Besides the extended ranges, the railgun also improves safety.
December 15, 2010 7:00 AM Subscribe
The railgun is a long-range, high-energy gun launch system that uses electricity rather than gunpowder or rocket motors to launch projectiles capable of striking a target at a range of more than 200 nautical miles with Mach 7 velocity.
U.S. Navy researchers notched a world record on Dec. 10 at the Naval Surface Warfare Center in Dahlgren, Va., when they fired off a projectile packing 33 megajoules of energy using an electromagnetic railgun (more better video). That's as much kinetic energy as a 33-ton semi has when it's traveling at 100 mph.
U.S. Navy researchers notched a world record on Dec. 10 at the Naval Surface Warfare Center in Dahlgren, Va., when they fired off a projectile packing 33 megajoules of energy using an electromagnetic railgun (more better video). That's as much kinetic energy as a 33-ton semi has when it's traveling at 100 mph.
I have a soft spot for these.
posted by Artw at 7:06 AM on December 15, 2010 [2 favorites]
posted by Artw at 7:06 AM on December 15, 2010 [2 favorites]
200 nautical miles? Doesn't the curvature of the Earth make that difficult?
posted by keratacon at 7:06 AM on December 15, 2010
posted by keratacon at 7:06 AM on December 15, 2010
three blind mice: "with Mach 7 velocity."
They'll never hear it coming.
posted by bwg at 7:07 AM on December 15, 2010 [2 favorites]
They'll never hear it coming.
posted by bwg at 7:07 AM on December 15, 2010 [2 favorites]
I still say every nuke plant should have one installed and launch small canisters of waste into the sun.
posted by Scoo at 7:08 AM on December 15, 2010 [3 favorites]
posted by Scoo at 7:08 AM on December 15, 2010 [3 favorites]
200 nautical miles? Doesn't the curvature of the Earth make that difficult? - Gravity lends a hand.
posted by Artw at 7:11 AM on December 15, 2010
posted by Artw at 7:11 AM on December 15, 2010
Velocitas Eradico--nice.
posted by MrMoonPie at 7:12 AM on December 15, 2010 [3 favorites]
posted by MrMoonPie at 7:12 AM on December 15, 2010 [3 favorites]
How did they manage to catch it with that panning camera view? Seems like turning the camera at Mach 7 would be pretty hard.
posted by notmydesk at 7:12 AM on December 15, 2010
posted by notmydesk at 7:12 AM on December 15, 2010
200 nautical miles? Doesn't the curvature of the Earth make that difficult?
Two words: Indirect fire.
posted by valkyryn at 7:13 AM on December 15, 2010
Two words: Indirect fire.
posted by valkyryn at 7:13 AM on December 15, 2010
The railgun is a long-range, high-energy gun launch system that uses electricity rather than gunpowder or rocket motors to launch projectiles capable of striking a target keep a whole bunch of military contractors gainfully employed and not building Dr. Evil-esque lairs, selling their services to the North Koreans, or worse yet, voting for The Other Guy.
It also has the side-effect of launching projectiles.
I have to admit I find it pretty awesome, honestly.
posted by Kadin2048 at 7:13 AM on December 15, 2010 [3 favorites]
It also has the side-effect of launching projectiles.
I have to admit I find it pretty awesome, honestly.
posted by Kadin2048 at 7:13 AM on December 15, 2010 [3 favorites]
Gotta break some eggs to make an omelet, NoMich.
What was the projectile, btw?
posted by notyou at 7:13 AM on December 15, 2010
What was the projectile, btw?
posted by notyou at 7:13 AM on December 15, 2010
We can haz spaceship now?!
posted by nomadicink at 7:13 AM on December 15, 2010 [2 favorites]
posted by nomadicink at 7:13 AM on December 15, 2010 [2 favorites]
When we one day fight a war with sentient pianos, our children will be well-prepared.
posted by Blazecock Pileon at 7:14 AM on December 15, 2010 [1 favorite]
posted by Blazecock Pileon at 7:14 AM on December 15, 2010 [1 favorite]
Why does it have a flame trail? All I can come up with is, "Well, it's moving pretty fast, maybe it's.. igniting.. the air?" but that seems pretty iffy.
posted by curious nu at 7:16 AM on December 15, 2010
posted by curious nu at 7:16 AM on December 15, 2010
Unless it makes that "peeeew" sound and does that spirally thing like the rail gun in Quake 2, it's not a rail gun. Sorry, but it's The Rule that all rail guns must make that "peeeew" sound and do the spirally thing.
Man, back in the day we had this little hack/add-on that would give you a zoom feature in Q2 and we would hide somewhere and snipe the shit out of my boss with the rail gun from across the map every single time he came through a door. It would be considered bad form now-a-days on a public server but when it's a private game at work and you're sniping your boss over and over it's the best damn thing ever.
I want a rail gun. But only if it goes "peeeew" and does the spirally thing.
posted by bondcliff at 7:16 AM on December 15, 2010 [12 favorites]
Man, back in the day we had this little hack/add-on that would give you a zoom feature in Q2 and we would hide somewhere and snipe the shit out of my boss with the rail gun from across the map every single time he came through a door. It would be considered bad form now-a-days on a public server but when it's a private game at work and you're sniping your boss over and over it's the best damn thing ever.
I want a rail gun. But only if it goes "peeeew" and does the spirally thing.
posted by bondcliff at 7:16 AM on December 15, 2010 [12 favorites]
Why does the railgun firing look just like any other conventional explosion? I thought it was all magnetic and no by-products in the chamber...
posted by Old'n'Busted at 7:17 AM on December 15, 2010
posted by Old'n'Busted at 7:17 AM on December 15, 2010
Artw: I have a soft spot for these.
Yes, right where your heart used to be. Because you were hit with a RAILGUN. You'll fall over in a moment.
posted by filthy light thief at 7:17 AM on December 15, 2010 [12 favorites]
Yes, right where your heart used to be. Because you were hit with a RAILGUN. You'll fall over in a moment.
posted by filthy light thief at 7:17 AM on December 15, 2010 [12 favorites]
This is seriously cool as the Navy is looking for something that is useful as a missile but as expendable as a bullet. Being able to do shore bombardments effectively from destroyers and cruisers would be pretty impressive, especially at long distances like that seen.
Still, I'm not blind to what this will be used for, and I am mournful that the human race and discovered a more effective way to kill people and destroy landscapes/buildings.
posted by Lord Chancellor at 7:19 AM on December 15, 2010 [2 favorites]
Still, I'm not blind to what this will be used for, and I am mournful that the human race and discovered a more effective way to kill people and destroy landscapes/buildings.
posted by Lord Chancellor at 7:19 AM on December 15, 2010 [2 favorites]
How did they manage to catch it with that panning camera view? Seems like turning the camera at Mach 7 would be pretty hard.
Pan and scan
posted by DU at 7:20 AM on December 15, 2010 [1 favorite]
Pan and scan
posted by DU at 7:20 AM on December 15, 2010 [1 favorite]
What was the projectile, btw?
An anvil, modified for aerodynamics. Coincidentally, we've also been investigating power armor that lets a human being safely collapse like an accordion after being hit by a high-mass projectile. Tiny umbrellas are also replacing parachutes for when soldiers' anti-gravity boots go out; there's a bug in them that turns them off if the soldier ever looks down.
posted by griphus at 7:20 AM on December 15, 2010 [21 favorites]
An anvil, modified for aerodynamics. Coincidentally, we've also been investigating power armor that lets a human being safely collapse like an accordion after being hit by a high-mass projectile. Tiny umbrellas are also replacing parachutes for when soldiers' anti-gravity boots go out; there's a bug in them that turns them off if the soldier ever looks down.
posted by griphus at 7:20 AM on December 15, 2010 [21 favorites]
I guess cool shit like this is what you get when you outspend the rest of the world (combined) on your military budget. Good thing we don't have crumbling infrastructure and starving kids in our country.
See, okay, but the other way to think about defense spending is direct stimulus.
Seriously, where do you think all that money goes? Defense contractor employees, that's where. There are almost a thousand engineers employed in my current city by some combination of Raytheon, General Dynamics, a Northrop Grumman subcontractor, and GE, and the vast majority of that funding comes directly or indirectly from the Department of Defense.
So when we talk about cutting defense spending, we're talking about cutting exactly the kind of high-paying, science-based jobs that we all tell our kids they should want. Thinking about the DoD as a sustained, $500 billion stimulus package--which is basically what it is--puts things in a slightly different light.
I'm not saying that we shouldn't probably cut the defense budget by a whole ton. I'm saying that it isn't exactly pouring money down a hole, because it's keeping about half a million people employed. Take a look at the list of defense contractors. Lockheed Martin, Boeing, Northrop Grumman, General Dynamics, and Raytheon, with the exception of Boeing (which has a profitable commercial airline business) get three quarters of their revenue from the government. Together, they employ something like half a million people, mostly in good jobs. Get rid of that and you're talking about sending unemployment up at least a point.
posted by valkyryn at 7:23 AM on December 15, 2010 [2 favorites]
See, okay, but the other way to think about defense spending is direct stimulus.
