Propeller, Replacement, Propeller Dia. (In.) 18 in, Bore Dia. (In.) 1/2 in, Number of Blades 4, Pitch (Deg.) 19 Degrees , Blade Material Spark Cast Aluminum, Keyway (In.) -, Number of Set Screws 2, Rotation Clockwise Facing Discharge, Required Motor HP 1/4, Required HP @ Higher RPM -, RPM Low -, RPM High -, Max. RPM 1,725 RPM, CFM @ 0.000-In. SP 2,840 cfm, CFM @ 0.125-In. SP 2,390 cfm, CFM @ 0.250-In. SP 1,940 cfm, CFM @ 0.375-In. SP 1,630 cfm, CFM @ 0.500-In. SP -