X-Mozilla-Keys:                                                                                 
Twotikes@aol.com wrote:

The TO4 isn't really the right turbo for your stunt.  I ran the model and
found a problem in the wg section that is relavent to this discussion.  On
the wg model I forgot to put in the if statement to limit effective (i.e.
able to make power) turbine P.R. to .55 a.k.a. 1.8.  The prblem is that when
the PR exceeds this value the turbine is choked.  Just like the turbine
housing is choked at a corrected flow of 38 lb/min.  So... in order to get
more power out of the turbine the exhaust pressure starts to jump up to
pressurize the flow and raise the density.  The result is a negative PR
across the engine with a MAP of 23 in hg and an exhaust pressure of 26 in hg.

 If you had a bigger turbine (e.g. T62) you could operate with an exhaust
pressure of like 17 in hg and your power and efficiency would go up
accordingly.  Also I haven't looked at the TN site to pick the right
compressor but you need a *reeaallly* big one by T04 standards.  See if they
have one for a corrected flow of about 58 lb/min at a pressure ratio of about
3.3.  That would get you maybe 125 hp if you're lucky with a too small T04
turbine.  The whole thing is kinda ugly.  

BTW, I don't have turbine maps for
the bigger turbos so you'd be flying blind.  Is there really a good reason
for this stunt???  I really don't get it.  It's not like there's a whole
section of the record books for 13B's or wankels.  Nobody is really gonna
care and the challenges are going to totally drive the design of your
airplane, cooling, turbo, etc, etc, off in some impractical direction.  

 How
'bout if you come back down to earth with the rest of us and we can all work
together more effectively.  I'm usually not one to dissuade but having seen
what it takes to go up high I just want to dose you up on reality.  I'm about
to cut you off on free high alt consulting anyway ;-)

Thanks for your excellent efforts on this. I will think about it Jeff.

Paul Lamar

 
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