| Summary: | 碩士 === 南台科技大學 === 機械工程系 === 101 === Nowadays, radio-controlled unmanned helicopter (RC helicopter) is not only used for entertainment purpose, it also serving as a useful aerial vehicle in many areas such as aerial photography, policing, observation or inspection. There are two main types for roll and elevator controls: first type is the flybar system which changing the pitch angles of main blades via flybar mechanism and the moving of swashplate. In addition, since the flybar stabilization movement is transmitted to the main blade mounts, it automatically help stabilizes the helicopter by changing the pitch angles of the main rotor blades. The second type is flybarless system which controls the roll and does stabilization without flybar. The two gyro sensors play a virtual flybar role in this system. Because of directly connect between servo motor and main blade, the flybarless system has a faster response but the stress placed on swashplate is also much more than on the flybar system. Therefore, it is necessary to take care of the reaction forces and stress distribution on those systems to build an optimal model. In this study, experimental and numerical methods were used to investigate the mechanical response of 450 sized electric collective pitch helicopters with/without flybar. The finite element analyses were used to investigate stress distribution on flybar and flybarless system. In order to get boundary and loading conditions for the numerical study, experiments were performed to acquire the force and moments generated by the rotary blades. The force response of helicopter was monitored during the operation of helicopters mounted on the test frame. The results of both flybar and flybarless systems were compared to see the differences between them, and the advantages and disadvantages of each system were investigated. Understanding the manner of operating, the forces response, stress distributions on the components of rotor head of the two rotor systems can provide important information in improving the RC-helicopter main rotor system.
Keywords: Flybar, Flybarless Rotor Head System, Finite element.
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