Interesting Coil Gun results

[WilliamN]

Searching the web I found a bunch of coil gun sites. I built a few small ones using what I had laying around. To my suprise I achieved the best results with the smallest diameter magnet wire I had (30g) Most people on the net say to use 18-22 gauge. My coil consist of 10 layers, 100 turns per layer. I used a small diameter coffe straw as a barrel. A bb just fits. I then replaced the weak capacitor in a photoflash circuit with a 400uf 650v Elec. capacitor. A SCR handles the switching. When I fire on full charge the thing will blow a hole through a coke can. Why? I wasn't expecting this kind of power with a single stage(especially my first one). Why would the smaller size wire give better results. If anyone can explain this it would be great!

 

[spuffock]

When I was playing around with coils and caps, I was using a coil of about 100 turns and a couple of 39uf 8Kv capacitors. An aluminium ring from an old hard drive placed on the end of the coil was repelled with astonishing force, but an old spanner was only thrown weakly. It seems that there is a conflict between the repelling effect caused by the current induced in the projectile and the magnetic attraction of iron. I would suspect that a number of slots cut in the projectile would reduce the induced current,and allow the magnetic effect to be more in evidence. Try chucking a bit of ferrite! The coils you are using with many turns will have a much higher inductance, and the accelerating pulse will last much longer. The current in the projectile will also be much less. Hope this helps

 

[tansis]

https://www.pskovinfo.ru/coilgun/indexr.htm

You may have seen this site allready if so my apologies, if not..