SilentEcoWing optimizes the boundary vortexes simply by changing the wing end or rotor blade tip. There is a separation into several small vortexes which reduces the induced drag and the noise level.
Induced drag develops at the end of the wing like a big compensatory boundary vortex which is caused by pressure differences at the wing’s upper and lower sides. Such a vortex is one of the reasons for noise development and drag.
Less drag means savings in energy because less driving power is required.