Potential thrust curve problem due to airspeed?


I am thinking about how to PID tune for hover as well as at high speed. Of course, when at high speed, the throttle is high, so it seems safe to assume that changing THR_MDL_FAC could affect the tune at high speed. My understanding of this parameter is that, effectively, the rescaling causes less variation in thrust output at high throttle values to account for the fact that at higher throttle values (without rescaling), a small change in throttle output results in a large change to the thrust.

This makes sense to me, but couldn’t utilizing this parameter have the opposite effect as potentially desired, due to the fact that at high airspeeds, the thrust of the propeller is inhibited? Since at high airspeeds you have less total thrust output, the change in throttle values will have less of an effect on thrust. It seems like utilizing the THR_MDL_FAC parameter could exacerbate this, so I’m not sure how to account for these effects.

Does anyone have experience with tuning at high airspeed that could help shed light on this situation?