From: muratlanne@gmail.com   
      
   "Richard Smith"  wrote in message news:m17bvcmql5.fsf@void.com...   
      
   Richard Smith  writes:   
      
   > Leon Fisk  writes:   
   >   
   >> On Sat, 22 Nov 2025 23:23:26 -0500   
   >> Clare Snyder  wrote:   
   >>   
   >>>no messages for several days.   
   >>   
   >> It's been quiet of late. Just Jim and Richard bantering about World   
   >> problems...   
   >   
   > You are welcome ;-)   
   >   
   > ...   
      
   I really wanted to get to that flight propulsion engine.   
   Must be some sort of jet - which is a heat-engine.  Therefore...   
   The Carnot Cycle shows us the efficiency of the engine has a   
   thermodynamic limit set by how hot is the high-temperature end and how   
   cold is the low-temperature end.   
   It trails no fission debris, so the nuclear reactor is encapsulated.   
   So - the external hot surface of the reactor encapsulation must get   
   rather hot...   
   Materials engineering challenge?   
      
   BTW - anyone got a good link or resource to how ramjets work?   
      
   Best wishes, Rich Smith   
      
   ---------------------------------------   
   My simple intuitive take: The intake transforms high air velocity into low   
   velocity pressure (like a sail), which pushes outward against the walls,   
   forward against the diffuser and rearward against the flame, which can   
   resist the inlet pressure through inertia because it increases the mass   
   (added fuel) and velocity (high temperature) of the exiting exhaust gas.   
      
   The unbalanced pressure against engine metal in front but against only hot   
   gas behind is thrust, like the recoil of a gun where the forward pressure   
   acts only on the freely exiting bullet.   
      
   Per Newton, F=MA.  F is from the combustion chamber pressure, MA from the   
   expanding exhaust.   
      
   The recoil force of a garden hose nozzle is from a similar unbalanced   
   pressure and acceleration. The recoil is much less without the nozzle though   
   the volume flow rate may be greater.   
      
   A nuclear reactor creates exhaust pressure by increasing only the   
   temperature to accelerate the air, similar to the added thrust from the   
   Mustang or Spitfire radiator. Hydrocarbon fuel also increases the mass and   
   its hydrogen doubles the oxygen to water vapor volume. C + O2 -> CO2, 4H +   
   O2 -> 2 H2O.   
      
   Complex:   
   https://www.seitzman.gatech.edu/classes/ae4451/ramjets.pdf   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)