Whisper Drone

The sound from the drones helicopter that floats for my fun can be a loud noise to someone. There is a unique type of drone that reduces this noise.
This is "Whisper Drone".
Whisper Drone has quad rotors that can produce the driving force that can fly.

Instead of a propeller, it uses a ring-like rotor with tall vanes extending from the surface.

• it makes less noise

Instead of the typical hive-like sound of drones, it produces the whoosh of air passing through a vent.