Patent ID: 6974309

Claim:
A straight blade type turbine having at least one two-dimensional blade positioned in parallel with and around a central axis of the turbine, the two-dimensional blade having a cross-section with a blade chord turned around a center of the two-dimensional blade by an angle of 3° to −2° relative to a line perpendicular to another imaginary line connecting the central axis with the center of the two-dimensional blade; a distance between a fore end and the center of the cross section is 15 to 40 percent is a chord length of the blade; a calculated NC/R of between 0.5 and 2.2, wherein R is a radius extending from the axis to the center of the two-dimensional blade, C is the chord length, and N is the number of the two-dimensional blades; and a maximum thickness of the two-dimensional blade is between 20 and 25 percent of the chord length.