For those of you who like Big Picture/Strategic subjects

[BigRed389]

Even if the railgun had a 200nm range, are we going to bring our super awesome CG(X) in to 20nm off a hostile shore to shell a target 180nm inland? Methinketh no.

Why not?

 

[Spekkio]

As far as the terminal velocity argument, who really cares what the final velocity is? Some 200lb heads apparently worked it out and think it works. I don't have the tools to do computer modeling accounting for hypersonic fluid mechanics or the air density variations at the extreme altitudes proposed, do you?

Drag does not change as objects go supersonic. I care about the final velocity because that is directly proportional to its destructive force. If a railgun shooting a round into space causes the same destructive force as dropping a bullet from a plane, it's not going to do enough to eliminate threats at sea.

So while I'm not going to declare whoever claims the round will do immense destructive force at mach 5 is completely wrong, I am questioning the validity of the statement without further explanation.

At the very least, a high density object traveling at high speed is going to be a great bunker buster, runway crater-er, etc. My worry would be its NSFS effectiveness compared to traditional artillery, particularly as it has no explosives to provide blast.

I think you and I have the same concern in this regard. But this also leads to two additional questions:

1) How much money does it cost compared to traditional missiles to develop a sufficiently high density round to cause a deadly impact?

2) How many of these super high density rounds can we really get onto a ship before it results in negatively affecting the ship's buoyancy.

Why not?

Well, it depends on the enemy. If we're up against a significant ASW threat, like the extremely quiet but short ranged AIP plants some of our current allies use and our aging 688 fleet is ill prepared to deal with, then no, you probably won't put the multi-billion dollar DD(X) 20 nm off shore.

 

[A4sForever]

Friggin' nerds ... :sleep_125

 

[BigRed389]

Well, it depends on the enemy. If we're up against a significant ASW threat, like the extremely quiet but short ranged AIP plants some of our current allies use and our aging 688 fleet is ill prepared to deal with, then no, you probably won't put the multi-billion dollar DD(X) 20 nm off shore.

Funny how the bubblehead comes up with a sub threat.

You're right, the answer is it depends. I was just trying to point out how saying that it would be unlikely without justification is pretty stupid.

And for every scenario you can come up with where it's risky to do so, there are plenty of controls you can use (ugh ORM) to mitigate/neutralize the risks.

Because it also depends on what we have available. But a WARSHIP, even on its own, is pretty capable of handling all warfare areas in moderate doses. Which is why I'd say it's pretty likely. As a TLAM replacement for smacking down terrorists, camels, and tents, just look at historical precedent.

Friggin' nerds ... :sleep_125

We hate you too. :icon_wink

 

[Will_T]

Spekkio,
The velocity at impact would be greater then a bullet dropped from a plane for 2 reasons. 1) planes cant go up that high and 2) Since the projectile will have forward velocity (i.e. not fired straight up), it will have kinetic energy at the top of its arc, the speed would be much greater then that of a projectile simply dropped.
If the 200lb heads say its going to land at mach 5, I'd hope it would land at a speed pretty close to that.
Also, drag is not the same at all velocities and altitudes.
And as for the super dense part, it wont have to be super dense. Most of the kinetic energy of the falling object (roughly mass*velocity squared) is dependent on velocity, and thus having it hit at huge speeds is going to transfer more energy to the target the a dense round.
I don't think extremely dense rounds are in development for the railgun, so I wouldn't worry about buoyancy.

 

[Spekkio]

Will, you're ignoring friction. You can't just do a direct PE---> KE conversion... that's the whole point of "terminal velocity." There is a point of no returns where friction force = gravitational force, so you don't gain any KE no matter how high the object falls from. All the PE after terminal velocity is being lost to friction.

You can google the equation for terminal velocity. Put in the speed for mach 5 and solve for mass/Area. You will need a really, really large m/A ratio to attain mach 5. Btw, when I said dropping a bullet I meant a likewise sized missile-shaped object...just couldn't call it a bomb because there's no explosives in it.

 

[A4sForever]

Will, you're ignoring friction. You can't just do a direct PE---> KE conversion... that's the whole point of "terminal velocity." There is a point of no returns where friction force = gravitational force, so you don't gain any KE no matter how high the object falls from. All the PE after terminal velocity is being lost to friction.

You can google the equation for terminal velocity. Put in the speed for mach 5 and solve for mass/Area. You will need a really, really large m/A ratio to attain mach 5. Btw, when I said dropping a bullet I meant a likewise sized missile-shaped object...just couldn't call it a bomb because there's no explosives in it.

Spekkio ... you really, really need to find a nice girl and 'settle down' ...whether this post is 'real' or tongue-in-cheek -- doesn't matter ...

 

[Will_T]

Its ok A4s, I think he's still shaken up from the thunderstorm we had in CT a couple days ago.
Just messing, but that storm was nuts.

Spekkio, friction, smiction, no body cares for friction. But really, is the drag on a bullet shaped object different then say a cylinder on the same diameter? I don't think that equation takes the shape of the object or its hypersonic properties into account.

 

[Spekkio]

Yes, it does. In the denominator of the terminal velocity equation includes the cross-sectional area and drag coefficient; the latter is dependent on material shape and smoothness.

 

[PropStop]

Spekkio ... you really, really need to find a nice girl and 'settle down' ...whether this post is 'real' or tongue-in-cheek -- doesn't matter ...

Oh my god these guys are KILLING ME! NERDS! Let's talk about girls...like Danica Patrick...

I gotta go to Sportsman's Warehouse...