I don't think that there will be much drag from the erected but not turning pylon and prop of the GP 14/15 design. The blades are folded backwards and the pylon looks pretty aerodynamic. I think it is a brilliant concept - with the added benefit of being a self launcher rather than a sustainer. If the GP 15 was more advanced through the certification and a more known design I would be waiting for one now instead of for a Solo engines self launcher.