12. Modification of technology as the main course in the military transport aircraft development

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.