From: nospam@127.0.0.1   
      
   It took forever for this article to finally getting around to mentioning   
   the technological leader, the Sabre engine from Reaction Engines.   
   Almost no mention of how a "Fenris" engine works. You have to follow the   
   link "Fenris" which takes you to a non-patent office page of what   
   appears to be a patent application, but isn't? It does look different in   
   fundamental design from the Sabre. But the lead illustration in the   
   Wired article is the Reaction Engine's Sabre engine not the Fenris. I   
   wouldn't be too happy with that if I were from Reaction Engines. I   
   haven't had time yet to study the Fenris, so I have no clue as to how it   
   works and in what ways it is different from a Sabre engine.   
      
   As Henry Spencer points out (again and again) LOX is cheap and   
   plentiful. These air breathing designs are optimizing for the wrong part   
   of the problem. You'd have to get enormous reuse out of these systems to   
   compete with a single Falcon Heavy launch. And once Starship becomes   
   fully operational, well, maybe they could launch Skylons out the cargo bay.   
      
   I wish these designs good luck from an engineering prospective I think   
   they are very interesting. Will they ever compete against traditional   
   two stage rockets? It could be the Stanley Steamer vs. the Gasoline   
   Engine all over again. I suspect these systems have a much better future   
   as quick deploy crewed military vehicles rather than cargo lifters.   
   There just isn't enough oomph there. And don't forget Starship in its   
   two stage version is also fully reusable w/o the technical complications   
   of a bleeding edge engine.   
      
   BTW if you an basing your fuel around the hyper hard to handle liquid   
   hydrogen in order to make the Reaction Engine work at all, you are   
   really really up against the fuel density issue.   
      
   Or as Ben Rich called them, Wide-Bodied Dogs....   
      
   Dave   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)