Airbus Helicopters continues to explore ways to reduce helicopter noise with both technology and new operating methods with an eye toward future urban air mobility environments.
While the company’s Fenestron tail rotor and Blue Edge main rotor blades can reduce a helicopter’s overall noise signature, the company continues to explore ways to minimize other variables that can be irritants to the human ear including impulsive, tonal, and high-frequency sounds, as well as the duration of the sound exposure. An example of impulsive sound includes the common “blade slap” generated by the intersection of the main blades’ vortex trail with subsequent blades.
Possible solutions to further lower rotorcraft noise include “improving the Fenestron, working on blade profiles, reducing rotor speed, integrating hybridization, exploring low-sound flight procedures, and inventing very specific solutions for reducing a helicopter’s perceived sound footprint in urban areas,” said Julien Caillet, sound expert at Airbus Helicopters.
Research into helicopter noise is being used to evaluate potential eVTOL designs. Earlier this year, Airbus Helicopters’ innovation and acoustics teams, supported by the French civil aviation authority DGAC, conducted a study to measure the sound levels of Airbus helicopters as perceived by urban residents to positively influence the design of future eVTOLs. The project’s objective was to measure how buildings can filter or amplify sound.