Impressive!

[dfacto]

http://news.yahoo.com/s/livescience/2008...4dD5Hg.OvYDW7oF (http://news.yahoo.com/s/livescience/20080201/sc_livescience/navytestsincrediblescifiweapon;_ylt=Ahim9rYyDovgr4 dD5Hg.OvYDW7oF)
vid: http://www.livescience.com/php/video/player.php?video_id=080201-railgun

I really kicks ass to see iconic sci-fi stuff getting closer and closer to reality. /images/graemlins/cool.gif

[Tumerboy]

LOL ya they've been working on it for a while now. Not exactly man portable. . . but still very cool.


Why is there so much fire in the slow mo video!?

[dejawolf]

here's another one, active protection called trophy:

http://youtube.com/watch?v=N1LOmm85cZ0

[Toomas]

AFAIK you have to recharge the capacitors after each shot and it can take a while.
Hand versions are pretty much out of question because of the energy requierments.

[dfacto]

[ QUOTE ]
Why is there so much fire in the slow mo video!?

[/ QUOTE ]

If I had to guess I'd say it's friction causing the insulation and some of the rail to shoot out with the projectile.

[Valandar]

So THAT'S what a real railgun sounds like - pretty much like a regular cannon but with a slight whine behind it...

[cochtl]

from wikipedia: "Full-scale models have been built and fired, including a very successful 90 mm bore, 9 megajoules (6.6 million foot-pounds) kinetic energy gun developed by DARPA, but they all suffer from extreme rail damage and need to be serviced after every shot. Rail and insulator ablation issues still need to be addressed before railguns can start to replace conventional weapons."

Explains all of the fire coming out of the barrel.

more railgun news (http://www.signonsandiego.com/news/military/20080202-9999-1n2gun.html)

[Saidin311]

I laughed a LOT when they panned down the barrel of the gun. Reminded me of the scene in spaceballs with the ridiculously large ship. It just seems excessive and unnecessary.

[rebb]

Humanity is getting really good at wiping itself out.
:P

[Sectaurs]

[ QUOTE ]
Humanity is getting really good at wiping itself out.
:P

[/ QUOTE ]

pfaw!

we haven't even done it once yet

[Illusions]

[ QUOTE ]

pfaw!

we haven't even done it once yet

[/ QUOTE ]

We made that virus thats 99.9% lethal to the human population, and its quite possibly easily transmissable. So I think we've got that angle covered if we ever wanted to...

[KeyserSoze]

[ QUOTE ]
So THAT'S what a real railgun sounds like - pretty much like a regular cannon but with a slight whine behind it...

[/ QUOTE ]

With a conventional gun/cannon, most the noise you hear is from the projectile breaking the sound barrier, so a railgun that fires a supersonic projectile should sound pretty similar.

[Sectaurs]

[ QUOTE ]

We made that virus thats 99.9% lethal to the human population, and its quite possibly easily transmissable. So I think we've got that angle covered if we ever wanted to...

[/ QUOTE ]

Granted, but I'll stand by my opinion until we've wiped out humanity at least once.

[notman]

[ QUOTE ]
Humanity is getting really good at wiping itself out.
:P

[/ QUOTE ]

Practice makes perfect :P

[TomDunne]

[ QUOTE ]
[ QUOTE ]

pfaw!

we haven't even done it once yet

[/ QUOTE ]

We made that virus thats 99.9% lethal to the human population, and its quite possibly easily transmissable. So I think we've got that angle covered if we ever wanted to...

[/ QUOTE ]

I Am Legend was a documentary?!

[MoP]

[ QUOTE ]
I Am Legend was a documentary?!

[/ QUOTE ]
And it was filmed in real-time!

[Ferg]

[ QUOTE ]
[ QUOTE ]
I Am Legend was a documentary?!

[/ QUOTE ]
And it was filmed in real-time!

