Paul F. Dietz wrote: > Henry Spencer wrote: > > >>Since the plumbing systems for the two propellants necessarily meet in the >>chamber, there is inevitably a path back as far as the lowest oxidizer >>valve(s). The question is whether procedural measures like purges can >>keep that path from ever being followed. The way you debug such measures >>is by having them fail. > > > This is a motivation for using a propellant like propane, > which can be driven off as vapor at room temperature. > > Commercial LPG has some higher molecular weight components, > though (butane at least).
Commercial propane also has mercaptans, which can leave a truly ghastly oily stinking sludge behind. Subcooling it to 100 K, then transferring it to a clean container will get rid of the low-volatility components, as will activated charcoal filtering. This was one of the reasons we shifted to ethane in our teacart engine, but isopropyl alcohol is very clean and easier to handle- indeed, standard commercial grade IPA is a popular cleaning solvent. We just ran the teacart engine a few times today on IPA/N2O, and pushed our stats up over 1500 runs since December 1999. Doug _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
