Annotation: The process of creating modifications of aircraft in the transport category is a very relevant and widespread phenomenon in modern aircraft construction. A separate group of military transport aircraft has been distinguished in connection with the specific character of their mission: – the need to formulate the characteristics “cargo – range” for light, medium, operational tactical and strategic military transport aircraft, since it is precisely according to this characteristic that they are positioned by their purpose; –specific requirements are imposed on military transport aircraft cargo compartment not only with respect to its geometrical dimensions and usable volume, but also with respect to the possibility of simultaneous accommodation of military equipment and people, as well as the placement of a stretcher with t he wounded during their evacuation from the war zone; – the possibility of airborne landing of military equipment and paratroopers, which requires specific hatches and means of maintaining weight balance in flight; – the possibility of basing on poorly prepared sites with a runway length of less than 800 m in the short take-off and landing (STL) mode, especially for operational tactical military-technical vehicles, which significantly expands their use in combat zones; – the possibility of conversion into a civilian aircraft: for the delivery of goods to areas of the far north, when fighting fires, when evacuating victims from disaster zones, etc. The article shows that creation of modifications of expensive military transport aircraft is the main direction of their development. All leading aircraft manufacturing companies in the world use modification procedures as the way to most quickly meet constantly changing requirements for military transport aircraft. Along with the traditional methods of designing the modifications, the domestic school proposed a new methodology for determining the necessary parameters for “deep” modifications in wing geometry and propulsion system. The methodology is based on the use of three principles: – ensuring growth of carrying capacity and the required range of modifications of military transport aircraft of various purposes; – geometric re-arrangement of wing and system of carrying surfaces “wing + tail units” according to the criterion of minimum inductive resistance when lifting forces are equal to basic version; – coordination of modifications in wing with the required parameters of propulsion system as a condition for ensuring the required fuel efficiency.

Annotation: This article considers the practical data on parts (specimens) manufacturing from powder metal material 316L using the innovative method of selective laser melting; the comparative study of the structure and physical and mechanical properties of 316L material, the combined influence of heat treatment and specimen orientation relative to the arrangement plate on the physical and mechanical properties and structure of specimens made of 316L alloy. Results are presented of the following: comparative study of the physical and mechanical properties and structure of specimens, manufactured using the selective laser melting technologies with horizontal and vertical placement relative to the arrangement plate; dependence of the ultimate strength and unit elongation on the annealing temperature. The possibility and suitability of the selective laser melting technology to manufacture parts and space-rocket hardware are evaluated. Experimental study of the specimens heat treatment conditions after selective laser melting enabled the definition of the optimal condition for the 316L alloy and have shown that heat treatment of the manufactured specimens under the heating at 1230 °С with the subsequent tempering at the temperature of 510 °С gives the homogeneous structure to the material of specimens made of alloy 316L, its dendritic structure, inherent in the specimen material in its initial condition, disappears after selective laser melting. Results of the mechanical tests of the obtained specimens have shown that the technology of selective laser melting provides development of products made of powder metal material 316L with optimal complex of physical and mechanical properties. It is shown that transition to the selective laser melting technology will enable production of the aerospace products, in particular geometrically-complex parts made of powder metal material 316L, in one technological cycle, excluding cutting, punching, refinement, cropping, welding, manufacturing of special tools or stamps