Acoustic Environment of an F-35B Aircraft During Vertical Landings

Measurements of the sound field near an F-35B during vertical landing operations are reported. Data are presented and discussed from the approach, hover, and descent of the aircraft, and compared with ground run-up measurements. Overall levels are comparable to published values for the F-35A at 50{\%} engine thrust ratio during ground run-ups. One-third-octave spectra are also presented, and spectra from various stages of the approach and landing are compared. Changes in the spectral shape during the landing process are discussed and impingement is presented as a possible cause of these changes.