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A comment on U.S. proposes to allow drone operation at night, over people. Parent comment

Re:U.S. proposes to allow drone operation at night, over people by alexis_fr on Tuesday January 15, 2019 @02:14AM (#18909349)
The speed of a propeller is low close to the rotor, and sometimes faster than sound at the extremity of the blades. Can’t reduce sound on that.
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Re:U.S. proposes to allow drone operation at night, over people by sokoloff on Tuesday January 15, 2019 @07:59AM (#18910809)
Propeller efficiency takes a nose dive when the tips go supersonic. Most props therefore do not operate in this range.
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