A vertical axis turbine is disclosed, having a vertically oriented rotor shaft, a plurality of radially extended arms rotatably mounted on the rotor shaft, and a chassis at the distal end of each. For each chassis, an upper blade set is on an upper portion, having upper blade panels interconnected pivotally by upper guide links, and a lower blade set is on a lower portion, having lower blade panels interconnected pivotally by lower guide links. Each chassis has an upper shaft with an upper gear, coupled to the upper guide links, and a lower shaft with a lower gear coupled to the lower guide links. The upper gear and the lower gear mesh, limiting rotation of the upper shaft and lower shaft to opposite directions with similar rotational speeds.