Sunday, October 2, 2011

Vans Aircraft RV-12 Build, Section 20: Center Section Bulkhead (part 2)

Reference: page 20-03; 5.5 hours

Step 1: Place Bottom Skin on the tabletop. Place F-1204 Center Section Asssembly over the bottom skin and cleco the bottom flanges of the bulkheads as shown in Figure 1 on page 20-03 of the RV-12 plans.

Step 2: Temporarily loosen the clamps holding the F-1204 Center Section Aft Bulkhead to the F-1204 Center Section Assembly and allow the parts to realign according to thiaer being clecoed to the bottom Skin. Tighten the clamps and match-drill #30 the holes in the center section aft bulkhead into the center section assembly beginning at the center and progressively drilling and clecoing outboard. See Figure 1 in Van's Aircraft's plans. Drill #11 two places, see Pg 20-04, Figure 1.

Builders Note: While drilling these holes make sure the drill is perpendicular to the bulkhead, as the table top can not be used as a reference.

Step 3: Un-cleco the bottom flanges from the F-1276 bottom Skin and remove the F-1204 Center Section Assembly and F-1204D center Section Aft Bulkhead. Set the bottom skin aside for later use. Un-cleco the center section aft bulkhead from the center section assembly, remove the AN4 bolts, and deburr all match-drilled holes.

Step 4: Machine countersink 100 degrees the holes in the F-1204 Center Section Assembly that receive an AN426AD4 rivet - see figure 2 page 20-03 and figure 1 page 20-04 of the RV-12 plans. A piece of thin scrap with a 1/4 inch hole drilled in it may be used to check the diameter (as described on page 14-02 of the RV-12 plans.) Dimple the corresponding holes in the F-1204D Center Section Aft Bulkhead.

Step 5: Cut apart the F-1204P Skin Attach Flange to make F-1204P-L and F-1204P-R Skin Attach Flanges.

Step 6: Cut apart the F-1204T Skin Stiffener to make the right and left Skin Stiffeners.