Brandon Fosdick wrote: BF> Hans Ulrich Ammann wrote: >> But personally I think his main problem at the moment is not the choice of >> a appropriate arrangement but the fact that whatever system he is going to uses >> the engine, or engines have to work in a consistent and predictable way.
BF> A lot of this discussion seems to be driven by the unpredictability of BF> the engines. Is this a characteristic of the chosen propellants? Would a BF> different propellant combination be inherantly more (or less) predictable? BF> Not that I'm advocating a switch, I'm just wondering out loud. There is no such thing as "easy" propellants. After discarding the liquid propellants that are no realistic choice for Amateurs like Hydrogen, the Hydrazines, Nitrogen Tetroxide, Nitric Acid... (In Ignition! from John D.Clark you can even find nastier substances), there is not much left. On the oxidiser Side there are LOX, NOX, and Peroxide, which in a biprop configuration can be burned with hydrocarbons like kerosene, alcohol, gasoline. Peroxide combined with a catalyst can be used as a monoprop. Any of these choices can be made to work reliably and safely and they all have their advantages and their draw backs. To bring a propulsion system to work in a consistent and predictable way, will take a lot of time, consume a considerable amount of money and require a big number of test firings. First and foremost one has to set up a reliable test stand with measuring equipment. There is virtually no way to cut corners in that business. And making more than one modification or even changing more than one parameter at a time is seldom a god idea. XCOR for instance has made hundreds of static tests with their engines, before the rocket plane made the first flight. And these guys had already some hands on engineering and propulsion experience, when they started their business. Hans Ulrich Ammann mailto:[EMAIL PROTECTED] _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
