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Bolt action coil gun

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How does it sound?

Total votes : 2
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Bolt action coil gun

Unread postAuthor: Tom » Tue Dec 11, 2007 1:11 pm

I´hm desgining a coilgun that has a springmagazine feed, the reloading is bolt action. I can make a semi-auto coilgun with a homemade solenoid, but it will take of to much power because it uses a part of the energy that´s generated in the coil. Further I still not now what the best configurations are, but I will base the desgin on a M4 and a AK-74.
I will use the stock to carry the batteries and the capacitors, I still don´t now what kind of capacitors and charge circuit I'm going to use. I'm still looking for information and doing some tests. So far I made a coilgun from a disposable camera, the results where a bit demotivating for me but my science will help me out(hopefully). I will post some pictures about the breech loading and desgin. If anywhone knows something that might help me please comment!!!
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Unread postAuthor: Ragnarok » Tue Dec 11, 2007 1:27 pm

Solenoids for semi auto could be run straight from the batteries. However, charging times on coilguns tend to be at least a couple of seconds if all is well, usually more, so there won't be enough capacity for ROF to need semi.

I suggest you should do some heavy research prior to starting, and http://www.anothercoilgunsite.com/ would be a very good place to start.
I'd also suggest reading the wiki and forums at http://www.4hv.com/

You're unlikely to get more than a few joules out of a coilgun, don't expect much power. A reasonable multistage coil gun might be anywhere up to 10 joules, and that's not exactly a lot.

You need high quality capacitors, and a good charge circuit.
Computer grade caps tend to get destroyed, and camera circuits are only good for tiny capacitances.
To get any power at all, you'll need at least 100J of capacitors, at 300V or more (higher is better, but more dangerous), controlled switching, and multiple stages.

A ZVS flyback driver running a transformer in the right sort of range for your coilgun would be a good power source, but be warned, they can kick out enough power to kill.
You can also use a boost converter, but the efficiency on those lowers as you step up the voltage more.

Last but not least, I wouldn't advise building it in the shape of a known firearm. That's risky, and provides size limitations which won't favour an efficient design.
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Unread postAuthor: TurboSuper » Tue Dec 11, 2007 8:00 pm

Well, if you want amazing power... i'd say stop right there, coilguns are generally not very strong unless you multistage them like Ragnarok said, and that takes some precision designing.

If you just want to plink nails across the room, then you could just charge up multiple capacitors and have them discharge one after the other, that way you could avoid having to wait between charges.
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Unread postAuthor: jimmy101 » Wed Dec 12, 2007 12:07 pm

Like Ragnarok and TurboSuper said, you probably won't be impressed with the performance.

It is easy enough to make a coil gun that works. But, you have to spend a fair amount of money and time to get a coil gun that will fire a given projectile as hard as you can throw it.

A bolt action with a magazine would be cool but you'll have to take into account the the performance of a coil gun is very sensitive to the starting position of the ammo and different ammo will have different optimum starting positions.
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