RE: Vintage ducted fan (1975)
Tim, I think it is more to do with the overall dia of the motor as it is larger than the center of the stator in the byron fan. With a few mods to the motor it fits quite well. Can't give a weight for the power unit but an AUW is around 11-12 Lbs, with retracts, which means that it should fly quite well. The motor is a monster amd works quite well, may be underated, but better than what others are using.
Cheers