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

파라메타 각 변화를 고려한 힌지없는 헬리콥터 로우터의 공력탄성학적 안정성

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.