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That_Baka

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  1. Tank You
    That_Baka reacted to Wiedzmin in Tanks guns and ammunition.   
    it's a BS, thats why nodoby post full report 
     

    100mm APDS and 125mm HEAT

    125mm APFSDS with core and 115mm APFSDS with core
     
     


     
     
  2. Sad
    That_Baka reacted to LoooSeR in General Naval Warfare News/Technology thread.   
    Great job, just a great job.
     

     
     
  3. Funny
    That_Baka reacted to LoooSeR in United States Military Vehicle General: Guns, G*vins, and Gas Turbines   
    Our military experts are most expert in their field! M48 is just an IS-3 with American paint over true Soviet Green camo! 
  4. Tank You
    That_Baka reacted to Wiedzmin in Contemporary Western Tank Rumble!   
    don't argue with religious fanatics
     
     
  5. Tank You
    That_Baka reacted to Beer in Contemporary Western Tank Rumble!   
    Sorry to jump into the discussion but this is outright silly. It's based on the believe that the schematics are perfectly correct in details they are not supposed to represent accurately. Anyway the general rule is that the only valid value from any drawing is the one with an explicit dimension - and that applies twice as much for any drawing from the old times when 2D was not yet simply generated from 3D by software. 
  6. Tank You
    That_Baka reacted to LoooSeR in United States Military Vehicle General: Guns, G*vins, and Gas Turbines   
    TV Zvezda show about BMPT. A bit from from it (24:30)
     

     
       "And not from German Panther or Tiger, but from our IS-3 Americans copied their M48".
    @Sturgeon @Collimatrix @Scolopax
     
       Capitalist pigs were exposed by this totally accurate show! Explain yourself, decadent bourgeois! And stop copying our shit!
     
  7. Tank You
    That_Baka reacted to skylancer-3441 in Documents for the Documents God   
    all IDR issues stored at RSL are photographed. This folder contains almost 100 Gb, probably some 70k photos - including about 30k duplicates. Once I delete those, and rename rest, I'll visit RSL for IDR issues once again - to reshoot those photos which turned blurry and unreadable, I expect to find at least couple of hundred of those.
  8. Tank You
    That_Baka reacted to skylancer-3441 in Documents for the Documents God   
    https://cloud.mail.ru/public/9dEX/djuwzbp4V/Jahrbuch der Wehrtechnik/Jahrbuch der Wehrtechnik 8 (1974)
    Vol.8 done from cover to cover (well, with the exception of covers themselves (as they do not contain anything except "Jahrbuch der Wehrtechnik 8") and last page of dust jacket)
     
    all 4 parts of article on nightvision are available.
     
    ...
    27.06.20
    https://cloud.mail.ru/public/9dEX/djuwzbp4V/Jahrbuch der Wehrtechnik/Jahrbuch der Wehrtechnik 1 (1966)
    Volume 1 (1966) done from cover to cover
     
    I've decided to decrease amount of "separately photographed" pics I take, as it takes simply too much time (~doubling it).
     
    ...
    01.07.20
    Volume 5 done from cover to cover
    https://cloud.mail.ru/public/9dEX/djuwzbp4V/Jahrbuch der Wehrtechnik/Jahrbuch der Wehrtechnik 5 (1970)
     
    https://cloud.mail.ru/public/9dEX/djuwzbp4V/IDR/1975 vol.8/04 
    International Defense Review 1975-04 done from cover to cover
     
    ...05.07.20
    https://cloud.mail.ru/public/9dEX/djuwzbp4V/Jahrbuch der Wehrtechnik/Jahrbuch der Wehrtechnik 3 (1968)
    Volume 3 done from cover to cover
     
    https://cloud.mail.ru/public/9dEX/djuwzbp4V/Jahrbuch der Wehrtechnik/Jahrbuch der Wehrtechnik 7 (1973)
    Volume 7 done from cover to cover except p.129 and 131
     
    all pages with odd page numbers are uploaded in Vol.2 (except p.65, 79, and 193-207) and Vol.6 folders.
     
