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LULZ

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Posts posted by LULZ

  1. On 4/9/2018 at 12:58 PM, SH_MM said:

    As for the Challenger 1's armor: 500 mm steel-equivalent protection might be possible, given the date of introduction and its huge weight, but it certainly is not set in stone. Confirmed is that the Shir (Iran) 2, which was used to develop the Challenger 1 tank, had a protection level of 325 mm along the 30° frontal arc (?) in 1978. Given the power-to-weight ratio listed in the British documents, the Shir (Iran) 2 tank weighed 63 to 64 metric tons, just as much as the Challenger 1. In so far the British engineers would have needed to completely redesign the armor array to reach the desired level of protection. In 1978, a protection level of 435 mm vs KE (as achieved on the MBT-80) was considered to be "enough". Originally the Shir (Iran) 2 was to be delivered in 1979 and 1980; but the deal was canceled with the Iranian revolution of 1979. The decision to not continue the development of the MBT-80 was made in July of 1980, the first Challenger 1 pre-series vehicles were delivered in 1982; so if the armor was massively redesign, it must have been done in a rather short period of time... so it remains questionable how much changes were made.

     

    As for the "engineer rumor": Given the source of this rumor, I would completely discard it until another source supports it.

     

     

    Hello

     

    I was curious if a possible explanation for the large jump in alleged protection levels of the Challenger 1 over the shir 2 in such a short period of time could be attributed to the inclusion of ceramics and other such materials.

     

    Spoiler

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    Something from Ed Francis at the Bovington tank museum on the matter

     

    Spoiler

    Once again they are confusing Chobham with early Burlington. Burlington was steel and rubber layers only occasionally mixed in with aluminium plates (The Iraqi Enigma was very similar) Early chobby has ultra-high-temperature ceramics, steels, rubber and an abrasive backing filler (like Kevlar) super compressed under great pressure. This causes it to bulge when hit somewhat forming a natural NXRA type reaction and abrades the round. Modern armour is all about dispersing the energy of the incoming round, in fact manufactures still use RHAe in the same way palaeontologist uses busses to discuss the mass and size of dinosaurs. It’s to make it easier for the layman to understand.
    If a round strikes with 20MJ of energy then the armour need to disperse 20MJ of energy before it can reach the interior of the vehicle. Ceramics such as Boron Carbide are very hard but brittle. As the round pierces the outer layer of face hardened steel the ceramics shatter this in turn help to disperse some of the energy – as the round carries on (picture in slow mo.) the round is undergoing massive forces. With the rear of the rod having considerably more energy retention than the front of it. This causes the round to actually bend a bit at a very fine level. The interaction between this and multiple layers of shattering ceramics and shifting steels deforms the rod further releasing yet more energy until it is spent. Contrary to popular opinion APFSDS rounds do not ricochet they will either perforate their target or shatter. Those seen on range footage hitting the ground is the rear tracer half spinning off in most cases.
    A good way of imagining what’s happening is to imagine a block of butter (steel) sandwiched between two layers of bread. Now poke you finger though quickly- no issues. Now fill that butter with shards of glass and try it again – though multiple sandwiches. See how your finger now looks all deformed and tattered like a leftover dog’s dinner.
    Regarding shaped charge attacks it’s slightly different, a SC does not melt armour as some would have you believe and in fact the temperature is only around 660 degrees when measured. The Jet of material is hydrodynamic and undergoing extreme plasticity being both a solid at the core and a liquid/gas the further you go from the centre. As this perforates using KE the outside of the jet interacts with the base material which flows back in on itself (a bit like trying to dig though very fine sand) the more material there is to go through the thinner the jet gets. This is known as fist to finger deformation. However conventional steel is not particularly good at stopping this. In fact as the depth of perforation is inversely proportional to the square root of the density of the target material; low density material offers better protection than steel relative to its weight. (See Diesel fuel as armour) in the case of ceramics the material does not flow like steel would and disrupts the jets shape and path causing massive energy loss and the deformation of the stream resulting in a loss of perforation.
    Later marks of Chobham, Mk 2, 3 and newer versions such as Dorchester 1 & 2 follow a very similar concept with differing materials, and arrangements inside. I am highly suspicious of Gaijins claims to have any accurate information on this and it certainly did not come from any British authority on the matter as it is still OSA. Challengers Chobham armour extend over the turret front and first 1/3 of turret sides. Over the glacis and first 1/3 of the lower hull. It does not have Chobham on the sides etc. as it was never built to be a particularly good tank, which was set aside for MBT-80.

     

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