Some of the larger helis draw some incredible power and put a bunch of load on the motor. I seem to remember seeing 2500w from 500mm bladed helis, I could never afford the big .60-.90 glow conversions so dont know what HV guys push through those but I could easily see them drawing 5-6000w.

Helis typicaly run the motors at higher RPM as well, something I've had a hard time with coming from helis to surface brushless.

The 3D fliers portion makes me wonder if some frames dont flex with hard inputs changing the gear mesh slightly.

I would imagine surface vehicles would put the same type of loads on the bearings, slipper clutches probably help alot. But I dont think we are pushing the motors as hard yet as the heli guys.

Not sure why they would only have that warning for the H versions though. Unless it has to do with the fan pulling crud into the bearings??