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Registered Member #1320
Joined: Sat Feb 16 2008, 01:31AM
Location:
Posts: 67
I don't have time right now to go into too thorough an explanation, but I thought I'd start a thread so I stop hijacking Zephir (sp?)
Anyways it uses 4 sets of 4 525Volt 2400uF Capacitors in parallel with a 1/2" lexan bore charged by a MOT and injected using a Dema 1500 Psi solenoid trigger for a 12oz paintball CO2 canister charged to 1200psi. Velocity was measured using two microphones on by the muzzle second by a 1/8" piece of wood and measuring time between hits on a distance of 20 feet. Final velocity of 620m/s at full charge (5.3Kj along with 636 joules imparted by injector). projectile was a 1/2"x1/2"x1/2" piece of aluminum weighing 8 grams. barrel length is 48 inches with 4 8inch long sets of independent rails (copper 3/4" x 1/8") inner barrel thats not covered by rails is 1/8" derilen thermal plastic. Supported by 1 1/2"x1/4" steel grade 8 bolts every 2 1/2" of the barrel. Final charger is powered by 2 9ah lead acid battery's though an inverter followed by the MOT.
Here's my website in early development (all the pictures are old, but it has my original designs)
I think the thing that helped the most with my efficiency was the independent multiple sets of rails which reduced peak current without having to add an inductor and still preserving total power.
Future development on second generation employing round bore and automatic feeding. Along with improved portable charger already started.
Registered Member #1389
Joined: Thu Mar 13 2008, 12:50AM
Location: Pittsburgh, PA
Posts: 346
That is an absolutely incredible design. If you don't mind me asking, how did you machine all the fine parts for that thing (and how much did all that cost)? Also, It is a pretty ingenious idea to stage a railgun. Also, I am very impressed with the efficiency of this setup. At 620 m/s you're putting over 1.5kJ of energy behind that cube, and with the injector energy taken away, its still at an impressive 901 J from EM forces. I mean, thats 17% efficiency! I think you may be onto something. Do you think you could give some bigger close up pictures of this thing, as well as some damage dealt by it?
Note: Before the Mods get here, the max picture width is 400 pixels. Thumbnail those shots!
Registered Member #1320
Joined: Sat Feb 16 2008, 01:31AM
Location:
Posts: 67
First, how do you thumbnail pictures I only know hot to do it in html.
I really have no fancy tools pretty much all I used was a table saw a drill press and a miter saw (along with a friend of mine who has a metal chop saw for the copper and aluminum). A lot of time and a lot of measuring. The actual rail gun is currently at my school (apparently they worry about people bringing in swiss army knifes, but railguns are fine) A different friend of mine took some pictures (he has a professional photography business and got some nice action shots of the muzzle while firing) when I fired it, but I still need to get them from him. The video is I got was kind of crappy since the person didn't realize there was a zoom, but I'll upload it later anyways. I Still have the 1/8" piece of wood that it made a perfect square hole in with barely any splintering (sign of high speed as little energy was transferred to the wood. After it traveled through the wood it went who knows how far into the side of the hill I shot it at. Since these pictures I have completely rewired my capacitor bank and remade my charging box (or am in the process of doing that), I'm going to start the V2 pretty soon. Cost wise the whole thing cost me about $500, but I got a $400 grant from the HAL department at my school for the project.
Registered Member #1471
Joined: Tue May 06 2008, 03:17AM
Location: Irvine, California
Posts: 13
wow, thats just amazing. Good job on coming up with the idea of a multi-stage rail gun. I haven't seen that before. I had a similar idea, but with a 2 stage rail gun instead. How are your rails wired? Do you have four separate sets of capacitors, one for each rail?
And for your rail gun test shots, you should consider a proper backstop if you don't already have one. Your projectile speed is just 90 m/s less of my rifle (710m/s, 8 gram projectile), which I know for a fact would horribly maim someone if I accidentally shot someone with it. You should have a proper backstop behind your wood target, to catch any rounds before you accidentally shoot someone. A large mound of sand or at least a sandbag wall would be sufficient.
and shouldn't this be in the projects section of the forum?
Registered Member #1320
Joined: Sat Feb 16 2008, 01:31AM
Location:
Posts: 67
zephir wrote ...
wow, thats just amazing. Good job on coming up with the idea of a multi-stage rail gun. I haven't seen that before. I had a similar idea, but with a 2 stage rail gun instead. How are your rails wired? Do you have four separate sets of capacitors, one for each rail?
And for your rail gun test shots, you should consider a proper backstop if you don't already have one. Your projectile speed is just 90 m/s less of my rifle (710m/s, 8 gram projectile), which I know for a fact would horribly maim someone if I accidentally shot someone with it. You should have a proper backstop behind your wood target, to catch any rounds before you accidentally shoot someone. A large mound of sand or at least a sandbag wall would be sufficient.
and shouldn't this be in the projects section of the forum?
The rails are physically separated in the gun. Each one of those 4awg red wires leads to a 8" copper set and the large black wire is a common ground. The piece of wood by no meens was meant to catch eh bullet it was only used to create a sound spike when the projectile hit it so I could measure the time between the muzzle and the piece of wood. there is a large flood control hill behind it which actually stops the round. Each stage uses 4 of those capacitors which after the charging circuit is unplugged are electrictly isolated.
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5KJ 4 stage rail gun (complete)
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