Propeller, Replacement, Propeller Dia. (In.) 18 in, Bore Dia. (In.) 1/2 in, Number of Blades 3, Pitch (Deg.) 23 Degrees , Blade Material Aluminum, Keyway (In.) -, Rotation Clockwise Facing Discharge, Required Motor HP -, Required HP @ Higher RPM 1/4 hp, Required HP @ Lower RPM 1/12 hp, RPM Low 1,140 RPM, RPM High 1,725 RPM, Max. RPM 1,725 RPM, CFM @ 0.000-In. SP 3,082/2,037 cfm, CFM @ 0.125-In. SP 2,842/1,656 cfm, CFM @ 0.250-In. SP 2,584/1,331 cfm, CFM @ 0.375-In. SP -, CFM @ 0.500-In. SP -