<p>The present invention discloses a method of determining the fine pitch angle of one wind turbine blade of a rotor comprising a plurality of rotor blades, comprising the steps of: calculating the lift of the said one rotor blade at a predetermined angle over a plurality of rotations; changing the pitch angle of the one rotor blade whilst retaining the other rotor blades at their existing pitch angle; calculating the lift of the one rotor blade over a plurality of rotations at the new pitch angle; and repeating the steps until the angle at which maximum lift of the one rotor blade is determined. The invention extends to a method of improving the performance of a wind turbine.</p>
