veratech aero [minnesota, usa] develops small uav's. a couple of years ago they presented their phantom sentinel, a single rotor uav.
based on the concept of persistence of vision, the phantom's single rotor y-shaped blade has a center of rotation outside of the uav's physical fuselage. as the aircraft spins, it disappears from vision.to maintain flight the uav is equipped with two propellers powered by very quiet electric motors and can be thrown by hand, launched, or dropped from a plane.this unique combination of silence and invisible stealth allows it to creep within 23 m of nearly any event and remain reasonably undetectable to the human eye.
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