National Aeronautics and Space Administration

www.nasa.gov

Acoustic Analysis of Multicopter UAS 7x10 Wind Tunnel Test

AbstractSmall Unmanned Aircraft Systems (UAS) are finding increaseduse in today’s civil market while the Federal AviationAdministration (FAA) has been working diligently towardcommercializing the use of these vehicles. Noise generated byUAS must be mitigated to minimize impact on the communityand environment. To aid in understanding the acousticsignature from these aircraft, acoustic measurements weretaken of several UAS vehicles during the Unmanned AircraftSystem Traffic Management Build 1 flight test at CrowsLanding. Additionally, in the winter of 2015 a multicopter UASvehicle performance test was conducted in the NASA Ames 7-by 10-foot wind tunnel. The acoustic data is organized,processed and analyzed for 5 different UAS vehicles. The twodifferent acoustic environments, wind tunnel and outdoorflight test, are compared to understand the quality of theacoustic environment in the 7-by 10-foot wind tunnel.

Motivation/Objectives

Results

Concluding Remarks

• Determine the feasibility of the Ames 7-by 10-foot windtunnel as an acoustic test environment

• Collect and analyze UAS acoustic data from severalmulticopters in hover and forward flight

• Correlate impact of tunnel speed on noise floor• Compare wind tunnel data to outdoor flight test data

• Rotor acoustic noise was measured in the Ames 7-by 10-footwind tunnel

• Blade passing frequencies (tones) can be identified infrequency spectrum

• Correlations can be made between wind tunnel speed andits impact on the noise floor

• Further research is required to determine if the 7-by 10-footwind tunnel can highlight acoustic differences in soundpressure level for various UAS designs

• Mic #1 and #3 are below and above the centerline of the UASrespectively

• Mic # 2 is below and forward of the UASs flight path• UAS has speed controller to accurately hold RPM

3DR SOLO

Multicopter Test Articles Data Processing

Sound Pressure Level

Fast Fourier Transforms

A-Weighting (dBA)

Experimental Set Up

DJI Phantom 3

3DR IRIS+

DAx8

Acknowledgments

• Dr. Bill Warmbrodt• Dr. Ben Sim• Natasha Barbely• Carl Russell

MIC #1

MIC #2

MIC #3

By: Jason Cornelius, Penn State University Mentor: Natasha Barbely