A method for reducing parasite drag of medium transport helicopter

At present, more and more stringent emission requirements are being imposed on helicopters. Carbon dioxide emissions are a function of fuel consumption, and fuel consumption is directly dependent on the power required for a helicopter cruise flight. The power, required for horizontal flight of a helicopter directly depends on the design of the fuselage and other non-lifting elements, and accordingly, on parasite drag. Therefore, the desire to reduce parasite drag is expected and understandable. Helicopter parasite drag reduction was hailed as one of the key topics of the Seventh Clean Sky Framework Conference. For sixty years of research on this topic, a tremendous amount of experience has been accumulated. In particular, it was found that the main contributors to the total parasite drag of the helicopter were the main rotor hub and swashplate. The subject matter of this article is the study of the parasite drag of the hub and swashplate of a medium passager/transport helicopter Mi-8/17. This study aimed to develop methods to reduce the parasite drag of the Mi-8/17 helicopter. Mi-8/17 is the most mass-produced twin-engine helicopter in the world. Currently, more than 4,5 thousand units are in operation around the world. Therefore, the task of reducing parasite drag for this helicopter is very relevant. Modern methods of computation fluid dynamics (CFD) are used. Modern methods of computational fluid dynamics with an acceptable degree of accuracy make it possible to consider the interference phenomena of the components of the hub, swashplate, and helicopter fuselage, which is not always possible, to obtain correctly during expensive wind tunnel tests. During the work, the following results were obtained. An analysis was made of the contribution of each element of the design of the hub and the main rotor swashplate to the total parasite drag. A method for reducing the parasite drag of a helicopter using a mast fairing is proposed. Several variants of the mast fairing were considered, and the most effective one was chosen. The effect, as well as its degree of influence, of the airflow blown by the fan cooling the air-oil radiators, on the general parasite drag of the helicopter was revealed. The results of the studies, given in this article have been implemented in the production.