Awesome Tank Pictures Thread

klesk, on 23 December 2013 - 08:16 PM, said:   Well... the thing is that RHA equivalent is very bad equivalent for armor thicknes and penetration, becouse... man this is complicated.   OK... if you want to penetrate more RHA you basicaly have to concentrate more force into smaller area. So now we have modern APFSDS penetrators that fly fast, they are dense and have small surface area, about 30mm caliber. Now if we simply want to penetrate more RHA we can make even slender and longer penetrator, and it will penetrate more RHA. But it will probably fail to penetrate more into modern composite armor.   Why?   When projectile hits RHA... basicaly rolled homonegous steel, with such forces and such pressures steel acctualy behaves as fluid. Armor "swims" throught armor, and it bends steel on the sides to penetrate... it's just like bullet traveling through water, force remains concentrate and projectile loses relatively small amounts of force while it travels.   But modern armor... the principle of basicaly every modern composite armor and even ERA is to spread the force of the projectile into the larger area, the principle is the same, but diferent armors do that in diferent ways.   One of those ways is to have sandwitch of britle but hard ceramics (even glass will do it), behind that tough steel, behind that air, then again ceramics, steel air.   When AP hits that sandwitch... first it hit ceramics, ceramics brakes into smaller pieces, and steel behind that ceramics bends. AP projectile has penetrated, but it has spent a lot of energy to do that kind of work (shatering ceramics, and bending the steel behind it) basicaly AP energy was disipetated over the larger area, and then it has to do the same on the every other layer of sanwitch. If the AP penetrator is too long, too britle it will broke into two or more pieces and then every piece will have less energy.   So... while the RHA equivalent was pretty good for WW 2, today it is... well basicaly poo, becouse in modern times things are much much more complicated. So many diferent kinds of armors, that work in diferent ways, and so many diferent penetrators... the only reliable data is from the testing ranges, and actual wars that were fought.   http://fofanov.armor.kiev.ua/Tanks/TRIALS/19991020.html