Main Phase of the ERATO Cooperation on Aeroacoustic Rotor Optimization

This report summarizes major steps and results of the second or main phase of the aeroacoustic rotor optimization programme (ERATO), which was jointly conducted by ONERA and DLR. In order to fulfil the ambitious design goal of 6dB reduction of the BVI impulsive noise during landing approaach compared to the 7AD reference rotor, extensive parametric studies on different rotor and blade design parameters were performed followed by the aeroacoustic optimization process which was based on the results of the parametric studies and on engineering judgement.