Results:

Number of blades- 3
Distance the fan is away the from windmill- 80cm

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Windmill blade angle- 20 degrees

Trial 1- 36 turns/rounds

Trial 2- 42 turns/rounds

Trial 3- 41 turns/rounds

Average- 40 turns/rounds
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Windmill blade angle- 40 degrees

Trial 1- 21 turns/rounds

Trial 2- 18 turns/rounds

Trial 3- 26 turns/rounds

Average- 21 turns/rounds

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Windmill blade angle- 60 degrees

Trial 1- 19 turns/rounds

Trial 2- 13 turns/rounds

Trial 3- 18 turns/rounds

Average- 16 turns/rounds

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Conclusion: the windmill blade angle 20 degrees and the round turn is the best. ( 20 degrees for a windmill blade angle is the most efficient.)

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