Coil Gun

[yorgie]

And...wont be classed as any form of firearm!!

what i was thinking. Surely all it'd need is a massive capacitator, a massive circuit breaker, and a very large source of AC current (i will not use mains!)

All i'd need to do is find a non conductive core (pvc piping), copper wire as a coil (do you think it'd need to be insulated, or bare?) something like chipboard to hold it all on, and projectiles (steel bolts, or ball bearings).
I think a lead acid car battery would work as a suitable power source. I read that the idea is to pump as much energy through the coil in a short period of time, so all i'd need to do is pump up the volts, for short periods of time. It's like building a solenoid, but with LOADS of current and pd- and the pin not returning

 

[Skeet]

If you want a massive capacitor...you cant go to far wrong with teh In Car Entertainment business...i once helped build a system, that had half the capacitance of teh entire planet...3.5Farads!! (Earth has a capacitance of around 7 Farads)

http://www.dvbcaraudio.co.uk/product/Campower_1.0_Farad_PowerCap_(with_terminals).html

 

[yorgie]

that is fairly large, i will probably have to get my hands on two high cap capacitors. as for an AC current, how about a 3 stage power suply?

and the ones above are powerful, but pricey!

http://www.caraudiodesign.co.uk/product_info.php/pName/pyramid-rdcap15-15-farad-high-performance-digital-power-capac/cName/-power-capacitors
that's better - the curcuit breaker will need to be pretty hefty too i imagine. :|


ok i just found this http://www.maplin.co.uk/Search.aspx?criteria=N22BX&DOY=13m8
it's a 4.7F capacitor for under £2 - electric chair anyone that'll do the trick - i can probably get 10 of these puppies, and put them in series, i'll need some thick concrete to shoot this at - the velocitie's going to be rediculous

 

[Skeet]

http://images.google.co.uk/imgres?imgurl=http://www.powerlabs.org/images/rail_gun.jpg&imgrefurl=http://www.powerlabs.org/railgun.htm&h=522&w=860&sz=151&tbnid=EkoK_x6mqJmtiM:&tbnh=87&tbnw=144&prev=/images?q=rail+gun&start=1&sa=X&oi=images&ct=image&cd=1

Looks just like teh kinda thing you can nock up in a weekend mate

Looking for 100,000Amps of power matey!!

 

[yorgie]

i was thinking more of making a coil style gun - railguns require a lot more work, and will need far more than a bored afternoon.

I will not need as much work or power as that guy - wow, that thing looks kinda powerful , wouldn't want to be near that when it fires - at least not infront of it

although from his calculations, it appears i could get a fair ammount of stored power in those super capacitors, and they're only £2 each so if i could get my hands on arround 15 or so, i'd have 70.5F - whereas he has 201, so i'd only need arround 200V - hello mains - any idea what kind of curcuit breaker i'd need, it must be AT LEAST 1MA, just from what i've done as rough numbers, but that seems a little small- although it is arround 500 more powerful than a home breaker.

oh yeah, almost forgot to say, that'd be 720V of dumpable energy, which is arround enough to power a house running off of a cell, which'd be released in split seconds - wow, this is really going to heat up, i'm not man enough to water cool it though :/

 

[Skeet]

Yeah...but...surely...surely..common sense tells you, that if he is using caps taht are teh size of a coke can...you would need to as well?

Is it not about how much energy they can store, and how quick they deliver it?

Heres a big one!!

http://www.military.com/soldiertech/0,14632,Soldiertech_RailGuns,,00.html

Cool it with Co2

Also...he states that, to prevent teh projectile from welding to teh rails, that it has to be moving pretty fast before it gets accelerated.

Let me look at coild guns if I can find them.

 

[Skeet]

http://www.coilgun.eclipse.co.uk/electromagnetic_pistol.html

Certinly looks fun!

http://www.coilgun.eclipse.co.uk/index.html

 

[yorgie]

this is going to be a lot of work. I know my dad (engineering degree) made something similair to a rail gun, but it only accelerated sheet metal to arround about 20mph, which hovered between two charged plates, but in order to shoot something up to these rediculous speeds, to prevent huge overheating issues, it'll need to have at least 2000 coils i think, and so i need to use a non conductive tube design (thin plastic, such as pvc), i could use something like a 3inch pipe, as i could also use co2 to cool the entire thing by wrapping it in say ... a 5inch tube, using some bondo, and making it airtight, so i can run co2 through it, putting a dump valve on the muzzle end.

As for dumping electricity, i'm sure that if i can get arround .... 30 capacitors, i could run arround 141F, or if i upsize to running 2 capacitor beds, or arround 22 in each, i could run off arround 206.8F - marginally less than the large "rail gun" n the above link.

as for the links above, i could run it off of possibly 2 lead acid car batteries, with diode circuits converting DC to AC, but i doubt that'd be enough PD- we need more power!!!

 

[Skeet]

http://en.wikipedia.org/wiki/Coilgun

 

[Strawb]

As skeet has pointed out a rail gun would be almost impossible to produce (unless your willing to invest silly amounts of time and money), however a magnetic cannon is slightly more achiavable (Probably still not cheap though).

The idea was mentioned earlier, a plastic tube with coils of wire placed along it. The idea is you need the first few coils close together and have them gradually spaced farther apart so the projectile is accelerated down the tube.

By far the easiest way to fire the coils is directly off a 3 phase supply, that way you just need to get the phase rotation right and the coils will energise in turn.
Obviously you won't have access to a 3 phase supply (Really only possible in a factory or some farms).
Watch yourself though as 3 phase hurts!! 415V instead of your normal 220V.

It could probably be done using car batteries and capacitors but you'll need to figure out some sort of switching circuit to energise the coils in turn, any difference in the switching time from one shot to the next will cause massive velocity fluctuations.


A few usefull tips to save you wasting your time on a hopless cause.

Batteries are only DC (an inverter can run off a DC source to produce AC)

Capacitors whilst used in AC and DC circuits can only store DC
If you expose a polarised capacitor (electrolytic) to AC (or DC reverse polarity) it will most likely explode. Not a big fireball but the can will launch accross the room and some nasty unhealthy gunk will be released.


AC and DC can kill you, it would only take around 30ma accross your heart to stop it.

Right handed people have a better chance of surviving a shock due to the heart being on the left side of the chest (assuming you get the shock in your right hand/arm). So always wourk with your right hand!