), replica of Renault FT, original LT-38, replica of tankette vz.33, replica of armoured car vz.30. A running LTP tank. Despite it being in Czechoslovak camo it is in fact an export predecessor of the LT-38. This particular one served in the army of Peru and fought against Equador. It served well in the high mountains for some 30-40 years.
  19. 1 point
    SH_MM

    The Leopard 2 Thread

    Not as far as I am aware. The difference in image quality also wouldn't be very large, as OPHELIOS was very simple in order to be cost effective in the early 1990s, when the manufacturing of electronic components still was cumbersome and expensive.
  20. 1 point
    That is a very emotional response to the topic. You cannot call bullshit without knowing the Austrian requirements and test conditions. Maybe the Austrian military used smaller targets, wanted an acceptable hit probability while firing on the move, wanted to engage targets at longer ranges or where expecting firing performance closer to the Leopard 2 or M1A1D/M1A2? That the fire control system of the M60A3 wasn't on par with the newer tanks is well known. In CAT it managed to get a third, an eight and a ninth place... It isn't really a matter of interpretation. The NP105 APFSDS wasn't tested with one single gun, it already was accepted for service in 1985 after demonstrating its ability to defeat the required targets (including an arrangement of three spaced steel plates). The complaints about the unsatisfactory dispersion with the NP105 lead to the investigations criticized by the Rechnungshof. The waffenseitiger Fehler either refers to all M68A1s being faulty or all M60A3s being considered faulty in regards to meeting the Austrian requirements. Not the single (?) M68/M60A3s in the trials, as otherwise the common soldiers would never have complained about the lack of accuracy in 1989 and 1990.
  21. 1 point
    SH_MM

    The Leopard 2 Thread

    Shouldn't matter. The prototypes were built with weight simulators, not the actual armor packages. The different shape of the mantlet is related to the different guns mounted on the tank. It is a drawing based on documents from the German national archives. Wiedzmin made it based on the descriptions/drawings in the declassified documents. You will find more about it in the earlier pages of the topic. Only new production Leopard 2A4 tanks made in and after 1988 received newer armor. All earlier Leopard 2A4s were made with the same armor as the original Leopard 2 production model of 1979. This armor is probably very similar to the one designed for the Leopard 2AV in 1976, as it is based on it. Yes. The OPHELIOS second-generation thermal imager for the commander was created as cost saving measure, as the new European second-generation thermal imaging modules (developed during the TRIGAT project that included Belgium, France, Germany, the Netherlands and the UK) weren't available in time for production and would have very expensive during the early 1990s. The plan was to later replace OPHELIOS's thermal imaging module and the WBG-X completely with a new design utilizing the TRIGAT's thermal imaging module (that was introduced with the UHT Tiger in German service and also used on various other weapon systems such as the other Tiger variants, the Leclerc, the Warrior IFV, the Scimitar scout vehicle and the T-90A as part of different thermal imagers), but upgrade plans came to an halt when the KWS III was canceled.
  22. 1 point
    LoooSeR

    Polish Armoured Vehicles

    PT-91 Twardy deploying smoke screen
  23. 1 point
    [title image] Hollow charges and armor protection - their alternating progression The term "hollow charges", which is commonly used in German, is not very accurate for the explosives so called. The somewhat more general American term "shaped charge" is a better description of the measures necessary to achieve the desired effects with these charges. Apart from the explosives used by glider pilots at Fort Emeal, it is of great importance for the vast majority of the extensive and versatile range of applications of shaped charges developed since the Second World War that their suitably shaped surface is covered with a layer of inert materials, preferably metals. The individual elements of the liner are accelerated to velocities of several km/sec and, through special selection of the initial shape and dimensions, it is possible to transform these liner bodies into projectile-like structures which are best suited to combat the respective target. This possibility of adapting the effector to the structure of the target to be engaged is very important for the use of hollow charges, but the application potential of these charges, given their early and impulsive nature, is far from exhausted by what has been developed in this field so far. This is particularly true when it comes to combating targets whose design is already tailored to protect against the known hollow charges. This will be explained in more detail below; in addition, examples will be used to illustrate the many different ways in which explosives can be used to obtain targeted effects and counteractions. The effect of explosive devices attached to armour panels - the "spalling effect" In most cases of using detonating explosives, the energy released by the detonation is transferred to inert materials. In the case of armour plates on which explosives are detonated, the direct effect is relatively small. Although the detonation pressure exceeds the strength of the armour material many times over, the material goes into a state of fluidity and is slightly pressed in