Power characteristics of horizontal axis wind turbines with loop-formed plastic ribbons as blades were investigated by wind tunnel tests. When blade mounting positions to the hub of ribbon both ends were twisted 10 degrees, turbine showed peak power. The power of a wind turbine with two blades was inferior to that of turbines with three and four blades. Solidity giving maximum power was found to be 0.5～0.6 by changing blade width and number of blades. Influence of installation location of blades in their width direction to hub was examined. Optimum blade setting angles were found to be 40° at windward and 30° at leeward. Deformation of blades in rotating turbine was observed and seemed to suppress overspeed.
