From: jimdavis2@earthlink.net   
      
   peter wrote:   
      
   > In looking at a ramjet/scramjet diagram, it seems that the burnt   
   > gas would want to go in both direction: towards both the inlet   
   > and the outlet. Since there is no valve to prevent a back flow,   
   > why wouldn't this push the air out of the inlet and stall the   
   > engine?   
      
   The inlet raises the static pressure of the incoming air by slowing   
   it down. In a scramjet the inlet is a carefully designed converging   
   duct. A supersonic flow in a converging duct will slow down although   
   in a scramjet the flow never goes subsonic. In a ramjet the inlet is   
   a (also carefully designed) converging-diverging duct which slows the   
   flow to subsonic speeds.   
      
   Jim Davis   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)