Seriously, where do you think all that money goes? Defense contractor employees, that's where. There are almost a thousand engineers employed in my current city by some combination of Raytheon, General Dynamics, a Northrop Grumman subcontractor, and GE, and the vast majority of that funding comes directly or indirectly from the Department of Defense.
So when we talk about cutting defense spending, we're talking about cutting exactly the kind of high-paying, science-based jobs that we all tell our kids they should want. Thinking about the DoD as a sustained, $500 billion stimulus package--which is basically what it is--puts things in a slightly different light.
I'm not saying that we shouldn't probably cut the defense budget by a whole ton. I'm saying that it isn't exactly pouring money down a hole, because it's keeping about half a million people employed. Take a look at the list of defense contractors. Lockheed Martin, Boeing, Northrop Grumman, General Dynamics, and Raytheon, with the exception of Boeing (which has a profitable commercial airline business) get three quarters of their revenue from the government. Together, they employ something like half a million people, mostly in good jobs. Get rid of that and you're talking about sending unemployment up at least a point.
posted by valkyryn at 7:23 AM on December 15, 2010 [2 favorites]
Heh. That's one of my dad's projects. Here's a video he made of firing a railgun set to the 1812 Overture.
posted by robocop is bleeding at 7:23 AM on December 15, 2010 [1 favorite]
posted by robocop is bleeding at 7:23 AM on December 15, 2010 [1 favorite]
I look forward to the day our wars are settled by the two sides' gigantic Rock 'Em, Sock 'Em Robots doing battle in an outer space Thunderdome. The pay-per-view revenue will fund the next war. Winner gets to store nuclear waste in losers' soccer stadiums.
posted by Buffaload at 7:28 AM on December 15, 2010 [3 favorites]
posted by Buffaload at 7:28 AM on December 15, 2010 [3 favorites]
Any spending will employ people. If these engineers weren't being paid to make railguns, the could be getting paid to, say, improve power and transportation infrastructure. This would actually provide economic benefits to society.
I'm pretty sure Boeing would have a high speed rail division instead of a missile division if there were money put toward it.
Remember the money that's paying them has to come from somewhere... if it's from people who would be spending that money anyway (many taxes), that's no benefit. Though actually if it's plain ol' deficit spending, it'll come from inflationary pressures, which luckily is going to make it essentially "come" from accumulated wealth, in which case it is beneficial. However, with military spending there's no long term payback that's going to offset the future payments on that debt.
posted by Zalzidrax at 7:28 AM on December 15, 2010 [23 favorites]
I'm pretty sure Boeing would have a high speed rail division instead of a missile division if there were money put toward it.
Remember the money that's paying them has to come from somewhere... if it's from people who would be spending that money anyway (many taxes), that's no benefit. Though actually if it's plain ol' deficit spending, it'll come from inflationary pressures, which luckily is going to make it essentially "come" from accumulated wealth, in which case it is beneficial. However, with military spending there's no long term payback that's going to offset the future payments on that debt.
posted by Zalzidrax at 7:28 AM on December 15, 2010 [23 favorites]
>>Good thing we don't have crumbling infrastructure and starving kids in our country.
>I'm saying that it isn't exactly pouring money down a hole, because it's keeping about half a million people employed.
Could they be employed fixing infrastructure or feeding starving kids?
posted by DU at 7:29 AM on December 15, 2010 [5 favorites]
>I'm saying that it isn't exactly pouring money down a hole, because it's keeping about half a million people employed.
Could they be employed fixing infrastructure or feeding starving kids?
posted by DU at 7:29 AM on December 15, 2010 [5 favorites]
If these engineers weren't being paid to make railguns, the could be getting paid to, say, improve power and transportation infrastructure. This would actually provide economic benefits to society.
Sounds good to me. I was just objecting to the idea that we're getting nothing out of this and that that huge block of spending can be made to magically disappear without any ill effects.
posted by valkyryn at 7:29 AM on December 15, 2010
Sounds good to me. I was just objecting to the idea that we're getting nothing out of this and that that huge block of spending can be made to magically disappear without any ill effects.
posted by valkyryn at 7:29 AM on December 15, 2010
Heh. That's one of my dad's projects...
posted by robocop is bleeding
Eponyterrifying
posted by griphus at 7:30 AM on December 15, 2010 [8 favorites]
posted by robocop is bleeding
Eponyterrifying
posted by griphus at 7:30 AM on December 15, 2010 [8 favorites]
Sir Isaac Newton is the deadliest son of a bitch in space.
posted by kmz at 7:31 AM on December 15, 2010 [6 favorites]
posted by kmz at 7:31 AM on December 15, 2010 [6 favorites]
Maybe the bad guys will listen to reason.
posted by katiewa at 7:32 AM on December 15, 2010 [5 favorites]
posted by katiewa at 7:32 AM on December 15, 2010 [5 favorites]
Could they be employed fixing infrastructure or feeding starving kids?
Look, if it wasn't for railguns, Steven Seagal never would have ridden in our minivan.
posted by robocop is bleeding at 7:34 AM on December 15, 2010 [1 favorite]
Look, if it wasn't for railguns, Steven Seagal never would have ridden in our minivan.
posted by robocop is bleeding at 7:34 AM on December 15, 2010 [1 favorite]
Why does it have a flame trail? All I can come up with is, "Well, it's moving pretty fast, maybe it's.. igniting.. the air?" but that seems pretty iffy.
ISTR it's either/both erosion from the rails (they get chewed up by the current and friction with the projectile) and/or ablation from the projectile moving real fast (like spacecraft reentry).
Also, the scientists and engineers might just liberally apply gasoline or other combustibles to enhance the effect. I know I would! I'd also make it weep blood.
posted by ROU_Xenophobe at 7:36 AM on December 15, 2010 [11 favorites]
ISTR it's either/both erosion from the rails (they get chewed up by the current and friction with the projectile) and/or ablation from the projectile moving real fast (like spacecraft reentry).
Also, the scientists and engineers might just liberally apply gasoline or other combustibles to enhance the effect. I know I would! I'd also make it weep blood.
posted by ROU_Xenophobe at 7:36 AM on December 15, 2010 [11 favorites]
So when we talk about cutting defense spending, we're talking about cutting exactly the kind of high-paying, science-based jobs that we all tell our kids they should want.
It isn't some kind of zero sum game where cutting defense jobs will put scientists out of work. In general they have better job prospects than the average person.
Also, my kids can grow up to be whatever they want, but I hope in my heart that they do not end up making weapons whose sole purpose is violence and death.
posted by infinitefloatingbrains at 7:37 AM on December 15, 2010 [2 favorites]
It isn't some kind of zero sum game where cutting defense jobs will put scientists out of work. In general they have better job prospects than the average person.
Also, my kids can grow up to be whatever they want, but I hope in my heart that they do not end up making weapons whose sole purpose is violence and death.
posted by infinitefloatingbrains at 7:37 AM on December 15, 2010 [2 favorites]
So when we talk about cutting defense spending, we're talking about cutting exactly the kind of high-paying, science-based jobs that we all tell our kids they should want.
Which is why we should cut defense spending and give it to NASA.
posted by nomadicink at 7:38 AM on December 15, 2010 [7 favorites]
Which is why we should cut defense spending and give it to NASA.
posted by nomadicink at 7:38 AM on December 15, 2010 [7 favorites]
Being a nerd, I first learned about railguns from the place any child of sci-fi readers learns about railguns: Bolo! A sure-fire way to turn any budding engineer into a heavy artillery geek.
posted by muddgirl at 7:40 AM on December 15, 2010 [1 favorite]
posted by muddgirl at 7:40 AM on December 15, 2010 [1 favorite]
making weapons whose sole purpose is violence and death.
Some of the pumpkin chunkin guys approached my dad about building a pumpkin-ready railgun. Sadly, the physics didn't work out - the result would have been high velocity pumpkin mash. But with just a bit more funding...
posted by robocop is bleeding at 7:45 AM on December 15, 2010 [2 favorites]
Some of the pumpkin chunkin guys approached my dad about building a pumpkin-ready railgun. Sadly, the physics didn't work out - the result would have been high velocity pumpkin mash. But with just a bit more funding...
posted by robocop is bleeding at 7:45 AM on December 15, 2010 [2 favorites]
Also note that railguns have many applications outside of offensive weaponry (although we have to sell the weaponry angle to get any sort of financing). Build a unit 10x that size and replace the anvil with, say, a sattelite payload and shoot it into space.
posted by muddgirl at 7:45 AM on December 15, 2010 [1 favorite]
posted by muddgirl at 7:45 AM on December 15, 2010 [1 favorite]
Pretty cool, but I'm still waiting for the wave motion gun...
posted by JoanArkham at 7:48 AM on December 15, 2010 [2 favorites]
posted by JoanArkham at 7:48 AM on December 15, 2010 [2 favorites]
my first practical exposure to railguns was at Cedar Point where linear induction motors using similar principles were used to propel us on some hilariously fast corkscrews. Which is to say, most military projects eventually find neat applications in the civilian sphere.
so, yeah, to all of the anti-milporn folks who are reflexively saying that all this spending is purely wasteful: open your minds a bit? thanks.
posted by bl1nk at 7:51 AM on December 15, 2010
so, yeah, to all of the anti-milporn folks who are reflexively saying that all this spending is purely wasteful: open your minds a bit? thanks.
posted by bl1nk at 7:51 AM on December 15, 2010
I'm saying that it isn't exactly pouring money down a hole, because it's keeping about half a million people employed.
