Originally Posted by
Walter Atkinson
Hm? That's not quite correct.
When ROP, power is determined by mass airflow. FF has little effect in the normally used ROP mixtures. Once they get overly rich, yes, power decreases.
When LOP, power is directly related to FF. Mass airflow plays no part.
The reason there is a Best Power mixture has nothing to do with FF. It is the mixture where the mass airflow is adequate to burn all of the fuel. That does NOT occur at stoichiometric (AKA, Peak EGT). It occurs at approximately 75-80dF ROP.
You're the only one talking about fuel flow. Yes, mixture ratio and fuel-flow are pretty tightly correlated, but you're interjecting words I didn't use.
Here's what *I* meant: If you had a power meter on your engine*, and you started with the throttle set and the mixture at full rich, then you started gradually pulling the mixture toward lean, you would see the indication on your power meter rise, peak, then fall as the mixture control moved toward Idle Cut Off.
I'm not sure what you mean about power not being a function of fuel flow exactly, and I'm not saying that you're wrong, but I think you may be making a semantic distinction that's not relevant to my statement.
* I flew for a number of years in an airplane which had power meters on the engines. For a constant RPM, a torque meter is a power meter. I have watched the needles rise then fall many, many times.