I own a model helicopter with a Brushless motor, and I still don't believe it.
That motor only replaces the TR gearbox. The TR gearbox of an R22 is pretty light, i doubt it weighs more than 2kg.
You still need the power regulator, cables, and mainly - a
15kW generator and some decent size buffer batteries.
Not to mention that the motor, like all brushless motors of comparable size/performance i have heard of, runs at high RPM. So you would still need a 3:1 reduction GB.
The TR thrust in helos is limited through the pitch angle of the blades to protect the drivetrain, the TR itself and the tailboom. If one wanted a stronger tailrotor, these components need to be made stronger. That problem doesnt change with an electric one, except you'd need to beef up the motor and generator instead of the drivetrain.
10-15% of the power to power the tail rotor in its most extreme condition?
A lot of books say up to 30%. I don't know though.
I think lot of RC flyers see the amazing performance they can get out of electric RC helos, and underestimate the problem of scalability.