파라메타 각 변화를 고려한 힌지없는 헬리콥터 로우터의 공력탄성학적 안정성

The Study on the Aeroelastic Stability of Hingeless Helicopter Rotor in Hover Considering Parametric Angle Changes

The effect of the changes in parameter angles(precone, droop, sweep) on the lead-lag damping was focused on. Experiment was made with hingeless 4-blade rotors and NACA 0012 airfoil. For the measurement of the rotating natural frequencies and lead-lag damping, non-rotating swash plate was oscillated at the regressing lag mode frequency and the data were acquired after the excitation was cut off. Analysis was made using a finite element formulation based on Hamilton's principle. The main blade is assumed as elastic beams. Quasi-steady strip theory is used to obtain aerodynamic forces, and non-circulatory forces are also included.