Research being conducted at Embry-Riddle Aeronautical University in the USA is to examine if the noise reductions claimed by eVTOL aircraft developers will be true for urban areas.
The noise generated by eVTOL aircraft is seen as a critical barrier to their potential widespread use in cities. While helicopters are extremely noisy, most eVTOL aircraft developers claim their designs will be significantly quieter, opening up large potential urban markets of passengers who want to dodge traffic congestion on the ground.
However, the potentially turbulent flight conditions within cities present new aerodynamic and aeroacoustic challenges.
The three-year, US$1.4 million research program at Embry-Riddle, which has been funded by NASA will focus on how air taxis can take off and land quietly at vertiports in urban areas where wind gusts tend to be unpredictable.
The research team will also provide guidance on suitable locations for city-based rooftop vertiports and flight corridors that would minimize noise during take-off and landings.
“Noise is a critical aspect for public acceptance,” said Vladimir Golubev, Embry-Riddle professor of Aerospace Engineering and a principal investigator on the project. “They need to be controlled through the development of accurate response-prediction tools and optimization strategies,”
Computational simulations of noise aerodynamics and the controlling of multi-rotor vehicles in urban environments will be used to model the noise generated. By focusing on the sound levels associated with UAM’s vertical lift capabilities, the team hopes to reduce the environmental impact of these vehicles, helping to ease their entry into new markets.
The project also involves researchers from Boston University, Virginia Tech, Tuskegee University and Joby Aviation. It builds on work conducted last year by NASA and Joby Aviation, which captured noise profile data from a full-size UAM prototype.
The two-week test program last year flew a remotely piloted aircraft loaded with the equivalent of a pilot plus four passengers at Joby’s Electric Flight Base in California. The aircraft registered decibel levels almost 1,000 times (30dB) quieter than that of a typical helicopter.
Co-principal investigator on the project Tasos Lyrintzis, distinguished professor and chair of the Aerospace Engineering Department said, “The advent of UAM will revolutionize the future of transportation. However, one of the persistent issues that needs to be addressed is noise. The proposed NASA project addresses several key issues for noise reduction, and the hope is that it will help move UAM closer to reality.”