Updated by Bill Lofton 11/11/16
Courtesy of Nikolay Kazakov and ul-segelflug.de, uavglobal.com, public.navy.mil
VTOL flight requires a lot of thrust, especially while hovering. Helicopters can fly forward at much higher altitudes than they can hover, because hovering requires more power than forward flight.
But electric aircraft should be quiet and you can’t create a lot of static thrust without a lot of noise. Or can you?
VTOL e-Propeller Optimization