Replacement Propeller Industrial/Commercial Heavy-Duty Propeller Dia (In.) 36 in Number of Blades 4 Pitch (Deg.) 38 Degrees Blade Material Galvanized Rotation CW Required Motor HP 2-3/4 Required HP @ Higher RPM 2 3/4 hp Required HP @ Lower RPM 1/2 hp RPM Low 500 RPM RPM High 850 RPM Max RPM 850 CFM @ 0.000-In. SP 18 417 CFM @ 0.125-In. SP 17 568 CFM @ 0.250-In. SP 16 590 CFM @ 0.375-In. SP 15 464 cfm CFM @ 0.500-In. SP 14 211 cfm Blade Height (In.) 5 1/4 in