US Patent 9404511 Free-tipped axial fan assembly with a thicker blade tip

A free-tipped axial fan assembly includes a fan having a blade tip geometry which minimizes the adverse effect of a tip gap. The maximum blade thickness exhibits a significant increase adjacent the blade tip. In some constructions, the maximum thickness at the blade tip is at least 100 percent greater than the maximum thickness 0.10 R away from the blade tip. In some constructions, the trailing-edge thickness at the blade tip is approximately the same as the trailing-edge thickness 0.10 R away from the blade tip. In some constructions, the increase in blade thickness follows the square of the distance from the position where the increase begins.