at the surface - something similar happens when damp clay is pressed. The depressions that occur are small because the time during which the detonation pressure is sustained and the material is in a flowing state is very short. This only lasts until the relaxation of the highly compressed explosive decomposition products towards the free surface of the detonator has taken place. If, for example, an explosive layer of 2 cm thickness is placed on an armour plate, the impact time on a surface element of the plate during detonation is about 2/800000 sec, i.e. 2.5 µsec. During this time only a slight displacement of the plate material can occur. The example of an explosive layer applied to the surface of an armour plate and detonated there is also suitable for explaining a phenomenon that is very important and is referred to several times in the context of the present comments: [Figure 1] Under certain conditions, material parts detach from the rear side of the armour plate and are propelled at quite high speed into the space behind the plate. This so-called " spalling effect " occurs whenever a limited area in a body, where the material is under very high pressure, reaches a free surface of the body (see figure 1). There, the material parts compressed under high pressure relax and advance perpendicular to the surface. The relaxation is thus associated with acceleration. While the relaxation spreads into the interior of the pressure area, all material parts that have been compressed by it are accelerated. If the relaxation wave reaches the rear end of the pressure area, i.e. the zone in which the material particles are not compressed and therefore remain at rest, the parts that have been set in motion by the relaxation break off at this point and continue their motion only outside, provided that the tensile stress that occurs exceeds the tensile strength of the material. In the case of the spalling effect, one observes a separation of disc-shaped plate parts on the back of an armour plate exactly opposite the surface covered by the explosive on the upper side (see also Figure 15). This surface must not be less than a certain size, because the accelerated, spalling parts must not only overcome the tensile strength of the detachment from the inner plate parts, which remain at rest, but also the shear stresses at the edge of the spalling plate. In general, this is only then the case when the diameter of the overlying explosive layer exceeds the thickness of the armour plate, otherwise a " bulge" appears on the underside of the plate. The effect of the " squash head " projectiles is based on this spalling effect. The explosive in the bullet cap is released when the projectiles impact on of the armour plate is spread and then detonated. 1) The effect of unshaped, uncontained explosive charges in the free atmosphere If an uninsulated explosive device is detonated in the open atmosphere without any special design or arrangement, its effect is relatively small at a distance from the source of detonation. Although the pressure behind the detonation front, which in modern explosives can reach speeds of is advancing at about 8 km/sec, is quite high. It is in the order of several hundred thousand atmospheres, but it rapidly decays as it spreads in all directions, distributing energy and momentum over areas that grow quadratically with distance. By contrast, special arrangements, which should be mentioned here because they are to a certain extent related to hollow charges, can be used to achieve a sufficient pressure effect even with unshaped, unchecked explosive charges at greater distances, for example against flying targets. If, for example explosive charges are arranged at the corners of a regular polygon and detonated simultaneously, a very effective superimposition of the pressure occurs on the axis of symmetry of the arrangement at distances of up to several diameters of the polygon - in the so-called Mach area. Towards the end of the Second World War, the possibility of using such charge arrangements from the ground against enemy aircraft flying in pulks had been considered. In model tests with 6 charges of 50 kg trinitrotoluene (TNT) each, regularly distributed on a circle of 100 m diameter, a pressure of about ~15 bar was measured 350 m above the ground in the vicinity of the axis of symmetry. Protective effect of multilayer armour In order to be protected against the spalling effect of squashing head projectiles and similarly acting warheads, it is advisable to provide armour which consists of at least two layers with a gap between them. For this reason alone, the development of anti-tank ammunition was therefore based on paying special attention to multilayered armour. The requirement for penetration of structured armour with air gaps is also indispensable in other respects. The same conditions apply, for example, when an armour is hit by a plate covering the running gear or by a "skirt" attached to the running gear. In the case of more or less abrupt impact, the point at which the ignition of a shaped charge warhead takes place can then be up to several metres away from the point at which its main effect should begin. In addition to standard single-layer targets, the testing of hollow-charge ammunition therefore includes targets consisting of several plates spaced at certain distances from each other (see Figure 2). [Figure 2] In principle, the mode of action of hollow charges meets the above-mentioned requirements very well, much better than is the case with conventional impact projectiles. When a kinetic projectile hits a armour surface, a