Well Im running 600's instead of 620's
FXaero models moto calc says
Motor: cen550 | Kv: 1470 rpm/v | Shaft Size: 5 mm | Weight: 7.2 oz. | Cell Count: 4 | Pinion: 11 | Battery: Lithium
Maximum rotor speed is approximately: 2156 RPM .
Heavy load rotor speed is approximately: 1858 RPM
No feild for rotor size but I assume
e-rappy550 from the drop down it sets the blade size.
I just hoverd it on the 600 motor/ 15c 4000 4cell lipo for about 5 min.
Not a drop of heat from the battery or motor.
RPMs sounded like around 1600/1700 but I was in the back yard.
So no FF.
I think I will just buy a data logging amp meter and go by the #'s
like I do on my fixed wings. Then I can be sure.