Paul,

I've made some major improvements to the turbocharger sizing spreadsheet.

I've added an altitude temperature correction feature so that the temp
at altitude is based on whatever temp you enter at sea level. Thanks for
the suggestion!

I've also added a Rotrex supercharger compressor map, which Doug is
using. Very nice unit. Notice that at cruise power at 15,000 feet, the
efficiency of this unit is 80 percent!

I've also added a prop speed feature, so that you can see your prop
speed with any of four reductions gears -- Tracy's 2 ratios, plus
Mistral and Bell.

I've also made a couple of small corrections so that calculations are
consistent. For example, if you enter the altitude as zero you will now
end up with the same figures for mass flow, fuel flow etc, as the SL
section. Previously I had corrected the altitude pressure to a different
standard, which caused a different reading.

I've removed the charts for the exhaust turbine because we don't have
the exhaust flow data to make those meaningful or interactive like the
compressor maps.

So that's next on the agenda for this project. We now have the
compressor side pretty well covered. We still need to get some data on
exhaust flow and then we can interpret those turbine graphs and choose
the right size turbine as well.

I'm also looking into whether the formulas in this spreadsheet will work
with alternative fuels like ethanol and I will update that if necessary.

There may still be some bugs in it, so please let me know if you find
anything wrong. Also let me know any suggestions.


Regards,

Gordon.


PS: Kudos to Heath for coming up with that neat method for making the
maps interactive. It may look easy, but it's a bear to get those grids
aligned. It took me two hours to do that one Rotrex map. I'm sure there
must be a trick that I'm missing...




The Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://www.rotaryeng.net
Copyright 1998-2006 All world wide rights reserved.