high pressure is created in both the armour material and the projectile. Starting at the tip, a pressure condition is built up in the bullet, which leads to the phenomenon described earlier in the treatment of the spalling effect on the free surface of the bullet. Tensile stresses occur which begin to tear the bullet body before it has penetrated the target surface. They can cause the bullet to disintegrate into individual parts after penetrating the first plate, which are then stopped by a second plate of a multilayer target (see Figure 3 a and b). [Figure 3] If, on the other hand, hollow charges with a lined cavity are detonated on the target surface, the so-called hollow charge jet is generated, which is sometimes called a "spike" because it is initially coherent and usually occurs in a solid state. With the hollow charges commonly used today, the jet disintegrates as it advances into a series of small - often spindle-shaped - very fast projectiles, whose frontal velocities can reach about 10 km/sec; the last ones still achieve about 2 km/sec. When the first particle hits the surface of the shell, a pressure in the order of 1 million atmospheres is created there; the shell material begins to flow and an approximately tulip-shaped crater is formed, similar to the penetration of a body of high velocity into water. The volume occupied by the crater is released by displacing the armour material towards the free surface. When the second jet particle hits the bottom of the crater, repeat the process, as well as the impact of the following particles. Each particle continues the displacement of the target material where the previous one stopped until schliefilich creates a channel of penetration through the whole plate. The flow of the material particles associated with the displacement of the target material ends at the free surface. Partly at the upper side, partly at the lower side of the armour plate and partly also at the already created penetration channel, which is subsequently narrowed again slightly. The following jet particles not consumed during penetration continue their path after passing through the penetration channel and act on obstacles that are on their path. If they hit another armoured plate, they can continue the penetration process there undisturbed. In contrast to the behaviour of the compact kinetic projectile, the individual elements act on the armour one after the other, independently of each other, and it does not seem so important at first whether the armour is massive or in separate parts, because a disturbance at the tip of the projectile does not affect the following parts. Nevertheless, the so-called "bulkhead armour", in which a number of thinner armour plates are arranged with air gaps between them, also provides increased protection against hollow charges: The penetration channel created by the impact of the particles of the hollow-charge projectile is relatively narrow and is of the same order of magnitude as the plate thickness when using thinner plates of the bulkhead armour. When the hollow-charge particles strike these thin plates, the hole in the plate is created essentially by the fact that the material elements of the plate which are caught by the high dynamic pressure are forced away from the plate under the influence of the tensile stress acting perpendicularly to the free surface, both on the upper and the lower side of the plate. The penetration channel therefore runs almost perpendicular to the plate surface, regardless of whether the hollow charge particles generating the pressure impact obliquely or vertically. The tensile stresses induced at the plate surface as a result of the dynamic pressure are in any case perpendicular to the plate and also have an effect in this direction (see Figure 4). [Figure 4] If now diagonally incident subsequent particles reach the previously created penetration channel running approximately perpendicular to the surface, they find a much reduced cross-section for their passage compared to the vertical incidence (see Figure 5). There is thus an increased probability that they will come into contact with the wall as a result of path variations, as a result of which their contribution to the penetration performance is lost. The affected particle disintegrates explosively, since - as described above - the high pressure occurring during wall contact induces tensile stresses on the free surface of the particle, causing it to burst. In Figure 6, a TRW image converter camera is used to illustrate how a steel ball of 2 mm diameter is sprayed after it has penetrated a very thin plastic film at very high speed. Figure 7 shows the piece of a hollow charge jet in which a similar burst was triggered on a particle by touching the wall. As can be seen from the figure, the small debris of the disintegrated particle spreads sideways to the direction of the beam, apparently away from the wall that was touched. It is important that the propagation of these fragments into the free space behind the plate is possible. At massive targets this free space is not available, the particle splinters would be held together and their impulse could contribute to the penetration even if the particle had touched the wall before. That's why it's important, armoured plates and air gaps of certain thickness should follow each other. [Figure 5, figure 6 and figure 7] This leads to bulkhead arrangements which, when hitting the wall at an angle, cancel out the effects of a high portion of the hollow charge jet due to the increased probability of the jet particles touching the wall and their