Joby’s eVTOL aircraft registers equivalent of 45.2 dBA during acoustic footprint testing with NASA
Joby Aviation has announced that its full-size pre-production aircraft has successfully demonstrated its low noise profile, following acoustic testing completed with NASA.
Following analysis of the data obtained over two weeks of testing, Joby’s aircraft was shown to have met the low noise targets set for itself.
The aircraft registered the equivalent of 45.2 A‑weighted decibels (dBA) from an altitude of 500 meters at 100 knots airspeed,with its acoustic profile to be below 65 dBA at a distance of 100 meters.
Joby Founder and CEO JoeBen Bevirt said: “With an aircraft this quiet, we are helping to make flight an everyday reality in and around cities.”
All measurements were conducted using NASA’s Mobile Acoustics Facility, with more than 50 pressure ground-plate microphones placed in a grid array at Joby’s Electric Flight Base near Big Sur, CA.
To measure the Joby aircraft’s acoustic footprint, it flew over the grid array six times at an airspeed of 100 knots.
Data recorded from the field of omni-directional microphones was then processed by NASA into an ‘acoustic hemisphere’, representing the sound emission in all directions below the aircraft at a radius of 100 ft.
Joby then applied standard processing techniques for spherical spreading and atmospheric attenuation, resulting in an average free-field overhead flight acoustic reading of 45.2 dBA at 500 meters.
Joby also conducted more than 20 take-off and landing tests above the grid array, using a variety of acceleration rates and climb angles to allow NASA to capture acoustics representative of likely operational procedures.
Each of the six propellers can also individually adjust its tilt, rotational speed, and blade pitch to avoid blade-vortex interactions that contribute to the acoustic footprint of traditional helicopters.
Joby’s piloted five-seat eVTOL aircraft can carry four passengers at speeds of up to 200 mph, with a maximum range of 150 miles on a single charge and zero operating emissions. With more than 10 years of development and over a thousand flight tests completed, Joby is targeting the launch of its aerial ridesharing service in 2024.
