From: hrubin@stat.purdue.edu   
      
   In article <1134509904.059395.104300@z14g2000cwz.googlegroups.com>,   
     wrote:   
   >How come the commercial airlines use jet fuel rather than LOX/H2?  I   
   >would have thought LOX/H2 would be lighter and would give the planes a   
   >longer range.  Is petroleum just cheaper?   
      
   You are wrong on all counts, except that petroleum is cheaper.   
      
   LH2 is so light that the amount of space and weight   
   needed for fuel for a flight is greater than that of   
   the same amount of hydrogen in petroleum, and that   
   on the conditions for burning used by jets, the   
   hydrocarbon gives off more energy than the hydrogen   
   in it provides, due to burning the carbon and   
   releasing the bonding energy.   
      
   Also, at the altitudes being flown, there is enough   
   air that the oxygen is free.  Since the ratio of the   
   mass of oxygen to hydrogen in maximal energy burning   
   is 8 to 1, why carry the oxygen at all?   
   --   
   This address is for information only.  I do not claim that these views   
   are those of the Statistics Department or of Purdue University.   
   Herman Rubin, Department of Statistics, Purdue University   
   hrubin@stat.purdue.edu         Phone: (765)494-6054   FAX: (765)494-0558   
      
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