Aerodynamic trimmer head for use in flexible line rotary trimmers

An aerodynamic trimmer head for use in flexible line rotary trimmers having an aerodynamic, generally ellipsoidal profile and a plurality of aerodynamic elements defined by the upper and lower head surfaces for directing air, during rotation of the head, off of and over the upper and lower head surfaces and preferably away from the line extending from the housing, thereby reducing the drag on the head and the line projecting from the housing. The aerodynamic elements on the upper head surface preferably are defined by a plurality of equidistantly spaced inclined troughs extending downwardly and forwardly along curvilinear paths on the upper head surface and the aerodynamic elements on the lower head surface preferably are defined by a plurality of dimples formed in an annular surface extending about the lowermost end of the spool and a plurality of rearwardly inclined troughs formed about and above the dimples.