HereForTheBeer
 First Officer
Flight distance : 5381368 ft
United States
Offline
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hard to say. lot to the equation as it isn't as simple as people think.
one of the biggest factors in how loud a drone seems is frequency of the sound.. higher frequencies are far more annoying and more easily detectable over surrounding noises, not only are we wired to hear certain frequencies as part of our survival (we are animals after all) but also higher pitched droning sounds are far less common so much more easy to pick out of other sounds in the environment. lower frequencies tend to not be as noticeable and can even much more easily blend into the environment, weather thats downtown city or in the farm fields.
the prop design, where most noise especially high pitched noises are mot made is at the tip of the props where air is most turbulent and traveling faster then rest of the air and being beaten around. this can be reduced by designing the tip of the prop to not cause so much turbulence, like winglet tips on the mavic prop plat and mavic 2 series. additionally more rigid props can resonate more but tend to be more efficient at moving more pressure but flexible props like one son the mavic mini while may not be best at moving a lot of air pressure can "absorb" more resonates (for a lack of better terms)
ESC switching.. if ESC uses digital square waves its switching on and off really fast which can actually makes it own high pitch tone reinstate out of the motor and props, a pure or near pure sinewave can reduce that high frequency pitch resonating or even eliminate it entirely depending on the RPM. higher RPMs will still resonate higher frequencies since still producing higher frequency sine waves.
motor design and power.. thrust and lift vs weight ratios basically. dji seems to gone with flatter motors on mavic mini, usually but not always this means they are targeting torque over rotation speed. also likely dji is targeting lower power limits since using li-ion 18650's in their battery pack this time and the drone only weighs 249 grams.. |
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