A hybrid Navier-Stokes/free-wake solver has been employed to investigate the performance of a rotor equipped with a Gurney flap in steady level flight and in descent. A scaled model of the BO-105 rotor was studied. The calculations were coupled to a comprehensive analysis to properly account for the effects of the elastic deformations on the aerodynamic loads and to account for trim. Fixed and dynamically deployed Gurney flaps were considered. In forward flight, it was found that a properly chosen azimuthal deployment schedule of the Gurney flaps may reduce the peak-to-peak variations in hub loads, potentially reducing vibrations. In descent flight, it was found that the deployment of a fixed Gurney flap decreased the descent rate needed to maintain autorotation.