[Objectives] We found a new component of propeller noises which is induced by the excitation of the low-frequency elastic mode of the propeller. In particular. the model where all the blades of a propeller vibrate in the same phase is stimulated will result in strong acoustic radiation. We have named the mode shape in which all the blades of a propeller vibrate in the same phase as "J... https://www.rawafricaonline.com/