In order to weigh en route noise emissions originating from future propfan powered aircraft, a data base of emission levels from conventional turboprop aircraft is needed. For this reason flyover noise measurements on two twin-engine turboprop aircraft were conducted at flight heights between 17,000 and 21,000 ft. Acoustic data are presented together with propeller operational parameters and environmental meteorological data. Narrowband spectral analyses demonstrate the characteristic features of the measured propeller noise signatures: Noise spectra are dominated by the propeller rotational noise fundamental frequency and pronounced noise beats occur as a consequence of different rotational speeds of the propellers.
En Route Noise of Two Turboprop Aircraft
1990
47 pages
Report
No indication
English
Acoustics , Air Transportation , Noise Pollution & Control , Aircraft noise , Environment pollution , Noise measurement , Prop-fan technology , Propeller fans , Propeller noise , Routes , Turboprop aircraft , Acoustic properties , Aeroacoustics , Data bases , Height , Meteorological parameters , Military air facilities , Narrowband , Noise spectra , Spectrum analysis , Foreign technology