If I have a motor use in 2 cases, the 1st case I use standard blade and 20% longer blade in the 2nd case.
People told me that longer blade will create higher CFM. However, I am not totally sure. First, I don't know any equation to relate blades with CFM change. Second, I think from the power point of view, longer blade will have larger surface area but the acceleration of the air particle will decrease. It means more air pass the blade area, but the air might move slower. I am really confused. Please help.