A cooling fan for an alternator. The cooling fan has a fan body and a plurality of fan blades extending from the fan body. A hinge is located where each one of the fan blades meets the fan body. The hinge allows the plurality of fan blades to pivot relative to the fan body. The degree of pivot is proportional to rotational speed of the fan body.

A fan assembly for gas turbine engine according to an exemplary embodiment of this disclosure includes, among other possible things, a plurality of fan blades rotatable about a fan rotation axis, each of the plurality of fan blades movable about an axis transverse to the fan rotation axis, a fan nacelle partially surrounding the plurality of fan blades, and a pitch mechanism coupled to the plurality of blades that changes an angle of pitch for each of the plurality of blades corresponding to a circumferential position of the fan blade about the fan rotation axis.

A fan of a turbine engine, the fan including a fan disk provided with blades on its periphery, the blades being pivotally mounted on the disk around a pivoting axis and having a center of gravity, and a pitch change mechanism for the blades, each blade being configured so that its center of gravity is positioned on or at a small distance from a fictitious plane which passes through the pivoting axis of the blade and which is perpendicular to the axis of revolution of the fan when the blade is in a minimum drag position.

A gas turbine engine is provided. The gas turbine engine includes a core and a variable pitch fan arranged in flow communication with the core. The variable pitch fan has a disk and at least nine fan blades coupled to the disk for rotation together with the disk. The gas turbine engine further includes a rotatable nacelle covering the disk such that the engine has a fan hub radius ratio of between about 0.1 and about 0.4.

A fan of a turbine engine, the fan including a fan disk provided with blades on its periphery, the blades being pivotally mounted on the disk around a pivoting axis and having a center of gravity, and a pitch change mechanism for the blades, each blade being configured so that its center of gravity is positioned on or at a small distance from a fictitious plane which passes through the pivoting axis of the blade and which is perpendicular to the axis of revolution of the fan when the blade is in a minimum drag position.