Friday, September 28, 2012

RV-12 Empennage Components Completed!

Riveting continued this sunny morning on the F-1278 top skin’s left side. An hour and a half of riveting later, the RV-12’s tail cone assembly was completed. The completion of the tail cone assembly is a monumental occasion at DOG Aviation in that it marks the completion of the empennage kit. There are a few miscellaneous parts such as the trim servo motor and bracket assembly that need to be attached, but those items are actually part of the final assembly process of all the completed empennage components … which will be done much later because of space constraints at the DOG Aviation assembly facility.
Beginning the riveting of the top F-1278 skin’s left side onto the tail cone assembly.
                               The end is near … just a few more rivets to set before the tail cone is completed.

For those RV-12 builders that are inclined to use flush rivets as I have will want to take note: … wait until the last moment to dimple your top skin. Way back in the tail cone assembly, one of the very first items in the instructions is to break the edges on the skins. There is mention of breaking the edge of the top skin even more between the F-1210 far aft fuselage frame and the aft bulkhead. I gave that area some extra break as suggested in the plans, however, it was still a little shy of what would have been ideal for the ultimate tight fit. Mine pulled in fairly tight during riveting and looks good. However, I can slide a piece of notebook paper under the very outside edge of the skin which I can not do anywhere else. So hindsight being 20/20 I would have test the break fit first and once happy with the fit, proceed to dimple the top skin. Because in that part of the tail cone, the top skin takes on more of a dome shape that narrows the further aft you get …  which explains why more edge break is necessary in that section. Unfortunately, once the skins are dimpled, the Cleaveland edge tool can no longer be run down the edge of the skin to add more break to the skin.
                                  Fully completed tail cone assembly ... and another empty box of 1,000 rivets.

The finishing of the tail cone assembly was also highlighted by the second empty box of 1,000 rivets … the RV-12’s rivet count is now approximately 2,000 flush rivets and counting.

Thursday, September 27, 2012

Tail Cone Top Skin Riveting Begins

The end of the empennage kit is in sight for the last tail cone skin left in the empennage box was the F-1278 top skin. Before riveting, there were a couple of holes that needed to be match drilled. Earlier in the build the instructions have the builder bend the outside edges of a bracket by fluting so it places a slight curve on the outer edges of the bracket.

The match drilling is necessary to place holes in the bracket were the curve was made so it was necessary to Cleco the top skin onto the tail cone assembly so the bracket could be match drilled to the top skin.
                                  The holes that need match drilled are to the left and right of the stubby Clecos.
                                                          Match drilling the F-1210C bracket to the top skin.
                                    Tail cone’s top skin clecoed in place and ready for riveting with flush rivets.

Yet another soggy day at DOG Aviation, perfect for settling into another long session of R&R  … nothing like riveting & rain while listening to classic rock & roll. Before the top skin is riveted to the fuselage frames and F-1279 L&R skins, the instructions call for a few items to be riveted onto the top skin first.   The F-12106 forward skin rib, left and right ADAHRS mounting brackets and the F1283-C stiffener are all riveted onto the top skin.
                                                  Riveting the F-1283-C “J” stiffener in place on the top skin.
                                                       Beginning the riveting on the right side of the top skin.
                               Right side of top skin finished … left side should be completed next work session.

Although there is one more side of the top skin yet to be riveted, it feels good knowing the empennage crate is now empty and all the major empennage components are nearly completed.
                                                      Empty empennage crate – signaling the wing kit is next.

Wednesday, September 26, 2012

Another Day Of R&R

It was another day of R&R at DOG Aviation … riveting and rain that is. Progress continued on the RV-12’s tail cone assembly as the F-1281 and F1280 left skins were riveted together with flush rivets. The work today was essentially a carbon copy of yesterday's work on the right side of the tail cone assembly.
                            Beginning the riveting of the seam where the F-1281-L & F-1280-L left skins overlap.
                     Setting the last rivet into the aft bulkhead where the F-1281-L & F-1280-L skins overlap.

As was the case for the F-1280 right skin, the plans call for the F-1280-L skin to be entirely riveted … so that skin was riveted to the three fuselage frames and also to the F-1279-L upper side skin.
                            Riveting the F-1280-L skin to the F-1210 fuselage frame with the pneumatic riveter puller.
                                            Finishing up the riveting of the F-1280-L skin to the F-1279-L skin.

