Hi Rogerio :
Thanks for your reply. If you don't mind, I have a few questions:
1) The Graupner prop is drilled 8mm. Did you find a commercially available vendor who makes reducing bushings from 8mm to 5mm ? Of course, one could always locate a machinist .
2) How much battery, percentage wise, do you have in reserve after a full pattern using your 4S 2200mAh?
3) Are you satisfied with the performance as compared to say two blade APC offerings such as their 10x5.8 F2B, 11x 4.5E, and 11x5.5 E
Thanks Again !