Originally Posted by
Pilot DAR
Turning the prop slowly has merit, but not "over square" unless the engine/propeller design specifically approves this type of operation.
It is important to know the limitations applicable, however, 'not over square' is not that useful a concept. Think takeoff in fixed pitch aircraft (a MP - if you had the gauge- of 29in and 2550 rpm) and almost all operations in turbocharged aircraft.
I have never understood why it is ok to run oversquare at full power for the whole climb (maximum power, maximum heat, low cooling airflow). but if in cruise flight you choose 25 in and 2100 rpm this is a problem.
Originally Posted by
Pilot DAR
The mixture setting of an engine will have nearly nothing to do with the speed at which the plane will fly. As the original question was asked about speed, as opposed to fuel flow, I suggest that mixture settings would not be an element of the answer.
You are of course correct the mixture has nothing to do with speed, However, the mixture setting you choose will have a considerable impact on the amount of time you can stay in the air (or the cost /hr), which is the whole point of flying at this speed.