    https://cloud.mail.ru/public/9dEX/djuwzbp4V/IDR/1975 vol.8/05
    International Defense Review 1975-05 done from cover to cover
     
    https://cloud.mail.ru/public/9dEX/djuwzbp4V/JDW/Vol.21 1994/
    1-10 issues and supplements of JDW 1994 (vol.21) done from cover to cover
     
    ...14.07.20
    https://cloud.mail.ru/public/9dEX/djuwzbp4V/_tmp
    Two dozen issues of JDW from 1990, one issue of IDR from 1975, four from 1991 and 11 from 1990 plus supplements, two (out of two stored at RSL) issues of 1998 Jane's Intelligence Review plus supplement,
    along with several pages from Military Technology issues from 2000 and 2001, and pages from Jahrbuch der Wehrtechnik Vol.2, Vol.4, Vol.6, Vol.12 were photographed.
    Unfortunately even basic processing (put_into_folder-rotate-delete_blurry_pages_and_doubles-rename_properly) takes too much time,
    so I've skipped "rename properly" part, and, in order to avoid confusion, put most of those photos into separate temporary folder - about 7Gb or ~6-7k files.
     
     
    https://cloud.mail.ru/public/9dEX/djuwzbp4V/Jahrbuch%20der%20Wehrtechnik/Jahrbuch%20der%20Wehrtechnik%2012%20(1981)
    JdWT Vol.12 (which, thanks either to some glitch of my phone's memory or to me forgetting that copying several thousand small files takes a lot of time, especially on old memory card which could go as slow as 50kB/s, and removing memory card while some files were still copying, lost 28 pages, which will be fixed sometime later)
    https://cloud.mail.ru/public/9dEX/djuwzbp4V/IDR/1975 vol.8/06
    IDR 1975-06
    https://cloud.mail.ru/public/9dEX/djuwzbp4V/JIntR/1998 (10)/
    and JIntR 1998
    were renamed and put into appropriate folders, though.
     
    ...16.07.20
    https://cloud.mail.ru/public/9dEX/djuwzbp4V/Jahrbuch der Wehrtechnik/Jahrbuch der Wehrtechnik 6 (1971)/
    Jahrbuch der Wehrtechnik Vol.6 now available from cover to cover.

    Also following things were photographed and uploaded to _tmp folder:
    International Defense Review 1990-12 with supplement, 1989-01, 02, 03 with supplement, 04; 
    all 16 issues of Jane's Defence Upgrades 1997 (Vol.1) stored at RSL (out of 24 published)
    I moved all 1990 IDR issues with all pages renamed properly (01, supplement to 02, 05 and two supplements, 06 with supplement) into temporary "a" folder.
     
    ...17.07.20
    https://cloud.mail.ru/public/9dEX/djuwzbp4V/_tmp/JDUpgr/1998 (02)/
    Jane's Defence Upgrades 1998 (vol.02) - 23 issues out of 24 published are stored at RSL, and were photographed and uploaded.
     
    https://cloud.mail.ru/public/9dEX/djuwzbp4V/_tmp/International Defense Review/1989 vol.22/05/
    Only one IDR issue was photographed (1989-05), and only 2/3 of it. Also uploaded.
  9. Tank You
    That_Baka reacted to SH_MM in Hollow charges and armor protection - their alternating progression   
    [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.
     
  10. Tank You
    That_Baka reacted to SH_MM in The Leopard 2 Thread   
    The Leopard 1A3's fire control system and optics were derived from the contemporary Leopard 2 development; in particular the EMES 12 steoroscopic rangefinder, the PERI R12 commander's sight and the FLER-H are based on early Leopard 2 components.
     
