A flowpath channel has a blade pivotally connected along a longitudinal axis thereof, at opposing top and bottom ends thereof, to respective top and bottom portions of the flowpath channel. The chord axis of the blade, between leading and trailing edges thereof, is capable of pivoting parallel to and skewed from the flowpath. The top end of the blade and an attachment structure secured to the flowpath channel each include a race. A bearing is disposed therebetween, and the blade is rotatable about the longitudinal axis.