Abstract: An elevated and elongated boom is centrally pivoted for rocking movement in a vertical plane through the horizontal plane. Provision is made to align such plane with the direction of the wind. A pair of free wings are mounted on the fore and aft ends of the boom with control panels being oscillatably mounted on such wings for determining, by their relative positions and aerodynamic equilibrium reaction thereto, the angle of attack of such wings. Provision is made to control the relative positions of the control panels with respect to their respective wings so that the wings have angles of attack of opposite sense, with such senses being reversed as the boom approaches each predetermined limit of its rocking motion. The fore (canard) and aft wings are positioned and sized relative to each other to equalize their moment contributions to the rocking motion of the boom. Alternative wing structures are disclosed.

Abstract: An elevated and elongated boom is centrally pivoted for rocking movement in a vertical plane through the horizontal plane. Provision is made to align such plane with the direction of the wind. A pair of free wings are mounted on the fore and aft ends of the boom with control panels being oscullatably mounted on such wings for determining by their relative positions and aerodynamic equilibrium reaction thereto the angle of attack of such wings. Provision is made to control the relative positions of the control panels with respect to their respective wings so that the wings have angles of attack of opposite sense, with such senses being reversed as the boom approaches each predetermined limit of its rocking motion.