Moving on with initial assembly of the tail cone, I faceted the tabs around the curves of the F-1006 bulkhead, and clecoed it into the front of the tail cone making sure that the tabs went over the skin stiffeners.
I also reamed #30 the holes common to the F-1006 bulkhead and bell crank ribs where needed.
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| Forward most tail cone bulkhead attached |
Next I deburred the edges of the F-1028 baggage bulkhead channel and clecoed it to the F-1006 bulkhead and right bell crank rib. The common #30 holes between the bulkhead and channel did not need to be reamed here because a rivet fit in easily.
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| Baggage bulkhead channel clecoed in |
I then separated the bellcrank rib angle into it's 4 parts, and labelled the pieces per the instructions. After deburring the edges of all the pieces, I checked all the holes and they were already final sized, so I just went ahead and deburred them.
Next I countersunk all the nutplate attachment holes on the F-1037B and F-1037C pieces flush from the outside of the bend on the drill press, and attached them to the bellcrank ribs.
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| Longerons inserted between the side skins and bulkheads |
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| Longeron bend lines up nicely with the skin angle change on both sides, and longerons are also level with the edges of the side skins |
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| Notches in longerons line up nicely with horizontal stabilizer attachment bars |
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| Longerons extend to the rear of the tail cone almost touching the F-1012 bulkhead |
I fabricated a spacer out of a 1" wide x 1/8" thick aluminum bar that sits on top of the Horizontal Stabilizer attachment angle. This was easily done using the band saw, disc sander and deburring wheels. I also measured a centerline 1/2" in from the longer side of the fabricated bar, and marked it.
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| Fabricated spacer with center line marked |
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| Spacer placed on top of Horizontal Stabilizer attachment angle and centered |
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| A couple pieces of carpet tape were used to hold the spacer in place |
I then deburred the edges of the aft deck and the stop/doubler, and clecoed those to the tail cone
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| Aft deck and stop/doubler clecoed to the rear bulkheads |
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| The front of the aft deck will be slightly bent when match drilling/riveting to account for the bend in the side skins |
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| Stop/doubler centered on the aft deck |
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Longeron bends line up evenly with the notches in the aft deck on both sides of the tail cone, and spacer center line is visible through the holes
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In preparation for match drilling the longerons, I clamped the aft deck and side skins to the longerons as specified in the plans, taking care to ensure that the aft deck and skins were aligned correctly with the apex of the longerons.
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| Aft deck clamped to the longerons... |
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| ...along with the side skin. Everything aligns along the edges! |
I then started carefully match drilling 3/32" each longeron to the side skin, starting from the rear of the tail cone, using the drill bit's reflection to ensure that I was drilling perpendicular to the skin.
I drilled, and clecoed, every hole in turn, without skipping any, and I alternated sides every 4 holes as I moved forward along the tailcone. I also took time to ensure that the longerons kept their alignment while drilling.
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| Halfway done with drilling the longerons. Holes take a little longer to drill due to the thicker 1/8" aluminum. |
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| Longeron fully drilled to skin, left side of tail cone... |
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| ...and right side |
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| Longerons clecoed and aligned perfectly with the skins. |
Once the longerons were fully match drilled, I match drilled the #40 holes in the skin to the F-1012B rear bulkhead flange, and also final drilled #40 the common holes in the F-1012A and F-1012B bulkhead webs.
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| Rear bulkhead fully match drilled to the skins... |
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| ...and final drilled through the web |
The rest of page 10-11 has you final drill all the remaining holes in the side and bottom skins to the bulkhead flanges, but I am skipping over these steps because the holes are already final sized. I will only debur the holes later when I take the tail cone apart for dimpling.
Build Hints
- One thing for builders who haven't started on the tail cone to consider is that match drilling of the Horizontal Stabilizer attachment angle to the F-1010 bulkhead is critical. The angle must sit exactly 1/8" above the bulkhead, otherwise the longerons and aft deck will not line up well with the skins since they sit on top of this angle. One option might be to match drill the angle to the bulkhead after clamping the longerons against the skins in their proper placement, and holding the fabricated angle firmly against the underside of the longerons and the F-1010 bulkhead.
- When drilling the longerons, ensure that the drill bit is held perpendicular to the skin (using the bit's reflection in the skin as a guide) to avoid any issues with rivets leaning when riveting.
Time Taken: 7.5 hours
Dates: February 21 - February 26 2023
Tail Cone Total Time: 55.1 hours
RV-10 Build Total Time: 311.1 hours
Priming Total Time: 26.4 hours (not included in build time totals)
