Horizontal Stabilizer 8-1 to 8-2-4

I read ahead in the plans, specifically section 8 on the horizontal stabilizer, and saw that the first few steps have you preparing the spar and doubler and then priming those before continuing. I decided to just go ahead and do these few steps so that I could prime these two pieces alongside the rudder and vertical stabilizer parts.

Before doing anything I decided to straighten the horizontal spar doubler as it had a significant bow. Using my vice and a mallet, and the instructions given in section 5, I slowly proceeded to remove the bow. After a few minutes of whacking the doubler with the mallet, the bow was virtually gone.

Using a mallet and a vice to straighten the doubler

Next I had to debur the edges and lightening holes of the spar and the edges of the doubler. The spar was one of the biggest pieces I had deburred to date, and I decided to chuck my 1" scotchbrite wheel into a drill to help speed up the process.

Deburring the horizontal stabilizer spar edges...

...and the doubler

Once everything was deburred, I clecoed the doubler to the spar and proceeded to match drill the two holes from the spar to the doubler that were missing in the doubler. I also countersunk the two holes in the center of the spar. All other holes were already final drilled, so I didn't bother drilling those again. I then had to debur all these common holes.

Fitting the doubler to the spar

Now that the spar and doubler were done, I moved on to final drilling the #12 holes on the 8 hinge brackets that attach to the spar. This was all done on the drill press. Here I also decided to final drill one of the #30 attachment holes in each hinge bracket to make the following steps easier.

Cleaning up and final drilling holes in the hinge brackets

Once the hinge bracket holes were drilled, I attached the brackets to the spar. Lining up the hole I had just final drilled to #30 with the corresponding hole in the spar, it was easy to insert a #30 cleco. Other holes had to be fastened with a #40 cleco as that is the only one that would fit through the powder coating in the. hinge bracket attachment holes. 

With the hinge brackets attached, I proceeded to final drill the remaining attachment holes, replacing the #40 cleco with a #30 cleco as each hole was drilled.

Using a mix of clecos to attach the powder coated hinge brackets

With that done, I disassembled all the parts, and deburred the hinge bracket holes I had just drilled. Now these parts were ready to prime, so that will be coming next... I promise!!!

Build Hints

• I found it easier to final drill powder coated hinge bracket attachment holes by first final drilling one of the holes on the drill press, then using a #30 cleco to align the hinge bracket in place, and #40 clecos to temporarily fasten the other holes (as #40 clecos fit better in undrilled holes). As each remaining hole was final drilled, I replaced the #40 cleco with a #30 cleco.

Time Taken:     3 hours

Dates:                July 16 2022

Horizontal Stabilizer Total Time:   3 hours

RV-10 Build Total Time:                  39.6 hours