    But on the Leopard 2 prototypes the EMES 12 was not just an optical rangefinder. Paul-Werner Krapke in his book essentially calls it an optical rangefinder with integrated laser rangefinder, which leaves tonnes of room for imagination. The Jahrbuch der Wehrtechnik from 1974 explains some details regarding this arrangement. Basically the laser rangefinder used the same lenses as the optical rangefinder, but was reflected at a semi-translucent mirror, while visible light could pass it. As the Bundeswehr considered laser rangefinders to be too inaccurate during the early 1970s (apparently they often picked up incorrect or multiple laser echos), the gunner had the task to double-check the laser rangefinder's measurements. For this purpose the result of the laser rangefinding was displayed in the gunner's eyepieces, so that he could quickly set the optical rangefinder to that range - if the measurement was correct, then the target would appear correctly ranged (sharp) in the optical rangefinder aswell.
    For the Leopard 1A3 the laser rangefinder was removed - probably as cost-saving measure.
     
    I wonder what this means regarding the reliability of the Tank Laser Sight adopted on the Chieftain already in 1970...
     
    On a side note, the FERO Z12 auxiliary sight on the early Leopard 2 prototypes also included a night vision option (of unknown quality - IR or image intensifier?) - the later FERO Z18 of the Leopard 2 and corresponding devices found on other modern tanks like the Abrams and Challenger 2 only work as daysights.
     
    But the really interesting aspect of the early Leopard 2 prototypes are the night vision devices. Basically two different designs were tested: the PZNG and NZG 200.
     
    The PZNG (this probably stands for "passives Ziel- und Nachtsichtgerät" - passive targeting and night vision device) was made by AEG. It consists of a fully-stabilized periscope incorporating a low light level television system with a 200 mm lens opening and basically the same second-generation image intensifier as used in the PZB 200 LLTV camera. The whole PZNG had a weight of circa 70 kilograms and was mounted on a retractable mast at the back of the turret. Full 360° traverse and elevation ranging from -10° to +20° allowed detection targets at all directions.
     

    PZNG with captions pointing towards the LLTV camera lens ("TV-KANAL"), thermal imager lens ("WB-KANAL"), as well as drives for elevation and azimuth
     
    A special feature of the PZNG was the so-called Wärmebildortung or Wärmebildpeilung (basically: thermal image detection/scanning). Thermal imagers at the early 1970s didn't offer sufficient resolution and contrast to be used as night vision devices in armored vehicles; yet they clearly offered a massive advantage in terms of detection capability. So AEG decided to add a thermal imaging system to the PZNG to be purely used for target detection, which projected the image onto the photocathode of the camera tube. Essentially by activating the Wärmebildortung the thermal imager produced images at a very slow rate (just one frame per minute, probably in order to reduce the required cooling system). These were laid over the image provided by the LLLTV system, essentially acting as a very early type of sensor fusion. Compared to thermal rangefinders, LLLTV systems at the time provided clearer images and longer ranges (up to 3,000 meters according to the optimistic values from the Jahrbuch der Wehrtechnik 1974). The modular design of the PZNG allowed to completely replace it with a newer thermal imager in the future.
     
    The NZG 200 was developed by Zeiss and Eltro. I believe that NZG might stand for "Nachtsichtzielgerät" - night vision targeting device. In terms of overall specs, it is largely similar to the PZNG - a 70 kg heavy, fully stabilized periscope with 360° travese and -10° to +20° elevation that sits on an elevatable mast which can be retracted into the turret. The main difference between both systems is the image intensifier - another type of video camera tube was used - and the íntegration of the still early thermal imaging technology. Instead of a small thermal sensor with a low framerate being used, the NZG 200 included a proper thermal imager. A mirror in the "dead" zone of the LLLTV's mirror lens directed the incoming light to it. As the resolution was still rather limited, the thermal imager also was to be only used for target detection - identification of the target aswell as aiming was to be done using the image intensifier instead.
     

     
    The NZG 200 didn't allow overlying the thermal imager's output onto the LLLTV image, instead the operator had to switch between switch between both modes. Alternatively one operator (gunner or commander) could view the thermal channel, while the other could view the LLLTV channel. The NZG 200 was designed in such a way, that the thermal imaging module could be easily replaced with newer ones in the future.
     
