Aeromechanics Analysis of Counter-Rotating Coaxial Rotor Systems

This thesis focused on the combined experimental and numerical aeromechanics analysis of counter-rotating coaxial rotor systems. Two different systems were regarded in the scope of this work. First, an experimental and model-scale coaxial lift-offset rotor system designed for high-advance-ratio forward flight that used closely-spaced rigid rotors in hover and wind tunnel operation, and second, a full-scale ultralight coaxial helicopter with farther spaced rotors in teeter configuration during free-flight. Both systems’ blade structural characteristics were modeled according to measured elastic properties. Reduced-order aerodynamics modeling using a free-vortex wake method was used to ensure computational efficiency.