Originally Posted by
old,not bold
I guess the fundamental reasons apply equally to a wind-milling propeller and a windmilling turbine; wind-milling consumes energy. Mrfox is on the button.
Which is why we were told, in the olden days, to stop the propeller of a SEP so as to extend the glide after it all goes quiet, if you need to. (I found out the hard way that doing that, for the first and hopefully only time, in cloud with a basic panel is challenging.)
There differences are most significant if the pitch changes between conditions . If nil difference in pitch than there should be nil difference in drag for large prop driven planes.