Date: Sun, 12 Dec 2010 11:40:51

Author: Rueckner, Wolf

Subject: Re: Simple Rail Gun

Post:

What a bank of capacitors ... really scary!! I'll try and duplicate it tomorrow in the shop :-) Wolfgang



________________________________________
From: tap-l-owner@lists.ncsu.edu [tap-l-owner@lists.ncsu.edu] On Behalf Of Paul Doherty [dohertypm@gmail.com]
Sent: Sunday, December 12, 2010 2:55 AM
To: tap-l@lists.ncsu.edu
Subject: Re: [tap-l] Simple Rail Gun

You want a railgun?
Here's a railgun

http://video.foxnews.com/v/4454912/navy-tests-electromagnetic-railgun/

Mach 7

Paul D



On Nov 18, 2010, at 1:15 PM, david kardelis wrote:

Your right, it doesn't reverse with reversing the current, So it must be working off its own B field. Although, I vaguely remember doing it in the past and reversing the current reversed the way it moved. I can be imagining that, but I remember doing RHR stuff in front of the class and then turning it on. Might have been a different demo.

Conduit spot welded, Aluminum arcs/splatters but does not stick. Will try copper In near future.

dave

On Thu, Nov 18, 2010 at 12:16 PM, William Beaty > wrote:
On Wed, 17 Nov 2010, david kardelis wrote:

Adam asked about my rail gun.

Simple setup, 2 3/4" aluminum rods on the table about 1/2 meter apart, Third
aluminum rod laid on top. B field comes from the earth.

Cool! I'll try 3000 Farad capacitors on this. Does it suffer from spotwelding to the rails? Maybe it only works within a certain window of (high) Amperes.

BTW, at high enough Amps, these classic railguns require no external field. The "bullet" always moves so as to increase the area enclosed by the current. Or see it as the field of the "bullet" interacting with the field of the rails. Reverse the current and the motion doesn't reverse. Turn it in different orientations, yet the motion doesn't reverse. In theory, a loose floppy cable should expand into a rigid ring, if given high enough current. It's the opposite of the pinch effect with parallel currents.


Also these railguns triggered off some controversy over the location of
the reaction force. I don't think it ever was resolved...

http://adsabs.harvard.edu/abs/1987JAP....62.3006G
http://iopscience.iop.org/0022-3727/20/3/023/pdf/0022-3727_20_3_023.pdf






http://s366.photobucket.com/albums/oo108/dkardelis/Rail%20Gun/
?action=viewĄt=003.mp4



I tried using conduit this morning, to see if *could get a longer *run, and
a lighter "bullet". The conduit just welded itself together when I flipped
the switch,

dave


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William J. Beaty SCIENCE HOBBYIST website
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