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namwireman
May 23, 2011, 07:40 AM
An anti-shipping missile Exocet type weight 1,500 lbs, with a 360 lbs. warhead traveling at 1,030ft/s. Hits a WW2 type US battleship on a turret with 17" of armor. How far will the missile penetrate?

Curlyben
May 23, 2011, 07:43 AM
Who cares as the explosives WILL kill you anyway.

Look at the General Belgrano (http://en.wikipedia.org/wiki/General_Belgrano) in the 80's..

Unknown008
May 23, 2011, 10:28 AM
Actually... I think I would be satisfied knowing how to work this out ;)

And on the other side... wrong link Ben! :eek: You put an 'i' which shouldn't be there.

ARA General Belgrano - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/General_Belgrano)

Curlyben
May 23, 2011, 10:44 AM
Right link, wrong spelling.

Now I must admit when I did Physics I was taught in SI units, so Imperial gets me stumped ;)

Unknown008
May 23, 2011, 10:49 AM
Ah, me too :)

I'll use my conversion script ;)


An anti-shipping missile Exocet type weight 680.39 kg, with a 163.29 kg. warhead traveling at 396.24 m/s. Hits a WW2 type US battleship on a turret with 0.43 m of armor. How far will the missile penetrate?

Curlyben
May 23, 2011, 10:54 AM
Of course I forgot the really important fact here that negates my previous comment.

The Exocet is a French made missile, so is likely to fail or surrender, before it explodes..

Anyway this is a momentum problem.
I can't remember the equations mind.
Mass is 1076.68 Kg
Speed is 396.24 m/s

So I'm guess force = mass x speed

And from there, well...

Unknown008
May 23, 2011, 11:01 AM
Hm... if that's merely momentum... then it should be more or less okay I guess...

wrong mass =S

Mass = 843.68 kg
Speed = 396.24 m/s

Momentum = 334299.76 N/s

Then... we don't have the mass of the battleship, nor the 'recoil' (I know it might not be the correct term :o) of the battleship when it is hit by the missile... otherwise, I'd apply the principle of conservation of momentum.

jcaron2
May 23, 2011, 01:15 PM
Namwireman, have you been given a formula for penetration depth as a function of kinetic energy or other properties?

Otherwise it seems we need to resort to the French DeMarre Armor Penetration Formula of 1890. In that case, I believe the correct form of the formula for homogeneous steel armor would be

Depth_{penetration}=k \( \frac 12 mv^2 \)^p,

where k and p are constants relating to projectile nose shape, projectile size, projectile damage, definition of "penetration," plate type, and obliquity of the angle of impact.