General Atomics electromagnetic rail cannon

[Old Man]

With a little test footage: http://defensetech.org/2010/05/05/killer-drone-builder-general-atomics-builds-killer-electromagnetic-rail-cannon/

[SSgt Baloo]

Re: General Atomics electromagnetic rail cannon

 

Cool!

[McCoy]

Re: General Atomics electromagnetic rail cannon

 

Cool!

What he said.

[tkdguy]

Re: General Atomics electromagnetic rail cannon

 

Now all we need is the Orion Battleship to put it in.

 

Thanks for posting this. I had been wondering about the progress of the railgun being pursued by the Navy but didn't find anything.

[Markdoc]

Re: General Atomics electromagnetic rail cannon

 

If nothing else, General Atomics is an awesome company name!

 

As for the rail gun .... meh. We had this exact same discussion - with the exact same claims as made by the guy in the video - 7 years ago in this thread. The same - so far unsolved - engineering problems exist too.

 

cheers, Mark

[Markdoc]

Re: General Atomics electromagnetic rail cannon

 

Now all we need is the Orion Battleship to put it in.

 

Thanks for posting this. I had been wondering about the progress of the railgun being pursued by the Navy but didn't find anything.

 

That's because the program was cancelled years ago. The DDX program - including the ships that were suggested as platforms for railguns - was cut from 70+ ships to 3 destroyers, renamed DDG-1000, and much of the fancy technology originally planned for them has been cut. With no ships capable of mounting railguns, the navy ended the weapons program. This model - like the one we discussed back in 2003 - is a proof of concept - a sort of technology demonstrator, intended to demonstrate that it might one day be possible to build railguns. PoC programs tend to run mostly under the radar, since they are relatively small, budget-wise.

 

I think that's smart - the DDX program looks like a gigantic boondoggle, spending hundreds of billions to deploy technology that hasn't been invented yet, mostly to benefit companies in the home turf of the congressmen who promoted it. In today's economic climate, projects like that have little chance of survival.

 

cheers, Mark

[Old Man]

Re: General Atomics electromagnetic rail cannon

 

So I figure that thing must do at least 3d6K. Str min looks pretty high, it's probably a tripod mounted weapon...

[Markdoc]

Re: General Atomics electromagnetic rail cannon

 

Not if you have - say - 50 STR Even if the rails burn out after a couple of shots, it'd still make a dandy club!

 

cheers, Mark

[Lawnmower Boy]

Re: General Atomics electromagnetic rail cannon

 

With a sling, you could fire it from the hip!

 

 

And now that I've watched the video, two thoughts.

i) "Hundreds of thousands of pounds of thrust." Hee. You American sure are crazy with your Imperial measuring system!

ii) "Could be fielded this decade." It's good to be a futurist in years that end in zero!

[Kraven Kor]

Re: General Atomics electromagnetic rail cannon

 

What about the college kid who built a man-portable rail gun a few years back? It had some impressive stats as far as energy imparted to target - several megajoules - and was about the size of your average tripod-mounted MG, not including the batteries.

[Zeropoint]

Re: General Atomics electromagnetic rail cannon

 

What about the college kid who built a man-portable rail gun a few years back? It had some impressive stats as far as energy imparted to target - several megajoules - and was about the size of your average tripod-mounted MG, not including the batteries.

 

Shh! We don't talk about things that didn't come through the established corporate channels!

 

Also, link? That sounds pretty cool.

[BlueCloud2k2]

Re: General Atomics electromagnetic rail cannon

 

What about the college kid who built a man-portable rail gun a few years back? It had some impressive stats as far as energy imparted to target - several megajoules - and was about the size of your average tripod-mounted MG' date=' not including the batteries.[/quote']

 

I thought that was just a hoax? I could be wrong though. *shrug*

[tkdguy]

Re: General Atomics electromagnetic rail cannon

 

I remember this website.

[tkdguy]

Re: General Atomics electromagnetic rail cannon

 

That's because the program was cancelled years ago. The DDX program - including the ships that were suggested as platforms for railguns - was cut from 70+ ships to 3 destroyers' date=' renamed DDG-1000, and much of the fancy technology originally planned for them has been cut[/url']. With no ships capable of mounting railguns, the navy ended the weapons program. This model - like the one we discussed back in 2003 - is a proof of concept - a sort of technology demonstrator, intended to demonstrate that it might one day be possible to build railguns. PoC programs tend to run mostly under the radar, since they are relatively small, budget-wise.

