Relative quiet and actual quiet are different things - I don't believe the physics exists to displace the noise/vibrations generated; you can change the propell

Relative quiet and actual quiet are different things - I don't believe the physics exists to displace the noise/vibrations generated; you can change the propeller shape and sizes, however that energy still needs to go somewhere, so you'll mostly just change where the energy's going and the frequencies and concentrations that are output. I'd love to be proven wrong.