Tail Cone 10-8-1 to 10-8-7

With the right tail cone skin attached, I flipped the tail cone over and placed it on the work bench. Here you really start to see how big this part is, and get a sense of how big the airplane will eventually be.

Tail cone placed on work bench ready for work on the left skin

Continuing on, I attached the remaining piece of tail cone skin in place. I then faceted the tabs around the curves of the last 2 bulkheads (as I had done with the other bulkheads), and clecoed those in place.

Aft bulkhead and skin clecoed in place

The remaining side skin stiffeners were inserted next and temporarily held in place with painters tape. The left skin was clecoed to the bulkheads from the top down, and the stiffeners were aligned with the holes at the forward end of the skin for match drilling.

Left J-channels inserted into notches and held with painters tape to prevent the falling out

Left skin clecoed to the ribs and bottom skin

Ready to start match-drilling the left skin to the stiffeners

I then match drilled #40 all the holes from the left skin to the stiffeners in the same manner I had done for the right skin and stiffeners. I did have one issue where the bottom stiffener was a little loose which resulted in it slipping down about 1/32" as I started drilling, and that resulted in a hole that was slightly off the center line on the stiffener, but I quickly adjusted the stiffener and brought the center line back into alignment. The few holes that are now slightly off the centerline still have more than adequate edge distance so I am not worried, and the stiffener still fits tightly against the skin.

The remaining 2 stiffeners were drilled without issue.

Drilling of left skin to stiffeners complete!

Once all stiffener holes were drilled, I removed the left skin and stiffeners, and deburred all edges and drilled holes. Before reattaching the skins and stiffeners to the tail cone, I moved the whole assembly over to the saw horses to clear space on my workbench, and also to make it easier to work on all sides of the tail cone.

Left skin and stiffeners reattached after deburring

Left side view of the tail cone

Top view... all tail cone parts aligned well

I then worked on separating the rudder stop skin stiffeners using the band saw, and cleaned up the cuts and all edges on the deburring wheels. These were then labeled and attached in the rear of the tail cone.

Rudder stop skin stiffeners clecoed in place

Next I fabricated the F-1056 rudder stop brace from a piece of 3/4" x 3/4" x 1/16" angle to the specified dimension by

• rough cutting the angles using the band saw
• finishing the cuts to the lines on the disc/belt sander 
• deburring the edges on the bench grinder

I then used a level to ensure that the front and back of the tail cone were not twisted relative to each other, and clamped the rudder stop brace to the rudder stop stiffeners while holding the brace against the aft tail cone bulkhead. Once clamped, I rechecked that both front and back of the tail cone were still level.

Using a level to check for twist... unfortunately my camera wasn't level!

Rudder stop brace clamped in place after ensuring there was no twist in the tail cone

With the brace clamped, I drilled #40 the holes from the aft bulkhead into the brace, switching to the 6" #40 bit for the outer holes to avoid hitting the skin with the drill chuck. The brace was then removed to debur the drilled holes and reattached.

I then match drilled the 4 holes from the stiffeners into the brace using a 12" #40 bit. The plans call to upsize these holes to #30, so I started drilling them using a 12" #30 bit, but the bit started catching on the edge of the stiffener holes and pulling burs off.

To not cause any issues, I decided instead to remove the brace and stiffeners, and as I had already match drilled #40 holes, I used clecoes to align the pieces, and a #30 reamer to upsize the holes at the work bench. This worked really well!

Upsizing the rudder stop stiffener/brace holes to #30 with a reamer

Rudder stop stiffeners and brace fully drilled and deburred

After all holes were drilled and deburred, I clecoed the brace and stiffeners into the tail cone, and all sides fit tightly against the skins and bulkheads.

Rudder stop stiffeners and brace clecoed into the tail cone

Build Hints

• Be careful when upsizing holes in thin material. Drill bits may have a tendency to catch the edge of the existing hole. Use a reamer if possible, or a drill press with the pieces clamped.

Time Taken:     9.2 hours

Dates:                February 15 - February 20 2023

Tail Cone Total Time:           47.6 hours

RV-10 Build Total Time:      303.6 hours

Priming Total Time:                     26.4 hours (not included in build time totals)