Part numbers and illustrations are for identification only © 1971-2010 w.d. armstrong corp. 274 PROPELLER BLADES You  must  always  specify  “CLOCKWISE"  or "COUNTER- CLOCK WISE"   construction   of each  blade.  The  illustration  is  of  a  CLOCK- WISE  blade.  Note  that  when  you  face  this blade,   it   must   be   rotated   CLOCKWISE   in order to blow air toward you. EXAMPLE:  Part  Number  20-27-4CCW  is  a  counter-clockwise,    20"  4-wing blade with a 27º pitch. A 6-pole (1050-1140 RPM) motor should be 1/5 HP for ventilators or 1/3 HP for condensing units. WIDE, SQUARE BLADES ARE DESIGNED SPECIFICALLY FOR HIGH STATIC PRESSURE TO FORCE AIR THROUGH HEATING OR COOLING COILS. HEAVY DUTY STEEL BLADES FOR VENTILATORS AND CONDENSING UNITS + Available in CCW only (Revcor)  * Has 1/2" hub installed.  CCW only (Lau) PART NUMBER REFERENCE Dia....Pitch..Wings 10 ........23 .............4 10 ........27 .............3 10 ........27 .............4 10 ........33 .............4 12 ........19 .............4 12 ........23 .............3 12 ........23 .............4 12 ........27 .............4 12 ........33 .............4 14 ........19 .............4 14 ........23 .............3 14 ........23 .............4 14 ........23 .............5 14 ........27 .............3 14 ........27 .............4 14 ........27 .............5 14 ........33 .............4 16 ........19 .............3 16 ........23 .............3 16 ........23 .............4 16 ........27 .............4 16 ........27 .............5 16 ........33 .............4 16 ........33 .............5 18 ........27...........2+ 18 ........27 .............3 18 ........27 .............4 18 ........27 .............5 18 ........30 .............3 18 ........30 .............4 18 ........33............2* 18 ........33 .............3 18 ........33 .............4 18 ........33 .............5 20 ........25...........2+ 20 ........27 .............3 20 ........27 .............4 20 ........27 .............5 20 ........30 .............3 20 ........30 .............4 20 ........33 .............3 20 ........33 .............4 20 ........33 .............5 22 ........27...........2+ 22 ........27 .............3 22 ........27 .............4 22 ........27 .............5 22 ........33 .............3 22 ........33 .............4 22 ........33 .............5 24 ........27............2* 24 ........27 .............3 24 ........27 .............4 24 ........27 .............5 24 ........33 .............3 24 ........33 .............4 24 ........33 .............5 26 ........24 .............4 26 ........27 .............4 26 ........27 .............5 26 ........33 .............4 26 ........33 .............5 Dia. ...Pitch..Wings Dia....Pitch..Wings Part No. Add Rotation Part No. Add Rotation Part No. Add Rotation FAN PITCH & ROTATION GAUGE 05099801 Tell at a glance the degree of pitch & direction of ro- tation (CW or CCW) or any size fan blade. Position flat end (B) of gauge shaft on flat surface of fan hub & Base (A) of gauge on surface of fan blade. Gauge will indicate rotation and degree of pitch. CENTER HUBS MUST BE ORDERED SEPARATELY CENTER HUB WITH MOUNTING SCREWS AND SET SCREWS, ORDER BY SHAFT SIZE. AH14 1/4" AH516 5/16" AH38 3/8" AH12 1/2" AH58 5/8" AH34 3/4" ORDER BY DIAMETER, PITCH, WING COUNT, AND DIRECTION.