OMG SOCIALIST!!!!!!!
posted by LordSludge at 7:51 AM on December 15, 2010 [4 favorites]
OMG SOCIALIST!!!!!!!
posted by LordSludge at 7:51 AM on December 15, 2010 [4 favorites]
I thought about this for a bit, and was curious as to exactly how destructive this thing actually is. We're talking about a 32 megajoule shot. As advertised, that's the approximate force of a semi moving at 100mph. Which would totally ruin your day, but... it's actually in the neighborhood of an Abrams moving at a decent speed. Again, ouch, but there are plenty of buildings that would survive something like that. Heck, burning a single barrel of oil releases approximately six gigajoules, and a small nuclear bomb produces sixty terajoules.
So I'd think to be competitive with existing battleship guns, which fire 1.4 ton shells about 24 miles at 1800 mph, we're going to need to seen an increase in power by several orders of magnitude. The range is certainly impressive, as is the speed (and thus theoretically the accuracy), but if a gun this size were deployed we'd be talking about taking out vehicles, not hardened bunkers or other targets of strategic significance.
posted by valkyryn at 7:53 AM on December 15, 2010
So I'd think to be competitive with existing battleship guns, which fire 1.4 ton shells about 24 miles at 1800 mph, we're going to need to seen an increase in power by several orders of magnitude. The range is certainly impressive, as is the speed (and thus theoretically the accuracy), but if a gun this size were deployed we'd be talking about taking out vehicles, not hardened bunkers or other targets of strategic significance.
posted by valkyryn at 7:53 AM on December 15, 2010
This is seriously cool as the Navy is looking for something that is useful as a missile but as expendable as a bullet.
Commenters are saying that the high energy partially vaporizes the rail into plasma, so maybe it can't be fired repeatedly.
posted by StickyCarpet at 7:57 AM on December 15, 2010
Commenters are saying that the high energy partially vaporizes the rail into plasma, so maybe it can't be fired repeatedly.
posted by StickyCarpet at 7:57 AM on December 15, 2010
Glitter boys taught me about railguns.
posted by georg_cantor at 8:09 AM on December 15, 2010 [6 favorites]
posted by georg_cantor at 8:09 AM on December 15, 2010 [6 favorites]
I look forward to the day our wars are settled by the two sides' gigantic Rock 'Em, Sock 'Em Robots doing battle in an outer space Thunderdome.
Robot Jox.
posted by mrbill at 8:12 AM on December 15, 2010 [2 favorites]
Robot Jox.
posted by mrbill at 8:12 AM on December 15, 2010 [2 favorites]
So when we talk about cutting defense spending, we're talking about cutting exactly the kind of high-paying, science-based jobs that we all tell our kids they should want.our kids can't afford the education to get.
ftfy.
posted by Thorzdad at 8:19 AM on December 15, 2010
ftfy.
posted by Thorzdad at 8:19 AM on December 15, 2010
So I'd think to be competitive with existing battleship guns
Yeahbut, they exist as museum pieces, not functioning weapons. I don't think there are many ships afloat with anything bigger than a 5" gun.
Even one that had only most of the kinetic energy of a battleship round would still be hugely preferable since you wouldn't have to have whopping great propellant stores waiting to go BOOM when struck by an enemy round... just a powerplant and fuck-you big capacitors or similar.
posted by ROU_Xenophobe at 8:25 AM on December 15, 2010 [2 favorites]
Yeahbut, they exist as museum pieces, not functioning weapons. I don't think there are many ships afloat with anything bigger than a 5" gun.
Even one that had only most of the kinetic energy of a battleship round would still be hugely preferable since you wouldn't have to have whopping great propellant stores waiting to go BOOM when struck by an enemy round... just a powerplant and fuck-you big capacitors or similar.
posted by ROU_Xenophobe at 8:25 AM on December 15, 2010 [2 favorites]
Commenters are saying that the high energy partially vaporizes the rail into plasma, so maybe it can't be fired repeatedly.
Now this makes sense -- the old gillette razor model. Give away the ... something ... and sell the rails.
posted by notyou at 8:25 AM on December 15, 2010
Now this makes sense -- the old gillette razor model. Give away the ... something ... and sell the rails.
posted by notyou at 8:25 AM on December 15, 2010
Why does the Navy's railgun project have its own mission patch? "Velocitas eradico" eh? Speed destroys. Isn't that the Department of Motor Vehicles' slogan?
posted by Civil_Disobedient at 8:29 AM on December 15, 2010 [1 favorite]
posted by Civil_Disobedient at 8:29 AM on December 15, 2010 [1 favorite]
Why does the Navy's railgun project have its own mission patch?
Man, every big project seems to get a patch nowadays. It's pretty awesome, actually - lots of anthropomorphic eagles all tossing satellites into space or punching blurry maps or something.
posted by muddgirl at 8:33 AM on December 15, 2010
Man, every big project seems to get a patch nowadays. It's pretty awesome, actually - lots of anthropomorphic eagles all tossing satellites into space or punching blurry maps or something.
posted by muddgirl at 8:33 AM on December 15, 2010
Dear Santa,
I never asked you for anything before...
posted by Splunge at 8:34 AM on December 15, 2010
I never asked you for anything before...
posted by Splunge at 8:34 AM on December 15, 2010
32 megajoules really isn't all that much.
32 megajoule /hamburger
posted by Zalzidrax at 8:34 AM on December 15, 2010 [1 favorite]
32 megajoule /hamburger
posted by Zalzidrax at 8:34 AM on December 15, 2010 [1 favorite]
Also, my kids can grow up to be whatever they want, but I hope in my heart that they do not end up making weapons whose sole purpose is violence and death.
That rail gun has no purpose, purpose comes from the people who fire the rail gun. The purpose of building a rail gun is to be able to make awesome videos that lead to further funding of making bigger rail guns. All of which are fairly impractical but may lead to breakthroughs in materials science, power storage and magnetism. Not shown in the video are the enormous power plants charging the ultacapacitors or whatever to actually make the rails send the huge power through the circuits, or the 3 month tear down / rebuild required after you fire the thing a couple of times.
posted by humanfont at 8:43 AM on December 15, 2010
That rail gun has no purpose, purpose comes from the people who fire the rail gun. The purpose of building a rail gun is to be able to make awesome videos that lead to further funding of making bigger rail guns. All of which are fairly impractical but may lead to breakthroughs in materials science, power storage and magnetism. Not shown in the video are the enormous power plants charging the ultacapacitors or whatever to actually make the rails send the huge power through the circuits, or the 3 month tear down / rebuild required after you fire the thing a couple of times.
posted by humanfont at 8:43 AM on December 15, 2010
Could we get a physicist to shed some light on the "33 megajoules" = "impact of 33 ton Semi at 100mph" comparison?
'Cause I was like: "Sweet! Holy shit, let's see what's that compares to. I'm gonna put that into Wolfram Alpha and... ffffffffffffuuuuuuuuuuuuuuuu...."
Somehow "the energy from burning a quarter of a gallon of gasoline" is less impressive. I don't know what I'm talking about, though, and I welcome the insight or clarification of someone who does.
posted by jjjjjjjijjjjjjj at 8:47 AM on December 15, 2010 [1 favorite]
'Cause I was like: "Sweet! Holy shit, let's see what's that compares to. I'm gonna put that into Wolfram Alpha and... ffffffffffffuuuuuuuuuuuuuuuu...."
Somehow "the energy from burning a quarter of a gallon of gasoline" is less impressive. I don't know what I'm talking about, though, and I welcome the insight or clarification of someone who does.
posted by jjjjjjjijjjjjjj at 8:47 AM on December 15, 2010 [1 favorite]
katiewa, sooner or later everyone listens to Reason.
Also, Heinlein uses a giant, iopen-sided railgun to bombard the Earth from the Moon in The Moon is a Harsh Mistress -- and Daniel Keys Moran has a character in a spacesuit launch himself from the Moon into open space the same way in a book called The Long Run.
Yay, railguns!
posted by wenestvedt at 9:10 AM on December 15, 2010
Also, Heinlein uses a giant, iopen-sided railgun to bombard the Earth from the Moon in The Moon is a Harsh Mistress -- and Daniel Keys Moran has a character in a spacesuit launch himself from the Moon into open space the same way in a book called The Long Run.
Yay, railguns!
posted by wenestvedt at 9:10 AM on December 15, 2010
Could we get a physicist to shed some light on the "33 megajoules" = "impact of 33 ton Semi at 100mph" comparison?
...
Somehow "the energy from burning a quarter of a gallon of gasoline" is less impressive. I don't know what I'm talking about, though, and I welcome the insight or clarification of someone who does.
