Halo Style 2 stage COILGUN

Wait a sec. Longer barrel? What for? You should reduce friction...only as long as needed!

How many Joules energy-storage do you have in total again? You said you had to change a few things...

Now I am excited how it looks when its completly done! ^^

Just 2010uF for .5 * 300volts^2 * .002Farads is equal to 90 joules. I have room for two more 120uF caps and I think that will get me to 100j. I'm not sure if the 8 layer coil was better than the 6 layer coil for my circuit. It didn't seem to be quite as powerful. .5 * 300volt^2 * .00225Farad = 101.25 Joules. I think this is where I want to be and with a six layer coil, not an 8 layer coil.

More power is never a bad thing ^^ even if its only 10J more.
Finish the thing and make a video!

I would try another barrel and slightly smaller projectiles...btw how much do they weight?

I don't have an accurate scale but whatever a pointed .25" x 1" steel projectile should weigh. I had to wind 3 coils before I was happy with the power of length, number of layers etc. But now I'm happy with the results. I have been using 1.5v non-rechargeable alkaline batters so I will purchase some 1.2v nimh recharchable batteries, and put them in parallel to get enough charge power. They seem weak a 1.2v instead of 1.5v for alkaline.

You have to calculate the volume. Density of steel is somewhere around 7.8g/cm³...you will get gramms out. No idea what units you have over there to measure smaller weights ;-)

Cant wait to see a video. ^^

I am in the process of adding 2 more 120uF caps to the capacitor bank. I just need Mooooaaaar POWER.

I would go for new flash caps 12uF 350V ^^ 50 of them...80 cent each maybe...300J ^^ BAM

Ok so I have 2250uF on the first stage, so I believe I am over 100J now. I'm locating some rechargeable batteries because I have used up over 60 non-rechargeable 1.5v alkaline batteries while getting everything to work. At least they were the free ones from those disposable Kodak bodies. I can puncture both sides of an aluminum can from 4 feet now, using my new .75 x .25 inch projectile which has a sharp point. After getting everything the way I want I will post a video(It will have a "charged" light on the exterior of the chassis). Maybe Tuesday night. I'm considering building some reuseable darts that have a short flight and sharp point. ^^

Well, I've been somewhat following this thread and now I'm convinced to build my own coilgun(s), just single stage to start off with. I've still got a lot of reading to do though, but I gotta say that both of you guys' guns look really good so far.

Thanks for following this thread. It has been a lot of fun. I have just internalized the barrel to the inside of the charging board enclosure. This was so I could mount some sights and or laser to get the projectile to hit an object at ~ 50 feet. Long range accuracy is not an option without higher powers.

@Anselmo
I just need my cap charger now..

@Prototype
I can help you if needed. I'm a begginner but I've read lot
you can get useable caps from PC PSUs and CRT monitors.. the wire I'm using is from a MOT (microwave oven transformer)... the thick one works very well!

I think I'll start small with the first one. Just a few disposable camera caps or so at first. The project I have in mind will use many much larger caps, I can't wait.


I found this last night looking for some really powerful capacitors on eBay, but I think that might be just a tad bit overkill :crackup:


Edit: @Leodashan, thanks for the offer. My main project will be using some caps from a large UPS, they're very high quality and very well priced.

Welcome to the thread! When you get your build going, please post some pics.

@Millirad
I'll build a coilgun too.. Nice to meet you!

I've never done a build with a disposable camera.. The results are somehow mediocre for a first timer, you can get annoyed and don't build anything more then. I still recommend getting a CRT and removing the two big caps, 400v 220uF looks very good.

You will need a high discharge, but some people said the better results come in 200 to 800v caps. 300kv is too much, will fry your coil, your projectile and probably YOU..
you need to check RLC simulator and Inductor simulator (need java). You build a coil in inductor sim (something doable pls, nothing like 31390413058²-5 turns) and put the resistance and inductance of the coil on the RLC simulator, together with your caps and capacitance. That will give you the peak current on the coil.. as anselmo teach me: You need a big spike up and nothing down (to remove suckback, when the projectile goes forward and comes back because of the BACK EMF). As you may already know, coils store energy, so when you discharge a caps there it pushes the project forward, and the unused energy goes back on the caps.. with reverse polarity. That damages the caps...

any questions post here, I'm sure millirad, anselmo or me could help!

Ahoihoi
Wow...so many replies.

Leo: Your charger? Will take some time to make some of them. Tell me asap if you need anything.

Prototype: I would aim for 250-350V for the beginning...but I would make it at least 2 stage. Ask milli...its worth the effort ^^

Coilguns havent to be portable...a nice desk-top coilgun can be cool as well.

@Anselmo

I want a portable one.. I have everything (the SCRS were working.. the owner of the store said it is KAG not KGA as I was testing.. wrong polarity ^^) even the two coils, I just need the leds and photoreceivers (for the 2 stage controller) and the cap charger. I wanted a 400W one (I would use a 30C battery, 500W capable, RC Model) but I don't think it exists.. 4hv didn't helped me a lot)...