Abstract: The leading edge method improves fan blade aerodynamics, which reduces energy lost into the airflow as acoustic noise. This results in a quieter fan, with no significant change to air moving capability. This is accomplished by increasing the radius of the fan blade leading edge, and by ensuring that any laminar boundary layer existing over the fan blade is tripped into a more energetic, and less likely to separate, turbulent boundary layer. Most fan blades are not fabricated with aerodynamic (airfoil) cross sections. Typically, they are either stamped from sheet stock, or molded out of thin material, in both cases with “sharp” leading edges with small leading-edge radius compared to fan blade chord length. Airfoils designed to operate at the Reynolds-numbers applicable to fan blades eschew sharp leading edges for large, rounded leading edges to control the surface pressure distributions and permit operation over a wide angle of attack range without boundary layer separation.