Measurements of Rotorcraft Hub and Fuselage Interactional Aerodynamics

Hub drag reduction and understanding the resulting interactional aerodynamic impact on performance is a critical need for high speed rotorcraft designs. Wind tunnel test results are presented for rotorcraft hub models and aerodynamic interaction with a generic fuselage model. Testing included a defeatured baseline hub model, which has been the subject of previous experimental and numerical studies, and a new, low-profile, low drag hub design. Separate load measurements with a rotor test stand balance and fuselage frame load cells allow for determining component contributions of the hub and fuselage models to total drag of each tested configuration. Wake measurements using a hot-wire survey allows for comparisons of velocity deficit, turbulence, and harmonic content from different hub configurations with the fuselage. Surface pressure measurements and flow visualization on the aft section of the fuselage model are used to document the significant changes of the fuselage flow field due to each hub configuration.