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The majority of noise you hear from a small prop plane flying above is from the engine. Also, the advanced height they're trying to achieve limits the amount o
by ryen 12y ago
The majority of noise you hear from a small prop plane flying above is from the engine.
Also, the advanced height they're trying to achieve limits the amount of noise relative to what you would hear from a small drone overhead.
- elihu 12y agoI'm sceptical that that's true. We can put mufflers on gas engines to make them quieter. The prop, though, is moving a lot of air, and there's no way to get around that and have it still work.
- mikeyouse 12y agoI found an old JPL document detailing "Aerodynamic Noise from Rotors, Propellers, and Lift Fans" (http://cafefoundation.org/v2/pdf_tech/Noise.Technologies/NASA.1970.Prop.Noise.Review.pdf http://cafefoundation.org/v2/pdf_tech/Noise.Technologies/NAS...) which has some interesting details. A 300hp hub, spinning a 9ft diameter propeller at 1584 RPM should be roughly 72dB as measured from 1,000 feet. From a mile away, it will be more like 57dB or about TV volume from 6 feet away. -- Then again, these are spinning far faster than you'd expect from a wind turbine.