The Tail Boom Repair - Part 2

With the replacement tail boom skin made, it's time to cut away the remaining broken glass and prep the areas for the new skin to bonded to.  








 

The next step was to cut and trim the replacement right skin half and to do a test fit.

The old plastic PE tubing for the rudder cables and TE prop were also removed. I replaced the tubing with new PE tubing.







I reused the static port pressure intakes from the old skin.

I cleaned up the pressure intake and attached it to the new skin using epoxy paste and glass.

The new skin was secured in place using tape, hot glue and clamps. Inside support strips were bonded to the seam lines and epoxy flock and cab-o-sil paste was applied to the outside seam to fill any uneven voids between the skins. 

After the seams had cured, it was time to scarf the area around the seams to create a beveled form to the seam line. There was a fit issue toward the forward seam due to the problems with the mis-matched length between the two PIKs.

I had to grind down the areas with the paste, and reinforce the internal backing to prevent a break through.





The aft seam was much easier to tackle. The scarfing process was fairly a textbook procedure.

After the scarfed areas were properly beveled. I did a final roughening of the surfaces and cleaned and prepped the outer areas before applying the glass.  

Using the PIK fiberglass lay-up schedule, I applied the replacement glass per the overlay repair instructions.

I used a plastic tile trowel to squeegee off the excess resin.

Wooden strips with plastic barriers were clamped in place to hold the glass and Peel-ply during the 24 hour curing time.

There is a final layer of glass that I will need to apply over the repair areas, but I will hold off on that until the repairs are complete and the fuselage is off the jig, so I can verify the contour. 

With the new skin in place, and the resin cured, I re-installed the aft bulkhead with epoxy paste and glass strips. The bond will be better than the original which was nothing but a micro-bubble filler.

Next, I attached the new GRP tubing support straps along the inside of the new skin using the old skin for a placement guide. I pulled new RG58 coax for the antenna back to the cockpit and spliced the break using new BNC’s and a barrel connector. The splice was sealed using shrink tubing. I tested the connection using one of my hand held aircraft transceivers. It was cool to listen to ABQ Center talking to incoming flights to the Sunport. And that was in the garage with the door closed! I also pulled a RG400 cable for the transponder antenna.

The PE tubing used for the rudder cable guides is a little trickier to splice. There is no cement available to bond the tubing (it requires heat to do that). I used a larger PE tube sleeve to cover the slice. I roughed the inside of the sleeve and the outside of the spliced tubes with 50 grit paper and the used super glue to secure it. The spliced sleeve was sealed with shrink tubing.

I created a transponder antenna cradle, using a mold from Robert. The location for the antenna need to be located at the top of the boom The elevator push rod was too close to the antenna if it were located at the near the underside of the boom.



Finally, I placed the antenna ground plate in to verify the clearance.

The RG400 cable was terminated and the antenna distance from the cockpit is 7 feet.


Next, I will be making the left skin and finish the fuselage boom repair.