МЕТОД ПРОЄКТУВАННЯ МОДИФІКАЦІЇ ЛІТАКА НА БАЗІ ІСНУЮЧОГО СІМЕЙСТВА ЛІТАКІВ ТРАНСПОРТНОЇ КАТЕГОРІЇ

The paper presents a method of creating a transport aircraft based on an existing family of passenger aircraft that provides for the possibility of determining the optimal parameters of the tail section of the fuselage and the fuselage itself. The family of domestic regional passenger airplanes AN-1X8 was taken as a basis. The unification of components and assemblies of the designed aircraft with the existing family of aircraft is described, the range of transported cargo and operating conditions are analyzed. At the stage of the preliminary design, based on statistical data, 5 variants of the fuselage tail sections with different schemes of sealed cargo doors were developed. A master geometry of each of the 5 tail sections was developed, taking into account the design features of a particular cargo door scheme. Aerodynamic studies of the flow of a separate model of the aircraft (fuselage, wing, landing gear fairing) of all 5 variants were carried out to determine the distribution of the pressure and friction coefficient on the fuselage surface, to assess the accompanying jet behind the fuselage, the formation of vortices and their intensity. Based on the results of the aerodynamic studies, appropriate conclusions were made about the aerodynamic perfection of the fuselage tail sections. Next, the weight characteristics of each of the fuselage tail sections were evaluated and the centering of the aircraft was checked. Considering, in addition to aerodynamic and weight characteristics, the operational features and characteristics of the designed aircraft, the most optimal fuselage tail shape and cargo hatch layout for the new aircraft was selected. This approach made it possible to select the optimal fuselage parameters for the new aircraft, which significantly improved its technical characteristics and, consequently, its competitive capabilities. In addition, this design method ensures high optimization of financial and production costs, since a significant number of existing developments are used to create a new aircraft.