Halo Style 2 stage COILGUN

[AnselmoFanZero]

Naw I dont like railguns that much. If you screw it up, every shot is like a cannonblast. When you do it right, its almost as silent as a coilgun ^^
Cant stand those set-ups using high pressure as injectors...inaccurate and its cheating imo. EM acceleration....no gas....

 

[StridAst]

Lol, I was thinking rather then shooting a solid projectile to intentionally shoot plasma. Hard on the rails of course. but no need for injection if you are simply putting in a wadded up piece of foil However, cannon blast at the right time of year would be a bonus, not a downside imo.

 

[AnselmoFanZero]

A plasma armature will ruin your rails fast. And: Plasma has no mass. Range would be like 2 feet. A projectile with brushes and proper contact to the rails should work best. Should....proven already....a German guy (making lasers as well...he has made them ALL...DIY...from HeCd, TEA, Co2 to Ruby and Marx Lasers) already fired a slug with mach 1.

Rapp-Instruments

 

[StridAst]

I'm aware that plasma would destroy the rails. Also that it has limited range. I'm thinking more along the lines of fun around the 4th of july (perfect time for fireworks etc) Sure it would require rebuilding the rails constantly, even if I went and bought copper tungsten for the rails it would wear out fast. (and that stuff is rather expensive for rails) However if I did eventually make a railgun, I would be going for flashy and loud, not quiet and long range. But then, I suspect the only time I use a railgun would be around the 4th of july. Though I suppose I could always cast up some aluminum slugs by melting down some soda cans, for actually shooting things, a coilgun seems far more suited to the task.

However it's a long term goal for me. First I have to get a coilgun up and running. (I need to learn to crawl before I run, so to speak)

This is along the line of what I was thinking of
emla-iii-p - futureexperimentalsystems

 

[millirad]

My first stage is now 1070uF and I believe that they charge to about 300volts. (.5 * 300volts^2 * .001Farads) So I calculated ~45 joules. Is this correct?

 

[AnselmoFanZero]

Strid:
Maybe you should check out the electrothermal gun then ^^ its like a freakin cannon....literally.

mil:
Sounds correct.
Another 1000 or 800 or maybe even more for the second stage would work.
I would get a big 150J cap...low ESR.

 

[millirad]

Well, I have gone with a budget approach for now. I obtained 16 Kodak disposable camera bodies free from a local photo dept. They usually recycle them, but were kind enough to allow me to have some of what they had. They will have either 120uF 330v or 100uF inside. ^^ I will let you know what I find. Then I can add 4 more to the first stage for ~1550uF. I should have enough left for ~1200uF in the second stage. ;-) I could get a few more of these camera bodies to reach the 100J first stage and 50J second stage that you recommend.

Also I'm curious as to what would happen if you asked your photo processor for disposable camera bodies? Is it possible to get them in Germany? I know you prefer to purchase larger caps that are low esr for your designs though.

Edit: I have a length of "C" channel aluminum 78" x 3" x 1", and I'll have to be creative designing the frame using it because 3" is a bit too wide. It's not a "hard" alloy and cuts reasonably well with my hacksaw, just slow and tedious.

Another 4 caps were added to the single stage for a total of 1550uF. It was able to penetrate the front of an aluminum can fired at it point blank, with the flat ended 6mm x 3/4" projectile. If it had a point on it, then it might go through both sides of the can. Therefore I have ~70 Joules so far. I will have to add about 5 more 120uF caps to reach 100J, after I get some more disposable Kodak camera bodies.

 

[AnselmoFanZero]

Piercing a can is a cool thing...I am working on a stronger 2 stage pistol as well. 300J in total. 2 bigger caps....maybe I will add another stage for pre-acceleration, because it will be semi-auto.

Those camera-ciruits have not enough power. I would use several of those and make several stages ^^ that would be most efficient I guess.
Actually I will use a bunch of smaller caps to decrease the ESR. In parallel, R shrinks....like regular Rs in parallel.

Post a draft of your design...always interesting to see the ideas other people have.

 

[millirad]

This is a diagram of the basic design I'm going to do..................

 

[AnselmoFanZero]

I would place the batteries in the handle and the first bank in the stock.
I avoid touching the section surrounding the caps ^^ in general. You never know.
And its easier to wrap your hand around the batteries I guess. Even 4 of them arent as wide as the cap bank is.

 

[millirad]

Alternate design...........................

 

[AnselmoFanZero]

Looks as cool as before, but the grip will feel better. Trust me ;-)
My first grips were too big...doesnt feel right.

 

[millirad]

So I have cut out 2 of the pieces of C channel aluminum. The frame is on it's way to becoming reality. I need to get more camera bodies tomorrow. Single stage is up to ~1800uF and almost goes through both sides of an aluminum can from ~5mm away, with the flat ended 6mm x 3/4" projectile. That's up to >80 Joules now. ;-)

 

[AnselmoFanZero]

Sounds good.
But why flat end? File them down...or grind em down. Put em in your driller and torture some sanding paper
A point tip should shoot thru a can like nothing.

 

[millirad]

Yes, you read my mind. I'm now creating a couple of projectiles from .25" mild steel rod. The other projectiles that are flat ended were already made chrome steel 6mm x 3/4" locking pins. But I only bought 5 because they were $0.60 apiece, so too expensive and I have lost 2. This means the inside diameter of my epoxy tubing is slightly larger than .25" . After testing with these shorter 5/8" and pointed projectiles I'll know more about the optimum projectile to use. Tomorrow I'll work on the frame for a little longer. I'm thinking that my next 1st stage coil could be 8 layers/21 awg, for more power. What is your opinion?

 

[AnselmoFanZero]

The first stage is very inefficient. I am making a 350J pistol...60J for pre-acceleration. Stage 2 and 3 120J each...
Only a matter of pulse-duration. But I will try some things and post them.

Probably on a new thread. The next one is a bit different. Semi-auto...bigger but better balance...at least I hope for better balance. Holding 2kg straight on target burns after a while ^^