Abstract
The technique of flow control has been developed in recent years. It is well known that drag force for an airfoil can be diminished and thrust could be produced by changing the arrangement of vortex street in the wake from Karman vortex street type to thrust producing vortex street type. We considered it possible to produce thrust of an airfoil adding pitching motion. In this study, the flow pattern behind a pitching airfoil has been visualized and thrust force measured. As a result, the relationship between the thrust producing characteristics and flow patterns in the wake has been clarified.