Abstract: A central axis water turbine is described which comprises a turbine body having a central axis; a rotor mounted on the turbine body for rotation about the central axis, the rotor comprising a central hub supporting a plurality of blades, each blade extending from a blade root mounted on the hub to a blade tip; a generator driven by the rotor; and a housing surrounding the rotor and adapted to direct water flow towards the rotor, the housing converging from a front opening forward of the rotor to a narrower throat adjacent the turbine body; wherein the blades are splayed rearward from the blade root to the blade tip by a tilt angle of 1° to 20° from a plane perpendicular to the central axis.

Abstract: A turbine blade is described which includes a blade root;a blade tip; a leading edge extending from the blade root to the blade tip; a trailing edge extending from the blade root to the blade tip; a blade root chord defined as a straight line between the leading edge and the trailing edge at the blade root; a blade tip chord defined as a straight line between the leading edge and the trailing edge at the blade tip; wherein the blade tip chord is angularly displaced from the blade root chord by a twist angle of between 50° and 90°.