From: johnhare@tampabay.rr.com   
      
   "Kelly St"  wrote in message   
   news:20040126205838.04554.00000829@mb-m10.aol.com...   
   > Opps,   
   > Sorry I didn't respond to your post earlier.  I've been busy and hadn't   
   checked   
   > in.   
   >   
   > My article isn't on the site yet.  The site editor is busy and getting   
   behind.   
   >   
   >   
   > You said,  "I have a bit of a problem buying HTHL SSTO as being able to   
   close   
   > the technical case.".  I'm not clear what your questions were.  For a Mach   
   3 to   
   > 6 airbreathing bird I was getting take off weights ( LOx Added later) of   
   > 170-200 tons.  And crafte weight on orbit of 50.  Weight on orbit minus   
   all   
   > tanks and engines of 23-29 tons.  Even cuting out 5 tons for reentry   
   systems,   
   > and 4-5 tons for landing gear, that still leaves 13-20 tons for frame   
   crew,   
   > crago, and such.  Which seemed doable from what I could see.   
   >   
   I have read a lot of information on using existing airbreathing engines, on   
   paper, disk, and web. None of them have been able to make a good case.   
   Most of the ones I have looked at use GLOW as the standard to judge by.   
   I'm looking for dry mass as the standard. A turbojet costs orders of   
   magnitude more per launch pound than LOX, or even RP. So far,   
   I have not seen one source that has dropped dry mass with the use of   
   any current airbreathing engines.   
   >   
   > I think the main difference between us is goals:   
   >   
   >   
   > >My interest is in finding the T/WxIsp curve that makes a compelling   
   > >arguement   
   > >for a new type engine. IMO T/W of 25+ is possible with 4 digit Isp.   
   >   
   > ===   
   >   
   > >My orriginal question is simply stated as, "what performance is required   
   > >of a new style air breathing engine that would win an ICH tee shirt?"   
   >   
   > I was interested in seeing if you could do it with current equipment, not   
   > searching for a justification for a new one.   
   >   
   I have concluded no on this question. I am trying to find the break point   
   where that answer becomes yes. Airbreathing engines offer certain   
   operational advantages. The target is to find the point where these   
   operational advantages can be had without a performance penalty   
   compared to pure rocket operation.   
      
   > I'm not saying a new engine with better perfomance wouldn't make things,   
   but   
   > I'm not at all clear Its needed to get the job done.  A first generation   
   craft   
   > that could drop cost to orbit by a order of magnitude or two, and greatly   
   > increase flexibility, would get the ball runing and later bankroll the dev   
   of   
   > better engines.   
   > Kelly Starks   
   > KellySt@aol.com   
   >   
   > "Humans are a race of compassionate predators."   
   >   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)