Abstract: In combination with a propeller disposed in an aircraft, aft from the nose portion of the craft, an improvement is provided for reducing noise, as well as mechanical load on the propeller blade, and includes a construction part situated upstream from the propeller and being exposed to the oncoming air flow prior to reaching the propeller, thus being an obstacle that has a particular contour in a plane transversely to an axis of rotation of the propeller, so that at least the rear edge, as seen in peripheral direction of rotation of the propeller, forms an angle that is not zero in relation to a leading edge of the propeller, when the propeller as a whole is in a horizontal disposition.