subsequent disintegration into the gap. The weight of the armour required for this, in relation to the unit area, is considerably less than in the case of solid armour. It is essential that this provides increased base protection against both balancing projectiles and shaped-charge ammunition, and it is noteworthy that this effect occurs in both cases by inducing the decay phenomenon on impact at high velocity. However, in the case of a balancing projectile, the entire mass of the energy carrier is captured by the destructive tension waves on first impact, whereas in the case of a hollow-charge jet only the mass portion corresponding to the respective impacting jet particles is captured. Measures to avoid disturbance of the shaped charge jet However, it is not clear why rear particles of the hollow charge jet must necessarily come into contact with wall elements of the penetration channel created by the previous ones. Should it not be much more possible to ensure that the particles aligned very cleanly and without "staggering" movement exactly on the cavity axis? However, this means that the slightest deviations from central symmetry must be avoided in the structure of the hollow charge. The whole rigor of this requirement is that it relates not only to the dimensions of the charge, but also includes the homogeneity of the materials used and that - as has already been shown - even differences in the size and orientation of the crystals in the explosive and in the copper of the liner have an influence. This requirement is even more stringent if one takes into account that the properties of the crystals mentioned above change over time, i.e. as they age, and that changes are also triggered during processing. A very sensitive influence can also be expected from the way the detonation is initiated. With the aforementioned and similar requirements with regard to precision, the production of hollow charges has set goals whose pursuit in the past has already brought about significant progress with regard to the generation of an undisturbed hollow charge jet during detonation, and in the future, through the tireless efforts of research and technology, even further perfection can be expected. In addition to this somewhat utopian-looking reference, however, it must be emphasized that the hollow charge principle is very flexible and includes a wealth of other possibilities for counteracting disturbances which oppose the effective targeted use of the explosive energy released during detonation. For example, it is not necessary for the hollow charge jet to dissolve into a number of particles as it progresses. Some of the irregularities in the behaviour of the particles will only develop during the tear-off process and can be avoided if the hollow charge jet is constructed in such a way that it does not tear. The reason for the dissolution of the hollow charge jet into a number of particles of different velocities is that the individual jet elements already have a different velocity when they are formed. In the case of the hollow charges currently in use, there is a velocity gradient in the beam from about 8-10 km at the tip to about 2 km at the end.The consequence is that the jet is constantly stretched as it progresses and eventually dissolves into more or less parts according to the strength properties of the material .2) The programmed shaped charge jet By special selection of the parameters of a hollow charge (type and density of the explosive, dimensions and shape of the cavity, wall thickness and material of the cavity lining, shape as well as wall thickness and material of the casing, position and extension of the ignition elements) it can be achieved that differences in the velocity of the individual elements of the jet are prevented at all. The relationship between the distribution of mass and velocity in the jet and the charge parameters was already known shortly after the discovery of the the lining of the cavity achievable effect by Thomanek quite detailed results. 3) This connection is achieved by following each individual sub-process during the detonation of the charge and the deformation of the liner by calculation. When the detonation front reaches the individual zones of the liner body, the material there enters a state of flow under the influence of the detonation pressure and is accelerated inwards. The speed at which the lining elements are accelerated depends on how long the pressure remains at the zone under consideration or, which comes to the same effect as how far the outer surface of the detonator is from this point. Thus, the influence of the width of the explosive coating on the velocity of a panel is obtained. For example, consider a cylindrical charge with a cone as a cavity and a diameter of 8 cm. The time required for the dilution wave to reach the top of the cone from the outer surface is then 4 cm/approx. 800000 cm/sec, i.e. approx. 