Description: Currently, helicopter companies in Europe, the United States and Russia have already built quite a large number of singlepropeller helicopters, which use fenestron as an alternative to a conventional propeller. When designing a fenestron many problems are solved, and first of all, the developers face a problem of determining the most preferable aerodynamic layout of the “ propeller in the ring” system and selecting its design parameters. At the same time, more attention is paid to the study of aerodynamic characteristics and the solution of problems associated with the controlling and stability of a helicopter with this steering device. At the same time, the parameters of the fenestron and the keel substantially effect all the characteristics of the helicopter, including the performance indicators of its application when a helicopter performs various types of tasks. Therefore, the development of the calculation algorithm, as well as the development of recommendations for the choice of most preferable design parameters fenestron is relevant. The purpose of the article is to work out the algorithm for selecting most preferable design parameters of the fenestron with a keel which is used as a steering device on a helicopter of a single- propeller scheme based on the developed algorithm. The methods of aerodynamic design of the tail propeller (fenestron) in the annular channel of a helicopter single- propeller scheme in the form of an axial fan made according to the impeller scheme, with a rectifier behind it, are analyzed. On the basis of the analysis performed, the main formula dependencies of the design parameters of the fenestron on its geometric parameters are presented. An algorithm is presented for selecting rational design parameters of a fenestron with a keel, which is used as a steering system on a single- propeller helicopter. Thus, the developed algorithm allows to solve the problem of calculating and selecting most preferable design parameters of the fenestron. In the future, the developed algorithm will be used to select the parameters of the fenestron in the helicopter being designed.
Keywords: aerodynamic characteristics, algorithm, single-rotor helicopter, tail rotor, fenestron
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