That’s right: It is noisy in cities. On average there is a background noise of 60 to 65 decibels. Our eCopters, which will fly at an altitude of 150 to 300 meters, will produce only 55 decibels on the ground – which means that you will probably hear nothing at all in a usual city ambience. We achieve this low value through a special concept: two sets of rotors mounted one above the other. They generate the necessary lift at a lower rotational speed than other drones or multicopters.