[/ QUOTE ]

if that's a shake quote, mop wins this thread

[Illusions]

[ QUOTE ]
[ QUOTE ]
[ QUOTE ]

pfaw!

we haven't even done it once yet

[/ QUOTE ]

We made that virus thats 99.9% lethal to the human population, and its quite possibly easily transmissable. So I think we've got that angle covered if we ever wanted to...

[/ QUOTE ]

I Am Legend was a documentary?!

[/ QUOTE ]

Seriously. The only reasons I haven't posted any art on here in a while is because I'm too damned busy fighting monster zombie vampires and hunting for food on the plains of Manhattan, all the while experimenting for a cure...

...send food.

[ElysiumGX]

*waits for someone to miss this thread, and post another with a more descriptive title*

[TomDunne]

[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
[ QUOTE ]

pfaw!

we haven't even done it once yet

[/ QUOTE ]

We made that virus thats 99.9% lethal to the human population, and its quite possibly easily transmissable. So I think we've got that angle covered if we ever wanted to...

[/ QUOTE ]

I Am Legend was a documentary?!

[/ QUOTE ]

Seriously. The only reasons I haven't posted any art on here in a while is because I'm too damned busy fighting monster zombie vampires and hunting for food on the plains of Manhattan, all the while experimenting for a cure...

...send food.

[/ QUOTE ]

I will send you cake!

(that's a lie.)

[Ott]

This is still not really that impressive when you really think about it. Atomic weaponry is still the most available and devastating stuff out there, (aside from obvious chemical/biological disasters) and it is also perfected. It is, unfortunately, a mythical power that will only be used by the mad and insane. No country with any sort of ethical premise will ever fire a Nuclear weapon.

It's about as effective as E-Peen - It only really matters as long as the guy you are standing up to doesn't knock on your door.

Railguns and whatnot seems pretty interesting, but high projectile lasers, long range sound "pain beams" and other forms of "sci-fi" stuff is more likely to be seen than this stuff as far as "on the field" goes.

P.S. - Did you see any equipment, personnel, or location that even remotely resembled the Navy? Looked like a bunch of rednecks shooting stacks of wood with a long rusty potato gun.

[KeyserSoze]

[ QUOTE ]
P.S. - Did you see any equipment, personnel, or location that even remotely resembled the Navy? Looked like a bunch of rednecks shooting stacks of wood with a long rusty potato gun.

[/ QUOTE ]

Well, I think weapons systems are usually developed by contractors, and not within the military apparatus itself. That would explain why you don't see guys dressed in pressed uniforms and spit-polished boots.

[MoP]

[ QUOTE ]
if that's a shake quote, mop wins this thread

[/ QUOTE ]

Well spotted, sir! /images/graemlins/smile.gif

[Mark Dygert]

Thats great and all, but how well does it deliver explosive rounds to the target? Firing solid projectiles is neat at pretty close ranges, but you have to be really accurate and hope it has enough energy left to actually do damage. When your projectile has a blast radius you don't have to worry about being as accurate or maintaining speed.

[Joseph Silverman]

The very point of a railgun is that you shouldn't need explosive munitions. Even beyond the range of conventional explosive weaponry, it should still deliver more force, more accurately.

Edit: according to wikipedia, the weapon in question is expected to deliver more force than a bgm-109 tomahawk (http://en.wikipedia.org/wiki/BGM-109_Tomahawk) by firing a seven pound slug. Seems a lot more cost effective.

[TomDunne]

You tell 'em, Vig! /images/graemlins/tongue.gif

[Mark Dygert]

=P I'll keep it going a bit longer since I don't have time to do research myself =P
[ QUOTE ]
according to wikipedia, the weapon in question is expected to deliver more force than a bgm-109 tomahawk by firing a seven pound slug. Seems a lot more cost effective.

[/ QUOTE ] They still have more questions to figure out.
- How many dumb slugs do you have to fire before you can hit the target? In the example shown it was a pretty straight forward targeting system, point, pray and fire, wash rinse repeat until you hit it. How effective is that method at keeping civilian causalities down?
- How many trillions is it going to take to come up with an advanced spotting system that replaces the guided system they have now? Sure the slugs might be cheap but how much more are we going to dump into R&D now that we have a working barrel? Is that still more cost effective then firing guided projectiles?
- How much energy does it take to fire it?
- I guess rail guns can only be placed on nuclear powered ships?
- What is the rate of fire, and how long can that be sustained.
- What does it take to maintain it all?

