From: johnhare@tampabay.rr.com   
      
   "Jim Davis"  wrote in message   
   news:Xns946BA6EAE4CE0jimdavis2earthlinkne@130.133.1.4...   
   > johnhare wrote:   
   >   
   > > This suggests that there would be 550 lbs available to the   
   > > 2,000 second air breather and   360 lbs available for the   
   > > 1,000 second air breather. T/W ratios required would be 28 and   
   > > 42 respectively for these systems to match pure rocket   
   > > performance on a VTVL.   
   >   
   > What kind of airbreathing engines do you have in mind here? If   
   > turbomachinery based your Isps are too low and your T/Ws are too   
   > high.   
   >   
   I believe I have invented a new arraingement for the turbomachinery   
   that is much lighter than that in current equipment. The aero/thermodynamic   
   cycle is a hybrid turbojet and air-turborocket. I finally figured a way   
   to build test models on my budget. The key point was finding a way   
   to build a blade row that operates efficiently as compressor over part   
   of its cycle, and partial admission turbine over the other part. The   
   blade row is regeneratively cooled during the compressor portion.   
   This allows much higher turbine admission temperatures than normal   
   and eliminates the afterburner. I am looking for the target performance   
   curve where the airbreather does not have a performance penalty   
   vs a pure rocket system.   
      
   > More importantly, I think if you want your airbreathers to do   
   > double duty during ascent and recovery you're going to have to   
   > address the issue of increased installation weight. An installation   
   > optimized for deceleration/hover may not work well while   
   > accelerating and vice versa.   
   >   
   Any increased installation weight will have to be charged off to the   
   airbreather, which makes the true curve possibly more difficult to   
   reach. I believe I have found an installation scheme for this particular   
   engine type that will operate somewhat effectively in both orientations.   
      
   There are three performance curves on the graph. The low one is   
   what many people shoot for. Airbreathing is so desirable that   
   substantial performance penalties are going to be overlooked in   
   order to incorporate them. The middle curve is where performances   
   just match. The most difficult one is where not including airbreathers   
   must be justified in terms of simplicity or cost. I am interested in the   
    middle curve.   
      
   > Jim Davis   
   >   
   John Hare   
      
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