Is it ok to discuss the details of a particular gas cannon I (and friends) experimented with when I was young. That is propellant, projectile and construction. Justin On 8 October 2013 09:56, RussellMc wrote: > > > Tis the age of paranoia. :( > > It is. > But, just because you're paranoid it doesn't mean that people aren't > talking about you! > :-) > > > A few years ago my nephew and his friends dabbled with potato > > mortars (pipe,butane). Despite it being a very rural area and them > > doing it in the middle of nowhere, the local cop said he'd rather > > they didn't > > Potato cannon or more generally gas cannon can be lethal - both to > target and users. > People tend to use PVC pipe and are as likely as not to use low > pressure waste disposal grade PVC. This is rated to quite low > pressures, shatters in a nasty way when overpressurised, and can send > nasty shards flying in worst case situations. Some people have made > rockets using such and found out why it was a bad idea. > > On the receiving end they can be 'dangerous enough'. Potatoes are, if > not harmless, then not too too dangerus mostly. But people tend to try > other things and I've seen photos of eg AA batteries which have been > used to shatter reasonably solid pine planking. If someone was killed > by a potato fired from such people would be suitably sad but should > not be surprised. > > Odds are the use of such a device may be classified as an unlicenced > firearm by the police if they so desire and, if that did happen, it > may be hard to convince a courtthat your opinion was superior to > theirs. > > Competently constructed water rockets made from soft-drink bottles > using CO2 pressurisation can reach maximum accelerations of round 100g > and altitudes of several hundred feet. > Water rockets made from long thin tubing can get to around 1000 feet > altitude. > Purpose built no effort speared water rockets have exceeded 2000 feet > altitude (World record 2044 feet average of 2 flights 2007) > > http://www.uswaterrockets.com/world_record/menu.ht= m > > http://www.wra2.org/WRA2_Standings.php > > A finned and nose coned 1.5l Pepsi bottle rocket without a parachute > or descent control system will impact at around 80 kph. [ !!!!] > > I hold the world record (probably) for launching a single water rocket > from the most countries (or single rocket launched from the most > countries, or ... ) but nobody seems to know or care ;-) > [Over 20 countries, in 2003 :-) ]. One of these days I'd like to > launch an Intercontinental Ballistic Water Rocket [ ICBWR] whih would > also be an ICBM. Across the Rio Grande from North to South America is > one possible location :-). > > _____________ > > Suitably impressive paper: Open access. BOAI (free) licence. > > Title :A more thorough analysis of water rockets: Moist adiabats, > transient flows, and inertial forces in a soda bottle > Language :English > Author, co-author :Gommes, C=E9dric [Universit=E9 de Li=E8ge - ULg > > D=E9partement de chimie appliqu=E9e > G=E9nie chimique - G=E9nie catalyti= que > >] > Publication date :Mar-2010 > Journal title :American Journal of Physics > > http://orbi.ulg.ac.be/handle/2268/36471/?locale=3Den > > > R > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .