From: cdorrough@nortonconsultants.com   
      
   "Andrew Nowicki"  wrote in message   
   news:40E9257C.6759D1E6@nospam.com...   
   > Iain McClatchie wrote:   
   >   
   > > A lightweight engine designed for gas-phase combustion   
   > > will explode if you fill it with LOX and liquid methane   
   > > and ignite it.  So at startup you'd have to release small   
   > > amounts of gaseous oxygen and methane into the combustion   
   > > chamber to get it going.  If you want to avoid propellant   
   > > valves that can throttle the engine (which sound hard to   
   > > get right), you'll want to just bang open the propellant   
   > > valves.   
   >   
   > The easiest way to heat up the propellants   
   > to the boiling point temperature is to make   
   > a small rocket engine and vent its exhaust   
   > into the propellant tanks.   
      
   .but then you wouldn't have a rocket - you have a bomb!   
      
   Heat + oxidiser (traces from your rocket exhaust) + fuel (in the tanks) =   
   bang, with the right mix.   
      
   AIUI, one of the reasons in favour of *liquid* propellants is that they are   
   harder to ignite (further away from their ignition temperature) than their   
   respective vapours, and hence safer and easier to handle - not being   
   vaporised until the last millisecond.   
      
   Cameron:-)   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)