Is that force being measured to a single point, or are they taking into account the different types of payloads and the guided nature of tomahawks? Remember that tomahawks can do more then just make something go boom.
Is that force constant or does it degrade over the maximum range? With a guided projectile you might have a shorter range but you can make sure that its payload delivers the same force within that range.

[Ghostscape]

[ QUOTE ]
Thats great and all, but how well does it deliver explosive rounds to the target? Firing solid projectiles is neat at pretty close ranges, but you have to be really accurate and hope it has enough energy left to actually do damage. When your projectile has a blast radius you don't have to worry about being as accurate or maintaining speed.

[/ QUOTE ]
The kinetic energy produced by the projectile moving at Mach5 is equivalent to a conventional explosive weapon. That's the point - not storing bombs on ships, putting the same artillery power out at longer ranges, keeping ships safer.

[ QUOTE ]
This is still not really that impressive when you really think about it. Atomic weaponry is still the most available and devastating stuff out there, (aside from obvious chemical/biological disasters) and it is also perfected. It is, unfortunately, a mythical power that will only be used by the mad and insane. No country with any sort of ethical premise will ever fire a Nuclear weapon.

It's about as effective as E-Peen - It only really matters as long as the guy you are standing up to doesn't knock on your door.

Railguns and whatnot seems pretty interesting, but high projectile lasers, long range sound "pain beams" and other forms of "sci-fi" stuff is more likely to be seen than this stuff as far as "on the field" goes.

P.S. - Did you see any equipment, personnel, or location that even remotely resembled the Navy? Looked like a bunch of rednecks shooting stacks of wood with a long rusty potato gun.

[/ QUOTE ]

This is about building better ship-based artillery, which puts heavy hitting weaponry in places where air support can't reach. This isn't about obliterating countries or being safer for anyone other than the people carrying the ammunition or firing the gun. And "pain beams" are a terrible idea for fighting wars (and a great idea for crowd control/suppression) because they don't remove the enemy's ability or capacity to fight, merely their desire to fight for as long as they're hit with the beam (which is why it's great for non-military action).

[Mark Dygert]

How is switching from a guided projectile that can guide itself around mountains, fly under radar and correct its own path, to a linear dumb slug going to be more effective? It does no good to pack the same punch if you can't hit the target. How is that slug going to hit the same target if it doesn't have access to it? How is it going to deliver different payloads when it needs to achieve different goals?

I see this tech as a nice cheap compliment to the existing tech and way of sparing the high tech when it isn't needed but is it really going to replace it? That is if it actually does cost less when you factor in everything besides the cost of the slug.

I like where they are going with this, but they still have a lot of hoops to jump through.

[Joseph Silverman]

-Targeting is pretty easy, actually. We have systems in place to target ballistic cannons already (see, tanks and ship cannons) it's the exact same system with the numbers for the railgun's speed/range put in. It's not actually that hard, when you think about it -- submariners used to do the math by hand to target torpedos, and we've had automated systems to aim projectiles for decades.

-It takes a ton of energy to fire it, that's why we don't have them issued already. The system isn't finished, it's just being tested.

-Of course it won't replace missles for firing over mountains. You also can't fire torpedos at land targets, but they aren't obsolete. We have specialized weapons for different situations. However, if you could choose between firing a (easy to counter, expensive) missle or a railgun at another ship or a coastal target, the railgun is easily more effective.

[Ferg]

Vig: They're planning on using projectiles with fold-out articulated fins that are fired into the upper atmosphere and aim themselves on re-entry with satellite assistance.

I wouldn't mind havin one of those for deer huntin...

