Anyone into Coilguns??

[cwazy1]

Heres mine:






its not very powerful right now because its running on two 12v batteries set in a series. i do not fully understand electricity yet and i wish not to electricute myself with 800+ volts using caps. It shoots a 1"x1/4" metal slugs about 3 feet. zero charge time, and perfectly silent. i plan on adding capacitors this winterbreak so it should be more powerful by then around 80fps in hoping.

anyone else into this type of stuff??

[Eddbot]

i started to make one then kinda grew away from it when i started building a pneumatic, still got the parts layin around though

[BigGrib]

dude that thing is pretty cool, I've never built one but I have always been interested, tell me about the coil wrapped around around the "barrel" what kind of wire did you use ect.

[cwazy1]

Eddbot: ahh, haha i did the opposite of you, i built all my cannons, got too cold, moved inside to quite propulsion..lol

BigGrib: thanks =) the way to build it is pretty simple as long as ur not getting into caps and all the things you can calculate..lol. the coil that is wrapped around the barrel is called magnet wire. all it is, is a copper wire that is enamel coated. its kinda pricy and hard to find. it sucks, but online places have plenty.

i just found 2 small 12v batterys!! i wonder if they have the same power.

[jackssmirkingrevenge]

Go to this site and scroll down for some very impressive inspiration:

World Coilgun Arsenal

[cwazy1]

oh yeah been there, thats a good place to look at only hand held ones, im more of a table top type.lol. and on the personal sites, they rarely tell you they build it. so i usually go onto a coilgun forum and ask there.

[spudgunnerwryyyyy]

Are these similar to rail guns cus my friend built this crazy powerful magnet for this kind of thing.

[Hotwired]

Besides both using electromagnetism to shift the projectile, not really.

One uses coils to give a pulse/pulses of energy to the projectile, the other accelerates the projectile along two energised rails.

[TurboSuper]

Well, I had a little coilgun a while back, but the flash circuit driving it broke and I didn't have another

Buut...one day, I'm going to rebuild it with a homemade driver that can handle extensive use.

Edit: This is the design i'm going to be using, not sure if it will work, though:

http://www.putfile.com/pic.php?img=7024358

[jimmy101]

How do you control the length of time that the power is turned on? Simply by pushing and releasing the red push button?

The first one I made used nothing but the parts from a toaster, indeed, it isn't even really modified, just the electronic guts of the toaster, even the launch coil is from the toaster;

from here (Crappy Earthlink web site that is down as much as it is up.)

Here is my second. A better, but still not great, design. It includes a way to monitor the discharge of the main power cap and has a muzzle chonometer.

[cwazy1]

spudgunneryy: what hotwired said, and also, amateurs dont tend to build rainguns because of their complexity and huge funds required =P

Jimmy: yeah the toggle is my main on/off and when i fire, i just time how long i hold down the push button trigger. its pretty inaccurate but i've played with it enough that i kinda got the hang..lol (low tech ftw!!)

[Hotwired]

Mmm... 15,000 VAC batteries 8)

Can't help thinking a lead acid battery with that voltage would be bigger... and produce DC

[cwazy1]

haha 15,000vac batterys would kill. . . pun intended.

[JDP12]

i want to build one really bad, been doin some research into them.. Here's a really nice one, very cleanly built

http://www.thinkbotics.com/military.htm

[jimmy101]

i want to build one really bad, been doin some research into them.. Here's a really nice one, very cleanly built

http://www.thinkbotics.com/military.htm

That is a pretty cool coilgun. But, using 8 AA batteries I wonder how many times it'll actually fire before the batteries go dead?

Lets see if I remember all the correct conversion factors...

The capacitor pack is 1000V at 600uF. Total power in the cap's is (1/2)cv²=300 Joules

A single brand new AA battery is about 2000 milliamp*hour at 1.5V, which is 3 watt*hours which is 10.8KJoules. There are 8 batteries so the total energy in them is about 86kJ.

So, the battery pack will fire the gun about 86KJ/0.3KJ = 290 shots. (YMMV, and I'm pretty surprised that it should fire that many times on one set of batteries!)

How fast might it fire a projectile? (Note that the linked page doesn't quote muzzle velocities.)

Figure a coil gun is 1% efficient, that means the projectile will have a muzzle energy of about 3J. Assuming a BB as the projectile (mass= 0.34g) and using Energy=(1/2)mv² we calculate that a BB might be launched at 133m/s (436 fps). Not too bad, but a $40 BB gun will out perform the coil gun.

Coil guns have huge bling factor but they are really crappy ways to get a projectile up to high velocities.

EDIT#1: speeling and engrish