IANAP, but I could see a loaded semi using 1/4 gallon to get up to 100mph. Most of that same energy is released when it hits the brick wall.
posted by CaseyB at 9:13 AM on December 15, 2010
I thought it was all magnetic and no by-products in the chamber
A railgun has two rails, a projectile that sits between them, and a sliding contact that carries current from one rail to the other and pushes the projectile. (In the simplest case the sliding contact is the projectile.) Getting a good sliding contact that works at Mach 7 is tricky, as you can imagine, and since it's carrying an absurd amount of current it sparks a lot. In fact some railgun designs simply embrace the sparking and use a bar of plasma as the sliding contact— it starts out as metal or something but it's plasma for the shot— and as you can imagine all this stuff comes out the end of the gun along with the projectile proper.
posted by hattifattener at 9:16 AM on December 15, 2010
A railgun has two rails, a projectile that sits between them, and a sliding contact that carries current from one rail to the other and pushes the projectile. (In the simplest case the sliding contact is the projectile.) Getting a good sliding contact that works at Mach 7 is tricky, as you can imagine, and since it's carrying an absurd amount of current it sparks a lot. In fact some railgun designs simply embrace the sparking and use a bar of plasma as the sliding contact— it starts out as metal or something but it's plasma for the shot— and as you can imagine all this stuff comes out the end of the gun along with the projectile proper.
posted by hattifattener at 9:16 AM on December 15, 2010
I still say every nuke plant should have one installed and launch small canisters of waste into the sun.
It would need at least 5 times as much energy. Probably significantly higher to get through the atmosphere.
posted by CaseyB at 9:17 AM on December 15, 2010
It would need at least 5 times as much energy. Probably significantly higher to get through the atmosphere.
posted by CaseyB at 9:17 AM on December 15, 2010
katiewa : Maybe the bad guys will listen to reason.
A sick part of me hopes that some engineer working on this is a fan of Reason, and put a brass name plate on there somewhere.
I look forward to the day our wars are settled by the two sides' gigantic Rock 'Em, Sock 'Em Robots doing battle in an outer space Thunderdome.
Robot Jox.
You know about Real Steel, right?
posted by quin at 9:19 AM on December 15, 2010
A sick part of me hopes that some engineer working on this is a fan of Reason, and put a brass name plate on there somewhere.
I look forward to the day our wars are settled by the two sides' gigantic Rock 'Em, Sock 'Em Robots doing battle in an outer space Thunderdome.
Robot Jox.
You know about Real Steel, right?
posted by quin at 9:19 AM on December 15, 2010
m = 33 tons = 2,993 kg
v = 100 mph = 44.7 m/s
E = .5mv^2 = (.5)(2993)(44.7^2) = 2,990,141 J = 29 MJ
posted by djb at 9:19 AM on December 15, 2010
v = 100 mph = 44.7 m/s
E = .5mv^2 = (.5)(2993)(44.7^2) = 2,990,141 J = 29 MJ
posted by djb at 9:19 AM on December 15, 2010
Somehow "the energy from burning a quarter of a gallon of gasoline" is less impressive. I don't know what I'm talking about, though, and I welcome the insight or clarification of someone who does.
Depends on how quickly it is burned and under what conditions.
Place a small amount of gunpowder spread out on a flat surface, ignite it, and it sort of goes *foof!*. Place the same amount of powder behind a projectile in a sealed tube, or packed into a tightly-sealed pipe....
posted by xedrik at 9:28 AM on December 15, 2010
Depends on how quickly it is burned and under what conditions.
Place a small amount of gunpowder spread out on a flat surface, ignite it, and it sort of goes *foof!*. Place the same amount of powder behind a projectile in a sealed tube, or packed into a tightly-sealed pipe....
posted by xedrik at 9:28 AM on December 15, 2010
I don't know what I'm talking about, though, and I welcome the insight or clarification of someone who does.
Well how much gasoline do you think it takes to get a 33 ton Semi up to 100mph? Apparently a quarter gallon, assuming the engine is perfectly efficient and there is no wind resistance, but probably somewhat more in reality.
posted by metaplectic at 9:33 AM on December 15, 2010
Well how much gasoline do you think it takes to get a 33 ton Semi up to 100mph? Apparently a quarter gallon, assuming the engine is perfectly efficient and there is no wind resistance, but probably somewhat more in reality.
posted by metaplectic at 9:33 AM on December 15, 2010
If these engineers weren't being paid to make railguns, the could be getting paid to, say, improve power and transportation infrastructure. This would actually provide economic benefits to society.
We could reasonably anticipate breakthroughs in capacitor and battery technologies for our hybrids, couldn't we?
Always assuming they aren't doing this with a thousand Prius' wired in parallel and hidden below decks in the first place.
Could you use graphite as a conductor/lubricant in these?
posted by jamjam at 9:38 AM on December 15, 2010
We could reasonably anticipate breakthroughs in capacitor and battery technologies for our hybrids, couldn't we?
Always assuming they aren't doing this with a thousand Prius' wired in parallel and hidden below decks in the first place.
Could you use graphite as a conductor/lubricant in these?
posted by jamjam at 9:38 AM on December 15, 2010
Also, Heinlein uses a giant, iopen-sided railgun to bombard the Earth from the Moon in The Moon is a Harsh Mistress
For sure they lobbed rocks at Earth with a mass driver, but was it a railgun?
Railguns aren't just any electromagnetic flinger. Railguns work through the rails -- you dump a motherfucking shitload of current down one rail and into the projectile that's touching it, and it comes back down the other rail. The resulting EM forces provide the almighty SHOVE to the projectile.
Coilguns/gaussguns != railguns.
posted by ROU_Xenophobe at 9:38 AM on December 15, 2010 [1 favorite]
For sure they lobbed rocks at Earth with a mass driver, but was it a railgun?
Railguns aren't just any electromagnetic flinger. Railguns work through the rails -- you dump a motherfucking shitload of current down one rail and into the projectile that's touching it, and it comes back down the other rail. The resulting EM forces provide the almighty SHOVE to the projectile.
Coilguns/gaussguns != railguns.
posted by ROU_Xenophobe at 9:38 AM on December 15, 2010 [1 favorite]
When it comes to the 33 ton semi at 100mph, consider how often you have 100mph semis dropping from the sky onto a roof of a building and how much damage that can cause. Better yet, concentrate that into one 20 pound projectile.
The potential is that you could have some of these bad boys on ships at sea. You can hit from 100 miles out, keeping your ship safe. The target would be reached in a few minutes from 100 miles. The projectiles are 20 pounds and non-explosive, removing the vulnerability of carrying around tons and tons of explosives on a ship. Also: carry 5-10 times the ammo on one ship, lowering the number of resupply missions. The hope is that they can get the guns to fire 6-12 shots per minute (Fox News Link). That's right. The energy of a 33-ton semi at 100mph dropping on your buildings every 5-10 seconds per ship firing upon you.
posted by Mister Fabulous at 9:43 AM on December 15, 2010
The potential is that you could have some of these bad boys on ships at sea. You can hit from 100 miles out, keeping your ship safe. The target would be reached in a few minutes from 100 miles. The projectiles are 20 pounds and non-explosive, removing the vulnerability of carrying around tons and tons of explosives on a ship. Also: carry 5-10 times the ammo on one ship, lowering the number of resupply missions. The hope is that they can get the guns to fire 6-12 shots per minute (Fox News Link). That's right. The energy of a 33-ton semi at 100mph dropping on your buildings every 5-10 seconds per ship firing upon you.
posted by Mister Fabulous at 9:43 AM on December 15, 2010
I still say every nuke plant should have one installed and launch small canisters of waste into the sun.
It would need at least 5 times as much energy. Probably significantly higher to get through the atmosphere.
You really don't want to miscalculate the energy when launching radioactive waste straight up...
posted by Artw at 9:45 AM on December 15, 2010
It would need at least 5 times as much energy. Probably significantly higher to get through the atmosphere.
You really don't want to miscalculate the energy when launching radioactive waste straight up...
posted by Artw at 9:45 AM on December 15, 2010
You really don't want to miscalculate the energy when launching radioactive waste straight up...
I dismiss your concerns as "depressing."
posted by griphus at 9:51 AM on December 15, 2010 [7 favorites]
I dismiss your concerns as "depressing."
posted by griphus at 9:51 AM on December 15, 2010 [7 favorites]
To be fair, that's how I feel about people who get all upset about NASA laucnhing stuff with RTGs.
posted by Artw at 9:54 AM on December 15, 2010
posted by Artw at 9:54 AM on December 15, 2010
I worked near a rail gun installation on a military range in the mid-90s. It was a smallish green industrial building with an 11kV power line heading into the back, and a door (usually closed) out front. About 200m from the door was a standard tank target. Behind the target was the Irish Sea.
The gun was alleged to fire a steel rod about 1m long. In chatting with the range operator, he said that they'd never found one of the projectiles after firing it; it either buried itself in the ground leaving a smear of vapourised metal, or splashed down somewhere in the sea. He admitted, rather ruefully, that they'd never actually managed to hit the target yet.
The capacitor bank took a day or so to charge. We were warned that they would be firing one night, so we stopped our activities (long range acoustic model verification over rough terrain, if you must know - all civilian, non-classified stuff) and retired to our cottage about 15km away.
Middle of the night we all felt something. A couple of glasses got knocked off a table from the blast. We all woke up and wandered about making bleary "whatthehell?" noises. When we got back to the range the next day, the target was still intact, the operator still as rueful.
