Originally Posted by DPATE
The there will be profile drag on the propeller whether it is producing thrust or not. Of course, this drag produces a torque on the shaft.
OK, let me put it another way.
If the propeller is doing no work in producing thrust, there is very little resistance to rotation (torque).
Angular velocity times very little equals an insignificant amount.
Torque required from motor - insignificant amount.
Power required - insignificant amount.
Battery life at maximum speed - about three years.
(Last sentence was a joke by the way, before you correct me)