GarryB Wed Sep 12, 2012 1:20 am
Well thank god because as far as I know the earlier BMDs sould only withstand 7,62 ball rounds and even worse had magnesium alloy armor that was pyrophoric if hit by a HEAT charge. BTW is the BMD-4 equipped with spall liners?
First of all you need to keep in mind that the purpose of the BMD is mobility. Protection from small arms fire and artillery splinters was the main goal of the design.
The western equivalent was either walking or a truck.
An armoured light vehicle will struggle stopping HEAT charges of any size... if the armour catches fire... well that is probably the least of your worries as a fire is easier to escape than an HEAT charge explosion.
Protection from the front will always be heavier than from the sides and rear... an M113 could be penetrated with hand grenade fragments let alone small arms fire.
Even if it stopped 50 cal from the front doesn't mean that it will stop it from the sides or rear or from above.
The early model BMDs used alloys because steel alone would be too thin.
Very simply if you make a box out of steel, to make it lighter you use thinner and thinner steel. The problem is that strength is not just about the material... it is also about thickness.
If you can only use 1 ton of armour then you might end up with steel that is too thin to be strong. If you use a lighter material... like a magnesium steel alloy then it can be made thicker and therefore stronger.
The later model BMDs were made of aluminium alloys which sounds worse than steel, but because it is much lighter it is also much thicker and therefore stronger and more useful.
Note the BMD-3 is a completely different design from 1 and 2, and 4 is an upgraded 3.
That I am not so sure about, at least BMD-4M without the uparmor kit.
Standard 30mm rounds, not anti armour.