World's Most Powerful Rail Gun Delivered to US Navy

An anonymous reader writes "The world's most powerful functional rail gun capable of accelerating projectiles up to Mach 8 has been delivered to the Navy. The new rail gun is a 32-megajoule Electro-Magnetic Laboratory Rail Gun. The Navy eventually hopes to have 64-megajoule ship mounted rail guns. 'The lab version doesn't look particularly menacing -- more like a long, belt-fed airport screening device than like a futuristic cannon -- but the system will fire rounds at up to Mach 8, drawing on tremendous amounts of electricity to generate the current for each test shot. That, of course, is the problem with rail guns: Like lasers, they're out of step with modern-day generators and capacitors. Eight and 9-megajoule rail guns have been fired before, but providing 3 million amps of power per shot has been a limitation.'"

Comments

Fusion Power...here we come

[clonan]

The REAL reason Fusion power will be perfected...so the Generals can fire their fancy guns more than a few times an hour.

Hmm, my SI is fuzzy...

[Anonymous Coward]

Amps of power?

I miss the days of gunpowder

[INeededALogin]

Seriously, how much energy does it take to kill someone.

Re:I miss the days of gunpowder

[JesseL]

The energy required to kill someone is nil.
The energy required to poke a hole in someone is somewhat higher.
The energy required to poke a hole in enemy armor is higher still.

This isn't for killing 'someone', it for poking big holes in things that are very hard.

Re: I miss the days of gunpowder

[Dolda2000]

In all seriousness, the article speaks of ship mounted guns, so I don't really think they are made to kill individuals. I would think that no amount of energy can ever be enough when it comes to sinking warships.

It makes me wonder, though -- they say 32 MJ per shot, but how much energy is in a normal-sized conventional weapon? They also say Mach 8, but how fast are normal rounds fired?

Re:I miss the days of gunpowder

[KTheorem]

> This isn't for killing 'someone', it for poking big holes in things that are very hard.

If you have that much energy, though, then surely lasers become a more practical alternative?
Lasers can't be shot on a trajectory to hit something 1000 miles away. Nor can they cause much damage outside of where they hit.

Re:I miss the days of gunpowder

[Anonymous Coward]

I've heard estimates that place the energy release on impact with that of around 15000lbs of TNT

Think about that critically for a second. For all action there is an equal and opposite reaction. In order for this gun to accellerate a projectile to the equivalent energy of 15000 pounds of TNT, assuming no losses, requires an event on the initiating end equivalent to 15000 pounds of TNT. Considering that a 500 pound bomb, which is only half explosives (typically a mix similar to TNT), can do a decent amount of damage to a ship, it becomes obvious whatever project you're referring to must be another project (probably the so-called "rods-from-god" concept).

In fact, the 32 MJ of energy described in the article (I don't know if that's kinetic or electrical) is only the equivalent of about 15 pounds of TNT. This is just barely more than is contained in the 5" inch shells currently fired by the standard deck gun in the US Navy. The key attraction here is the added range.

whatcouldpossiblygowrong

[Anonymous Coward]

I noticed that almost every story today has this tag on it. What could possibly go wrong if you stop using this tag for every article?

Re:whatcouldpossiblygowrong

[stephencrane]

Seriously. This tag is being used way too much. A rail gun is, for all its complexity, a relatively straightforward concept. A story about, oh, releasing genetically-manipulated mosquitoes into the wild really should set the benchmark. Standards, people, standards. We're -geeks-, fer crissakes.

Re:whatcouldpossiblygowrong

[Goaway]

It's simply an expression of the closet technophobia that affects so many Slashdotters.

Einstein on rail guns

[sakdoctor]

I don't know if World War III will be fought with railguns or belt-fed airport screening devices, but World War IV will be fought with sticks and stones.

Hey, don't knock it

[Sycraft-fu]

We get a lot of cool technologies because the military wants new toys. You can argue about if it should be that way or not, but it is how things go. GPS is a great example. No civilian organization would invest in something that big. Are you crazy? Who would want that? However the cost wasn't a problem for the military and hence we got one of the most amazing navigational aids ever. Even now that the technology has been proven feasible and useful, or rather essential, the military run systems remains the only one. The European civilian governmental version remains snarled up in political battles.