(still, doesn't compare to the time that they forgot I was working there and test-fired a couple of surface-surface missiles out into the sea past me. I think my eyes and ears have only finally recovered now. The range operator was very apologetic, even though all I could do was stand there, ashen, making "feep feep" noises while he was talking.)
posted by scruss at 9:58 AM on December 15, 2010 [14 favorites]
The gun was alleged to fire a steel rod about 1m long. In chatting with the range operator, he said that they'd never found one of the projectiles after firing it; it either buried itself in the ground leaving a smear of vapourised metal, or splashed down somewhere in the sea. He admitted, rather ruefully, that they'd never actually managed to hit the target yet.
The capacitor bank took a day or so to charge. We were warned that they would be firing one night, so we stopped our activities (long range acoustic model verification over rough terrain, if you must know - all civilian, non-classified stuff) and retired to our cottage about 15km away.
Middle of the night we all felt something. A couple of glasses got knocked off a table from the blast. We all woke up and wandered about making bleary "whatthehell?" noises. When we got back to the range the next day, the target was still intact, the operator still as rueful.
(still, doesn't compare to the time that they forgot I was working there and test-fired a couple of surface-surface missiles out into the sea past me. I think my eyes and ears have only finally recovered now. The range operator was very apologetic, even though all I could do was stand there, ashen, making "feep feep" noises while he was talking.)
posted by scruss at 9:58 AM on December 15, 2010 [14 favorites]
You really don't want to miscalculate the energy when launching radioactive waste straight up...
I dismiss your concerns as "depressing."
I dismiss these concerns as "lacking curiosity" and "no fun".
posted by quin at 10:05 AM on December 15, 2010 [5 favorites]
I dismiss your concerns as "depressing."
I dismiss these concerns as "lacking curiosity" and "no fun".
posted by quin at 10:05 AM on December 15, 2010 [5 favorites]
The potential is that you could have some of these bad boys on ships at sea. You can hit from 100 miles out, keeping your ship safe.
The range of the Dong Feng 21D is approximately 2,000 miles.
posted by mr_roboto at 10:17 AM on December 15, 2010
The range of the Dong Feng 21D is approximately 2,000 miles.
posted by mr_roboto at 10:17 AM on December 15, 2010
Oops, my tons to kg conversion is off by a factor of 10th. End result is still 29 MJ.
posted by djb at 10:19 AM on December 15, 2010
posted by djb at 10:19 AM on December 15, 2010
In fact some railgun designs simply embrace the sparking and use a bar of plasma as the sliding contact— it starts out as metal or something but it's plasma for the shot— and as you can imagine all this stuff comes out the end of the gun along with the projectile proper.
Yeah, and from what I recall from my dad's lectures, plasma's a great thing for reducing friction. He had a proposal for coating the underside of long range bombers' wings with plasma, thus reducing friction and fuel requirements while maintaining THE MOST AWESOME FLEET OF LASER WINGED BOMBERS.
My seven year old self insisted that they be called Laserbeaks. I maintain that if he had worked that into his proposal, they'd be rolling off the production line by now.
posted by robocop is bleeding at 10:21 AM on December 15, 2010 [4 favorites]
Yeah, and from what I recall from my dad's lectures, plasma's a great thing for reducing friction. He had a proposal for coating the underside of long range bombers' wings with plasma, thus reducing friction and fuel requirements while maintaining THE MOST AWESOME FLEET OF LASER WINGED BOMBERS.
My seven year old self insisted that they be called Laserbeaks. I maintain that if he had worked that into his proposal, they'd be rolling off the production line by now.
posted by robocop is bleeding at 10:21 AM on December 15, 2010 [4 favorites]
Yeah but what happens if we put the railgun on a rolling runway?
posted by slater at 10:40 AM on December 15, 2010
posted by slater at 10:40 AM on December 15, 2010
Sweet. Now we don't even have to get close to the brown people before we shoot them.
posted by TrialByMedia at 10:53 AM on December 15, 2010 [1 favorite]
posted by TrialByMedia at 10:53 AM on December 15, 2010 [1 favorite]
Technologies that are automatically awesome:
-Airships
-Nuclear powered things that move
-Railguns
Put them all together and what do you get?
posted by Artw at 10:54 AM on December 15, 2010
-Airships
-Nuclear powered things that move
-Railguns
Put them all together and what do you get?
posted by Artw at 10:54 AM on December 15, 2010
Artw: I have a soft spot for these.
Yes, right where your heart used to be. Because you were hit with a RAILGUN. You'll The meaty-bits and fine red mist will fall over settle to the ground in a moment.
I think you meant...
;-)
posted by Pirate-Bartender-Zombie-Monkey at 10:58 AM on December 15, 2010
Yes, right where you
I think you meant...
;-)
posted by Pirate-Bartender-Zombie-Monkey at 10:58 AM on December 15, 2010
Technologies that are automatically awesome:
-Airships
-Nuclear powered things that move
-Railguns
Put them all together and what do you get?
Sucker Punch?
posted by Pirate-Bartender-Zombie-Monkey at 11:02 AM on December 15, 2010
-Airships
-Nuclear powered things that move
-Railguns
Put them all together and what do you get?
Sucker Punch?
posted by Pirate-Bartender-Zombie-Monkey at 11:02 AM on December 15, 2010
robocop is bleeding: "Could they be employed fixing infrastructure or feeding starving kids?
Look, if it wasn't for railguns, Steven Seagal never would have ridden in our minivan"
If it weren't for my horse, I never would have spent that year in college...
posted by notsnot at 11:15 AM on December 15, 2010 [1 favorite]
Look, if it wasn't for railguns, Steven Seagal never would have ridden in our minivan"
If it weren't for my horse, I never would have spent that year in college...
posted by notsnot at 11:15 AM on December 15, 2010 [1 favorite]
I look forward to the day our wars are settled by the two sides' gigantic Rock 'Em, Sock 'Em Robots doing battle in an outer space Thunderdome.
Totally.
When I was a kid i wondered why instead of whole wars, the President's, PM's Dicatators or whatever of each respective country didn't just have a boxing match to settle their differences and just leave everyone else in their countries the heck out of it.
Also, I wondered why everything couldn't simply be free, if people simply worked for free, that way no one would be poor and I was pretty surprised when I told my father my big plan for the future (I was probably around 8) and he said that was Communism.
posted by Skygazer at 11:19 AM on December 15, 2010 [3 favorites]
Totally.
When I was a kid i wondered why instead of whole wars, the President's, PM's Dicatators or whatever of each respective country didn't just have a boxing match to settle their differences and just leave everyone else in their countries the heck out of it.
Also, I wondered why everything couldn't simply be free, if people simply worked for free, that way no one would be poor and I was pretty surprised when I told my father my big plan for the future (I was probably around 8) and he said that was Communism.
posted by Skygazer at 11:19 AM on December 15, 2010 [3 favorites]
It's how I'd want to go.
Wouldn't you rather be the projectile?
posted by ROU_Xenophobe at 11:28 AM on December 15, 2010
Wouldn't you rather be the projectile?
posted by ROU_Xenophobe at 11:28 AM on December 15, 2010
Or, if you were going to be hit by a fictional weapon of ludicrous destructive power, I think it would be better to take you out with a twin particle-beam phalanx.... FWAP! Fry a whole artw with that puppy.
posted by ROU_Xenophobe at 11:29 AM on December 15, 2010
posted by ROU_Xenophobe at 11:29 AM on December 15, 2010
When I was a kid i wondered why instead of whole wars, the President's, PM's Dicatators or whatever of each respective country didn't just have a boxing match to settle their differences and just leave everyone else in their countries the heck out of it.
Two Tribes
posted by Pirate-Bartender-Zombie-Monkey at 11:30 AM on December 15, 2010
Two Tribes
posted by Pirate-Bartender-Zombie-Monkey at 11:30 AM on December 15, 2010
Valykarie: 200 nautical miles? Doesn't the curvature of the Earth make that difficult?
Two words: Indirect fire.
Ahh. But can the projectile be guided once it leaves the gun?
Also does this thing need to be rebuilt every few shots? And what does plasma look like, is it a liquid metal? And why use anvils, or was that a joke.
In regards to all the good jobs the military companies provide (and not only for engineers), I've always thought it stupid these companies did not have little commercial divisions for consumer electronics and whatnot and American factories making consumer electronics as a show of good faith and pride in the country's taxpayers for giving it TRILLIONS of dollars and being their bread and butter for decades. Or am I, inadvertently being a Communist again?
posted by Skygazer at 11:33 AM on December 15, 2010
Two words: Indirect fire.
Ahh. But can the projectile be guided once it leaves the gun?
Also does this thing need to be rebuilt every few shots? And what does plasma look like, is it a liquid metal? And why use anvils, or was that a joke.
