What Combination of Angle and Number of Blades on a Wind Turbine Propeller Will Generate the Most Electrical Voltage in a Wind Turbine?

Jeremy P.
8th Grade, St. Teresa Catholic School, Titusville, Florida
Teacher: Patricia Taurasi
Jeremy P's Science Fair project board
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Hypothesis: The researcher believes the propeller with six blades at a 45^o angle will generate the most electrical voltage in a wind tunnel. The researcher believes this because 45^o is half way in between flat (0^o)--where the wind would hit the blade and produce no thrust; and vertical (90^o)–where the wind would just pass by the blades. He believes that six blades will perform the best because the propeller with six blades has the most surface area.

Results: The propeller with five blades at an angle of 35^o produced more voltage than any of the other fourteen propellers in the wind tunnel. It produced an average of 0.256 volts (DC). The 35^o four-bladed propeller came in after the five-bladed and tied with the six-bladed propeller; followed by the three, then two-bladed propellers. The 35^o angle propellers produced more voltage than the other propellers in its blade number category. In fact, the two-bladed 35^o propeller produced a higher voltage than all of the 45^o and 55^o angle propellers.
The five and six-bladed 45^o angle propellers produced more voltage than the other 45^o angle propellers with an average voltage of 0.196 volts (DC). All of the 45^o angle propellers created a higher voltage than the 55^o angle propellers. The 45^o propeller with four blades came in after the five and six blades followed by the three then two-bladed propellers.
The five- and six-bladed 55^o angle propellers produced more voltage than the other 55^o angle propellers with 0.152 volts (DC). The 55^o propeller with four blades came in after the five- and six-bladed propellers followed by the three then two-bladed propellers.

Conclusion: The researcher’s hypothesis was that the propeller with six blades at a 45^o would produce the most voltage. The hypothesis was proven incorrect by the results of the project. The five-bladed 35^o angle propeller produced the most voltage, not the six-bladed 45^o propeller.
The lowest of the 35^o angle propellers, which was the two-bladed propeller, produced a higher voltage than all of the other 45^o and 55^o propellers. The five and six-bladed propellers, except in the 35^o angle class where only the five-bladed propeller, produced a higher voltage than the other propellers in their respective angle classes. The two-bladed propellers produced the least amount of voltage in their respective angle classes.
The researcher believes that the 35^o angle propellers produced the most voltage because more wind contacts each blade at one time than the other angles. More wind hits the 35^o angle at one time because it is closer to 0o which produces more drag so the propeller spins at a more rapid rate. The researcher also believes that the five-bladed propellers did better than or as good as the propeller with six blades because the blades on the six-bladed propeller are closer together so each blade passes through the turbulence of the previous blade; therefore, slowing it down. The researcher believes that the five-bladed propellers produced more voltage than the four-, three-, and two-bladed propellers because the propellers with five blades have a greater surface area, therefore, producing more drag than the other propellers.