[TomDunne]

I was reading around about this tech today, and it looks like they will be guided as well as able to be fired over mountains. At the maximum range (250-some miles), they'd reach an apogee of 95 miles up. That'll make it over pretty much anything /images/graemlins/laugh.gif

http://fredericksburg.com/News/FLS/2007/012007/01172007/251373

[jdevin]

An interesting fact about this type of railgun is that they use aluminum rounds. The round melts mid flight and causes much much more damage than a regular round. I think its cool that molten aluminum makes such a great armor piercing round. Plus it sprays molten shrapnel into the other side of the barrier.

[Mark Dygert]

holy crap that is much more impressive then the yahoo link of "look what these rednecks are doing BOOM! slow-MO!".

[Ghostscape]

[ QUOTE ]
holy crap that is much more impressive then the yahoo link of "look what these rednecks are doing BOOM! slow-MO!".

[/ QUOTE ]

Are they rednecks because they're not test firing giant cannons in populated urban areas and are instead surrounded by trees?

How else do you demonstrate what the gun does in video other than video taping it?

Maybe I have a different reaction to it because I was pretty current on rail guns prior to the article and the video, but I don't understand the vitriol. It's a giant goddamn gun that fires bullets without anything explosive, and the bullets fire so fast THEY IGNITE THE AIR AROUND THEM. LIKE RE-ENTRY FOR SPACECRAFT. That is totally badass.

Despite this gun looking similar to other guns, it isn't using anything approaching conventional propulsion methods. And just seeing it being test-fired in what amounts to a defense contractor's backyard makes it much more real (and therefore cool) to me than reading about stuff without actually seeing it.

[IronHawk]

I thought the bud light cap, oakley knockoff shades and camo hoody were dead giveaways for redneck. The gun was pretty cool though. /images/graemlins/wink.gif

[cochtl]

some info and vids on an early rail gun project

Do it! (http://www.powerlabs.org/railgun.htm)

video of mini rail gun in action (http://www.powerlabs.org/movies/inductorplasma.MPG)

[Soccerman18]

Gonna be a quick post cause dinner's cookin.

Railgun in a nutshell.

Two metallic rails with a voltage going across them. Non-conducting slug. Very strong magnet with the magnetic field pointing up (or down). So looking down at the parallel rails, the magnetic field would either be pointing towards or away from you. Fuse behind slug (this is the source of the fire).

When the fuse is lit (Boom! Fire!) it becomes an ionized (conducts electricity) gas. This gas essentially connects the two rails allowing current to flow. Moving electrons in a magnetic field will have a force on them that is perpendicular to both the magnetic field and the direction of the current flow. So if the current is going to the left, magnetic field is going up, then there will be a force on the gas going out. The gas then pushes the slug, which I'm guessing is why the bottom if the slug looked rounded. The stronger the magnet and the more current flow you can get the more force it pushes out with.

This is exactly how an electric motor works. Lots of wires have a current on them in a magnetic field, force on the wires causes the motor to turn. /images/graemlins/smile.gif

[Mark Dygert]

[ QUOTE ]
[ QUOTE ]
holy crap that is much more impressive then the yahoo link of "look what these rednecks are doing BOOM! slow-MO!".

[/ QUOTE ]

Are they rednecks because they're not test firing giant cannons in populated urban areas and are instead surrounded by trees?

[/ QUOTE ]You might be a redneck when your work and casual wardrobe are the same as your hunting. I'm sure thats just a personal hang up, but I would choose to wear something other then my deer gutting cloths when filming what could amount to be a revolutionary moment in modern warfare. Honestly, if it works, and hes the right man for the job who cares, it just sparks odd thoughts of backyard homebrew wrestling and banjo music when I see people wearing cammo coats and Bud Light hats, especially when they are loading big guns... Who knows maybe it was important that he blend into the trees...

[ QUOTE ]
How else do you demonstrate what the gun does in video other than video taping it?

[/ QUOTE ]Yahoo could have provided a lot more info about the whole thing. Really if no one said it was a rail gun it would be easy to mistake it as a regular explosives driven gun in anyones backyard.