     
    The PZNG was fitted to the Leopard 2 prototype turrets T12 and T17, while the NZG 200 was fitted to the turrets T11 and T16.
     

     
    Leopard 2 prototype with turret T11 (the only one with 20 mm autocannon). The NZG 200 is visible at the center-left side of the photo. Next to it is the pulse spotlight, which could be used with the LLLTV system in the oimnous "gated viewing mode".
     
  11. Tank You
    That_Baka reacted to Wiedzmin in The Leopard 2 Thread   
    so, my bad again, 81 no used against hull, 127 and 107
     
    127mm-600-636mm pen
    107mm-480mm pen


     
     
    as far as i understand, because of this hull front failure they later made this hull 
     

     
    and only after this version get to 2A0/4 style hull, but i don't know is 2A0/4 a capable of stoping 127mm warhead or not...
     
    and there is a scheme of firings of 2AV in US, without any good details, only that tank have 39 hits, of which 16 germans consider to be "good", of which 3 actually was penetration in turret front and mantlet by 127mm warhead, remaining 23 hits, they didn't  mention...
     


     
    penetration was hit 6, 5 and 13, which version of hull front was used in US trials i don't know
     
     

    p.s scheme of US trials seem to match trials i previosly posted here, so it's seems that they used improved hul, or germans repeat all hits that they recieved during US trials later at home with improved hull front
     
