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Re: Railgun - Sonic Boom
Posted: Fri Feb 17, 2006 2:14 am
by furry_wolf2001b
There be light!
Hmm, yeah, i think i might have written my post once before...
Re: Railgun - Sonic Boom
Posted: Mon Feb 20, 2006 10:22 pm
by ANTIcarrot
I wonder if the velocity of this bullet causes it to instead of breaking the air, to part it--similar to the way an airfoil works.
NASA has had some succcess at reducing the peak pressure (~loudness) of a sonic boom by shaping the nose of an experimental aircraft, but I can't see how any property of Jason't first railgun barrel would produce a similar effect.
I think this is just one to chalk up to genuinely wierd science, and leave it at that.

Re: Railgun - Sonic Boom
Posted: Tue Feb 21, 2006 12:53 am
by Were_Fan
ANTIcarrot wrote:I wonder if the velocity of this bullet causes it to instead of breaking the air, to part it--similar to the way an airfoil works.
NASA has had some succcess at reducing the peak pressure (~loudness) of a sonic boom by shaping the nose of an experimental aircraft, but I can't see how any property of Jason't first railgun barrel would produce a similar effect.
I think this is just one to chalk up to genuinely wierd science, and leave it at that.

Wierd science? Ayup! The recoil get dumped by Faey tech. Maybe the projectile noise gets warped into the aether? <grin>
In the real world, coils of rail guns take a beating. Accelerating the projectile puts an opposite and equal force on the coils. There was a prototype rail gun tank killer that destroyed the "barrel" on every shot.
I was disappointed when I first fired varoius military weapons. Where was the ear shatterineg roar from Dirty Harry's 44 mag? The M16 had a little pop followed by the faint noise of a round going down range. There is a lot more noise from projectiles though most folks don't usually hear much. From the rear, the noise is very faint. Having been to the sides of 5.56 to 50 cal, they all make a "tearing" noise similar to that of a jet or bottle rocket but very intense.
Had a battery of 6 to 8 inch SPGs (self propelled guns) guns fire several salvos one night only a few hundred meters to the rear. That woke me up about two feet off the ground but I don't remember hearing projectile noise or even the impact. I was to stunned and disoriented from the nasty wake up call! I kept thinking "short rounds"!
--
Jim/Were Fan
Re: Railgun - Sonic Boom
Posted: Tue Feb 21, 2006 4:34 pm
by Were_Fan
Here is a followup with some links to bullet and other shock waves.
Lots of photos:
http://www.galleryoffluidmechanics.com/ ... s_proj.htm
Technical description and animations:
http://www.kettering.edu/~drussell/Demo ... ppler.html