 

I think that's smart - the DDX program looks like a gigantic boondoggle, spending hundreds of billions to deploy technology that hasn't been invented yet, mostly to benefit companies in the home turf of the congressmen who promoted it. In today's economic climate, projects like that have little chance of survival.

 

cheers, Mark

 

Thanks. I remember reading about the DDX program being scrapped, but I didn't know the railgun project was scrapped too. Still, didn't BAE deliver one to the Navy back in 2008?

[NuSoardGraphite]

Re: General Atomics electromagnetic rail cannon

 

Really? Thats pretty darned cool. I just started working at General Atomics recently, I'll see if I can spot one for you guys! (I can't divulge any details though etc etc)

[tkdguy]

Re: General Atomics electromagnetic rail cannon

 

Really? Thats pretty darned cool. I just started working at General Atomics recently' date=' I'll see if I can spot one for you guys! (I can't divulge any details though etc etc)[/quote']

 

Maybe you'll even get to work on it.

[Markdoc]

Re: General Atomics electromagnetic rail cannon

 

What about the college kid who built a man-portable rail gun a few years back? It had some impressive stats as far as energy imparted to target - several megajoules - and was about the size of your average tripod-mounted MG' date=' not including the batteries.[/quote']

 

There's been a lot of similar projects - if you go here, you can see a bunch of videos showing amateur/semi-amateur rail guns some of which generate pretty impressive energy to projectile stats - but all of which suffer from two minor technical problems

1) they tend to explode violently when used, since they are also imparting an impressive amount of energy to the rails

2) they impart energy - but not momentum. There's a number of videos demonstrating the difference - a railgun that imparts 16000 J to the projectile (about 32x the muzzle exit energy of a 45. ACP round) which fails to penetrate a leather glove at near point blank range. Like many of the nifty videos show, most of that energy is boiled off as the projectile turns to plasma.

 

Those two teensy-weensy problems - how to make a gun that doesn't explode when used, and how to make a projectle that doesn't melt away when fired - still remain to be solved, before moving onto weapons projects.

 

cheers, Mark

[Markdoc]

Re: General Atomics electromagnetic rail cannon

 

Thanks. I remember reading about the DDX program being scrapped' date=' but I didn't know the railgun project was scrapped too. Still, didn't BAE deliver one to the Navy back in 2008?[/quote']

 

They delivered a prototype "proof of concept" back in 2006, though it wasn't supposed to reach live test firing status until 2008, due to lack of capacitors powerful enough to drive it.

 

That's this guy:

 

Here's what it actually looks like:

 

It's a 16 ton weapon mounted on a railway car, powered by a nearby building full of capapcitors - total weapon weight, an estimated 20-30 tons. Still if it works, it will be ..... almost as powerful as ordinary, much smaller, much lighter, faster-firing guns currently available. An AT round from an Abrams generates (so I'm told) around 7 MJ, so this behemoth will be almost twice as powerful as a tank mounted weapon - if they can stop it blowing up.

 

Here's a nifty picture of a similar weapon being fired:

You may note the giant cloud of superheated gas and molten metal, which is mostly coming from what used to be the gun. You better hope you hit what you shooting at - and that you only have one target - because you only get one shot per gun.

 

But here's the kicker - that photo above is of a low power version, with a muzzle velocity of 430 meters-per-second - slightly faster than a standard infantry 120 mm mortar. Not exactly a tank-killing weapon. Hell, not even an APC-killing weapon. And at 200 times the weight, 1/50th the rate of fire and 300x the cost, it doesn't even make a good mortar.

 

Where we are right now is basic research. DoD has several scales for funding projects - proof of concept, test-bed, prototype and pre-production.

Proof of concept is for wacky stuff - killing goats by staring at them, for example. Relatively small budget, just "can we even make this work" kind of stuff.

Then there's test-bed, which is bigger-budget "We think this will work - let's try and build something that resembles a workable version"

Then there's prototype, which is much bigger budget "Let's try and make a version that could actually be used outside a lab"

Then there's pre-production, at which point you are trying to make the actual thing that could be given to the military.

 

Railguns at the moment are proof of principle, being conducted by open-bid, non-classified research groups. In short, they are looking for someone - anyone - who can come up with an idea on how to build one that that , you know, won't blow a huge hole in the side of your ship the first time it's used.

