US Navy Kills Level Boss, Grabs Power-Up: You Got The Lightning Gun

A railgun projectile strikes a target.

The future and its enemies? The enemies should be worried.

A futuristic weapon getting a trial run by the Navy demonstrated its destructive power at the Naval Surface Warfare Center in Dahlgren.

In the demonstration Thursday, engineers fired the electromagnetic railgun at what they said was a record power level: 10 megajoules.

The previous railgun power-use record was about 9 megajoules of muzzle energy.

Railguns use electromagnetic energy to launch projectiles long distances — more than 200 nautical miles.

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The Navy hopes the railgun will eventually replace the standard 5-inch gun on its ships. The weapon isn't expected to be deployed until at least 2020.

The railgun tested Thursday actually has a capacity of 32 megajoules, but the Navy is slowly building up the energy level in a series of tests.

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According to the Navy, the railgun, when fully developed, will be able to launch solid projectiles at Mach 5, or about 3,700 mph.

Click on the link to find video of the railgun about midway through the article.

Thanks to Driver.

A Whole Lot of Hell: Defense Tech writes that a single destroyer armed with railguns could pretty much wipe out every strategic target in North Korea.

Maybe that's overstated. Okay, maybe it will take two or three.

I found that looking for proposition I think is true but haven't been able to establish yet: I think railgun projectiles are not tipped with chemical-explosive warheads, but rather rely on the awesome kinetic energy of a heavy metal object flying at Mach 6 or 7 for their explosive effects. Not sure of that yet; still searching.

My only evidence of this so far comes from this discussion of a railgun's statistics in the Champions/Hero role playing game, which of course I find utterly convincing.

Let's try a different approach wherein an attack is required to simply punch through hex after hex in a straight line to total up the damage done. Actually, I can see a major problem with this. the frontal area of the ship is 25*50=1,250 hexes, which means that punching a hole clean through the ship lengthwise would only do 30/1250=0.24 BODY to the ship, but would require (20+10)*2 + (8+6)*200 = 2,860 Body from a human scale attack. For comparison, that's the average damage on an 817d6+1 RKA (12,260 pts). I don't have that many dice and you still have to do that four times to inflict one BODY on the ship. This approach is not going to work, I think.

Real-world anti-ship weapons, such as mines, missiles, shells, and torpedoes all have one thing in common: the letter E, which stands for "explosives". Science-fictional weapons such as lasers and hypervelocity solid projectiles also tend to release their energy as an explosion. Let's see what happens if we use an attack with the Explosion advantage to try to destroy our quota of hexes.

5ER lists an option for RKAs which I'll be using here: subtract 2 points of damage for every hex of expansion. That will make things much easier to calculate.

We can see from the numbers in the last post that to inflict one point of BODY damage on the ship, we need to damage the component hexes of the ship out to a radius of 16 hexes, at which point the damage will be 32 less than the damage at the point of impact. To destroy an internal hex will require 14 Body. Therefore, the damage at the point of impact must be 46 Body, the average result of a 13d6+1 RKA, Explosion (+1/2) (300 pts).

On this same model, a 20d6 RKA, Explosion (+1/2) (450 pts) would do an average damage of 70 Body at the point of impact and would do 14 Body out to a radius of 28 hexes. Assuming a hemispherical damage pattern again, this would destroy 91,952 hexes for a total of 11 BODY to the ship.

It would also appear, at first glance, to pretty much cut the ship in half, but the hole in the hull will "only" be 20 hexes in radius.

Exactly. I wish the Navy would stop talking in abstract scientific gobbedly-gook like "10 Megajoules" and speak in terms that the average American can understand, like 10d6 Mega RKA + AoE Explosive Effect. Or old school, like +6 Vorpal Holy Avenger Shells.

Oooh...

Thanks to a bunch of folks for that, including Exurban Jon and Buzz.

Entropy writes like he knows what he's talking about (though on the Internet you could always be talking to a dog, of course):

They're not going fast enough for real 'explosive' effect yet. Mach 5 would be getting close, but that's with 3 times the power this one used. So how fast was this one?

Mach 8 is hypervelocity. That's when metal reacts more like liquid and you get giant meteor craters as the ground vaporizes on impact, causing the freaking dirt to explode.

Not 'blow up the dirt'. No. I mean 'the dirt blows up'. You don't hit the dirt with explosives, the dirt it hits becomes the explosive when it's hit, and turns into rapidly expanding gas.

We're not going nearly that fast yet though. But I guess it still counts for something beyond just your basic "holy shit" forcepower...which this seems to be exceeding.

Even still it has a shitload of power, but without the explosiony goodness one would think there'd be a high chance of just penetrating the target straight through and actually doing just a little damage.

Eleven writes that these projectiles can't be tipped with conventional chemical warheads, because they'd explode on launch due either to the electrical firing (I don't know about that; it's electromagnetic, not electric) or maybe just because the sudden acceleration is not really any different than sudden deceleration, like hitting something, that can easily set off an explosive round.

It's Old: So says Fresh Air. Well, obviously we've had these in the works for a while, but the new record is fresh.

Fresh Air points to this great article by Wretchard from 2004 about these coming weapons. A must read. (By the way: Wretchard confirms the projectiles are solid darts without chemical explosive tips.)

A first-order analysis comparing the 200-mile volume of fires capability of a single hypersonic naval rail gun to the ordnance delivery capacity of a carrier air wing of F/A-18s is instructive. In the first eight hours of conflict, a single naval rail gun could deliver twice the payload, three times the energy, to ten times as many fixed aim points as carrier aviation.

He writes that such capability is not decisive, however, without a valid military doctrine behind it -- what exactly do you actually do with such firepower? seems to be his point.

I'm only being somewhat glib and sophomoric when I say don't worry, grant us the firepower and we'll come up with as much doctrine as you like to justify it.

I have to admit that the subtlety of Wretchard's point eludes me, though.

(Oh, I see: He's talking about the will to use such a ferocious weapon, or, more accurately, the lack thereof.)

posted by Ace at 04:51 PM

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