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LAN_403

Bust_A_Cap

Thu Jun 26 2008, 12:07PM

Registered Member #1561 Joined: Mon Jun 23 2008, 07:58PM
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Posts: 25

So I was reading Phil's railgun project log and some people were talking about using gun powder to inject the projectile into the rails. I was wondering beyond the gun powder residue issue, what other issues are there with this?

I was thinking that you could make a homemade firing device, something basic, like clamp with the bullet in it, a tube for the barrel and then something to hit the back of the bullet in order to launch it. Then in front of this have the railgun, so basically youâ€™re just firing a bullet into the railgun. An obvious consideration would be would the bullet be big enough/magnetic enough to even be effected by the electromagnetic propulsion? Also you'd have to set up a timing device to fire the rails at the right time, as far as that is concerned you could just use an optical sensor, like one in a multistage coilgun. Also another thing to consider is that you'd have to have the rails lined up perfectly.

Anyways just doing some random brainstorming, I know this is stupidly dangerous and I'll probably never try this, but I'm still interested. One last thing to consider is maybe this would work better in a coilgun, due to the bullet being rounded...? Anyways let me know what you guys think

Hon1nbo

Thu Jun 26 2008, 01:49PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: North Texas
Posts: 1040

question is if the residue of the gun powder could cause a short across the rails... maybe not on the first shot, but a least after a few...

nabiul

Thu Jun 26 2008, 02:41PM

Registered Member #1558 Joined: Sun Jun 22 2008, 08:22PM
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Posts: 8

Is not the residue that will be a concern, modern smokeless gun powder doesn't leave much in terms of that, but any kind of combustion produces highly ionized gasses as a by product which might turn the rails into a spark gap.

Using a compressed air injection system, like what the guy at powerlabs uses is more practical.

Hon1nbo

Thu Jun 26 2008, 04:53PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: North Texas
Posts: 1040

nabiul wrote ...

Is not the residue that will be a concern, modern smokeless gun powder doesn't leave much in terms of that, but any kind of combustion produces highly ionized gasses as a by product which might turn the rails into a spark gap.

Using a compressed air injection system, like what the guy at powerlabs uses is more practical.

good point about modern powder, and a paintball tank is a good source of air (or nitrogen/CO2)

rp181

Thu Jun 26 2008, 06:21PM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
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what about electrothermal gun? it could use the plasma as the plasma armeture?

Dont bullets have alot of lead?

phil

Thu Jun 26 2008, 08:03PM

Registered Member #314 Joined: Mon Mar 13 2006, 03:12AM
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Posts: 52

Det cord? This is probably overkill as it is a very powerful explosive for the small size.

aonomus

Thu Jun 26 2008, 09:17PM

Registered Member #1497 Joined: Thu May 22 2008, 05:24AM
Location: Toronto, Ontario, Canada
Posts: 801

What about making (this is a stretch since the machining will be hard) a light gas gun to inject the projectile into the rails. As a side advantage you could theoretically load the gun with something that has a higher breakdown (SF6?) to prevent arcing.

Hon1nbo

Thu Jun 26 2008, 10:45PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: North Texas
Posts: 1040

aonomus wrote ...

What about making (this is a stretch since the machining will be hard) a light gas gun to inject the projectile into the rails. As a side advantage you could theoretically load the gun with something that has a higher breakdown (SF6?) to prevent arcing.

a pneumatic injection? paintball tanks are fine, that is what I used on my hand-held railgun... but I don't know how well sulfur hexafluoride would work, and most of all I do not know how easily compressed it is or it's breakdown ratings... but it is surprising to see someone has it available, who is you supplier? I have been trying to get ahold off a bunch of it to float small objects and make my voice deeper :)

Andyman

Fri Jun 27 2008, 01:17AM

Registered Member #1083 Joined: Mon Oct 29 2007, 06:16PM
Location: Upland, California
Posts: 256

How about a rifle/railgun hybrid? The projectile would be an ordinary bullet but with no gunpowder, just the primer. The railgun portion would be the forward part of the gun and provide most of the acceleration to the bullet.
One question though. If the injection speed is high enough, say with a full loaded rifle cartridge, will the wear on the rails be lessened? Or will it be magnified? Is there a limit to how fast the electromotive force can accelerate the projectile?

rp181

Fri Jun 27 2008, 01:45AM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
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Posts: 1529

Faster the projectile = less erosion and more effeciancy.
Ide advise against co2, it has a slow expansion speed, you wont get more then 800FPS at even 800PSI.

Theoretically, railguns can accelerate to the speed of light, but that is with a massless projectile, no friction, or resistances.

High pressure hydrogen would be great injection, fastest partical speed, easy to get past mach 1.

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