In regards to all the good jobs the military companies provide (and not only for engineers), I've always thought it stupid these companies did not have little commercial divisions for consumer electronics and whatnot and American factories making consumer electronics as a show of good faith and pride in the country's taxpayers for giving it TRILLIONS of dollars and being their bread and butter for decades. Or am I, inadvertently being a Communist again?
posted by Skygazer at 11:33 AM on December 15, 2010
In the video, the projectile is blunt-nosed, it appears. Wouldn't it make sense to have a more streamlined....dart...or something, to prevent energy loss in the atmosphere?
posted by Thistledown at 11:35 AM on December 15, 2010
posted by Thistledown at 11:35 AM on December 15, 2010
Two Tribes
I know!! Frankie Goes to Hollywoood stole my freakin idea!
posted by Skygazer at 11:36 AM on December 15, 2010
I know!! Frankie Goes to Hollywoood stole my freakin idea!
posted by Skygazer at 11:36 AM on December 15, 2010
Robocop is bleeding: Heh. That's one of my dad's projects.
Man, I am hating you, a little bit.
Here's a video he made of firing a railgun set to the 1812 Overture.
Wow, making a railgun doesn't look so difficult, just seems like a whole fuck of a lot of elbow grease and half blocks worth of electrical generators.
Also, how does this not break all sorts of classified rules for top secret new Sci-fi weapons?
posted by Skygazer at 11:41 AM on December 15, 2010
Man, I am hating you, a little bit.
Here's a video he made of firing a railgun set to the 1812 Overture.
Wow, making a railgun doesn't look so difficult, just seems like a whole fuck of a lot of elbow grease and half blocks worth of electrical generators.
Also, how does this not break all sorts of classified rules for top secret new Sci-fi weapons?
posted by Skygazer at 11:41 AM on December 15, 2010
Or am I, inadvertently being a Communist again?
You're not being a Communist any more than any other state industry is. Plus, those industries tend to BUY consumer electronics and whatnot FROM the American public to make their direct military inventions work. You could call that an act of faith in the country's producers.
And a projectile can't be guided after it leaves the gun. The poin of indirect fire (like artillary shells) is that projectile arcs can be calculated and with accurate enough data (environmental factors, location of target) a firing solution can be determined that would hit.
No, they don't really use anvils. They do use heavy materials that have a high kinetic impact when it lands (so dense, small materials).
posted by Lord Chancellor at 11:42 AM on December 15, 2010
You're not being a Communist any more than any other state industry is. Plus, those industries tend to BUY consumer electronics and whatnot FROM the American public to make their direct military inventions work. You could call that an act of faith in the country's producers.
And a projectile can't be guided after it leaves the gun. The poin of indirect fire (like artillary shells) is that projectile arcs can be calculated and with accurate enough data (environmental factors, location of target) a firing solution can be determined that would hit.
No, they don't really use anvils. They do use heavy materials that have a high kinetic impact when it lands (so dense, small materials).
posted by Lord Chancellor at 11:42 AM on December 15, 2010
Ahh. But can the projectile be guided once it leaves the gun?
I'd read a year or so ago that one of the projects hotly being worked on is how do you hard-wire electronics inside something under that much acceleration, and how do you adjust the steering in flight without ripping the fins off.
posted by Pirate-Bartender-Zombie-Monkey at 11:57 AM on December 15, 2010
I'd read a year or so ago that one of the projects hotly being worked on is how do you hard-wire electronics inside something under that much acceleration, and how do you adjust the steering in flight without ripping the fins off.
posted by Pirate-Bartender-Zombie-Monkey at 11:57 AM on December 15, 2010
I know I don't have nearly the science fu to understand the rail gun, but I wanted to add to the chorus of "awesome" for post and links.
posted by immlass at 12:15 PM on December 15, 2010
posted by immlass at 12:15 PM on December 15, 2010
There are almost a thousand engineers employed in my current city by some combination of Raytheon, General Dynamics, a Northrop Grumman subcontractor, and GE, and the vast majority of that funding comes directly or indirectly from the Department of Defense.
You also forgot the nearly six corporate executives who's salaries equal those thousand engineers'!
posted by The 10th Regiment of Foot at 12:16 PM on December 15, 2010 [3 favorites]
You also forgot the nearly six corporate executives who's salaries equal those thousand engineers'!
posted by The 10th Regiment of Foot at 12:16 PM on December 15, 2010 [3 favorites]
You're missing the cardinal rule of sci-fi weapons - unless the invader is about to crush you or some such, brag loudly about your biggest bestest weapons systems. Wars cost a lot of money and the other side tends to keep trying to blow up all your best stuff - Deterrence, on the other hand, gets you invited to diplomatic cocktail parties with really good hors d'ourves.
posted by Kid Charlemagne at 12:23 PM on December 15, 2010 [1 favorite]
posted by Kid Charlemagne at 12:23 PM on December 15, 2010 [1 favorite]
Obligatory EVE Online railgun reference.
(Though I'm a Gallente pilot -- who generally tend to blasters -- in the game, I've always preferred the extra range of railguns.)
posted by Gelatin at 12:24 PM on December 15, 2010
(Though I'm a Gallente pilot -- who generally tend to blasters -- in the game, I've always preferred the extra range of railguns.)
posted by Gelatin at 12:24 PM on December 15, 2010
Some of the pumpkin chunkin guys approached my dad about building a pumpkin-ready railgun. Sadly, the physics didn't work out - the result would have been high velocity pumpkin mash. But with just a bit more funding...
No fair, that was my idea! Seriously, I thought it up watching the most recent competition on TV. Ah that bites.
posted by scalefree at 12:29 PM on December 15, 2010
No fair, that was my idea! Seriously, I thought it up watching the most recent competition on TV. Ah that bites.
posted by scalefree at 12:29 PM on December 15, 2010
ROU_Xenophobe: ISTR it's either/both erosion from the rails (they get chewed up by the current and friction with the projectile) and/or ablation from the projectile moving real fast (like spacecraft reentry).
The turbulence in the smoke just doesn't look like a super fast moving object, yet it looks like it is coming from the object. It is pretty weird. Anyway, there is one other possibility, rail guns are often boosted to some starting speed using compressed gas.
infinitefloatingbrains: It isn't some kind of zero sum game where cutting defense jobs will put scientists out of work. In general they have better job prospects than the average person.
It is harder than you think. Once you eliminate petrochemical and military jobs, you are pretty much left with inventing your own career. Having some technical knowledge is still a huge benefit in life and business, but it is closer to a zero sum game than anybody wants to admit.
nomadicink: Which is why we should cut defense spending and give it to NASA.
That isn't sufficiently cynical. Hell, you don't even have to be cynical, just realistic. NASA is just a beard for the military contractors. Not unlike the entire nuclear energy industry. Not that either NASA or nuclear energy are completely useless for non-military endeavours, but they wouldn't look anything like they do if it wasn't for the direct tie to US military ventures.
muddgirl: Also note that railguns have many applications outside of offensive weaponry (although we have to sell the weaponry angle to get any sort of financing). Build a unit 10x that size and replace the anvil with, say, a sattelite payload and shoot it into space.
See what I mean? The G-loading of that acceleration is not at all realistic for general purpose satellite launch. Sure, at some point they might figure out that some specialized tasks can be performed with sufficiently G-hardened payloads, but...
posted by Chuckles at 12:36 PM on December 15, 2010
The turbulence in the smoke just doesn't look like a super fast moving object, yet it looks like it is coming from the object. It is pretty weird. Anyway, there is one other possibility, rail guns are often boosted to some starting speed using compressed gas.
infinitefloatingbrains: It isn't some kind of zero sum game where cutting defense jobs will put scientists out of work. In general they have better job prospects than the average person.
It is harder than you think. Once you eliminate petrochemical and military jobs, you are pretty much left with inventing your own career. Having some technical knowledge is still a huge benefit in life and business, but it is closer to a zero sum game than anybody wants to admit.
nomadicink: Which is why we should cut defense spending and give it to NASA.
That isn't sufficiently cynical. Hell, you don't even have to be cynical, just realistic. NASA is just a beard for the military contractors. Not unlike the entire nuclear energy industry. Not that either NASA or nuclear energy are completely useless for non-military endeavours, but they wouldn't look anything like they do if it wasn't for the direct tie to US military ventures.
muddgirl: Also note that railguns have many applications outside of offensive weaponry (although we have to sell the weaponry angle to get any sort of financing). Build a unit 10x that size and replace the anvil with, say, a sattelite payload and shoot it into space.
See what I mean? The G-loading of that acceleration is not at all realistic for general purpose satellite launch. Sure, at some point they might figure out that some specialized tasks can be performed with sufficiently G-hardened payloads, but...
posted by Chuckles at 12:36 PM on December 15, 2010
I've always thought it stupid these companies did not have little commercial divisions for consumer electronics and whatnot and American factories making consumer electronics as a show of good faith and pride
That doesn't make any sense. "Good faith" and "pride" are human emotions, and large corporations do not experience them.
There are certainly a lot of companies that employ US personnel despite it being disadvantageous in terms of cost structure and probably an irrational business decision, but they are generally small companies. Once a company gets big enough so that it's no longer basically an extension of a single person's will (or gets bought by a hedge fund), they tend to be run much more 'rationally.'
posted by Kadin2048 at 12:38 PM on December 15, 2010
That doesn't make any sense. "Good faith" and "pride" are human emotions, and large corporations do not experience them.
