Well my point in asking is that if motor/controllers are not presently very inefficient, then even a new type of 100% efficient motor/controller would not make a significant contribution to your efforts. As an example, if we assign a number to the best present day efficiency of say ~85%, then there is only a 15% possible gain left to conquer. Assuming that we are all humble enough to not believe that we can create a 100% efficient motor/controller, then this might leave say, a net 10% left to a better mousetrap. 10% is not going to be an enormous impact on range or anything else because it implies a maximum improvement of, well 10%.

In fact, I would venture that typical propeller efficiency is typically worse than typical motor/controller efficiency. Particularly so in smaller propellers as is used on small and model aircraft. So any motor efficiency gain would be partially overshadowed by propeller losses.

Q