[ QUOTE ]
Maybe I have a different reaction to it because I was pretty current on rail guns prior to the article and the video, but I don't understand the vitriol. It's a giant goddamn gun that fires bullets without anything explosive, and the bullets fire so fast THEY IGNITE THE AIR AROUND THEM. LIKE RE-ENTRY FOR SPACECRAFT. That is totally badass.

[/ QUOTE ]I was totally out of the loop and didn't have any time to do extra searches, its nice that Polycount members where able to fill in the gaps, thanks again guys. I have no animosity toward the rail gun, I'm all for it and excited to see it progressing this far. I just didn't see how it could out right replace guided projectiles, and they didn't address any of the other issues that would keep it out of use. Thankfully people more in the know where able to answer those questions, it would have been nice to have gotten that info from the article, but I totally understand that in modern media well thought out and researched articles are few and far between.

[ QUOTE ]
And just seeing it being test-fired in what amounts to a defense contractor's backyard makes it much more real (and therefore cool) to me than reading about stuff without actually seeing it.

[/ QUOTE ]I guess I would like both, to see and read, but this news article was pretty much just a link to a video.

[TomDunne]

[ QUOTE ]
Gonna be a quick post cause dinner's cookin.

Railgun in a nutshell.

Two metallic rails with a voltage going across them. Non-conducting slug. Very strong magnet with the magnetic field pointing up (or down). So looking down at the parallel rails, the magnetic field would either be pointing towards or away from you. Fuse behind slug (this is the source of the fire).

When the fuse is lit (Boom! Fire!) it becomes an ionized (conducts electricity) gas. This gas essentially connects the two rails allowing current to flow. Moving electrons in a magnetic field will have a force on them that is perpendicular to both the magnetic field and the direction of the current flow. So if the current is going to the left, magnetic field is going up, then there will be a force on the gas going out. The gas then pushes the slug, which I'm guessing is why the bottom if the slug looked rounded. The stronger the magnet and the more current flow you can get the more force it pushes out with.

[/ QUOTE ]

That's not how it works. /images/graemlins/smile.gif
http://en.wikipedia.org/wiki/Railgun

[Soccerman18]

uh, the only difference between what I wrote and what's in the wiki (granted I didn't have the time to go into detail, was a good dinner though) is that my description used a fuse whereas the wiki had the projectile being a conductor. The result is the same, an electric current moving through a magnetic field has a force on it, but my method allows for a triggering system similar to current guns instead of the projectile firing as soon as it's loaded.

[TomDunne]

I'm trying to avoid these types of threads where I get into 'arguments' with people, but again it appears I'm going to fail.

You said it uses gas propulsion. That's wrong and defeats the entire purpose of using an electromagnetic system. A projectile weapon that uses gas expansion as propulsion is nothing special - that's what a modern gunpowder bullet does. A primer (your 'fuse') ignites the gunpowder, creating a rapid expansion of gases and pushing the bullet out of the barrel. Sticking a "very strong magnet" in there doesn't change anything about how gas expansion projectiles work.

A railgun involves no gas expansion at all. That wiki entry specifically says "the limits of gas expansion prohibit launching an unassisted projectile to velocities greater than about 1.5 km/s and ranges of more than 50 miles [80 km] from a practical conventional gun system." A railgun slug travels at more than twice that speed and several times as as far because it is propelled by Lorentz force down the length of the barrel, generated by the electromagnetic rails.

The jet of flame from the barrel in that demo video is a by-product of the railgun's tremendous heat. The slug travelling down the barrel generates so much heat energy that it ignites aluminum particles and residual gases in the barrel. The expansion of those gases again do not contribute to the slug's velocity.

The above is all what I've learned about railguns from the web in the last two days. If you've got a reference that says firing a railgun involves lighting a fuse and gas pushes the slug out of the barrel, I'd like to read it.

[Joao Sapiro]

love when people try to sound smarter than they are !!

*fetches popcorn*

Railgun is a gun that makes awesome light trails that pukes a hole thru everything and makes people laugh and rejoyce !