There are certainly a lot of companies that employ US personnel despite it being disadvantageous in terms of cost structure and probably an irrational business decision, but they are generally small companies. Once a company gets big enough so that it's no longer basically an extension of a single person's will (or gets bought by a hedge fund), they tend to be run much more 'rationally.'
posted by Kadin2048 at 12:38 PM on December 15, 2010
-Airships
-Nuclear powered things that move
-Railguns
Put them all together and what do you get?
The first section of Count Zero.
posted by lodurr at 12:47 PM on December 15, 2010
-Nuclear powered things that move
-Railguns
Put them all together and what do you get?
The first section of Count Zero.
posted by lodurr at 12:47 PM on December 15, 2010
NASA is just a beard for the military contractors. Not unlike the entire nuclear energy industry.
Really, it's more symbiotic than straight legitimate cover. There's always a tension between pure scientists who want to do cool shit but also wants to get paid, and the military which wants cool shit as long as it will blow something up. I was once asked if I could weaponize my undergraduate biomechanics research into tendrilling cucumbers.
The G-loading of that acceleration is not at all realistic for general purpose satellite launch.
I don't think that's necessarily true, but I'm too lazy to do any math. Also, even if the G-load is too high we could use them in our inevitable war against the moon people.
posted by muddgirl at 12:57 PM on December 15, 2010
Really, it's more symbiotic than straight legitimate cover. There's always a tension between pure scientists who want to do cool shit but also wants to get paid, and the military which wants cool shit as long as it will blow something up. I was once asked if I could weaponize my undergraduate biomechanics research into tendrilling cucumbers.
The G-loading of that acceleration is not at all realistic for general purpose satellite launch.
I don't think that's necessarily true, but I'm too lazy to do any math. Also, even if the G-load is too high we could use them in our inevitable war against the moon people.
posted by muddgirl at 12:57 PM on December 15, 2010
Shooting a kinetic projectile 100 miles in the atmosphere sounds kind of...unproductive? Muzzle energy might be high, but after 100 miles of flight it has to be a reduced significantly. And as noted above, these muzzle energies are not comparable to the energy of conventional explosives found in a typical shell.
posted by roquetuen at 1:04 PM on December 15, 2010
posted by roquetuen at 1:04 PM on December 15, 2010
No doubt they are working on a hardened projectile that can deliver a payload or warhead.
No doubt some science geek read Bolo! as a kid and is working on a deuterium projectile that can be ignited with a laser.
posted by muddgirl at 1:19 PM on December 15, 2010
No doubt some science geek read Bolo! as a kid and is working on a deuterium projectile that can be ignited with a laser.
posted by muddgirl at 1:19 PM on December 15, 2010
I've always thought the city in which Delany's 'Dhalgren' took place was an every-city representing middle America. Now that I know there is a city named 'Dahlgren' in which the Navy operates a weapons testing facility, I've realized what caused the mysterious disaster. Railguns! Of course.
posted by StrangerInAStrainedLand at 1:45 PM on December 15, 2010
posted by StrangerInAStrainedLand at 1:45 PM on December 15, 2010
-Airships
-Nuclear powered things that move
-Railguns
Put them all together and what do you get?
The first section of Count Zero.
posted by lodurr at 12:47 PM on 12/15
Don't forget the neurally-controlled fighter jet!
posted by newdaddy at 2:16 PM on December 15, 2010
-Nuclear powered things that move
-Railguns
Put them all together and what do you get?
The first section of Count Zero.
posted by lodurr at 12:47 PM on 12/15
Don't forget the neurally-controlled fighter jet!
posted by newdaddy at 2:16 PM on December 15, 2010
Oh, I always like those.
Think in Russian!
posted by Artw at 2:37 PM on December 15, 2010 [1 favorite]
Think in Russian!
posted by Artw at 2:37 PM on December 15, 2010 [1 favorite]
Science funding goes to snooty, elitist eggheads. Defense funding goes to our brave soldiers fighting to keep America free. Guess which funding is easier to cut?
posted by JoanArkham at 2:39 PM on December 15, 2010
posted by JoanArkham at 2:39 PM on December 15, 2010
In the video, the projectile is blunt-nosed, it appears. Wouldn't it make sense to have a more streamlined....dart...or something, to prevent energy loss in the atmosphere?
At a guess, it's to stop the shell from burning up - at hypersonic speeds, frictional heating of the projectile is a bigger concern than drag. A blunt body creates a detached shock wave ahead of its leading edge, which gives lower overall heat transfer. This is why ICBM nosecones and other re-entry bodies (such as the Apollo command module) have blunt shapes.
posted by Jakob at 3:04 PM on December 15, 2010
At a guess, it's to stop the shell from burning up - at hypersonic speeds, frictional heating of the projectile is a bigger concern than drag. A blunt body creates a detached shock wave ahead of its leading edge, which gives lower overall heat transfer. This is why ICBM nosecones and other re-entry bodies (such as the Apollo command module) have blunt shapes.
posted by Jakob at 3:04 PM on December 15, 2010
That's as much kinetic energy as a 33-ton semi has when it's traveling at 100 mph.
Well, with the recession and the drop-off in shipping, why not just use the semis?
posted by mmrtnt at 4:12 PM on December 15, 2010 [1 favorite]
Well, with the recession and the drop-off in shipping, why not just use the semis?
posted by mmrtnt at 4:12 PM on December 15, 2010 [1 favorite]
No doubt they are working on a hardened projectile that can deliver a payload or warhead.
Yeah, but that goes against the selling point of the navy's own press release (second link); the "railgun also improves safety for Sailors and Marines because it will eliminate the need for a high-energy explosive warhead and traditional gun propellants." Other sources state that the ultimate goal is a 40lb projectile travelling 200 miles, not exactly much room for payload at all. Wikipedia states a 155mm howitzer projectile weighs more than 43 kilos and is only about 15% high explosive by weight.
posted by roquetuen at 4:18 PM on December 15, 2010
Yeah, but that goes against the selling point of the navy's own press release (second link); the "railgun also improves safety for Sailors and Marines because it will eliminate the need for a high-energy explosive warhead and traditional gun propellants." Other sources state that the ultimate goal is a 40lb projectile travelling 200 miles, not exactly much room for payload at all. Wikipedia states a 155mm howitzer projectile weighs more than 43 kilos and is only about 15% high explosive by weight.
posted by roquetuen at 4:18 PM on December 15, 2010
Putting a payload on a kinetic energy weapon is kind of missing the point.
posted by Artw at 4:19 PM on December 15, 2010 [1 favorite]
posted by Artw at 4:19 PM on December 15, 2010 [1 favorite]
Y'know, it'd be interesting to see what one of these things could do fired downward....from orbit.
I'm showing my scifi nerdhammer stripes here, but I remember in Peter Hamilton's "Night's Dawn" Trilogy where they did an assault from orbit by firing these kinetic spears into the ground that basically leveled a city.
A projectile accelerated to these speeds and THEN further aided by gravity would surely be pretty devastating. And cheap.
posted by Thistledown at 5:28 PM on December 15, 2010
I'm showing my scifi nerdhammer stripes here, but I remember in Peter Hamilton's "Night's Dawn" Trilogy where they did an assault from orbit by firing these kinetic spears into the ground that basically leveled a city.
A projectile accelerated to these speeds and THEN further aided by gravity would surely be pretty devastating. And cheap.
posted by Thistledown at 5:28 PM on December 15, 2010
The "rod from god" - no railguns required.
posted by Artw at 5:35 PM on December 15, 2010 [1 favorite]
posted by Artw at 5:35 PM on December 15, 2010 [1 favorite]
Once you reach terminal velocity, any extra energy input on the front end is just wasted. Unless you're going to keep driving it down, just let the thing fall.
posted by scalefree at 5:42 PM on December 15, 2010
posted by scalefree at 5:42 PM on December 15, 2010
Artw - Putting a payload on a kinetic energy weapon is kind of missing the point.
Explosive/incindiary bullets?
I'm surprised that the kinetic energy of the projectile is (still) so low. Maybe the size (20kg chunk of metal vs. a coupla-busses-sized semi) makes a difference in effect?
Also surprising - wasn't Sadam Hussein reviled and demonized for having a "superweapon" which was supposed to be an electromagnetic railgun (which didn't, and never, existed... and now compared to current US efforts, woefully underpowered and ineffectual)?
Rail guns are are really really cool. I wish I had the expendable income and the maths (and the time) to improve on the PowerLabs' efforts.
There're schematics for making a "model" using neodynium magnets in series with ball bearings where you can initially "let go" a ball bearing that gets sucked towards the first magnet, which dislodges the next ball bearing which gets accelerated by the next magnet, &c&c - where the maximum acceleration achievable is limited by the shatter-energy of a neodynium magnet. Can't find a good link to that hobby experiment, though.
posted by porpoise at 8:17 PM on December 15, 2010
Explosive/incindiary bullets?
I'm surprised that the kinetic energy of the projectile is (still) so low. Maybe the size (20kg chunk of metal vs. a coupla-busses-sized semi) makes a difference in effect?
Also surprising - wasn't Sadam Hussein reviled and demonized for having a "superweapon" which was supposed to be an electromagnetic railgun (which didn't, and never, existed... and now compared to current US efforts, woefully underpowered and ineffectual)?
