Flows over helicopter blades are very complex and turbulent. The blades experience dramatically different flow fields at various azimuthal angles. Also, a rotor normally consists of many elastic blades, with a strong coupling between aerodynamics and structure. The problem is indeed multidisciplinary. Current helicopter blade designers use computational models, which depend heavily on experimental data and cannot be used to predict any novel design, which is a significant departure from existing designs. To simulate this multiscale and multidisciplinary physics with confidence, we have developed a robust multidisciplinary computational tool called WINDUS-HELI based on the WIND-US code by coupling CFD with CSD, adopting state-of-the-art numerical approaches, and applying high fidelity physics models. Very reasonable results have been obtained for both the aerodynamic loads/performance and acoustics predictions for all the validation cases studied.