Aerodynamics Analysis of Helicopter Rotor in Flight Test Using Strain Gauge Sensors

The acquisition of aerodynamic loads on helicopter rotors is fundamental to the study of helicopter performance optimization, structural design, flight control, and other aspects. However, at present, aerodynamic loads on rotors are primarily obtained through theoretical calculations, simulation analysis, and wind tunnel tests, with few reports on flight measurements. This paper proposes a method for obtaining helicopter rotor aerodynamic loads by flapping moment measurements in flight with strain gauge sensors. First, strain gauge sensors are installed at different cross-sectional positions on the rotor blades to measure strain during flight. Then, the strains are incorporated into the blade flapping motion equations to establish the relationship between rotor aerodynamic loads and flapping moment. Finally, the aerodynamic loads on the rotor are calculated by the relationship. This method can provide more accurate load calculation results compared to simulation computations and wind tunnel tests. In this paper, the distribution patterns of rotor aerodynamic loads were investigated, which aligned with theoretical analysis and can offer valuable insights for blade design optimization.