A Comparison of Helicopter Main Rotor Features Due to Stiffness of Rotor Blade-Hub Connection

The paper presents results of simulation calculations concerning an influence of stiffness of blade-hub connection on rotor loads and blades deflections in hover, level flight and pull up maneuver. The three versions of rotor are considered with articulated, elastic and stiff connections of blades and hub. The blades with the same distributions of stiffness, mass and the same aerodynamic characteristics are applied for all rotor cases. The rotor loads are calculated applying Runge-Kutta method to solve the equations of motion of deformable blades. According to the Galerkin method, the parameters of blades motion are treated as combination of considered blade bending and torsion eigen modes. The results of calculations indicate for possibility to generate the greater rotor control moments and to improve helicopter maneuverability in the case of applying the non-changed blade of articulated rotor combined with elastic rotor hub.