The article is dedicated to the substantiation of the complex parameter that characterizes the technical level of an unmanned aerial vehicle (UAV). This parameter includes the maximum lift-to-drag ratio, propeller efficiency, specific fuel consumption, and other components, on which the main flight characteristics, such as flight range and flight duration, depend. To make a comparative assessment of UAVs of different types, a special scale is developed.

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The authors of the paper presented some of the models describing the process of micro-cracks’ development. In this study, the process of a selected model of micro-cracking was analyzed. In the model it was assumed that the damage to the material has some “thermodynamic properties” or rather universal properties inherent in most complex systems. In order to calculate the long-term fatigue strength properties of a structure, it is important to have a good understanding of the distribution parameters of the number of defects of different sizes. A model was built using the entropy principle, which is effectively used to test complex systems that are difficult to formalize. As a result of many experimental studies it was found that the development of fatigue damage is closely related to the process of plastic deformation of the material at the contact point of local defects. The results of computer calculations and simulations led to the conclusions presented in the final part of this paper.

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