So while you jest, there could be truth in the statement. Fusion is all well and fine, but there's only so much money going to be thrown at it. We have other cheap power sources in terms of commercial use, so not a lot of commercial dollars, and it just isn't sexy or pressing enough to get much government research dollars... However if there's a major military application, well that could get billions easily.

That's one reason I'm not always opposed to defense spending. Though it is very often wasteful and it seems there are better things to do with the money, it does seem to be one way for getting projects that just don't get built otherwise. A great many things come directly from defense research.

Re:Newton

[dorix]

Well yeah, but it still makes for a funny mental picture.

How long will the barrel be?

[jollyreaper]

Are these things going to be turret-mounted like with battleships or will the rail have to be as long as the ship, requiring the whole vessel to turn to align the weapon?

Watts!

[Roger W Moore]

Eight and 9-megajoule rail guns have been fired before, but providing 3 million amps of power per shot has been a limitation.

I agree. This would be extremely hard to achieve since amp is a unit of current. The problem is not that but rather that in combination with the voltage required to drive it.

Re:Newton

[doctor_nation]

Sorry, but everything works that way (unless maybe if you're near the speed of light). I don't care how you do it, but if you shoot something one way, there is an equal and opposite force the other way. Obviously in this case the ship won't notice, but if the rail gun wasn't bolted down I bet it would jump pretty good.

Re:uh, wrong. please check your math.

[Shakrai]

I think this will be a bit like a naval sniper, aiming to destroy major vessels command center before its even detected, and then leave the area quickly and let the big ships take over.

Uhh, wouldn't that require a line of sight to the intended target? Naval combat within visual range went out of style after Coral Sea. If you don't need a LOS then it would seem to be that this is a guided projectile and you don't exactly need a railgun for that (see harpoon, exocet, etc, etc).

I would suspect that the Naval interest in rail-gun technology is probably aimed at point-defense (i.e: shooting down incoming anti-ship missiles) more then anything else.

Re:It's all fun and games...

[AKAImBatman]

It's all fun and games until someone decides to make a nuclear-capable artillery shell for this thing.

There are some serious problems to mounting a nuclear munition on this sucker. First off, the weight of the round currently being fired is actually quite small. The weapon would need to be scaled up by many, many fold just to fire the nuclear munition.

Second, no existing type of warhead would survive the shock of launch. A gun-type device would detonate on launch. (NOT good.) An implosion device requires that the plates surrounding the charges that surround the plutonium core be carefully calibrated. A single charge or plate out of place and the bomb will fizzle out. Advanced hydrogen weapons are out as well, as they require an atomic explosion as a trigger. Plus, the cores of hydrogen bombs need to be kept even more precisely in place in relation to the uranium shell of the weapon.

All in all, the only thing you'd accomplish by combining a rail gun with a nuclear warhead is to either blow yourself up or damage your highly-expensive-bomb-that-could-have-been-more-easily-deployed-with-a-super-sonic-missile.

Re:How silly

[Chris Mattern]

You're already carrying God knows how many gallons of high-test jet fuel--the fuel oil, being considerably less inflammable, isn't adding that much to your fire hazard.

Re:How silly

[aproposofwhat]

If my memory serves there was significant damage to a layer of paint at the point of impact.

Sorry, mate, but that's just sick.

17 crew members died, and another 39 were injured.

The explosion knocked a 40 ft hole in the ship, and your dismissal of it is disgusting.

Re:How silly

[Shakrai]

The Arleigh Burke has a range of 4,400 miles at 20 knots, that would be about 2,000 miles at 30 knots. 70 hours of operation (or three days at top speed) is not much (especially considering they would want to fill as often as possible).

It's often said that amateurs study tactics, while professionals study logistics. Having the carrier carry bunker fuel to top off her escorts provides more logistical flexibility to the battle group commander.

Presumably everybody around here has heard of the attack on Pearl Harbor? Half of the reason that the Japanese had to retreat (instead of conducting more strikes) had to do with the fact that remaining on station any longer would have risked running too low on fuel. They stretched their logistical abilities to the max to conduct that attack and weren't in a position to exploit their advantage any further. (Of course the other half of the reason was Nagumo's caution.... but the logistical situation was surely in the back of his mind...)