Is it OK to compare all three moment coefficient together given that the reference points are different?
No, it's not ok. The pitching moment will be different at different reference locations, unless lift is 0.
Do I have to change the reference point to 0.25c for the two last results? if so, how can I achieve that without restarting the simulations and ...
Well, you knew to be specific about the plane, the RPM, the airspeed, and the attitude.
Pulling the yoke back without changing anything else will create excess lift, and a climb begins. This is the only point in the scenario you have excess lift because: increasing AOA increases drag.
The plane then slows down for 2 reasons. First a higher AOA means more ...
The general answer goes something like this:
Level flight, at it's most basic involves a balance of 3 factors:
How fast are you going, relative to the wind?
What is the angle of attack (AOA) of your wings, relative to the wind?
How dense is the air that you are flying through, based on altitude, temperature, humidity, etc.?
Speed and AOA are variables that ...