| What should my next project be, if time and materials allow? |
| Railgun |
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44% |
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| Electrothermal gun |
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34% |
[ 10 ] |
| I don't know what either of these are. Also, I like to eat dogfood. |
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20% |
[ 6 ] |
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| Total Votes : 29 |
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| FeLeX |
 Posted: 02/09/2008 21:59 PM Post subject: |
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Captain
Joined: 10 Mar 2007
Posts: 313
265.27 Spud Bux
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| Hey just wondering do you have any info about how electro thermal guns work? Always wanted to build one but I have a very limited knowledge about them. Maybe you could give me a link to a website or something. |
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| Hailfire753 |
| Posted: 02/09/2008 22:07 PM Post subject: |
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Captain
Joined: 28 Jun 2007
Posts: 343
44.15 Spud Bux
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| Wow, amazingly sweet. I do not know what an "eee-lek-tro-thur-mil" gun is, and I LOVE dogfood. |
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| Velocity |
| Posted: 02/09/2008 22:47 PM Post subject: |
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Brigadier General
Joined: 07 Feb 2006
Posts: 1049
168.61 Spud Bux
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That video was very nice... even though the speed figure of 65 fps is well below what even the simplest spudgun can achieve with heavier projectiles, the ergonomics of that gun, demonstrated in a very nice way with you firing, made that thing seem like the greatest thing since the barrel-sealer  .
Great job! |
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| jon_89 |
| Posted: 02/09/2008 23:21 PM Post subject: |
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Colonel
Joined: 11 Apr 2007
Posts: 606
826.20 Spud Bux
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| I like it. I am getting ready to build one myself. Did you put anything between each layer of the coil? Can you explain the breech loader. Wouldn't the magnet holding the ammo decrease performance? |
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| frankrede |
| Posted: 02/10/2008 0:04 AM Post subject: |
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FMF HM
Joined: 20 Jul 2006
Posts: 3252
698.54 Spud Bux
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| Velocity wrote: | That video was very nice... even though the speed figure of 65 fps is well below what even the simplest spudgun can achieve with heavier projectiles, the ergonomics of that gun, demonstrated in a very nice way with you firing, made that thing seem like the greatest thing since the barrel-sealer .
Great job! | I think 65fps is a far understatement |
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| Fnord |
| Posted: 02/10/2008 10:04 AM Post subject: |
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reenigne
Joined: 13 Feb 2007
Posts: 1904
3926.49 Spud Bux
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Felex: Google is your friend.
jon_89: No, I just put a dab of superglue on it every once in a while to keep it together.
As for the magnet decreasing performance,
1. It just barely holds the projectile in.
2. The forces applied to the projectile are immense. Keep in mind that the projectile accelerates to 65 fps in the space of only 1/2", which, according to GGDT would take an equivalent pneumatic gun running at 1000 psi.
Thanks guys. |
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| FeLeX |
| Posted: 02/10/2008 12:15 PM Post subject: |
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Captain
Joined: 10 Mar 2007
Posts: 313
265.27 Spud Bux
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| I know I know I tried looking and all I came up with was the electro labs. As far as I understand a bank of capacitors is discharged through a wire or a spark gap thus rapidly vaporizing what ever liquid is in there. |
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| dumdog123 |
| Posted: 03/01/2008 11:34 AM Post subject: |
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Private
Joined: 19 Oct 2007
Posts: 6
17.08 Spud Bux
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| i have been trying to make a coilgun for a while now how can I easily wrap the coil and what did you use for your barrel? |
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| dumdog123 |
| Posted: 03/01/2008 12:35 PM Post subject: |
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Private
Joined: 19 Oct 2007
Posts: 6
17.08 Spud Bux
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| do you have some kind of wire wraping jig? cause whenever i try to wrap a coil the wire layers get way to small I have a flash circuit but instead of 1 doble A powering it could i use a 9 volt? |
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| Jared Haehnel |
| Posted: 03/01/2008 13:29 PM Post subject: |
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Colonel
Joined: 19 Feb 2008
Posts: 615
168.61 Spud Bux
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If I recall an electro thermal uses a dense metal for the projectile like mercury or lead...it is vaporize by a strong electrical current and because of the heat it moves upwards at an insane velocity and punches a hole through what ever gets in its way...
I would think it would take a lot of energy to make one work and I'm not certain what you would use for ammo but if you could get it to work it would be sweet. |
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| windshrike |
| Posted: 03/01/2008 13:36 PM Post subject: |
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Sergeant Major
Joined: 28 Jun 2007
Posts: 178
444.10 Spud Bux
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Mercury wouldn't make a very good projectile  .
Usually tungsten or depleted uranium is used with a gun of this type.
An ETC gun accelerates the combustion of it's fuel by dumping large amounts of current into it at once, essentially starting burns from almost every point in the mixture.
I suggested a while ago an ETC hybrid. Most modern ETC guns use solid fuels though, and a stoichiometric mix hasn't been tried.
EDIT: Nice little gun you have there. 65 fps out of a 1/2" barrel is amazing, I'd love to build a larger optical triggered gun, but I can't design electronics  .
Last edited by windshrike on 03/01/2008 13:42 PM; edited 1 time in total |
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| Jared Haehnel |
| Posted: 03/01/2008 13:40 PM Post subject: |
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Colonel
Joined: 19 Feb 2008
Posts: 615
168.61 Spud Bux
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| I wasn't even close.... thanks for the explanation I must have been thinking of something else I read about... |
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| windshrike |
| Posted: 03/01/2008 13:47 PM Post subject: |
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Sergeant Major
Joined: 28 Jun 2007
Posts: 178
444.10 Spud Bux
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| It's ok, we all have little lapses. It sounds like you were talking about an explosively formed penetrator. |
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| The_Crow681 |
| Posted: 03/19/2008 19:24 PM Post subject: |
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Private
Joined: 31 Jan 2008
Posts: 16
34.18 Spud Bux
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what projectile are you shooting from it, BB's? by the way that is very impressive. I had a similar idea but i couldn't get it to work well because i left out the capacitators but now i can! thanks for showing me the way  |
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| Fnord |
| Posted: 03/19/2008 19:58 PM Post subject: |
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reenigne
Joined: 13 Feb 2007
Posts: 1904
3926.49 Spud Bux
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I recently cut up bits of screwdriver to use as projectiles, and they seem to work the best of anything despite the slight magnetism.
Spheres are a bad choice to use in a gauss gun due to the small amount of interaction between the projectile and the field. you need a long thin projectile. |
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