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mini railgun - micro plasma rg

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Plasmaniac

Mon Jun 26 2006, 12:23PM

Registered Member #206 Joined: Sat Feb 18 2006, 03:17PM
Location:
Posts: 72

I finaly finished my mini railgun project. Here some pics:

Here you can see my capbank. It's 33mF 400V (the caps are from '81 to '83 but I've got them for free

) and the charger draws more then 10A

I had huge problems with my old 3x15mm aluminium connections, so I've made some chopper busbars from 15mm cu-pipe yesterday... my ass! 30 times I had to torture my vise and my hands by pressing that tube together... I had to diassamble and repair my vise, but I really think it was worth all the pain.

This is the rg istelf. It is double series augmented and and should stand much more than my crappy 2kJ bank. Maximum projectile height is 5mm, maximum width is 10mm. I stopped using projectiles like the one you see on that pic. Now I use aluminum foil or chopper brushes.

This is my spring injector. It doesn't make the projectile travelling very fast. I just use it because I've blown my puk scr

During a plama shot, the out-travelling plasma let the bank discharge between the supporting aluminium plate and the augmentation's wire. I've fixed it with some tape

Now some shots:

A projectile with cu-brushes. You can see why I've made the chopper busbars

Just some aluminium foil and a piece of perspex in front of it:

And this it how it looks like when I try to shoot through the bottom of a can with one of my perspex/aluminium foil projectiles. The Bank was charged to 350V and I also might use more aluminium foil (it vaporised completely). Though, I had to pull VERY hefty to get that projectile out again. As you can see, I've used the can for my 500J can crushing tests before

I think I can still improove my railgun or maybe try other projectiles, whereas I really think aluminium foil and perspex projectiles are the best way to go, especially for my rails... They even blewn away the chopper oxide which I've had between my rails after some chopper brush projectile shots

Plasmaniac

Tue Jun 27 2006, 08:23AM

Registered Member #206 Joined: Sat Feb 18 2006, 03:17PM
Location:
Posts: 72

My parents are away so I'm torturing the can again:
]aluminium foil + projectile[/file]
just plasma (some aluminium foil)

Heiders

Wed Jun 28 2006, 05:42AM

Registered Member #268 Joined: Tue Feb 28 2006, 02:44AM
Location: Ontario, Canada
Posts: 48

Looks neat! I don't know much about rail guns, but it looks fun and effective. Good stuff!

McFluffin

Wed Jun 28 2006, 05:42AM

Registered Member #119 Joined: Fri Feb 10 2006, 06:26AM
Location: USA
Posts: 114

Cool! The construction looks very sturdy. For all of the trouble that you had with the bus, it looks pretty good. By chance, have you tested how much the augmentation helps? Can you give a pic of a projectile? I am curious to see how you make them such that the injector can push them and not tear them apart. Are they just a triangle sort of shape? I found that aluminum was nice too. It was building up rather than taking off :) The only problem was that the initial blast was too big. I'd get another SCR to reduce that. They are very reasonably priced for the puck type if it was that type. Its all in the clamps. Do you have a triggering mechanism for it such as a laser?

Plasmaniac

Wed Jun 28 2006, 09:44AM

Registered Member #206 Joined: Sat Feb 18 2006, 03:17PM
Location:
Posts: 72

I've never tested what happens if I shoot without my augmentation because I can't measure the projectile's speed anyway, but I FEMMed it and the results are pretty neat: Around twice the field strengh between my main-rails when I'm using my series augmentation. The augmentaion also works as inductive load (a little...), so current rise is a little "smoother".

You just have to take much aluminium foil

I'm gonna glue a single layer of aluminium foil on my projectile, so I don't have huge aluminiumoxid clouds in my room anymore...

I've bought a puk scr for my railgun and thomson launcher, but I blew it with my thomson launcher cap. So I had to build an injector, whereas I really think even my small injector saves some of my rails chopper, so the fakt that I've blown my scr somehow's good also

I'm going to build a railgun desingned for plasma shots. I was messing around with FEMM for hours and also simulated iron shielding and augmentating magnets. Iron shielding is very critical, because I don't know how much current I will have in my rails. Though, the iron must not saturate. I the iron doesnt saturate, its much better than magnets on your rg. I also don't know how long my rails should be, so I'll just try 22cm, because I still have ~45 cm of 3x10mm chopper and calculate everything using 4kA as current (or should I use an other value?). I'm going to use a flyback to pre-ionize the air between my rails. Maybe I should put some water in there also to increase the thermoelectric aceleration of my projectile.

Plasmaniac

Wed Jul 12 2006, 01:37PM

Registered Member #206 Joined: Sat Feb 18 2006, 03:17PM
Location:
Posts: 72

Ok, I finally tested my micro plasma railgun. No aluminium foil, no wire, just some plasma made from air. The rails are 3x10mm, 5mm space between them, 5mm thick perspex and a trigger electrode that is made from 1mm tungsten is in the railgun's closed back.

Before:

After:

Surprisingly, the rails' last few cm are damaged most. I need some thicker perspex and longer rails.

I think I gotta build a nano plasma rg now

Madgyver

Wed Jul 12 2006, 06:02PM

Registered Member #177 Joined: Wed Feb 15 2006, 02:16PM
Location: Munich, Germany
Posts: 214

The Problem is, that the holes are to close. The holes inthe rails facing each other weaken the structure, by implying large stress peaks (Spannungspitzen) around them (in between would be the maximum).

Use pieces of bigger width and place the bolts farther apart.

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