This paper reports the experimental study for the helix-Darrieus type wind turbines.
A drawback of the Darrieus type wind turbine is their low self-starting ability due to small generated torque at start.To alleviate the problem, we propose an effectiveness of helix-Darrieus type wind turbines modified from the straight bladed Darrieus type one, and conducted a series of wind tunnel tests.
The model of wind turbine tested has a diameter of 700mm, rotor height of 700mm, blade number of 3, and chord length of 100mm.We prepared 4 types having the different swept-backangles of 0 degrees, 10 degrees, 20 degrees, and 30 degrees.Moreover, we made 2 types having the different blade number of 2 and 4 with same swept-back angle of 20 degrees and solidity of 0.141.The chord length of 2 bladed turbine is 150mm, and 4 bladed is 75mm.
As a result of experiment for the starting characteristics, the helix-Darrieus wind turbines of 3 bladed with swept-back angle of 10 degrees and 30 degrees consistently started by themselves in wind velocity of 7m/s whereas straight bladed-Darrieus wind turbine (swept-back 0 degrees) needed wind velocity of more than 8m/s to start by itself In addition, for swept-back of 20 degrees, self start was observed from wind velocity of 6m/s.As a result of experiment of a power characteristic, when we changed a swept-back for 3 bladed type at wind velocity of 8m/s, it worked most efficiently at 20 degrees.Furthermore, we found that an output characteristic improved more when the number of blades is 2.
It became clear that the helix-Darrieus type wind turbines showed better performances for both the self-start characteristic and the power characteristic than that for the straight bladed Da rrius type.

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