Current state-of-the-art aeroacoustic models for multi-rotor electric Vertical Takeoff and Landing (eVTOL) aircraft lack sufficient validation against full-scale measurements. This research will advance the state of the art by expanding the capabilities of current aeroacoustic models and by acquiring research-quality acoustic measurements of Archer Aviation’s full-scale, multi-rotor eVTOL aircraft, Midnight. These innovations will meet NASA’s need to validate aeroacoustic models for full-scale, multi-rotor eVTOL aircraft. Validated aeroacoustic models will enable NASA and the advanced air mobility industry to identify vehicle configurations and operations that drive community noise, expand the understanding of eVTOL acoustic emissions, and accelerate the design cycle of full-scale eVTOL aircraft. Blue Ridge Research and Consulting (BRRC) is partnered with The Pennsylvania State University to acquire research-quality acoustic measurements and to validate aeroacoustic models of full-scale, multi-rotor eVTOL aircraft. The team will expand the capabilities of state-of-the-art aeroacoustic models to better predict rotor-rotor and rotor-structure interactions, broadband self-noise, turbulence ingestion noise, and stochastic noise source modulation. In partnership with Archer Aviation, the team will conduct model-informed acoustic flight tests of Midnight. The flight tests will gather research-quality acoustic data at flight conditions expected to produce rotor-rotor and rotor-structure interactions. The team will analyze the measured acoustic data to validate the aeroacoustic models for full-scale, multi-rotor eVTOL aircraft. The team will deliver the aeroacoustic models, detailed flight test plans, and flight test data archives to NASA. The flight test data archives will include aircraft geometry and performance data, research-quality acoustic measurements, and meteorological data to support NASA’s model validation efforts for full-scale eVTOL aircraft.

The proposed innovations support NASA’s Aeronautics Research Mission Directorate’s strategic thrust #4 for quiet vertical lift air vehicles. The acoustic measurements of Midnight will provide NASA with a research-quality dataset to validate aeroacoustic models of full-scale, multi-rotor eVTOL aircraft, with an emphasis on rotor-rotor and rotor-structure interactions. The acoustic measurements will also support NASA researchers in assessing community responses to eVTOL noise.

The proposed innovations will support the advanced air mobility industry’s need to design quiet eVTOL aircraft and operations. Validated aeroacoustic models will accelerate the design cycle of eVTOL aircraft by enabling industry and other government organizations to evaluate noise while designing vehicles and operations, siting vertiports, planning land use compatibility, and writing regulations.