In order to improve the torque performance of the propeller type wind
turbine, and to increase the relative rotational speed of the generato
r, two-staged wind turbines were proposed. The experimental results of
a wind tunnel test showed that self-starting characteristics of two-s
taged co-axial type were improved by attached front wind turbines for
two bladed main wind turbine, and the relative rotational speed of cou
nter-rotating type was increased. Then, a counter-rotating type trial
machine was constructed and a wind tunnel test was also conducted. The
test result demonstrated the technical possibility of conter-rotating
type wind powered generator.