Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!gem.mps.ohio-state.edu!tut.cis.ohio-state.edu!att!cbnews!military From: d9bertil@dtek.chalmers.se (Bertil Jonell) Newsgroups: sci.military Subject: Re: Particle Gun Message-ID: <10669@cbnews.ATT.COM> Date: 27 Oct 89 03:29:27 GMT Sender: military@cbnews.ATT.COM Lines: 51 Approved: military@att.att.com From: Bertil Jonell > A more serious objection is that this had better be the main gun on a > tank, because the recoil is going to be large. If the pellet is .1 g, the > recoil force is 30 MN. If the tank weighs 30 tonnes, it will acquire a > velocity of .7 metre/second. The main problem is the acceleration that will work on the tank and its crew. In the above example (.1g pellet at .7c) that acceleration, even if you assume an extremely long barrle length, will be around 3 700 000 g's ! (Barrle length of 20 metres gives an flight time in the barrle of 19 microsecond ie the tank will accelerate to 0.7 m/s on 19 microseconds. thats bad for the health!) The energy required for this feat is about 2.2 TJ (Tera-joule). A quick calculation gives that this approximates the energy in an 0.5 kt warhead. ( aorund 4.2e9 J in one ton of TNT if my memory is correct) [mod.note: Paul F. Dietz (dietz@cs.rochester.edu) confirms this figure. - Bill ] And you got to pump all those 2.2 TJ into the gun (and the projectile) in just 19 microseconds!!! That will be around 1.2e20 Watts! An *astronomical* figure! This kind of guns is better adapted to fleet air defence: short flight time to target, great energy requirement and the large mass of naval vessels (to counter act recoil) all contribute to that. Also, Whats wrong with lesser speeds? a APFSDSDU at 10km/s will do damage enough to kill anything that moves on the ground. Relativistic speeds aren't necessary to make an "impression" on the target. (APFSDSDU (my resarvation for the order, could be APDSFSDU): Armor Piercing Fin Stabilized Discarding Sabot Depleted Uranium: Anti-armor munition) > Anyone want to fire one of these from their > shoulder ? Only if it was available in an recoilless configuration B^) > utgpu!bnr-vpa!bnr-fos!hwt%bmerh490 | BNR is not | All that evil requires > hwt@bnr.ca (BITNET/NETNORTH) | responsible for | is that good men do > (613) 765-2337 (Voice) | my opinions | nothing. -- Bertil K K Jonell @ Chalmers University of Technology, Gothenburg NET: d9bertil@dtek.chalmers.se VOICE: +46 31 723971 / +46 300 61004 "Don`t worry,I`ve got Pilot-7" SNAILMAIL: Box 154,S-43900 Onsala,SWEDEN (Famous last words) "There's Medellin. Drugs 'R Us, all in that one little city in the valley. One nuke could settle things..." Tom Clancy 'Clear and Present Danger'