[mdlug] OT - IR jamming

[Aaron Kulkis]

allen wrote:
>> I think you missed one part of the physics of the copper in a EFP - it 
>> becomes molten at that point and acts like a plasma cutter when it comes 
>> in contact with simple armor. That is why the M1 and other advanced 
>> systems employ composite armor in many places - steel on the outside for 
>> conventional projectiles, and other layers of other materials 
>> (classified) to stop the plasma injection. The M60 in the Nam had simple 
>> steel armor easily penetrated by the Russian RPG with their cone shaped 
>> copper in the explosive, so the troops would get badly burned from the 
>> molten copper injecting into the tank. This copper at that point did 
>> little damage other than burn everything.  So, reactive armor panels 
>> were added to the outside of the steel - basically explosive charges 
>> that would detonate when the molten copper entered them, thus blowing 
>> the plasma away.
>> -dave
>>
>> PS - the demolition crews world wide use this technique to topple steel 
>> structures like old buildings - they have sticks of plastic explosive 
>> about 2.5" in diameter with about a 1" copper piece in the shape of a 90 
>> degree right angle running the length of the explosive. It will cut 
>> through quite a chunk of structural steel.
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> For what it's worth, you're conflating explosively-formed projectiles or 
> penetrators with shaped charges which produce a jet of molten copper not 
> a solid, bullet-shaped projectile.
> 
> The difference shows up best with the utility of the slat armor used on 
> Strykers which detonates the the RPG warhead prematurely thus robbing it 
> of effectiveness but is essentially useless against an EFP.
> 
> The shaped-charge, in order to be effective, has to detonate within a 
> fairly narrow minimum and maximum distance in order for the copper jet 
> to either form, at the minimum distance, or remain in a solid stream at 
> the maximum distance. EFPs are not so encumbered being effective from 
> substantially greater distances.
> 
> The shaped-charge you refer too is a good example of the difference. A 
> half inch or so beyond its maximum range and it's ineffective. An EFP is 
> effective from at least tens of yards.
> 
> That sensitivity to conditions is also how one type of active armor 
> works. The explosive sandwiched between the steel layers of active armor 
> detonates quickly enough to upset the conditions necessary to form a 
> coherent jet of molten copper rendering the munition ineffective. 
> Although I'm not certain, I'd venture a guess that this type of active 
> armor is ineffective against an EFP.

Everything Allen wrote above is 100% correct to the best
of my knowledge.