First 12kJ railgun shot

[rp181]

my simplified theory: http://rp181.wordpress.com/railgun/railgun-theory/

[McCoytheGreater]

Nifty. I'd love to make one one day, but I'd have no clue where or how to get started. I'll leave that to theLesser. Is that a teflon type plastic you're using before the projectile hits the rails?

[rp181]

yep, some .125" thick teflon strips.

[paaiyan]

Forgive me if this was answered elsewhere, but what exactly was the projectile?

[psycix]

Cool, ok, can anybody explain how these things work, I know there is something to do with an electromagnet, but I really don't understand what's going on there...

Short explanation:
Current flows through projectile and rails, current causes magnetic field, which in turn causes a Lorentz force and projectile goes flying.

For more information,click here.

[rp181]

The very bottom one. Note the aerodynamics on these SUCK. Working on a sabot.

[paaiyan]

Oh I see, so it's actually using the projectile itself to complete the circuit. Now it makes more sense.

It's been too long since I've been around. You guys have come up with all kinds of new playthings.

[DYI]

I still contend that it would be worthwhile for you to build a good mechanical switch or trigatron rather than continuing with injection switching. Doing so would allow you to use a very well fitting projectile, eliminating the problems with alignment on entering the rails and probably a good deal of the arcing.

Until you get a better fit, all you're doing is chewing through rails and making noise.

Congratulations on finally firing it though

[maverik94]

Oh wow, that is simpler than I thought. Thats amazing that an electromagnet can do that!!! How does this differ from a "coilgun". (I've heard of these but i'm not sure exactly what they are)

[jackssmirkingrevenge]

How does this differ from a "coilgun". (I've heard of these but i'm not sure exactly what they are)

Same magnetic principles but oriented in a different manner

[rp181]

@ DYI: yes. I found my stash pile of copper, so Hopefully I can melt them down and cast two electrodes within the next two weeks.
@JSR: Actually, Its opposite magnetic principles. coilgun's use magnetic attraction and ferrous materials, railguns use magnetic diamagnetism and non magnetic projectiles.
Railgun's win, you could shoot anything: [youtube][/youtube]

(provided the frog doesn't vaporize...)

[paaiyan]

I would stay away from the frog. Spudgunners and frogs tend to not mix well....

For those of you who remember what I'm referring to, bonus points.

[rp181]

oh yes, forgot about that...

the point is its not as limited

@DYI: I think I am going with a trigatron, 2" facing side. The back will be 3", and the whole thing .5" thick.

[maverik94]

Ah I see, very interesting....a bit too complicated for me though, I've built an electromagnet for a homemade telegraph set (lots of fun to play with) once, but I think this is a teensy bit more advanced

[jackssmirkingrevenge]

Actually, Its opposite magnetic principles.

Fair enough, I might have oversimplified the science

For those of you who remember what I'm referring to, bonus points

Who could forget?