Electronic Gun shoots .375" round ball.

[BigBoy1]

Perhaps the lack of a reply results from the person's tinfoil helmut being untuned from the passing UFOs.

[BillC]

I would bet we will never see a drawing on this project he does this on PM site also.

[motorcyclemac]

That is the funny part about the internet. Folks use the same screen name and then scatter crap about like that.

I have nothing against using the same screen name...I do that myself. It is almost funny how a fellow like our ballistic engineer figures that no one will notice the same act on another site.

Cheers
Mac.

[xarlock667]

I came across this thread when I was researching the site looking for help last night. It was part of what made me join the forum.

There are a couple of misconceptions I noted that I might be able to clear up. I have studied physics a bit, and railguns in particular (Would love to build one, but lack the funds.

First, the power to a rail gun must come from capacitors. The power wave must be digital, and not analogue, or you will have **** for results. The wave must be a square, or a sudden charge, or the projectile will roll out of the barrel instead of fly. The reason for this is that only while in contact with the rails does the projectile accelerate.

Second, Batteries are great for charging capacitors, and most will be fine for that purpose, it just becomes a question of charge time, and who many shots you can get out of one. If you doubt the power of a battery and capacitor, I invite you to try the fun experiment of touching a live taser or stun gun. Most of the old ones ran on a single 9v battery, and put out 50kv or better.

Third, while you can make a rail gun fairly easily, the problem is that 50kv hitting a metal object tends to fuse it in place. A lot of rail gun enthusiasts have opted for using injection as a means of making the projectile fire, as it is less likely to fuse if still moving.

If you want to build one, this is the base pattern:
Take 2 metal bars of equal length, and preferably good conductors. Seperate them by an equal distance, parallel, and bolt them in place to a nonconductor. (I have heard of plexiglass being used, but do not quote me.)
Hook your power lines to whatever end you want to be the rear, and then drop in your projectile. Hit it with your power source, and it will either:
a) fuse in place;
b) rocket down the rails and hit something;
c) catch fire; or
d) short out and blow up the capacitors.

The thing to remember about these things is that they are dangerous from several angles. **** loads of voltage, heat, an open circuit, and a high speed projectile, all in one little package. It might be better to give your enemy a kit and let him kill himself!

If anyone has the spare time and parts to build one, please post a vid or pic.

If you are good (I mean really good) at math and you want to know how strong it will be before you fire it, then the force equasion is:
f=bild/m^2
f=force
b= strength of the magnetic field in telsa (1kg@1m)
i= current measured in ampres
l= Length of the barrel
d= width of the barrel (distance between the 2 rails)
m^2= the weight of the projectile squared.
This formula was taken from "Principles of physics for science and engineering" by Brown if I remember correctly. It is one of the Schaum's Outlines series.

[Forestgnome]

Xarlock, I suspect many of the members here understand rail guns. Don't underestimate the knowledge base of the members here. The OP wasn't really talking about a rail gun, which is what you described, but was talking an electromagnetic or solenoid gun. Rail guns don't shoot plain steel balls. The good ones can shoot a plexiglass slug through plate steel though.

[xarlock667]

A rail gun can shoot anything that conducts electricity, where did you see it shoot plexiglass? Can you post a link?

Aside from that,

I have been playing around with electronic magnet railguns for years just for fun so I finally got serious and built a real nice gun.

He did actually specify rail gun. I am not meaning to imply that anyone here does not know what they are doing, I am just a newbie machinist, but I know railguns fairly well. Some posters I will not quote specified using a drill's batteries, and some said a battery lacked the power to get the job done. I just clarified that capacitors were an integral component, like an engine in a car, or it won't go. Aside from that, the posters were all right on. I had a few issues with his post as well, how did he avoid welding his balls to the rails? How did he get past the friction wearing down the rails every few shots? How did he get enough capacitors in series to push a ball that size to that velocity, with enough inertia to blow a hole in 2 pieces of wood? I have seen them built, and used, but not with that much power.

[Forestgnome]

Generally railguns work by first developing a plasma, which is what actually gets accelerated, pushing the projectile forward. To create the plasma a sacrificial conductor is placed between the rails. In the case of the plexiglass, a layer of aluminum or copper foil is attached to the rear of the slug. If you were using a steel slug, it would arc and by not fully vaporizing, would weld itself along the ways slowing it down.

[xarlock667]

Ok, so the plexiglass is used like a sabot round, with an aluminum coating that flashes to plasma, and then it just rides the plasma wave out the end. That would make for a LIGHT projectile, and shotloads of velocity!

I have seen steel shot (BB's), copper shot, aluminum, lead, and various metals. In the case of poor conducters they typically use an alumimum armiture as it flash a low flash point, and will protect the projectile, but I did not know the projectile could ride on top of the plasma though! That makes things much cheaper.

OK, I have decided to build one. I found some plans that make the thing reasonably cheap. It will NOT be big, or fancy, but it will be able to at least kill a rabbit, even if I have to toss it onto the rails. Fried rabbit anyone? If I don't eat it, my wolf will.

I can get suitable capacitors from a disposable flash camera, and I can scavenge rails from somewhere, though I am not sure on that. I have ****LOADS of batteries in my house, (Lots of 360 controllers, and they eat batteries for breakfast) so that is not an issue. I have some 2x4's left over from a construction project that are rigid, and non conductive. And I have a couple fire extinguishers for when the thing catches fire and burns to the ground. This is going to be FUN!

What is a good conductor to use to make the rails that can be easily scavenged? Any ideas?

[xarlock667]

Ok, I may have found something for the rails, I have a couple of 440 steel sword blades that broke off their handles way back when. No one will miss the blades, and so I won't have to listen to my sons whine. Besides they will have fun with the rail gun too.

I will start a new thread when I start, and post lots of pics and maybe a movie or two.

[CLARKMAG]

15 years ago when some Space Defense Initiative [Star Wars] hardware was auctioned off, I know someone who got some rail gun capacitors.

If you were a big time defense contractor, you probably got the tour of the rail gun and saw a spinning Copper disc that was the power supply.

This must have been plan B surplus.

After some rail guns and then steam guns, the hardware found it's niche, shrinking coins.


Shrunken quarter, next to a regular quarter, using surplus rail gun hardware.