 

cheers, Mark

[McCoy]

Re: General Atomics electromagnetic rail cannon

 

My principle interest in rail /gauss guns is scaling them up to throw (extremely tough) payloads to LEO. Imagine supplying a space station by throwing MRE's into a metal shell, toping it with water and freezing it, then loading it into your gun and pushing the button. The astronauts in LEO (or their robot counterparts) recover the payload. The MRE's go into the pantry, the melted ice into the life support system OR is broken down by solar power into H2 and O2 and used as fuel (like for that mini-tug that recovers the slugs thrown by the gun), and the metal shell used as feed stock for a rapid prototyping machine shop system to make what is needed.

 

Couldn't use the gun for any payload that can't survive >25 G's, say fragile electronics or anything living, but could work to routinely supply food, water, fuel, and very tough spare parts/raw materials.

 

The downside is political. a gun that can throw a payload to LEO can throw a bomb (or at least a very big very fast bullet) to any point on Earth.

[Cancer]

Re: General Atomics electromagnetic rail cannon

 

Eeep! You want to escape to LEO with a single-impulse muzzle-velocity launcher? That's Mach 31+ at the muzzle, minimum, before air-friction losses, even including the 0.46 km/s you can get for free by using all of Earth's rotation velocity. Most meteoroids in that size regime don't survive passage through the atmosphere due to thermal and aerodynamic stresses, and they're trying to do it in the "right" direction, starting from the low-density end of the atmosphere!

[McCoy]

Re: General Atomics electromagnetic rail cannon

 

Eeep! You want to escape to LEO with a single-impulse muzzle-velocity launcher? That's Mach 31+ at the muzzle' date=' minimum, before air-friction losses, even including the 0.46 km/s you can get for free by using all of Earth's rotation velocity. Most meteoroids in that size regime don't survive passage through the atmosphere due to thermal and aerodynamic stresses, and they're trying to do it in the "right" direction, starting from the low-density end of the atmosphere![/quote']

Mach 31, about 7 miles per second, LEO in, um 45 seconds more or less. Assuming we can find some way for a payload to not react to hitting air at that speed like it would hitting concrete (OK, a BIG assumption), should be able to devise a heat shield that could keep the payload safe for less than a minute.

[Basil]

Re: General Atomics electromagnetic rail cannon

 

Mach 31' date=' about 7 miles per second, LEO in, um 45 seconds more or less. Assuming we can find some way for a payload to not react to hitting air at that speed like it would hitting concrete (OK, a BIG assumption), should be able to devise a heat shield that could keep the payload safe for less than a minute.[/quote']

 

The velocity needed to get to LEO is ~8000 m/s, and ANYTHING will turn to plasma at ~4000 - 4200 m/s. Anything "shot" into orbit will have most or all "boiled away" long before it gets to the stratosphere.

 

Unless the heat shield is significantly more massive than the payload it's protecting, trying to "shoot" into LEO can't be done. And since the heat shield would be completely lost, it's highly uneconomical.

 

Mind you, a sled-like set up to get a capsule up to ~3000 m/s would work, assuming the capsule has a rocket motor. The fraction of "take off" mass that must be propellent drops pretty rapidly with a decrease in the velocity the rocket has to add to its starting velocity.

[BlueCloud2k2]

Re: General Atomics electromagnetic rail cannon

 

What about the stuff the Space Shuttle is coated in... isn't is some sort of ceramic? Maybe a Ceramic re-inforced with Carbon Nano-Tubes as a munition? Or how about making the round a little bit bigger with an ablative coating that sluffs off?

 

And if it is the atmosphere that causes Rail Gun rounds to turn to plasma, does that mean it would be a suitable Space-to-Space weapons platform?

[Markdoc]

Re: General Atomics electromagnetic rail cannon

 

Yp, rail guns would be far more suitable as weapons in space - though you still have to deal with the whole "Blows up when used" thing. However, I'm guessing that if we have sufficiently advanced tech that space warfare becomes possible, it's likely that we'll be able to solve that problem. As for the space shuttle, yes, it has ceramic tiles to help resist heat. But it's only traveling at a fraction of the speed we are talking about: if it tried traveling at 8000 m/s, you'd end up with a fine streak of fire across the sky as it vaporised. Not that the crew would care - at that speed they'd already have been crushed to paste against the back wall.

 

cheers, Mark

[gewing]

Re: General Atomics electromagnetic rail cannon

 

tiny quibble, wouldn't whether or not the astronauts were pasted on the back wall be a function of acceleration, not velocity?