5 microseconds; in the central zones of the cone with an explosive coating of 2 cm, this time is only half as long and the impulse transmitted to the lining elements by the detonation pressure in this time is therefore half as large. Of course, the speed also depends on the wall thickness of the lining body at this point and the density of the lining material. The initial velocity of the lining elements can be specifically influenced by a suitable choice of the wall thickness and it can change at will between the tip and base of the lining cone. One speaks of "progressive" or "degressive" liners, depending on whether the wall thickness increases or decreases towards the base. The influence of the liner's wall thickness/explosive coverage ratio then has a further effect on the jet elements that are emitted when the liner zone converges on the cavity axis. In addition, the mass and velocity of the jet elements formed depend on the angle at which the convergence takes place, i.e. the opening angle of the cavity. Peak angles result in high velocities for small masses, and the opposite is true for obtuse angles. The previous remarks should serve to explain, at least by way of indication, how it is possible to determine the dependence of the distribution of mass and velocity in the jet on the charge parameters. With the knowledge of these interrelationships, it now seems possible to create projectile-like structures from the cladding bodies, in which the initial length and the distribution of mass and velocity over this length are predetermined, i.e. the hollow charge jet can be programmed. Up to now, almost all attempts have been made to obtain a jet with the greatest possible penetration capacity. This led to the familiar design forms: cylindrical on the outside, cavity for example 60° cone with copper liner, initiation of the detonation now often by detonation wave deflection at the rear edge of the detonator, whereby better use of the explosive volume and higher beam tip velocities are achieved (compare also Figure 16). The resulting beam is then a constantly stretched structure with a velocity of up to 10 km/sec at the tip and about 2 km/sec at the end, which is followed more slowly by the rest of the cladding mass, the so-called "slug". 4) As already mentioned several times, the differences in the velocity of the individual beam elements cause the initially coherent structure to be broken up into a sequence of particles. Nevertheless, very good results have been achieved with the described type of charges, especially against massive targets. Penetration depths of up to 6 charge diameters have been achieved. In contrast, when using targets with air gaps, the distance travelled in the massive parts of the target is greatly reduced. In the future, requirements for the performance of hollow-charge ammunition should be geared to these reduced amounts; this would mean that modern hollow charges should be developed to penetrate structured targets rather than exaggerated penetration performance in massive targets. An attempt should be made to program the hollow-charge jet, i.e. to adapt it to the structure of the target. In the following we will try to explain by means of examples that there are many possibilities to modify the beam of the currently used hollow charge. A completely different motion sequence of the particles of the beam from this type of charge can be obtained by replacing the centrally symmetrical ignition by a (one-sided) eccentric one.The individual beam particles then no longer move one behind the other on the cavity axis, their paths point in a fan-like manner in different directions (compare Figures 8a and b) 5) The following example is intended to show how even a slight change in the cavity shape can noticeably influence the beam and its effect. Figure 9a shows a cladding body whose shape can be roughly described as a cone which ends at the base in a spherical zone. Figure 9b shows the penetration channel of an externally cylindrical charge produced using this liner. [Figure 8 and figure 9] The explanation for the peculiar shape results from the velocity distribution in the hollow jet. The front part of the jet comes from the cone-shaped part of the cavity and corresponds to the jet from a cone, which stretches as it advances. For the subsequent jet elements, which originate from the spherical zones at the base, it is decisive that the tangent at the cavity becomes steeper and steeper towards the base. The consequence is that the successive jet elements become faster and faster towards the rear, thus approaching each other and leading to a thickening of the jet in this rear area. On impact, the effect is increased in the form of a widening of the penetration channel. While with the hollow charge described above, a concentration of energy occurs in the rear jet section, it is also possible to achieve this in the front jet section. For this purpose, the cavity must be spherical at the apex and end in a cone at the base (see Figures 10a and b). The penetration channel is wide at the top and has the shape of a hemisphere followed by a narrow conical part. 6) If the cavity, which is essentially delimited by a cone, is spherical at both the apex and the base, the penetration channel will consist of a wide part at the armour surface, followed by a narrow conical part and a further widening at the end. Following these examples, it should be considered possible that the effectiveness of the individual sections of the hollow charge jet can be determined in quite a different way, especially if it is taken into account that other parameters of the hollow charges can also contribute to this by their specific choice. [Figure 10] As explained in the previous section, other velocity distributions are possible in addition to the velocity gradient in the jet of the commonly used hollow charges that leads to rupture. It is also possible to achieve that all beam elements have the same velocity, provided that the relevant charge parameters are adjusted to it in each zone of the cavity. If, for example, the wall thickness of the cladding is selected in such a way that it is in the same ratio to the corresponding width of the explosive coating for all zones, the cladding elements of all zones receive the same initial