Over the last few years, the drone industry has grown tremendously. Drones are being used in countless industries and will continue to represent a massive job and economic market stimulator. As of January 2021, the FAA had registered over 1.7 million commercial and hobby drones in the United States. With the support of FAA and drone industry insiders, regulations on how drones can be used are being changed for the better. We are on the cusp of drones being able to fly in complex environments, autonomously, and BVLOS (Beyond Visual Line Of Sight).

With more and more drones taking up shared airspace there is the possibility of one issue impeding their progress. Drones are noisy. The propellers on an average drone spin between 800-900 rpm (rotations per minute). In a smaller drone, the rpm can sound like bees buzzing in a garden. The larger propellers in most commercial drones can be as loud as a whole hive of bees buzzing. And with the proposed notion of drones for human transportation, the noise could be as loud as several leaf blowers. With so much noise pollution, people are bound to complain, forcing new regulations into action that could limit the use of drones.

Assistant Professor of Aerospace Engineering at the University of Cincinnati (UC), Daniel Cuppoletti, is working to solve the noise pollution issues caused by drones. After earning his B.S and then Ph.D. from UC, Daniel spent just under 3 years as a Postdoctoral Research Associate at the United States Air Force Research Laboratory. In 2019, he returned to his alma mater where he and a group of engineering research students have been developing ways to lessen the noise made by the propellers of a drone.

In his lab, Daniel has built an anechoic chamber to test the noise made by drones. The chamber is covered in thick padding that blocks out all ambient noise and echoes. There are 8 microphones arranged around the room to record the sounds of a drone placed in the chamber. These recordings give Daniel a pure way of monitoring noise production. Daniel is measuring the frequency, wavelength, and amplitude of different drone propellers. This data is then used to engineer propellers that will be capable of emitting less noise.

In January of 2022, Daniel and several of his students joined the American Institute of Aeronautics and Astronautics (AIAA) Science and Technology Forum and Exposition in San Diego, California. For nearly 60 years, AIAA has been shaping the aerospace engineering industry. As stated on AIAA’s website, the “AIAA SciTech Forum is the world’s largest event for aerospace research and development. The 2022 forum will explore the science, technologies, and policies that are shaping our industry’s future and enabling sustainability.” Daniel and his students presented their findings at the forum with the hopes that drone manufacturers will use their research to build drones that produce less noise pollution. “This is a very exciting time for aerospace,” Daniel said. “New aircraft designs are at the preliminary and conceptual design stages. We can influence what they will sound like based on decisions designers make now.”

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