Saturday, December 11, 2010


And thanks to Sean Price for sending me this one. I've seen this on You Tube but now apparently they've broken their own record. This was a 33 megajoule firing and: 'A single megajoule is roughly equivalent to a 1-ton car traveling at 100 mph. Multiple that by 33 and you get a picture of what would happen when such a weapon hits a target.' Ouch.

A theoretical dream for decades, the railgun is unlike any other weapon used in warfare. And it's quite real too, as the U.S. Navy has proven in a record-setting test today in Dahlgren, VA.

Rather than relying on a explosion to fire a projectile, the technology uses an electomagnetic current to accelerate a non-explosive bullet at several times the speed of sound. The conductive projectile zips along a set of electrically charged parallel rails and out of the barrel at speeds up to Mach 7.


Joe Mansfield said...

Using the accepted values for TNT's explosive power 33MJ is equivalent to around 8kg of TNT. That's a lot of energy and I wouldn't want to be on the receiving end of it but it pales in comparison to the century old tech of a Naval 16" gun.

The kinetic energy of a 1 ton shell just after leaving the barrel of a 16" is around 600MJ (assuming it's moving at around 800m/sec). The kicker is that those shells could carry a ton of HE to the target and that's more than 100x the destructive potential of the Rail Gun projectile when it arrives.

It's still pretty cool though.

Ryan said...

As cool as this type of thing is I wonder how fully useful it is. To clarify my point, a handheld coil gun I see the possible advantage with. Using a rail gun in vacuum as a mass driver (or bombardment) I see as well and as a tank cannon or something. BUT in many pictures ive seen from the US navy its been a cannon on a ship (sometimes firing inland). Surely this is going to run into the same problem that most artillery has had in the past? for long range action missles are far better

Neal Asher said...

These points, from the article, are perhaps relevant to both your comments, Joe and Ryan:

"For one thing, a railgun offers 2 to 3 times the velocity of a conventional big gun, so that it can hit its target within 6 minutes. By contrast, a guided cruise missile travels at subsonic speeds, meaning that the intended target could be gone by the time it reaches its destination.

Furthermore, current U.S. Navy guns can only reach targets about 13 miles away. The railgun being tested today could reach an enemy 100 miles away. And with current GPS guidance systems it could do so with pinpoint accuracy. The Navy hopes to eventually extend the range beyond 200 miles"

Ryan said...

I read the article after my post (rookie mistake) and saw the point of a lot of what it said. Especially the idea of hitting the magazines of an opposing ship. But I don't see how pinpoint accuracy can be insured over longer distances. At mach 7 this projectile will be hitting air as if it was brick and its surely not going to fly in a perfect arc. At 100 miles wouldn't the resistance and turbulence of the air A) slow the projectile down massively and B) Knock it off course to such an extent to be far far off target?

I'm perfectly accepting that I'm probably wrong and these things have indeed been taken into account but I'm wondering how

vaudeviewgalor raandisisraisins said...

now to find some insurgent families whose mineral-land amples out weigh their life expectancy. it's the american way.

also speaking of ridiculous bounty:

"Used-Like New"
w t f.
you could pay for a plane ticket to here, sell 2 dozen copies (at the low price of 300 bucks), and fly back financing an internet system for the whole of Crete.

i have to assume here; this must have your pinnacle of writing chops for them to charge that price. cant wait to get mine.

Killer Kalamity said...

Couldn't find where to post this. Seeing this railgun awesomeness got me thinking about other aspects of Asher's world, like AI.

Neal Asher said...

Ryan, I'm guess the point here is that since a joule is a unit of energy we really need to think about the size and weight of the projectile (and its profile). Nice to find that out.

What crap, Vaude. The listing is even as a paperback, which isn't out yet! No one is stupid enough to pay that price. are they? Your package is on its way.

Killer, creativity programs? Maybe my time as a writer is limited...

vaudeviewgalor raandisisraisins said...

this is a country that is churning out "Palin for President 2012" stickers.

yes, that stupid.

Jebel Krong said...

i don't think ballistics or projectile aerodynamics play much part in the effectiveness of something that's blink-and-you'll-miss-it quick, plus it's also much cheaper than a cruise missile.

in other weapons areas there's northrop's laser, which has just passed endurance tests:

or, on a more sedate and perhaps, romantic, point, there's NASAs slow-motion shuttle launch videos:

Ryan said...

"blink-and-you'll-miss-it quick"

It's travelling up to 100km though, even at mach 7 it will still take the best part of a minute to get there. And if the projectile is just one degree off course it will land anywhere up to 1.7km from the target. Add that to the turbulance and the resistance and i dont see this as an effective long range weapon. short to mid its deadly but at long range it must be inaccurate.

"Maybe my time as a writer is limited..."

Perhaps a turing style face off between you an a computer to write the next polity book? see if we can tell the difference...

Paul said...

One advantage over the good old 16" gun is that your ship isn't full of HE shells and propellant. Much harder to blow up an arsenal of solid tungsten darts.

16" guns still take some beating for shock and awe.

Keith said...

From the atmospheric heating trail that is following this missile, I suspect that the US Navy has just found another billion dollar boondoggle. Waste of effort using a railgun in an ablative/drag inducing environment. All that heating you can see is the 33Mj dwindling away. Also not mentioned is the recovery method for the moving armature, which if it is non reuseable renders economies of space/weight null.

Neal Asher said...

Keith, I didn't know that about the moving armature. As for the ablative effects ... ceramic nose-cones like the missiles in my books? I would also guess that the Manhattan Project was considered a bit of a boondoggle when it was begun.