it heats up here, not good for the greenhouse effect !!
Eh yes, very good analysis by Olivier22 (thanks by the way for the crobards)
The propeller acts well as an "active" or "relative" sail
the shape of the propeller should be a pressure type propeller, a little like those of American water mills, where the entire surface of the wind is exploited
It nevertheless emerges that only the force recovered by the "sail" is exploitable, nevertheless, this allows to advance in the wind, on the other hand in downwind, it is enough to disengage and use the propeller as simple sail