Interferencja wirnik nośny - wirnik ogonowy

W artykule przedstawiono modele zaburzeń opływu śmigłowca w płaszczyźnie wirnika ogonowego wywołanych bliskością wirnika nośnego. Przedstawiono model śladu zawirnikowego w oparciu o zasadę Biota i Savarta w celu określenia zaburzeń pola prędkości indukowanej przez wirnik nośny w płaszczyźnie wirnika ogonowego [4].

The influence of disturbances to the flow around a helicopter resulting from a resultant reaction of the wake from the main rotor on the tail rotor, on the loading as well as control and noise of the helicopter was presented. The analysis was based on a rotational model of the system. The basis of the model of the interference is the replacement of wake generated by rotors and fixed lifting surfaces by a uniform rotational model in the form of discrete rotational grids. This allows for the integration of fields induced through all rotational elements of the system, in accordance with the Biot-Savart law. This law was accepted in view of the fact that, as the only law included in the flow model, it enables a constant processing of load calculations in an undefined flight, with the retention of a reasonable calculation time. The undertaking of this subject should help explain phenomena not completely recognized and which exert a significant influence on safety when operating helicopters certain states of flight. The results of modeling, carried out for the SW4 helicopter, contain an evaluation of disturbances of the field of flow around the tail rotor in given states of flight, in which the case of take-off in a sidewind and with the carrying out of a directional maneuver is of primary significance. In other cases, when the tail rotor does not enter into intensive disturbances of the velocity field by the main rotor, the interference phenomena are of lesser importance. The numerical program used allows for information about flow around and loads on the taił rotor in flow disturbed by the (main) rotor to be obtained. Resultant loads on the tail rotor can be evaluated, along with its chosen elements.