# Number of blades in a fan

How does the number of blades in a fan affect the flux of air? I read that 3 blades are the best option but some companies uses more blades because there's a misconception among people that more blades generates more air.

• What is your fan trying to do? Does it try to move air without (significant) pressure difference or does it try to build pressure? Those are completely different applications requiring different solutions. I believe that fewer blades are better for the first case, but fan compressors have to be built with a large number of blades, as the case of gas turbines shows. – CuriousOne Sep 6 '14 at 14:51

But typical engineering goal for fans is different: maximum performance / noise. More blades $\implies$ slower rotation for same performance $\implies$ less turbulence $\implies$ less noise.