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Description
Propellers are the dominant source of noise in drones,with the blade tip region playing a critical role due tohigh local flow velocities and strong aerodynamic interactions.In addition to overall sound pressure level,the spectral content of the emitted noise significantlyinfluences human perception and annoyance.This study investigates the effect of blade tip geometryon A-weighted sound pressure level with FASTtime weighting (LAF ) and the frequency spectrum offused deposition modeling (FDM) 3D-printed dronepropellers in the hover regime. A baseline propellergeometry was modified by varying blade tip sweepangle (−30◦, 0◦, and +30◦) and tip chord length (baselineand 50% of the baseline). Acoustic measurementswere conducted under zero inflow conditions over arotational speed range from 5000RPM to 8000 RPM.The results show that blade tip modifications influenceboth tonal and broadband noise components, leadingto measurable differences in sound pressure level andspectral characteristics across operating conditions.In particular, certain configurations exhibit reducedvariability in both acoustic and performance metrics,indicating more stable aerodynamic behavior.These findings contribute to the understanding ofaeroacoustic mechanisms in small drone propellersand support the development of low-noise propellerdesigns.