From: vince@offshore.ai (Vincent Cate) Newsgroups: sci.space.tech Subject: Re: Cheap, easy to handle fuels/oxidizers References: <58866faa.0308240646.3c0a4a42@posting.google.com> NNTP-Posting-Host: 207.42.133.230 henry@spsystems.net (Henry Spencer) wrote in message news:... > N2O, nitrous oxide, is what I meant. > > Its performance is better than you would think based on its small oxygen > content, because it also has quite significant stored energy. The combination of Nitrous-Oxide(N2O) and Propane(C3H8) seems interesting. It seems to have a high ISP. Both self pressurize, and are relatively safe and easy to handle. At the URL below they say "an ISP of 230 at sea level, 290 at high elevation". I have not verified this, but if accurate, that is rather good. Anyone else have ISP numbers? http://web.wt.net/~markgoll/rse3.htm Somewhere I found that propane has a pressure of 124 PSI at 70° F. I think Nitrous Oxide is about 750 PSI at room temp. Seems like we use the N20 to cool the engine (since it has extra pressure) and run the engine with just 124 PSI feeds. Or maybe a simple pump that uses some of the extra pressure from the N2O to increase the pressure on the propane. Not needing separate tanks to pressurize the Nitrous-oxide or Propane simplifies things a little. As a guy who thinks the rocket only need to get to about 5 km/sec and then tethers/ion-drives can do the rest, the N2O/Propane seems like it has a high enough ISP and would be easier/safer than most fuels/oxidizers. But is this ISP of 290 seconds real? Can we get that at 100 PSI? -- Vince ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Vincent Cate Space Tether Enthusiast vince@offshore.ai http://spacetethers.com/ Anguilla, East Caribbean http://offshore.ai/vince ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ You have to take life as it happens, but you should try to make it happen the way you want to take it. - German Proverb