Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!udel!rochester!dietz From: dietz@cs.rochester.edu (Paul Dietz) Newsgroups: sci.electronics Subject: Re: How to make a RAIL GUN? Message-ID: <1991Mar24.211121.6669@cs.rochester.edu> Date: 24 Mar 91 21:11:21 GMT References: Organization: Computer Science Department University of Rochester Lines: 30 In article jon%vector0@sactoh0.SAC.CA.US (Dazed N. Confused) writes: > Hi. I was talking to a friend about a Rail Gun --- a device that >through magnetic induction is able to fire an object at enormous >speed. I was wondering if I could build a scaled-down model. Whoa! You are confusing rail guns with electromagnetic launchers in general. A rail gun is a one-turn linear DC motor. Current flows up one rail, across an armature on or behind the projectile, and down the other rail. Rail guns are high current, low voltage devices. Perhaps you are thinking of a coil gun. In one kind of coil gun, a coil in the projectile is energized and accelerated by electromagnetic induction from stator coils. Quite a different concept -- no sliding contact is necessary. The drive coils can have many turns, so coil guns can be higher voltage, lower current devices. You can build a crude toy coil gun by making an iron core solenoid and placing an aluminum ring on one end of the rod. When AC is fed into the solenoid the aluminum ring will shoot several feet into the air. This is a standard high school demonstration of EM induction. You might also try driving the ring with a short current pulse from a large capacitor fed into a planar stator coil. For details on many different kinds of EM launchers, see IEEE Trans. on Magnetics. They occasionally have special issues containing the proceedings of the Electromagnetic Launch Conference. Paul F. Dietz dietz@cs.rochester.edu