weighing points is 75 inches, the weight of the nosewheel  (F) is 340 pounds, and the distance between main wheels  and nosewheel (L) is 78 inches. The total net weight of the  airplane (W) is 2,006 pounds. The location of the CG may be determined by using the  The CG is 19.7 inches behind the datum. The datum of the airplane in  Figure 3-14  is located at the  intersection of the wing root trailing edge and the fuselage. This places the arm of the main gear (D) at –80 inches. The  net weight of the tailwheel (R) is 67 pounds, the distance  between the main wheels and the tailwheel (L) is 222 inches,  and the total net weight (W) of the airplane is 1,218 pounds. Since the datum is aft of the main wheels, use the formula  formula in  Figure 3-11 . The CG location is a negative value, which means it is 88.2  inches forward of the datum. This places it 13.2 inches  forward of the main wheels, exactly the same location as  when it was measured from other datum locations. The location of thedatum is not important, but all  measurements must be made from the same location. Locating the CG of a tailwheel airplane is done in the same  way as locating it for a nosewheel airplane except the formula  is . R × L W The distance (D) between the datum of the airplane in  Figure 3-12  and the main-gear weighing points is 7.5 inches,  the weight of the tailwheel (R) is 67 pounds, and the distance  (L) between the main-wheel and the tailwheel weighing points  is 222 inches. The total weight of the airplane (W) is 1,218  pounds. Determine the CG by using the formula in  Figure3-13 .  found in  Figure 3-15 .  The CG is 67.8 inches forward of the datum or 12.2 inches  aft of the main-gear weighing points. The CG is in exactly  the same location relative to the main wheels, regardless of  3-7 Figure 3-12.  The datum of this tailwheel airplane is the wing root  leading edge. Figure 3-16.  Determining the CG with datum aft of the main wheels  in an airplane with tailwheel landing gear. Figure 3-14.  The datum is aft of the main wheels, at the intersection  of the wing trailing edge and the fuselage. Figure 3-11.  Determining the CG with datum aft of the main wheels  of an airplane with nosewheel landing gear. Figure 3-13.  Determining the CG with datum forward of the main  wheels in an airplane with tailwheel landing gear. CG  R × L W = D + = 7.5 + 19.7 = ( ) 67 × 222 1,218 ( ) CG  F × L W = − D +  = − 75 + −88.2 = ( ) 340 × 78 2,006 ( ) Datum L = 222.0 D = −80 142 67.8 Location of Datum Datum Forward of the Main Wheels—Tailwheel  Landing Gear CG  R × L W = −D + = −80 + = −67.8 ( ) 67 × 222 1,218 ( ) D = 7.5 Datum 229.5 L = 222.0 19.7 Datum Aft of the Main Wheels—Tailwheel  Landing Gear