Waterproof Cooling Fan blade design

"Waterproof Cooling Fan" Tip Gap: How to adjust the gap that exists between the fan and the fan frame design is a major problem. Here the gap is too small will make the airflow and blade, frame friction, increasing noise; increase the gap is due to the influence of the flyback airflow and so reduce fan efficiency.
"h5雷竞技 " blade Arc: In addition to having a curvature of the blade in cross-section, the plane is not in the plan view extends along the radial straight, but slightly bent toward the direction of rotation, was a certain arc. If the blades radially extending straight, driven by rotation of the fan at the outlet side of the air show a widely scattered, air distance is short, and the "power" is not focused; slightly curved as the current product version, you can ensure that the blowing airflow focus within the columnar space in front of the outlet, adding "h5雷竞技 " blowing away with the wind pressure.