From: someone@microsoft.com   
      
   [snippage]   
   >> A problem with scramjets, which attempt to achieve combustion at   
   >> hypersonic   
   >> speeds, is that the high speed means the air is producing so much drag   
   >> that   
   >> it is difficult to achieve net thrust when combusting with just the   
   >> oxygen   
   >> in the air.   
   >>   
   >> So what if we also combusted with the nitrogen? Nitrogen makes up 80% of   
   >> the   
   >> air mass so perhaps this could provide sufficient thrust. The problem is   
   >> nitrogen is commonly present in the atmosphere as N2, a molecule that is   
   >> very stable, i.e., non-reactive.   
   >>   
   >> But at hypersonic speeds so much heat is produced that the N2 is   
   >> "cracked",   
   >> generating various nitrogen species, such as N, NO, NO2, etc.   
   >>   
   >> So how much energy could be produced by reacting hydrogen fuel with the   
   >> various nitrogen species? How much for methane fuel?   
   >>   
   >> The energy density and thus Isp would be less than for reacting with   
   >> oxygen   
   >> but conceivable the thrust could be greater because of the greater mass   
   >> of   
   >> the nitrogen.   
   >>   
   >>   Bob Clark   
      
   > Even at hypersonic velocities, is there enough heat to crack N2?  N2 needs   
   > 945 KJ/mol to break that triple bond. That's a lot of energy.   
      
   We published a paper about a specific combustion process in Proceedings of   
   the ASME. The mathematical model was solved in an eleventh order system of   
   nonlinear equations, with parameters from steam tables, thermodynamics data   
   tables and whatever was needed a priori. We produced graphs that reproduced   
   laboratory results. At high temperature, nitrogen oxides, NOx are produced,   
   consistent with engine studies. Since then, catalytic converters are   
   required by Law. Nitrogen did not added to reaction enthalpy, NOx subtracted   
   from total enthalpy.   
      
   Air is not the best oxidizer. NASA prefers LOX, H2O2 or nitrogen tetroxide,   
   N2O4. Racers prefer laughing gas, nitrous oxide, N2O which is less dangerous   
   than other choices. H2 or RP1 are not as dangerous as other fuels, except in   
   a firestorm.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)