The effects of modifying the inboard portion of the experimental NREL Phase VI rotor using a thickened, blunt trailing-edge (or flatback) version of the S809 design airfoil are studied using a compressible, three-dimensional, Reynolds-averaged Navier–Stokes method. A motivation for using such a thicker airfoil design coupled with a blunt trailing edge is to alleviate structural constraints while reducing blade weight and maintaining the power performance of the rotor. The numerical results for the baseline Phase VI rotor are benchmarked against wind tunnel measurements obtained at freestream velocities of 5, 7 and 10ms−1. The calculated results for the modified rotor are compared against those of the baseline rotor. The results of this study demonstrate that a thick, blunt trailing-edge blade profile is viable as a bridge to connect structural requirements with aerodynamic performance in designing future wind turbine rotors. Copyright © 2007 John Wiley & Sons, Ltd.