Researchers at the Massachusetts Institute of Technology (MIT) have developed new low-noise propellers that can make current multirotor drones much less of an acoustic annoyance.

A team working at the MIT Lincoln Laboratory says it has come up with a closed-form propeller design that can significantly cut down the loud noise commonly associated with consumer drones. The configuration that the facility has gotten patented almost makes the propellers sound more like a rushing breeze rather than high-pitched buzzing — and it does so without sacrificing thrust.

Named after their donut-like shape, MIT’s quieter toroidal propellers consist of two blades looping together so that the tip of one blade curves back into the other. This closed-form structure minimizes the drag effects of swirling air tunnels (i.e., vortices) created at the tips of blades and strengthens the overall stiffness of the propeller. The result is that the acoustic signature of the propellers…

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Source: dronedj.com