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Today’s progress in the rotorcraft is mostly associated with an optimization of aircraft performance achieved byactive and passive modifications of main rotor assemblies and a tail propeller. The key task is to improve their performance,improve the hover quality factor for rotors but not change in specific fuel consumption. One of the tasks to improve thehelicopter is an active optimization of the main rotor providing for flight stages, i.e., an ascend, flight, a descend. An activeinterference with the airflow around the rotor blade section can significantly change characteristics of the aerodynamic airfoil.The efficiency of actuator systems modifying aerodynamic coefficients in the current solutions is relatively high andsignificantly affects the increase in strength. The solution to actively change aerodynamic characteristics assumes a periodicchange of geometric features of blades depending on flight stages. Changing geometric parameters of blade warping enablesan optimization of main rotor performance depending on helicopter flight stages. Structurally, an adaptation of shape memoryalloys does not significantly affect rotor blade fatigue strength, which contributes to reduce costs associated with an adaptationof the system to the existing blades, and gains from a better performance can easily amortize such a modification and improveprofitability of such a structure. In order to obtain quantitative and qualitative data to solve this research problem, a number ofnumerical analyses have been necessary. The main problem is a selection of design parameters of the main rotor and apreliminary optimization of its performance to improve the hover quality factor for rotors. This design concept assumes a three-bladed main rotor with a chord of 0.07 m and radius R = 1 m. The value of rotor speed is a calculated parameter of anoptimization function. To specify the initial distribution of geometric warping, a special software has been created that uses anumerical method of a blade element which respects dynamic design features such as fluctuations of a blade in its joints. Anumber of performance analyses as a function of rotor speed, forward speed, and altitude have been performed. Thecalculations were carried out for the full model assembly. This approach makes it possible to observe the behavior ofcomponents and their mutual interaction resulting from the forces. The key element of each rotor is the shaft, hub and pinsholding the joints and blade yokes. These components are exposed to the highest loads. As a result of the analysis, the safetyfactor was determined at the level of k > 1.5, which gives grounds to obtain certification for the strength of the structure. Theconstruction of the joint rotor has numerous moving elements in its structure. Despite the high safety factor, the places withthe highest stresses, where the signs of wear and tear may appear, have been indicated. The numerical analysis carried outshowed that the most loaded element is the pin connecting the modular bearing of the blade yoke with the element of thehorizontal oscillation joint. The stresses in this element result in a safety factor of k=1.7. The other analysed rotor componentshave a safety factor of more than 2 and in the case of the shaft, this factor is more than 3. However, it must be rememberedthat the structure is as strong as the weakest cell is. Designed rotor for unmanned aerial vehicles adapted to work with bladeswith intelligent materials in its structure meets the requirements for certification testing. Acknowledgement: This work hasbeen financed by the Polish National Centre for Research and Development under the LIDER program, Grant Agreement No.LIDER/45/0177/L-9/17/NCBR/2018
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