[Ferg]

actually, there is a black mage that lives in Denver. He channels evil Neuter-on radiation from dimension X, which they use to propel tiny metallic baby fetuses through a black hole in new york, which in turn causes the rail gun to fire somewhere in the Midwest. Also, an eagle explodes mid-flight every time they use it. Nobody knows why.

Science!

[Soccerman18]

Verm, no argument at all. I agree with you that it doesn't use gas expansion to push the slug. The reason for the fuse in my example is that in a solid state it is not a conductor, so everything can be charged and ready to go. When the fuse is lit it becomes an ionized gas, this allows current between the two rails to flow. The current causes a force to be placed on the gas which pushes the gas along, thus pushing the slug. So the gas isn't expanding like in a gun, it's moving. As for the cause of the fire, that was just a guess (lot of current + gas = heat seemed reasonable).

All that's happening is that some conductive object exists allowing current to flow resulting in a force on that object. So we are thinking the same thing, just a different object.

[dfacto]

Soccerman, when you want to trigger a railgun at your leasure instead of when a contact is made upon sabot insertion you use a button/trigger/switch/etc to let the current flow.

No jackass is going to design a railgun that is electrified all the time. Loading that would be an extreme hazard, and running it would be an extreme waste of energy.

So the need for a fuse is non-existant.

EDIT: and upon re-reading, you're not proposing a gas expansion system, but a system where the gas acts as the primary projectile that the rails are working upon, pushing the actual round out of the barrel. This is needlessly complex and wastes energy that would be better put towards moving the actual projectile rather than a cloud of gas. Additionally, I've got the feeling that the cloud of gas would dissipate backwards despite the electric current, and you would lose a lot of energy per shot.

[TomDunne]

[ QUOTE ]
love when people try to sound smarter than they are !!

[/ QUOTE ]

I starting my post by saying I had been trying to avoid these threads, which I have been since I PM'd you a couple months ago. I really don't get what your problem is with me, but I'm not going anywhere so how about you just fucking learn to deal with it?

[TomDunne]

[ QUOTE ]
Verm, no argument at all. I agree with you that it doesn't use gas expansion to push the slug. The reason for the fuse in my example is that in a solid state it is not a conductor, so everything can be charged and ready to go. When the fuse is lit it becomes an ionized gas, this allows current between the two rails to flow. The current causes a force to be placed on the gas which pushes the gas along, thus pushing the slug. So the gas isn't expanding like in a gun, it's moving. As for the cause of the fire, that was just a guess (lot of current + gas = heat seemed reasonable).

All that's happening is that some conductive object exists allowing current to flow resulting in a force on that object. So we are thinking the same thing, just a different object.

[/ QUOTE ]

Okay, I see what you're saying. In the railgun descriptions I've read, the slug itself is conductive and completes the circuit (and I suppose that contact/friction with the rails is what causes the massive heat issue.) I was reading your post literally and thinking "Fuse? What fuse??"

And I'm glad dinner was good /images/graemlins/cool.gif

[Mongrelman]

Be intresting to see if they manage to achieve rifling in the barrel, as just corkscrewing the rails won't work.

[Joseph Silverman]

Why would you need to rifle the barrel of a railgun?

[Soccerman18]

dfacto, I was thinking earlier that an electrical switch would be simpler but I would think that there would be a problem with charging the rails.

If the rails aren't charged until you push a button then you have to charge the rails very quickly as the projectile would begin to move as soon as there was any potential going across the rails. Large metal rails would take a while to charge up and the current would ramp up, and you wouldn't get as much force out of it as you would if the rails were fully charged. Would be interesting to see a plot of the current and see how it behaves. But then like you said there's the safety issue, don't touch it. Might sting a little. Shouldn't waste much energy though, it's essentially a large capacitor at that point, storing energy.

[Mongrelman]

[ QUOTE ]
Why would you need to rifle the barrel of a railgun?

