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.
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.
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.