My technique for using K factor and RETRN parameter.
To Tony and others interested in more accurate fuel flow indications,
I posted the following today in the Dynon forum. You can read the entire thread at:
http://dynonavionics.com/cgi-bin/yabb2/YaBB.pl?num=1306605633/0
Dynon Support - Thanks for the reply and the explanation. Armed with that information, I went to the airport today and did the following:
1. Set the K factor back to 68000, the recommnended value for the FT-60.
2. Went into the RETRN field and while running the electric fuel pump, with engine off, noted the fuel flow indication.
3. Began incrementing the high end of the RETRN field. As I did this the indicated fuel flow went down. When the RETRN value reached 130000 (one hundred thirty thousand) the fuel flow indication was down to zero.
4. Ran the engine. I calculated that at 4000 RPM I should see a fuel flow of about 3.5 GPH. While holding 4000 RPM, I adjusted the K factor to achieve an indication of 3.5 GPH. This value turned out to be 79000.
5. I flew the airplane. Indicated fuel fows were very close to what I believe they should be at various power settings.
I realize this method may not yield perfect results, but I think I am pretty close - certainly closer than before with the K factor at 99999. On my next cross-country flight I will compare calculated fuel burn to actual, and tweak the K factor further as specified in the manual.