Normal rail guns use little or no shielding for the rails, which endure corrosion from arcing. If argon was used to inject the projectile, the rails would be shielded from oxidation. Some railguns already use gases to inject the projectile, so little modification would be necessary.-- js_530, Jun 28 2004 Railgun.org http://railgun.org/An explanation of railguns, as well as how they built a railgun. [js_530, Oct 04 2004] You need either Iridium or Graphite rails. Iridium won't oxidize, but Graphite won't pit from the arcing.-- kbecker, Jun 28 2004 There's no problem with oxidation, because the argon will be surrounding the rails, but graphite would work.-- js_530, Jun 28 2004 You could inject solid helium along the rails internally, because solid helium are some of the smallest ball berrings you can find. +-- sartep, Jun 28 2004 Helium would be a good choice, because of its low density, the speed of sound is raises, thus the projectile could be injected faster.-- js_530, Jun 28 2004 You said "Coil Guns" and "Shielded" twice and did'nt mention Star Trek, so you get my vote.-- macncheesy, Jun 28 2004 What I love about this place is the way in which whatever field your idea may be in, however far out it may be, there are always many people out there with constructive and informed comments. Unfortunately I can provide no comments as I didn't even know rail guns existed, I thought they were just sci-fi inventions. Keep up the good work.-- wagster, Jun 28 2004 nitpick: coil guns and rail guns are two totally separate beasts.
The problem here is that a cold pressurized gas cannot move through a parallel-walled tube at greater than the speed of sound without additional motive force. (even if it starts out faster, standing shocks will form on every imperfection, quickly slowing the flow to sonic.) Once the projectile exceeds sonic velocity, the injected gas will not be able to keep up. A rifle only works because the gases are very hot, and the speed of sound is higher in hot gas. The "cold" air in front of a bullet is heated as it goes sonic and is forced to flow through all the standing shocks. I could go on, but it's irrelevant to this issue.
An argon injection doesn't help much, but if you purge the barrel with argon just prior to firing, it just might work as you describe. Helium, being of lower molecular weight, would be an even better choice.-- Freefall, Jun 28 2004 I thought a rail gun was something found only in Quake.-- Eugene, Jun 28 2004 The oxidation is probably the smallest problem, the corrosion is mainly thermal and electrical.-- loonquawl, Apr 03 2009 random, halfbakery