US Patent 10392104 Shaft-mounted operators for folding and opening propeller blades

Aerial vehicles may be equipped with propellers having pivotable blades that are configured to rotate or fold when the propellers are not rotating under power. A pivotable blade may rotate about an axis of a propeller with respect to a hub in the presence of wind flow until the pivotable blade is coaligned with a fixed blade, in a direction opposite to the wind flow. A pivotable blade may also fold over a hub of a propeller in the presence of wind flow, with the pivotable blade and a fixed blade being oriented in directions opposite to the wind flow. A center of mass of the pivotable blade may be caused to be on the same side of an axis as a center of mass of a fixed blade, even where the axis is not normal to the wind flow, thereby reducing an amount of drag generated by the propeller.