     
  12. Tank You
    That_Baka reacted to Wiedzmin in The Soviet Tank Thread: Transversely Mounted 1000hp Engines   
    T-55 shelling in Germany, 1971.   turret   105mm APDS DM13 (aka L28 / M392 / L36)   hit 42: - thickness at the point of impact 119mm - angle (Aufschlagwinkel) 30g - impact speed 1471 m / s (v25), range 200 meters - penetration   hit 43: - thickness at the point of impact 140mm - angle (Aufschlagwinkel) 30g - impact speed 1473 m / s, range 200 meters - bulging with a crack   hit 44: - not taken into account, because the projectile hited into the embrasure of the sight.   hit 45: - thickness at the point of impact 160mm - angle (Aufschlagwinkel) 44 gr - impact speed 1460 m / s, range 200 meters -  penetration   hit 13: - thickness at the point of impact 100mm - angle (Aufschlagwinkel) 24g - impact speed 1437 m / s, range 100 meters - bulging with a crack   hit 14: - thickness at the point of impact 100mm - angle (Aufschlagwinkel) 24g - impact speed 1438 m / s, range 200 meters - bulging with a crack   hit 15: - thickness at the point of impact 100mm - angle (Aufschlagwinkel) 26g - impact speed 1333 m / s, range 1000 meters -  penetration with a plug   hit 16: - thickness at the point of impact 100mm - angle (Aufschlagwinkel) 26g - impact speed 1331 m / s, range 1000 meters -  penetration   hit 17: - thickness at the point of impact 100mm - angle (Aufschlagwinkel) 25g - impact speed 1287 m / s, range 1500 meters - bulging without crack   hit 18: - thickness at the point of impact 100mm - angle (Aufschlagwinkel) 28g - impact speed 1280 m / s, range 2000 meters -  penetration     Hull   105mm APDS DM13 (aka L28 / M392 / L36) 105mm HESH 90mm HESH   hit 1: - thickness at the point of impact 100mm - UFP - angle (Aufschlagwinkel) 65g (the body was apparently specially tilted to a larger angle) - impact speed 1427 m / s (v25), range 200 meters - bulging with a crack   hit 2: - thickness at the point of impact 100mm - UFP - angle (Aufschlagwinkel) 62g (the body was apparently specially tilted to a larger angle) - impact speed 1436 m / s (v25), range 200 meters - penetration   hit 3: - thickness at the point of impact 100mm- UFP - angle (Aufschlagwinkel) 66g (the body was apparently specially tilted to a larger angle) - impact speed 1433 m / s (v25), range 200 meters - bulging with a crack   Hit 10 (HESH): - thickness at the point of impact 100mm- UFP - angle (Aufschlagwinkel) 60g - scab with a diameter of 200mm and a thickness of 20mm   Hit 18 (90mm HESH): - thickness at the point of impact 100mm - UFP - angle (Aufschlagwinkel) 60g - nothing   hit 4: - thickness at the point of impact 80mm - board - angle (Aufschlagwinkel) 70 gr (course +20) - impact speed 1427 m / s (v25), range 200 meters - bulging with a crack   hit 5: - thickness at the point of impact 80mm - board - angle (Aufschlagwinkel) 68 gr (course +22) - impact speed 1427 m / s (v25), range 200 meters - penetration   hit 6: - thickness at the point of impact 80mm - board - angle (Aufschlagwinkel) 70 gr (course +20) - shock speed 1397 m / s (v25), range 200 meters - bulging without crack   hit 7: - thickness at the point of impact 80mm - board - angle (Aufschlagwinkel) 50 gr (course + -40) - impact speed 1416 m / s (v25), range 200 meters - penetration   hit 8: - thickness at the point of impact 80mm - board - angle (Aufschlagwinkel) 60 gr (course + -30) - impact speed 1416 m / s (v25), range 200 meters - penetration   hit 12: - thickness at the point of impact 100mm -- UFP - angle (Aufschlagwinkel) 60g - shock speed - m / s (v25), range 1000 meters - hit the tow hook   hit 13: - thickness at the point of impact 100mm - UFP - angle (Aufschlagwinkel) 60g - shock speed - m / s (v25), range 1000 meters - penetration   hit 2: - thickness at the point of impact 100mm - UFP - angle (Aufschlagwinkel) 60g - shock speed - 1332m / s (v25), range 1000 meters - penetration   hit 9: - thickness at the point of impact 100mm - UFP - angle (Aufschlagwinkel) 62.5g - shock speed - 1341m / s (v25), range 1000 meters - penetration   hit 10: - thickness at the point of impact 100mm- UFP - angle (Aufschlagwinkel) 62.5g - shock speed - 1353m / s (v25), range 1000 meters - bulging with a crack   hit 4: - thickness at the point of impact 100mm - UFP - angle (Aufschlagwinkel) 60g - impact speed - 1292m / s (v25), range 1500 meters - penetration   hit 8: - thickness at the point of impact 100mm -- UFP - angle (Aufschlagwinkel) 62.5g - shock speed - 1278m / s (v25), range 1500 meters - bulging without crack   hit 11: - thickness at the point of impact 100mm - UFP - angle (Aufschlagwinkel) 61.5g - impact speed - 1296m / s (v25), range 1500 meters - bulging with a crack   hit 6: - thickness at the point of impact 100mm - UFP - angle (Aufschlagwinkel) 60g - impact speed - 1274m / s (v25), range 2000 meters - bulging with a crack   hit 7: - thickness at the point of impact 100mm -- UFP - angle (Aufschlagwinkel) 60g - impact speed - 1260m / s (v25), range 2000 meters - bulging with a crack  

  13. Tank You
    That_Baka reacted to LoooSeR in ATGMs and RPGs for infantry - a thread for rebels around the world to choose their ATGM supplier.   
    RPG-18 "Mukha" 

       64 mm caliber, 2.6 kg, 114 m/s muzzle velocity of rocket, about 200 m max effective range. Can be used against AFVs and buildings/infantry in cover.
     
     
     
  14. Tank You
    That_Baka reacted to LoooSeR in The Small Arms Thread, Part 8: 2018; ICSR to be replaced by US Army with interim 15mm Revolver Cannon.   
    Navy SF unit members with ADS

     
       AFAIK ammunition for those assault rifles - PSP and PSP-UD.

     

  15. Tank You
  16. Tank You
    That_Baka reacted to SH_MM in Main Ground Combat System (MGCS) and Euro Main Battle Tank (EMBT)   
    Well, I already mentioned that Soviets were a different case, because they actually encourage competition between different design bureaus (but then bought nearly all products, rather than choosing the best). I have seen conflicting data regarding the layout of Agava-1/Agava-2 and Avaga-M1, while there is little to none available on the Nocturne thermal imager. Nocturne was however developed as successor to Avaga-2, so it seems likely that it had a better sensor.
     
