Abstract: An apparatus for oscillating and orienting a vane comprising a main lever (7,8) connected to a main pivot (5,6); a main drive linkage (13) adapted to pivot the main lever from side to side about the main pivot in a pivot plane, a vane (16,17) pivotally connected to the main lever remote from the main pivot and adapted to pivot about a vane axis (18,19); an angle change assembly (24,25) adapted to pivot the vane about the vane axis during pivoting of the main lever such that the orientation of the vane relative to a fixed axis in the pivot plane is independent of the orientation of the main lever, the apparatus further comprising a displacement means (20,21) connected to the angle change assembly and adapted such that displacement of the displacement means alters the orientation of the vane relative to the fixed axis.