[/ QUOTE ]

Accuracy. If you're going to be firing a round a couple of hundred miles that does it's damage by direct impact instead of an explosion, best make sure it hits.

[dfacto]

Soccerman, electricity moves at the speed of light (or close enough). It's not as if you need to physically move it yourself, you just need to have a large capacitor ready to discharge into the rails when you press the button. I'm pretty sure that's how the current tests systems work.

Lupus: At the ranges we're talking about rifling won't be much of an aid anyways, as wind, and any small course deviation would throw the round way off target after 200 miles. That's why they are looking at fin stabilized GPS guided designs.

As a side note, the Abrams battle tank uses a fin stabilized rounds, as it has a smooth bore barrel. Seems to work pretty well. /images/graemlins/smile.gif

[Mongrelman]

True, I'm just curious as to how they would go about it if it's something they went for on smaller scale guns. Just twisting the path of the conductor/projectile would mean areas of no force or reversed force, so I'd just find it interesting to see how rifling could still be achieved like that /images/graemlins/smile.gif

Using a railgun to launch a missile which then kicks in would give some impressive range. Sort of like the Shagohog from MGS3 hehe.

[dfacto]

Lupus, considering that railgun rounds use discarding sabots, rifling wouldn't make a bit of difference, as the round separates from the sabot anyways. (Edit: well, I suppose if the sabot rotates while keeping a nice tight grip on the round, but I'm not sure that'd work, or if it's necessary. Seems like something that would just increase rail ablation.) And as such, a smaller system could still use fin stabilization. If we're talking "handheld" small, then I don't know.

As for the railgun/missiles combo I have a feeling that might come to pass. It would be a very effective way to speed a missile up enough to activate a scramjet engine and let it fly further at hypersonic speeds. That would let you eliminate a lot of mass from the missile by removing the first rocket stage necessary to speed it up enough for the scramjet to be able to work.

[Mongrelman]

I'm not saying rifling is a better way of doing it, I'm just saying it would be interesting to see how it was done if they managed.

[Soccerman18]

The problem is in discharging the capacitors. A capacitor isn't going to completely discharge instantly, so the current is going to be limited. To give ya some numbers, or the means to get some actual numbers, the charging and discharging of a capacitor is based on a time constant which is equal to the capacitance * the equivalent series resistance. It take 5 time constants to fully charge and discharge a capacitor. And shorting a cap like that will cause the dielectric material in the cap to break down, so you'd have to replace the cap each time.

Unfortnately I don't know off hand the specs for some really large caps to see what the discharging current rate is, but then I have no idea what strength of magnet they used.

hmm, gonna have to do a little experiment this weekend, connect a battery to two large pieces of metal, see what the potential is between them.

[dfacto]

Well, from what I've found the test guns use capacitors. So either you don't have the whole story, or the smartasses figured out how to make it work.
http://www.popularmechanics.com/technology/military_law/4231461.html

They mention that they use multiple capacitors, so perhaps they have quite a few capacitors set up with each discharging to only one portion of the rail in sequence.

[ QUOTE ]
I'm not saying rifling is a better way of doing it, I'm just saying it would be interesting to see how it was done if they managed.

[/ QUOTE ]

I'd be interested too, especially if that would be possible, but I doubt they'll bother.

[Ghostscape]

Soccerman I don't know what the heck you're talking about, and I suspect you are more in my camp than you'd admit /images/graemlins/smile.gif

They charge capacitors and discharge them into the rails to fire the gun. The projectile itself is usually a non-conductive metal slug like tungsten, that sits in a conductive sabot. All this gas nonsense is goofy, and as for caps blowing, I wouldn't be surprised if that's one of the problems they're working on ironing out, along with the problem of projectiles and sabots melting and fusing to the rails, or the outward force created pushing the rails apart, all of which are problems that are being worked on, which is why the technology has been understood well enough to test for a while (hell, I know a guy who built one himself - it shot pennies and had a capacitor array the size of a milk crate - I think he might have blown a cap once actually but I don't remember) but isn't yet implemented in the field.