  17. Tank You
    That_Baka reacted to LoooSeR in The Leopard 2 Thread   
    Tetris reached Leos

  18. Tank You
  19. Tank You
    That_Baka reacted to Alex C. in The Small Arms Thread, Part 8: 2018; ICSR to be replaced by US Army with interim 15mm Revolver Cannon.   
    Absolutely. I cant contribute much in the way of SVD testing (that guy pretty much nailed it) but you do see a lot of photos of guys holding them by the magwell. The bipod mine came with (apparently made by a gunsmith in Russia who is well known for them) clamps onto the receiver recesses near the trunnion. Looks silly but there isnt really a good way to attach a bipod otherwise.
     
    The SVD is an amazing rifle and does *exactly* what is was designed to do, people in the west (and apparently Russia according to that guy) just hold them to mythical status. I mean the gun has a detachable scope *and* cheekpiece so you can see the irons and engage in an assault. It also had a damn bayonet lug if you expend your fiddy rounds of ammo while your squad is advancing. 
     
    Most accurate rifle? No but it could well suppress an enemy position by pinning them, detect fucking night vision with the flip-down screen, had a distance calculator, and even without optics is a capable self-loading rifle. And yes I realize I’m preaching to the choir!
  20. Tank You
    That_Baka reacted to LoooSeR in Tanks guns and ammunition.   
    Was posted on otvaga - diploma work on ramjet APFSDS design (in russian). PDF

     
     
  21. Tank You
    That_Baka reacted to Militarysta in Polish Armoured Vehicles   
    This time, photo taken by myself.
    APC Rosomak firing single 81mm camouflage granate GAK-81
     
    single 81mm in 1st salvo:

     
     
    and single 81mm in 2th salvo:

     
     
    And this one was mucht difficult due to weather conditions.
     
    Six 120mm motar round on one picture:

     
    And twins:

     
     
    And the result:

     
     
     
     
    In summary - 120mm SMK Rak is very good weapons, very powerfull modern and now the best serial produce in the world. Nice that at least one type of weapons producing in my country can be on top lvl... 
  22. Tank You
    That_Baka reacted to LoooSeR in The Soviet Tank Thread: Transversely Mounted 1000hp Engines   
    Again that Suvorov idiot with his autobahn tanks. Can we get to something less stupid and overdone?
  23. Tank You
    That_Baka reacted to Wiedzmin in The Leopard 2 Thread   
    first variant (from what i have) of L2AV hull front(fuel tank between 1st and 2nd armour arrays), drawing name "Vorerprobungsmuster Wannebug SK150-1800.00.012.0 Krauss-Maffei AG Munchen-Allach"
    25.04.75
    it's test rig for firing trials, later they changed armour inserts, maybe someone can translate german part about "Peco Bolzen" etc ? 
     
     
    it can't

     
    HOT
     

     
    MILAN
     
    and even this graph's is a mean crater depth, not penetration
  24. Tank You
    That_Baka reacted to N-L-M in French flair   
    For those keeping track at home, the D9 for example has a lot of rollers (good MMP), deep grousers for excellent traction in soft soil, and oil coolers for the torque converter. Unlike armored vehicles in which the torque converter is intended to lock up quickly and therefore not get very hot, the torque converter in the D9 is designed to work in slippage at all times. This results in a lot of power being turned into heat in the oil, which then needs to be cooled to prevent the seals from dying. You could run a tank in 1st gear and 100% slip on the torque converter and get pretty good tractive effort, but not for any length of time. The D9 is a very well designed tool.
  25. Tank You
    That_Baka reacted to LoooSeR in GLORIOUS T-14 ARMATA PICTURES.   
    Possible layout of T-14 frontal armor
    http://otvaga2004.mybb.ru/viewtopic.php?id=2159&p=2#p1244215

     

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