A supplemental wing for a rotary wing aircraft rotates about a pitch axis between a forward flight position and a hover position. The supplemental wing generates lift and generates both positive and negative pitching moments that balance and that may passively rotate the supplemental wing to an equilibrium position. The supplemental wing may use power assist to overcome friction to move to the equilibrium position. The lift generated by the supplemental wing reduces at high forward speeds to preserve main rotor control authority. The supplemental wing rotates to avoid aft translation when in the hover position. The supplemental wing may be retrofitted to existing helicopters and flown using existing helicopter controls without pilot re-training.