U.S. proposes to allow drone operation at night, over people

Re:U.S. proposes to allow drone operation at night, over people by mediaman on Monday January 14, 2019 @08:49PM (#18908250)

Both propellers and wings are fundamentally the same thing: airfoils.

However, air passes over a propeller much, much faster than over a wing, and creates shock waves in a way that wings don't.

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Re:U.S. proposes to allow drone operation at night, over people by mikeash on Monday January 14, 2019 @09:13PM (#18908362)

Does it? The same airfoil needs the same speed to provide a given amount of lift, regardless of whether it’s a wing or a propellor.

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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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Re:U.S. proposes to allow drone operation at night, over people by Gibbon1 on Monday January 14, 2019 @09:23PM (#18908404)

Wings don't rotate and thus don't efficiently produce sound waves.

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