Tail Cone 10-12-1 to 10-13-2
It was now time to work on attaching the top skins to the tail cone. I began by deburring and clecoing the F-1009 bulkhead frame to the aft deck. I left the aft deck clamps in place to keep it tight to the longerons.
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| Aft bulkhead section clecoed to aft deck |
I then fluted each of the bulkhead tabs sitting above the longerons that had two holes, adding a heavy flute evenly spaced between the holes.
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| Tabs with 2 holes heavily fluted |
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| Top stiffeners put in place, ready for the skin to be attached |
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| Top stiffeners, view from below |
I then proceeded to cleco the aft top skin in place. I worked from the center of the skin, down each side of the tail cone as suggested in the plans. Then skin was somewhat difficult to bend, especially around the F-1008 bulkhead, but it came together nicely and all holes lined up without too much trouble.
After I had finished clecoing, I did notice some very minor pressure from a couple of tabs pushing hard against the skin, causing a slight outward deformation around the F-1008 bulkhead. I made a note to facet those tab edges even more when I remove the skin later for deburring.
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| Aft top skin being clecoed in place down each side |
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| Aft top skin fully clecoed on the left... |
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| ...top... |
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| ...and right |
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| Tail cone starting to close up, view from inside |
With the aft top skin clecoed in place, I lined up the aft stiffener marks with the appropriate skin holes and proceeded to match drill the skin to the stiffeners, following the same pattern I used for other stiffeners. I drilled the center stiffener first, followed by the 2 outer stiffeners.
Next I prepared the forward top skin by removing the strip attached to the leading edge. I cut the outer tabs using a hacksaw, and the middle tab on the band saw, then cleaned up the tab cuts using a file, belt sander and bench grinder. I also removed the blue protective plastic from the inside surface. The aluminum strip was set aside for later use.
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| Forward top skin, with strip removed |
I then clecoed the forward top skin in place, again starting from the center and working outward.
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| Stiffeners match drilled to aft top skin, and forward top skin clecoed to the bulkeads and longerons |
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| Forward top skin match drilled to stiffeners |
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| Stiffener match drilling complete! |
I also noticed that after removing the blue plastic along the rivet lines, deburring, and reattaching the top skins, the skin deformation I had noticed along the F-1008 bulkhead due to the tabs pushing against the skin was now virtually non-existent. I'll still facet those tabs a little more after disassembly, but I am happy with how the skins sit now.
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| Top skins reattached after deburring |
There are two more pieces I had to fabricate in section 10, those being
- a Horizontal Stabilizer Attachment Bar Support Angle (F-1011D), and
- an Up Elevator Stop (F-1012D)
The updated Up Elevator Stop bracket has to be fabricated from a piece of 1-1/4" x 1" x 1/8" Aluminum Angle. Conveniently, there is a 5" (the exact length of the bracket) piece of this angle included in the empennage kit. You may think that Van's included this specifically to address this Service Bulletin, however that piece is actually intended to fabricate additional brackets in the Empennage Attach section 12 of the plans. I decided to use this piece of angle to fabricate the updated F-1012D bracket, and I added additional 1-1/4" x 1" x 1/8" Aluminum Angle to my fuselage kit currently on order.
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| Using clamps to help hold the straight edge in place so that hole positions could easily be measured and marked |
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| All cut lines and holes positions marked prior to making any cuts |
After marking the cut lines and hole locations on the Aluminum Angles, I proceeded to rough cut the brackets using the band saw, and trim them to size with the disc/belt sander. I then used the drill press to drill the 1/8" holes. It was easy to get the holes aligned by using a piece of Aluminum bar as a guide.
For the radiused inside corners of the F-1012D bracket, I used a 1/4" drill bit (after first drilling with the 1/8" bit) along with the bar guide, and that worked very well in creating the desired corners.
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| Drilling holes on the drill press using a piece of bar stock as a guide |
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| Finished brackets, with the F-1012D conforming to the specs in SB 18-03-30 |
Build Hints
- Heavy fluting is needed on the 2-hole bulkhead tabs to ensure the holes line up
- When drilling a straight line of holes using the drill press, clamp a bar in position to allow the piece being drilled to be placed against the bar in such a way that the holes are at the correct distance from the edge. Then drilling each hole is just a matter of sliding the piece being drilled along the bar to the correct hole location.
- Drilling slowly with the drill press resulted in rounder holes, especially at the exit point. Don't exert too much force on the drill press handle. Firm but adequate pressure to keep the drill bit in contact with the surface is all that is required.
- Rather than using a punch to mark hole centers, instead with the drill press (without turning it on) I lowered the drill bit against the surface to be drilled to make a small mark which indicated where the center of the hole would be. Small adjustments were made if needed to place the hole center correctly, and this worked extremely well to determine hole placement.
Time Taken: 10.0 hours
Dates: February 26 - March 4 2023
Tail Cone Total Time: 65.1 hours
RV-10 Build Total Time: 321.1 hours
Priming Total Time: 26.4 hours (not included in build time totals)