velocity on detonation and thus also all the beam elements that are separated from them when flowing together on the cavity axis. As a result, the jet is represented here by an "overlong projectile" with a rather high velocity. A sketch of the principle of such a charge is shown in Figure 11. The nozzle-shaped body attached to the base has the purpose of preventing the decomposition by-products from coming into direct contact with the free atmosphere when the base zone is accelerated, thus avoiding a premature drop in pressure. In a similar way, other causes of disturbance are to be avoided, whereby a number of experiments are always necessary before a principle path can be realized. [Figure 11] Instead of a single rod-like projectile, a sequence of several such rods can be obtained in which the individual elements have the same velocity, with the velocity of the rods differing from each other. In addition, from the special solution of the identical velocity of all beam elements, transitions to the common hollow charge with the large velocity gradient in the beam can also be developed. In particular, the case can also be realized in which the difference in the velocity of the following beam elements is so small that the beam is only broken when all obstacles of the target have been overcome. How such a continuous beam reacts to protective measures that disturb a particle-dissolved jet is still to be investigated. In any case, the disturbances caused by the rupture process are avoided here (compare Figure 12). [Figure 12] Also, the range of possible variations in the structure of the shaped charge jet is so wide that an adaptation to very different target compositions seems possible. Not insignificant is the fact that the energy of the effect carriers from a hollow charge can be distributed in a targeted manner to mass and velocity, i.e. the jet can obtain a greater mass at the expense of the velocity of its elements and vice versa. As investigations have shown, the protective effect of certain materials depends on the speed of the projectiles. 7) However, such measures need not refer to the entire jet, but can be limited to parts of it, for example to the front or rear parts of the target. A special group of shaped charges has not been mentioned so far, namely those with a flat, especially blunt conical cavity. ln contrast to the pointed conical cavity, the attainable velocities are lower here. The speed of the structure previously referred to as the jet is no longer very different from that of the so-called following slug. It can be achieved by methods which will not be discussed in detail here, that the jet and slug components - i.e. the entire mass of the liner - merge into an at least temporarily coherent structure. lf the difference in the speeds of the front and rear parts is sufficiently small, it is absorbed by internal expansion work, and a projectile with a uniform speed of about 2000 m/sec is created. Figure 13 shows a series of such projectiles from charges with a flat cavity, using X-ray flash images. Figure 14 shows a section through a captured specimen of cohesive projectiles. Such projectiles are particularly characterized by stable flight at long distances and have already found 'a versatile application today, especially as a replacement for natural fragments (see also cover picture and Figure 15). [Figure 13, figure 14 and figure15] In connection with the efforts to combat future targets, which may be unknown at present, it should be mentioned that it is possible and possibly very useful to arrange projectile-forming hollow charges in a special way one behind the other. If this is done taking into account all the side effects of the detonation, and if such an arrangement is ignited appropriately, one obtains a sequence of projectiles flying one behind the other at fairly high speed, the mass of which is considerably greater than that of particles of the hollow charge jet. It is also possible to combine a projectile-forming charge with a jet-forming charge with an acute-angled cavity. Figure 16 shows such a charge, also known as "tandem charge". It was designed to create a strong follow-on effect inside the tank. On detonation, the jet from the rear charge penetrates through an opening in the apex of the front flat-cone charge. Only after this has been done is this charge also detonated; the flat liner body is formed into a projectile which follows the jet from the rear charge through the channel created by it and comes into effect there depending on the intended purpose. [Figure 16] These examples are intended to show that there are almost no limits to the imagination when it comes to exploiting the potential inherent in the principle of forming effective projectiles by transferring explosive energy to inert materials. There are many ways to develop explosive charges that can be effective against complex targets and do not necessarily require a gun to reach the target, but can be used in warheads of missiles. Of course, there will always be possibilities to achieve sufficient protection by suitably constructed armour. What should be particularly emphasized here, however, is the view that there is hardly likely to be a miracle cure for all types of shaped charges and that, apart from a temporary predominance on one side or the other, there will probably continue to be mutual efforts to perfect shaped charges on the one hand and protective armour on the other.
  24. 1 point
    Bundeswehr tested effects of an absolutely enormous VBIED on HESCO barriers and other fortifications and stuff. Definitely worth watching.
