Saturday, March 31, 2012

Vans Aircraft RV-12 Build, Section 21: Mid Fuse Bibs & Bottom Skins (part 10)

Reference: page 21-16, page 42D-14; 5 hours

During this entry we will install the bottom skin on the Van's RV-12s forward fuselage. Also, Van's Aircraft has an option on this page of the airplane plans for adding optional nutplates for the antenna mount (at least I believe it is the comm antenna as it would be a bad place for the GPS antenna!) Also I am installing the Dynon Skyview avionics package and now is the time to start with the airframe alterations

Step 1: Dimple the four sets of nutplates attach rivet holes around each access hole in the Bottom Skin.

Builders note: This is was a good time to install the optional nutplates for the antenna mount. First I made a nutplate centering tool out of a nutplate and bolt. Then after drilling them the rivet holes need to be dimpled. One way is to use a blind dimpler and a hand rivet puller as pictured below. Being I still have my C frame dimpler from building the RV-10 I used this.

Builders note: I used floating nutplates part number MS21059-08 as I was unsure how precises the center of the holes were compared to the antenna base. These do require more work as a standard female die will not fit into the nutplate. So I made one to do the job as can be seen in the pictures below.

Step 2: Dimple the twenty nutplates called out in the airplane plans page 21-16, then rivet them around each access hole in the bottom skin.

Builders note: Before attaching the nutplates I etched, alodined and primed the inside of the bottom skin.

Step 3: Break the edges along both sides of the F-1276 Bottom Skin.

reference: page 42D-14:

Step 1: Drill #30 a pilot hole in F-1203A Bulkhead using the deminsions shown in the Van's avionic plans for the Dynon Skyview. USe a step drill to enlarge the #30 hoe per the callout in Figure 2 on page 42D-14.Insert a snap bushing into the hole per the callout.

Builders note: the picture above is looking up from the bottom of the skin. It shows the forward face of the F-1203A former.

Step 2: Drill #30 a pilot hoe in F-1202F Bulkhead using the dimensions given in figure 3 on page 42D-14. Use a step drill to enlarge the #30 hole to 3/4". Insert a snap bushing into the hole per the callout from Van's Aircraft plans.

This completes page 42D-14 for installing the Skyview avionics alterations for this section. Now we will con tinue on with 21-16.Below is one more picture of the two holes after they are completed.

Page 21-16; Step 4: Cleco the Bottom Skin to the fuselage.

Step 5: Reach through the openings in the side of the fuselage or through the access holes in the Bottom Skin, then cleco the F-1204A-l & -R Bottom Stiffeners, and the F-1204A & D Center Section Bulkhead flanges.

Step 6: Cleco the F-1268A, B, C, D & E Doublers to the F-1276 Bottom Skin, to the F-1204A-L & -R Bottom Stilleners and the F-1204A & D Center Section Bulkhead flanges.

Step 7: Except for the holes indicated in the plans, rivet in place the Doublers, the Bottom Stiffeners and the Bottom Skin using the rivets called out by Van's Aircraft.

This completes page 21-16. As for the notes about installing the Dynon Skyview, my guess is the newer kits will have these holes predrilled, but time will tell.