Silent Propeller for Paramotors

Has anyone tried to make silent propeller like the one in Zipline for a paramotor? Electric paramotor with a Silent propeller would be a killing combo!!!

Check out these video - How Do Zipline's Silent Propellers Work? - YouTube
Amazing Invention- This Drone Will Change Everything - YouTube


Agree! But Zipline has patented their design, so they would need to offer a licensing option to manufacturers…hopefully not as expensive as the torodial designs (Sharrow props for boats are $4500 more than the standard $500 prop.). Seems like something that would be great for Zipline as extra revenue. Generally speaking, I would love to see an advanced prop design to reduce the noise and modify the sound profile from small aviation.