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Registered Member #485
Joined: Sun Jul 09 2006, 01:14AM
Location: San Francisco
Posts: 36
currently i have have 2 scrs so i am limited to 2 stages. the caps i have are 4 400v 3900uf and one 450v 2400mdf (same as uf right?) i need to make a new barrel and was wondering about what size and material i should get at the local store i saw copper and galvanized steel and pvc i think the pvc is out of the question because of the thick walls for the metal i can cut a line down to reduce eddy currents. and then the projectile size will depend on the barrel
Registered Member #95
Joined: Thu Feb 09 2006, 04:57PM
Location: Norway
Posts: 1308
At those power levels and capacitances I would go for a large projectile. The pulse time will be long, so a small/light projectile would be in the target before the current even gets to peak. And anything small would just saturate in no time. I haven't seen it done before, but try a heavy (100 gram like) projectile. That should give you efficiency and power to smother soup cans. Even a meager 1% efficiency would move 100 grams to 15m/s. After all, isn't a coil cannon more fun than a coil gun? Personally I would go for PVC, but I don't know if it comes strong enough or thin enough, so you'll probably have to use metal. The less conductive and magnetic the better, as eddy currents will become a problem. I'm not sure about barrel size, but maybe you should suit it to fit your projectile?
Registered Member #95
Joined: Thu Feb 09 2006, 04:57PM
Location: Norway
Posts: 1308
I don't know either. Just look for something big. You could try a long rod, but that would also require a long coil I think. I've never tried a projectile longer than the coil, so it might work just as well with a shorter coil. A coil longer than the projectile isn't good though.
Registered Member #191
Joined: Fri Feb 17 2006, 02:01AM
Location: Esbjerg Denmark
Posts: 720
its not really that high power, i had a 200J single stage firing 3/16 dia projectiles that weight less than 4 grams. quarter inch should be a good value to start with for you. and coils should be the same length or slightly longer than the projectile for better coupling.
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new coilgun q's about barrle and progetile size
Even a meager 1% efficiency would move 100 grams to 15m/s. After all, isn't a coil cannon more fun than a coil gun? Personally I would go for PVC, but I don't know if it comes strong enough or thin enough, so you'll probably have to use metal. The less conductive and magnetic the better, as eddy currents will become a problem. I'm not sure about barrel size, but maybe you should suit it to fit your projectile?
Just look for something big. You could try a long rod, but that would also require a long coil I think. I've never tried a projectile longer than the coil, so it might work just as well with a shorter coil. A coil longer than the projectile isn't good though.