Rail guns are are really really cool. I wish I had the expendable income and the maths (and the time) to improve on the PowerLabs' efforts.
There're schematics for making a "model" using neodynium magnets in series with ball bearings where you can initially "let go" a ball bearing that gets sucked towards the first magnet, which dislodges the next ball bearing which gets accelerated by the next magnet, &c&c - where the maximum acceleration achievable is limited by the shatter-energy of a neodynium magnet. Can't find a good link to that hobby experiment, though.
posted by porpoise at 8:17 PM on December 15, 2010
The railgun is a long-range, high-energy gun launch system that uses electricity rather than gunpowder or rocket motors to launch projectiles capable of striking a target at a range of more than 200 nautical miles with Mach 7 velocity.
This is the "where is my flying car already?!" of the armaments industry. They've been banging on about rail guns since I can remember.
posted by uncanny hengeman at 9:38 PM on December 15, 2010
This is the "where is my flying car already?!" of the armaments industry. They've been banging on about rail guns since I can remember.
posted by uncanny hengeman at 9:38 PM on December 15, 2010
The Iraqi Supergun was something closer to the V3 cannon.
posted by Artw at 10:49 PM on December 15, 2010
posted by Artw at 10:49 PM on December 15, 2010
I'm surprised that the kinetic energy of the projectile is (still) so low
It's because the muzzle velocity is so low - Mach 7 is only 2.4k m/s. For comparison, the M256 main gun on an Abrams, firing a sabot-launched KE penetrator, manages a muzzle velocity of 1.75k m/s (being pretty much the upper limit for any gun using conventional propellants).
Since the energy density of high explosives is around 7 MJ/kg and E(k)=m.v.v/2, you need a projectile velocity of sqrt(1.4E7)=~3.75k m/s to achieve energy equivalence with an HE payload of the same mass. Of course a conventional projectile isn't 100% HE, and HE has a relatively low density (~2kg/l compared to between 8(steel) and 19(tungsten)), requiring a larger projectile for a given mass with all the logistic and aerodynamic considerations that entails.
posted by overyield at 11:15 PM on December 15, 2010
It's because the muzzle velocity is so low - Mach 7 is only 2.4k m/s. For comparison, the M256 main gun on an Abrams, firing a sabot-launched KE penetrator, manages a muzzle velocity of 1.75k m/s (being pretty much the upper limit for any gun using conventional propellants).
Since the energy density of high explosives is around 7 MJ/kg and E(k)=m.v.v/2, you need a projectile velocity of sqrt(1.4E7)=~3.75k m/s to achieve energy equivalence with an HE payload of the same mass. Of course a conventional projectile isn't 100% HE, and HE has a relatively low density (~2kg/l compared to between 8(steel) and 19(tungsten)), requiring a larger projectile for a given mass with all the logistic and aerodynamic considerations that entails.
posted by overyield at 11:15 PM on December 15, 2010
Will railguns be any more accurate than conventional naval guns? Because it doesn't really matter how fast and far the projectile can go if you can't hit what you're aiming at.
posted by Ritchie at 5:54 AM on December 16, 2010
posted by Ritchie at 5:54 AM on December 16, 2010
Overyield: It's because the muzzle velocity is so low - Mach 7 is only 2.4k m/s. For comparison, the M256 main gun on an Abrams, firing a sabot-launched KE penetrator, manages a muzzle velocity of 1.75k m/s (being pretty much the upper limit for any gun using conventional propellants).
Since the energy density of high explosives is around 7 MJ/kg and E(k)=m.v.v/2, you need a projectile velocity of sqrt(1.4E7)=~3.75k m/s to achieve energy equivalence with an HE payload of the same mass. Of course a conventional projectile isn't 100% HE, and HE has a relatively low density (~2kg/l compared to between 8(steel) and 19(tungsten)), requiring a larger projectile for a given mass with all the logistic and aerodynamic considerations that entails.
That's exactly what I was thinking.
*fist bump*
posted by Skygazer at 9:54 AM on December 16, 2010
Since the energy density of high explosives is around 7 MJ/kg and E(k)=m.v.v/2, you need a projectile velocity of sqrt(1.4E7)=~3.75k m/s to achieve energy equivalence with an HE payload of the same mass. Of course a conventional projectile isn't 100% HE, and HE has a relatively low density (~2kg/l compared to between 8(steel) and 19(tungsten)), requiring a larger projectile for a given mass with all the logistic and aerodynamic considerations that entails.
That's exactly what I was thinking.
*fist bump*
posted by Skygazer at 9:54 AM on December 16, 2010
Will railguns be any more accurate than conventional naval guns? Because it doesn't really matter how fast and far the projectile can go if you can't hit what you're aiming at.Hmm, well, exterior ballistics are better at higher velocities - total momentum increases linearly while momentum error caused by interaction with the medium does not, so ratio of error displacement to total displacement falls.
Interior ballistics, who knows - conventional guns have shot-to-shot variation caused by dozens of factors (charge packing, ignition dynamics, barrel/projectile coupling, blah blah), but railguns are going to have their own issues (armature/rail coupling, thermal variation in rail conductivity and power-system performance, and so on). Given comparable manufacturing precision and maintenance, I could see it being a wash, pretty much, but for one thing - with a rail gun there is some possibility of monitoring the evolution of the system during the shot and applying feedback...
Is that feasible? Looking at their railgun, the rails seem to be on the order of 10m long, so assuming constant acceleration and a muzzle velocity of 2.5k m/s we get a residence time of 8 ms. Some (very rough) calculation from the photos suggest they can store about 300MJ in their caps (railguns aren't super efficient by any means - 10% is actually amazingly good, 0.5% is more typical of high-quality amateur efforts), so if they dump that into an 8 ms pulse the average power is about 40 GW. That's a lot, but there are plenty of IGBT or IGCT modules that will switch 10 MW at tens of kHz in millisecond bursts and GW-class semiconductor choppers are used commercially in HVDC power transmission, so it's within the ballpark for modern power electronics. The power electronics are the hard bit - monitoring the projectile's progress optically would be a snip and computer power is cheap and plentiful, so it's just a matter of making the world's largest DAC and perfectly repeatable muzzle velocity is yours.
posted by overyield at 10:43 AM on December 17, 2010 [1 favorite]
Will railguns be any more accurate than conventional naval guns? Because it doesn't really matter how fast and far the projectile can go if you can't hit what you're aiming at.
I think you are misled in beliving conventional artillery (naval or land-based) to be particularly inaccurate. The inherent accuracy of modern systems is actually pretty good — the M777 (new 155mm howitzer) has a specified CEP of 200m at 25km. HE rounds have a casualty radius of 100m, so you can basically bombard a 400m circle with fairly high confidence, and that is with dumb ammunition.
If that's not accurate enough, there are 'smart' rounds like the Copperhead (laser guided), Excalibur (GPS guided), and SADARM (autonomous), where you are basically just using the artillery piece as a way of launching the projectile into the right general direction and area, and then letting it guide itself to the target.
Pretty much anything you can do with a 'smart bomb' you can do with an artillery round, it's just a matter of making the electronics rugged enough to withstand the initial 0-to-800-m/s acceleration.
posted by Kadin2048 at 3:25 AM on December 20, 2010
I think you are misled in beliving conventional artillery (naval or land-based) to be particularly inaccurate. The inherent accuracy of modern systems is actually pretty good — the M777 (new 155mm howitzer) has a specified CEP of 200m at 25km. HE rounds have a casualty radius of 100m, so you can basically bombard a 400m circle with fairly high confidence, and that is with dumb ammunition.
If that's not accurate enough, there are 'smart' rounds like the Copperhead (laser guided), Excalibur (GPS guided), and SADARM (autonomous), where you are basically just using the artillery piece as a way of launching the projectile into the right general direction and area, and then letting it guide itself to the target.
Pretty much anything you can do with a 'smart bomb' you can do with an artillery round, it's just a matter of making the electronics rugged enough to withstand the initial 0-to-800-m/s acceleration.
posted by Kadin2048 at 3:25 AM on December 20, 2010
Weeeellll, it's all about how it's used I guess. I've been present at naval gunnery live-fire exercises where they blast away at static and towed targets. Now, I freely admit I'm not some aficionado - loud noises scare the hell out of me and there's not much that is louder than a naval barrage - but it seemed to me, looking at the relatively unmolested state of the target post-barrage, that there's a good reason why guided missiles are all the rage. But that was a few years ago. Maybe it's all changed.
I've also read accounts of people who were on the receiving end of a modern naval gun barrage, and they came off as not all that shaken up by it. Now, I grant you that in these instances the navy was bombarding targets on land, and so I'm open to the argument that there are special circumstances at play. Maybe it's different when the target is another warship.
posted by Ritchie at 4:15 AM on December 20, 2010
I've also read accounts of people who were on the receiving end of a modern naval gun barrage, and they came off as not all that shaken up by it. Now, I grant you that in these instances the navy was bombarding targets on land, and so I'm open to the argument that there are special circumstances at play. Maybe it's different when the target is another warship.
posted by Ritchie at 4:15 AM on December 20, 2010
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posted by punkfloyd at 7:02 AM on December 15, 2010 [3 favorites]