A pair of airfoil blades having a longitudinal axis coincident with one another. Each blade is bent at the center on the plane of the chord. Each blade has an airfoil tip blade placed at the outer most trailing edge. The blades are affixed by their root ends to opposite ends of a torsion shaft. The blade chords are offset from one another, which defines a blade pitch angle. The torsion shaft is journaled perpendicular through a driveshaft, whereas the rotation of the blades can transfer through the torsion shaft to the driveshaft and cause the driveshaft to turn, eliminating the need for a hub. The blades are adapted to pivot along with the torsion shaft. The blades lie in substantially the same plane, and are adapted for rotation in a plane orthogonal to the longitudinal axis of the driveshaft. Each blade has an airfoil shaped fluid gate valve disposed on the leading edge.