Pentagon building new 15 ton bomb.

Hmm. Even though a 13 tonne penetrator seems impressive, according to these Penetration figures from Wiki, 40 m of "moderately hard rock" isn't exactly a depth I'd call deep enough for anything important.

There are 3 ways they can improve it's preformance. 1. Mass, 2. Velocity, 3. Harder penetrator. Although route 3 is already taken (as I understand it, the penetrator head is DU), and route 1 is already kinda done (13 tonnes is purdy big), I'd say, that if we were to try to up this, we should slap on some ramjets on it and make it dive at Mach 5 on the bunker. That'd probably bust a few more meters.
 

My2Cents

Active Member
Hmm. Even though a 13 tonne penetrator seems impressive, according to these Penetration figures from Wiki, 40 m of "moderately hard rock" isn't exactly a depth I'd call deep enough for anything important.

There are 3 ways they can improve it's preformance. 1. Mass, 2. Velocity, 3. Harder penetrator. Although route 3 is already taken (as I understand it, the penetrator head is DU), and route 1 is already kinda done (13 tonnes is purdy big), I'd say, that if we were to try to up this, we should slap on some ramjets on it and make it dive at Mach 5 on the bunker. That'd probably bust a few more meters.
Does anyone here have a definition for what ‘moderately hard rock’ is? As a rough guess that is going to be something other than sedimentary rock.

There are limits on penetrator velocity. At some point added velocity will just cause the tip to shatter and the penetration drops off until you reach velocities where penetration is by ablation. That requires a completely different design.

You left out 4. Sectional density. Not that it matters, the MOP is already as long and as heavy as can be carried in a B-2’s bomb bay.
 
I'd take a guess and say that the rock they built NORAD under is "moderately hard".

It doesn't have to be Mach 5, and of course, there are super-hard materials you can use to supplement it's penetrator head.
 

My2Cents

Active Member
I'd take a guess and say that the rock they built NORAD under is "moderately hard".
Could be. Although solid granite is mighty hard it is not as bad as say basalt. It is not easy [understatement] to tunnel through either, though you generally do not need shoring.

But if that is the case, then the MOP should penetrate well over 200 ft in the permeable materials (sandstone and slate) that predominate in the Middle East.
 

My2Cents

Active Member
The easiest solution would to be just dig under 60 meters, but how the IADS deal with it is the first line of trouble.
That is 60 meters of rock equivalent to reinforced concrete. So you need to dig that far into bedrock, not just beneath the surface. Well OK, you can count part of the overburden, say 20 to 25% if it is really thick. And 60 meters is just the depth that the bomb will penetrate to, you also have the effects of 2.4 tons of highly tamped HE to consider.

And below the bedrock means that the bunker will automatically be below the water table, so if it is cracked by a near miss flooding will be a major problem.
 

wormhole

New Member
I've read that they are working on the next generation of penetrators which will be in the 3000lb-class or thereabouts which will have rocket boost to increase velocity and achieve greater penetration.
The smaller size and weight means that strike fighters will have a significantly increased ability to take out hardened, subsurface targets complementing the bomber force. I'm curious though if they will be able to cram it into the F-35 weapons bay?
 
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