Andrew Miller's experiment was to improve wind turbine performance by applying protuberances to turbine blades. Andrew did his testing in a homemade wind tunnel to determine the best configuration of placing protuberances on a 22" propeller blade. The optimum configuration was then field tested on a downwind, horizontal 1.9 kw turbine, the Skystream 3.7. The results indicated that placing protuberances on the leeward side of a mid-size wind turbine blade can significantly improve power output at low to moderate wind speeds. This invention is valuable not only because it improves the performance of home turbines, but also because it is easy to retrofit currently existing wind turbines.