Vans Aircraft RV-12 Build, Section 20: Center Section Bulkhead (part 3)

I guess with the center bulkhead almost done this puts me well into the "are you building a canoe?" phase of building the RV-12 aircraft. Compared to the tail cone and wings there are a lot of smaller parts; this will slow things down a bit because I am alodining and zinc chromating parts as I build. Reference: page 20-03, page 20-04; 4 hours

Step 7: Attach the F-1204P-L and -R Skin Attach Flanges to the F-1204 Center Section Assembly.



This completes page 20-03.

Reference page 20-04

Step1: Attach the F-1204D Center Section Aft bulkhead and the F--1204F-L and -R Aft side Bulkheads to the F-1204 Center Section Assembly.

Builder's note: The plans call for AD4-8 rivets along the top edge of the of the Bulkhead. These proved to be too short on my plane, so I used -9. In the picture below you can see the resulting shop head of an -8 in the rivet gauge. All the other ones pictured are 4-9.





Step 2: Place the F-1204 Center Section Assembly upside down on the work surface. Install clecos as shown in Figure 1 on page 20-04 of Van's Aircraft plans for the RV-12. This is to prevent drill chips from falling between the center section assembly and the Center Section Aft Bulkhead while drilling. Cleco the f-1270-L Fuselage Side Skin to the center section assembly and to the F-1204T-L Skin Stiffener. Match-drill #30 the skin stiffener to the center section assembly. Repeat the process for the right side skin stiffener. Deburr holes and rivet the stiffener to the center section.





Note: These are LP 4- that are used not 4-3. This completes the Center Section bulkhead. Next entry I will continue with section 21 of the fuselage for the RV-12.

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.