  25. 1 point
  26. 0 points
    Friends, rejoice! After a long stint at the Dakota Union reeducation camp I have returned. There the evil blackguards who preach the word of small, weak bullets tried to convert me to their blasphemy. But I was too cunning for them - I learned their ways and have returned to turn their secret fires against them! Here is my creation, the shining spawn of my mind. Behold, the 7x48mm FGM2! Although still a bit petite for those amongst us who still follow the true creed of big, girthy, manly-man bullets, it shall serve as a dagger thrust into the heart of the snake that is the second joint committee for cartridge development. For it meets, nay exceeds the requirements of their grotesque mockery of a competition. Now, truly, the scales will fall from the eyes of the people as they are forced to test it and admit its might! And here is the proof: And even at lower velocities, it still almost very nearly juuuuuuuust doesn't make the requirements: And the news only gets better from here! The recoil is low enough even for the atrophied shoulders of the testing committee (10.49 ft-lb). The penetration into pine boards easily exceeds requirements even at the lower velocities (26 pine boards at 600y at the lower test velocity, 29 at the higher velocity). And the cost is fantastically cheap (5.63c) thanks to the use of an annealed, copper-washed mild steel mono-bullet and a lacquered steel case. Truly this is an expedient cartridge that every soldier can take into battle aplenty, to distribute to his foes liberally. And best of all, the use of a long, finely-profiled bullet (OOC note: dimensions taken from here and properly adjusted this time) means that there is plenty of volume for specialty loads (incendiary, armour piercing and so on) that can be ballistically matched to the standard round. My friends, it truly feels good to be able to say this: our great Dakota Union now has a cartridge fit for a man. Edit (OOC note): so I'm a dumb-dumb in more ways than one, and needed a lot of background assistance from @Sturgeon to put together something that actually made requirements (kinda, sorta, almost). So a big thanks to him for taking the time to answer all my questions and provide feedback.
  27. 0 points
  28. 0 points
    Toxn

    Mini-Competition: Sioux Scout Rifle Caliber

    Having now delved into this issue a bit, the bias of the judging committee becomes clear. They are determined to snuff out the manly, big bore cartridge and replace everything with weak, womanly micro-bullets! Well, two can play at that game. Here is the 5x58mm PoS (Poodle Shooter); a cartridge designed specifically to wound small animals and burn up barrels: We considered other names: the 5x58mm WaNK (Wound and Not Kill), the .197 StFU (Stupid-small, Fast and Useless), the 19-55 Shamebringer and so on. We would be happy to elaborate on these monikers further should the committee so require. The bullet (barely more than a pellet) is turned brass, because we cannot imagine anyone wanting to make the fiddly tooling to jacket it. The case is lacquer-coated steel, so that soldiers can waste ammunition more easily without so much as having to stoop to pick up expensive brass. Proof that it fulfils the despicable requirements of the biased commitee is provided below (OOC note: the BC is based on the Berger 6.5mm 140gn VLD bullet, using 0.307 G7 BC): This includes the lower-velocity requirements: I think we scarcely need to provide proof that such a pathetic round meets the recoil requirements - simply give weapons to women and children and ask them for their opinion (OOC note: 3.8186). Penetration is... uh, acceptable (OOC note: 27 1/2" pine boards, stopping in the 28th at 600y using the lower-velocity test cartridge). Moving on: as to the economy of the round, the calculated value is 8.77 cents. This proves that, even when shooting such microscopic bullets, there is simply no value for money over the venerable M80! Given how expediently we intend our offering to be produced (because we intend to warn our government, not rob it), we cannot imagine that our competitors will do anything more than burn through tax-payer's money in their feckless pursuit of speed over power. A final word: know that we, the designers, have seen through this comical charade and are one step ahead! We have now bought into a barrel making and rifling tooling company, in the expectation of making a fortune on future government contracts for worn-out barrels when this contract is inevitably handed to one of the small-bore "iconoclasts" that litter this great city. In conclusion; we hope that the government of our great Dakota Union soon sees the light and kicks out the charlatans running this rigged competition out. Until then, we offer the 5x58mm PoS as a warning, and a plea to return to a more sensible procurement approach based on the stopping power of big bullets. Edit: so, as @Sturgeon pointed out, I done goofed up with the bullet's BC. When you use something more appropriate, the bullet actually fails on the energy requirement. Which is just more proof of the inferiority of micro bullets! Etc etc.
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