Prior to test fitting the top skin, the instructions call for working on the F-12106 forward skin rib which is for mounting the vertical stabilizer’s forward skin. The rib was dimpled prior to priming so the only thing left to do was dimple the eight nutplates that will attach to the rib and rivet the nutplates onto the rib.
                                     Dimpling the nutplates for the forward skin rib using the pneumatic squeezer.
After the nutplates are dimpled, Clecos are used to hold the nutplates in place on the forward skin rib for riveting.
                                                   Squeezing the nutplate rivets with the pneumatic squeezer.
                                               Finished forward skin rib ready to be installed onto the upper skin.

I have to say, I have been very pleased with the work bench having wheels in the low position. I found myself moving the tail cone assembly a couple of times to make it easier to rivet … it sure was handy having wheels to move the tail cone assembly around.

Tuesday, September 25, 2012

Riveting Of Tail Cone's Right Side Skins

There were high hopes of getting both the left and right sides of the tail cone all riveted today, but weather concerns took me away from the project all afternoon for yard chores before the monsoons set in.

There was progress, albeit slow, there are lots of rivets to set and it is just a time consuming process. Plus, as mentioned in earlier posts, extra care must be used when setting the flush rivets because the nose of the pneumatic rivet gun hides the head of the rivet.
                            Beginning the riveting of the seam where the F-1280-R & F-1281-R right skin's overlap.
                                                      Finishing up the F-1280-R & F-1281 right skin’s seam.

To help aid the alignment of the rivets prior to setting them, found it very helpful to grab the backside of the rivets and pull on them to help keep them centered and fully seated in the dimpled holes as the nose of the pneumatic rivet puller is slid down the mandrel … then letting go of the rivet just prior to setting the rivet with the pneumatic squeezer. This really made perfectly positioned rivets but also took a little extra time and effort.
                                                             Setting rivets into the F-1209 fuselage frame.
                                 The home stretch – finishing up riveting of the F-1280-R & F-1279-R skin’s seam.

Much to my surprise the plans only want the F-1279-R&L upper side skins riveted only where the seam is on the F-1280 skins at this time … all the rest of the holes will be riveted later, presumably after the top skin is fit.
                                                              Right side done and left side for tomorrow.

Monday, September 24, 2012

Plumbing The RV-12 Tail Cone

Work continued on the plumbing of the RV-12’s tail cone by attaching vinyl tubing to the two static air port rivets that were installed yesterday. Two 24” pieces of 1/8" vinyl tubing are cut and connected to each static air port rivet then routed up the sides of the F-1208 fuselage frame to a "T" that is placed at the top of the F-1208 frame.
                                       Routing the left side static air line through the wire ties on the F-1208 frame.

The static air lines were then slipped over the static port rivets which had a bead of sensor-safe silicone placed on them before sliding the static air lines onto the rivets. Additional silicone was then placed on the outside of the vinyl line where the line touched the inside of the side skin.
                                        Sensor-safe silicone sealing the static air line to the static air port rivet.

The “T” which is centered on the top of the F-1208 frame gets a little strange to put together in that a 15” tube, which will eventually be connected to supply static air to the ADAHRS, is a larger diameter than the T’s connecting tubes. The plans call for cutting a small piece of 1/8” tubing to first slide over the T’s center fitting then the 1/4" tubing is heated with a heat gun to soften it enough to allow it to slip over the 1/8” tube. It appears to be a tight connection but if it leaks, rest assured, it will be slathered with silicone sealant.

The last bit of pluming is comprised of a 1/4" tube which will be the air line from the pitot tube and will terminate at the ADAHRS unit.
                                                                 All tail cone wiring and pluming in place.

Note: The wire ties on the left side of the F-1208 fuselage frame and forward are not to be cinched down at this time because when the ADAHRS unit is installed later in the build, a wire will be routed through the wire ties and up to the ADAHRS unit.

Once all the pluming was in place, the left and right upper side skins are added to the tail cone assembly.
                                           Upper side skins locked into fuselage frames and ready for Clecos.

After the upper side skins were clecoed in place, there are a couple of snap bushing brackets which get installed just forward of the aft bulkhead. Each bracket will hold a grommet that control cables will be routed through. The bushing  brackets need to be match drilled to the J stiffeners of the upper side skins and then riveted onto the J stiffeners.
                                                  Snap bushing brackets in place and ready for match drilling.

Left snap bushing bracket riveted onto the J stiffener of the upper left skin.
                                                     Tail cone skins minus the top skin all ready for riveting.