BTW, yesterday evening I applied a flywheel to the driveshaft of the module. It was late, so I couldnt test it extensively, but rotation seems to be a bit smoother now.
What I also noticed is, that the sometimes jerky movement of the rotor is caused by slight collisions in the rotor structure itself. For example the DBG hinge (1) slightly touches the black connector plate (2) in one specific position of the rotor. This always results in a sligthly stuttering movement. Is it normal or did I something wrong?
Also the scoops of rotor 2 and 3 are touching in a specific position.