plane icon Welcome to Microsoft Flight Simulator’s SDK Q&A Platform!

You have questions regarding the SDK? DevMode Tools? SimConnect? You would like to submit an idea for future improvements, seek help or exchange knowledge? You’re in the right place.

Please take a moment to read the platform’s guidelines before you get started!


WxMarc avatar image
WxMarc asked WxMarc edited

How is fuel flow related to mixture for rich mixture values?

In piston engines at fuel/air mixtures above 0.095, the expected relationship between fuel/air mixture and fuel flow appears to break down. Here is a plot of ENG_FUEL_FLOW_GPH vs. RECIP_MIXTURE_RATIO (data collected by simconnect) for the Flysimware Chancellor:


As fuel/air ratio rises above 0.095, EGT continues to fall as expected, but the fuel flow abruptly stops rising and begins a gradual decrease. The pattern becomes more exaggerated at excessively rich mixtures. At around 0.110 fuel/air ratio, the fuel flow decreases more rapidly, and above 0.120, the decrease is even faster. Here is a plot from the stock G36 Bonanza:


It appears that fuel flow is serving as some kind of proxy for engine power or perhaps fuel burn rate at very rich mixtures. Why does this happen? Is there a way to tune fuel flow for more realistic values at high mixture ratios?

10 |10000

Up to 5 attachments (including images) can be used with a maximum of 4.8 MiB each and 23.8 MiB total.

0 Answers


Write an Answer

Hint: Notify or tag a user in this post by typing @username.

Up to 5 attachments (including images) can be used with a maximum of 19.1 MiB each and 23.8 MiB total.