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Registered Member #1471
Joined: Tue May 06 2008, 03:17AM
Location: Irvine, California
Posts: 13
Have have my capacitors already, 12 of 400v, 3900uF, but now I'm wondering what is the best rail gun voltage? I've doing series-parallel, so I can have 1200, 1600 or 2400 volt bank. which is the best voltage? Does it really matter?
And what kind of wires would i need to charge/discharge this bank? would 4 gauge car jumper cables work? how much insulation should i have on the wires at 1200-2400 volts?
I'm using a bus bar for the capacitor bank. There shouldn't be any resistance problems there. Its a pretty big bar.
Registered Member #1320
Joined: Sat Feb 16 2008, 01:31AM
Location:
Posts: 67
I just finished and tested my railgun about a week ago. I think slightly higher voltages would have been a better choice, but I used 16 525volt 2400uF in 4 sets wired in parallel. To charge I used a MOT from MOT to capacitors I just used some 18 gauge 1kv rated wire. just don't touch it in case of corona. From the capacitors to the rails I had each of the four stages wired with 4 gauge wire with a common ground of 00 Gauge wire. The less resistance the better, so way the cost/difficulty/weight to the performance benefits. I'll post up soem pics of my rig if it would help. Careful though they are a lot more work then you would originally think, and if your not good at fabricating no amount of electrical knowledge will help. Last, any ideas on what for of injection your using as I had a heck of a time finding a solenoid for mine.
edit: btw with injection I got 620m/s velocity using a 8 gram alluminum cube
Registered Member #1471
Joined: Tue May 06 2008, 03:17AM
Location: Irvine, California
Posts: 13
thanks for the tips. I'll use 2400 a volt bank.
and injection, most people say they use some type of pneumatic setup, I decided to skip that because its too complicated, too much work. I've got a shotgun, 20 gauge. I've already done some test shots using modified shells so that only the primer is fired, no gunpowder and no lead shot. I've figured out how to make it shoot projectiles less than .61 caliber or square projectiles, I made some very specially designed inserts to put into the barrel of the gun. I can skip all the thingys that makes gas injection complicated, all i gotta do is muzzle load the special projectile down the inserts, chamber a modified shell, and then simply pull the trigger and volia! it works. I decided on this method because: its readily available, i don't need to buy anything extra (like an air compressor), and i'm very familiar with this since i regularly use this method to shoot paintballs, airsoft BBs, and other projectiles.
the 620m/s, thats amazing! I hope i get that much too.
Registered Member #158
Joined: Sun Feb 12 2006, 09:53PM
Location: Central Ohio
Posts: 282
zephir wrote ...
the 620m/s, thats amazing! I hope i get that much too.
Yes, that's like over 2,000 FPS, about the same as a common riffle. I guess that's a pretty darn light projectile though. I think we would like to see some more info, pics, video on this railgun... on a new thread of course.
Registered Member #1320
Joined: Sat Feb 16 2008, 01:31AM
Location:
Posts: 67
zephir wrote ...
thanks for the tips. I'll use 2400 a volt bank.
and injection, most people say they use some type of pneumatic setup, I decided to skip that because its too complicated, too much work. I've got a shotgun, 20 gauge. I've already done some test shots using modified shells so that only the primer is fired, no gunpowder and no lead shot. I've figured out how to make it shoot projectiles less than .61 caliber or square projectiles, I made some very specially designed inserts to put into the barrel of the gun. I can skip all the thingys that makes gas injection complicated, all i gotta do is muzzle load the special projectile down the inserts, chamber a modified shell, and then simply pull the trigger and volia! it works. I decided on this method because: its readily available, i don't need to buy anything extra (like an air compressor), and i'm very familiar with this since i regularly use this method to shoot paintballs, airsoft BBs, and other projectiles.
the 620m/s, thats amazing! I hope i get that much too.
that sounds like a good idea, but be careful. the minute you put gun powder in it is the minute the police can start arresting you. Also repeated fires are probably going to create carbon trails for flash over. I don't know a whole lot about firearms not the composition of the primer, but anything on the rails will increase your resistance and make it less efficient. I'll start a new thread sometime today so I don't end up hijacking yours
Registered Member #1320
Joined: Sat Feb 16 2008, 01:31AM
Location:
Posts: 67
well, you won't get much power out of that since most PVC pipe is only rated for about 150psi, but it does work. I think the shotgun shell will probably be more efficient. Just saying to be careful with it. I used a 1200 psi 12oz CO2 tank for mine with a dema 1500psi 3/8" NPT solenoid valve.
Registered Member #1471
Joined: Tue May 06 2008, 03:17AM
Location: Irvine, California
Posts: 13
ea6b607 wrote ...
that sounds like a good idea, but be careful. the minute you put gun powder in it is the minute the police can start arresting you.
yeah, i'm very well aware of that. I won't be breaking any laws since my shotgun's legal and the law only bans flash suppressors, sound suppressors. Theres no law against mounting a rail gun at the muzzle... yet. And if the government decided to make a law, it'll never pass since most people has no clue what rail gun is and there'll be a grandfathering clause in it. So that older existing devices will not be banned.
and gunpowder burns surprisingly clean, I've done barrel swabs after a couple regular shots, my Kleenex always comes out without any sign of dirt or partially burnt powder. Even with powder solvent (which will definitely get dirty if there was any residue at all) the Kleenex is still clean. Either its just the brand of ammo i use or all the shotgun powder burns cleanly.
Registered Member #1262
Joined: Fri Jan 25 2008, 05:22AM
Location: Maryland, USA
Posts: 451
ea6b607 wrote ...
I just finished and tested my railgun about a week ago. ...I used 16 525volt 2400uF in 4 sets wired in parallel ...I got 620m/s velocity using a 8 gram alluminum cube
Capacitors are 5.3kJ, kinetic energy is an amazing 1.53kJ!!!! 28% eff. WOW!!! That is only a few hundred joules ballistic shy of an M16!!! What did you use as a target for that?
Registered Member #1320
Joined: Sat Feb 16 2008, 01:31AM
Location:
Posts: 67
Backyard Skunkworks wrote ...
ea6b607 wrote ...
I just finished and tested my railgun about a week ago. ...I used 16 525volt 2400uF in 4 sets wired in parallel ...I got 620m/s velocity using a 8 gram alluminum cube
Capacitors are 5.3kJ, kinetic energy is an amazing 1.53kJ!!!! 28% eff. WOW!!! That is only a few hundred joules ballistic shy of an M16!!! What did you use as a target for that?
ya but that's with 636 joules of energy from the CO2
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Ideal Railgun Voltage?
