[Fraxiel]

I'm currently conducting a CFD analysis of a pusher propeller on a medium-sized aircraft. To study the increase of the drag on the entire aircraft (I have done a separate analysis of the aircraft with CLEAN geometry, meaning no propellers or landing gear). To do this I have created 2 cell zones. The enclosure and a rotary zone (a cylinder with the propeller geometry subtracted from it) that rotates at a given RPM. My mesh is very high quality and my number of cells is around 15 million. using the mesh motion I set the RPMs and the rotation origin and axis. My issue comes with the results. When I report the CD I choose the aircraft geometry only as if I include the propeller the CD will reach a not reasonable value (very high for an aircraft at that altitude and speed). meaning I only choose the wall surfaces of the aircraft. However, after comparing the CD of the aircraft with the pusher propeller I got a value that is lower than the CLEAN geometry CFD analysis. The value should increase. Any ideas on how to better this case? anything could be of help. Thank you!!