Abstract: An apparatus for oscillating a vane comprising a main lever pivoted at one end about a reference axis, and pivotally coupled at the other end to the vane about a vane axis remote from the reference axis; an angle change assembly connected to the vane such that rotation of the angle change assembly rotates the vane; and, a drive assembly, the drive assembly comprising a crank arm adapted to be pivoted about a fixed crank axis; a lever drive arm pivotally connected to the main lever at a point remote from the reference axis and pivotally connected to the main crank remote from the crank axis; a coupling member having first and second coupling arms connected together at a base, the base being adapted to pivot about a coupling axis; an angle drive arm connected at a first end to the angle change assembly for rotation thereof and pivotally connected to the first coupling arm remote from the coupling axis; the second coupling arm being pivotally connected to the lever drive arm remote from the coupling axis, the