Horizontal Stabilizer

Tonight I drilled the forward spar caps. These are spar stiffeners that sit inside the spar flange, reinforcing the angle between the spar web and the spar flange. One for the top edge, and one for the bottom. The caps are not pre-punched, and they are slightly bowed, meaning a lot of clamps and Clecos are needed to keep them in position while the holes are match drilled from the spar. Everything looks good, although I anticipate some very minor alignment issues. It’s very hard to keep everything exactly lined up.

Yesterday I drilled, countersink and debuted all of the holes between the Horizontal Stabilizer rear spar and the doubler, and the drilled and deburred the hinge attach brackets.

For all of the final drilling on the doubler, I used a reamer to compare results with the drill bit. There is slightly less burring from the reamer, and it feels like it produces a better result. I tested it first, seen in the picture below.

Today I picked up a few new tools, including a cheap bandsaw to trim some of the thicker pieces that need trimming.

I also clecoed and drilled the flange bearing that makes up the inboard hinge bracket assembly.

Then using the new bandsaw and my vixen file, I trimmed the stringers and spar caps. The bandsaw makes a chattery mess of a cut (I probably need a different blade), but the file cleans it up nicely. A little sanding with scotch brite, and they came out nicely.

Next I’ll be clecoing the spar caps to the front spar, along with the front spar doubler, then doing some more drilling. I’m planing to get all the drilling, deburring and countersinking done, then prime everything (except skin), and then start riveting. This is slightly out of order from the instructions, but the Vans plans have you riveting parts together before priming. I’m sure there’s a really good reason, but it seems counter-intuitive.

Tonight I finished up the deburring on the forward spar, and touched up a few other parts. It’s not really “finished” deburring, since I will need to drill a bunch of holes and debur them, but I completed all the edge deburring for all parts. I then spent some time reading ahead and setting up to start drilling the rear spar tomorrow. The first steps include final drilling the spar doubler, and final drilling the hinge attachments. These hinges are where the elevators will attach, much like how the Rudder attaches to the Vertical Stabilizer.

After several evening sessions this week, I’m almost finished deburring the HS parts. Tonight I finished the rear spar, which leaves just the forward spar before I’m finished. It’s been quite time consuming with substantially more parts than the VS and Rudder. The vixen file made quick work of the edges of the spar, and left a nice smooth edge. Some polishing with scotch brite and the edge came out great.

Hopefully will be done with the deburring by the weekend.

Spent time deburring parts for the Horizontal Stabilizer today. It’s a time consuming process, especially with the ribs which have many corners and crevasses. I’m using a combination of edge deburrers, small round files, small flat files, and maroon colored scotch brite to finish.

The items in the foreground are done, and in the background are next.

I also need to debur both spars, for which I have a new Vixen file, attached to my Dad’s old file handle. This will help on the thicker edges of the spars:

I spent an hour tonight deburring more Horizontal Stabilizer parts, finishing the doublers, stringers and stringer web.

I ordered a vixen file, which will be helpful in deburring the edges of the HS spars. These are far too long (10 feet) to use the bench grinder’s scotch brite wheel, and I think a file will be a better approach. The file will be here on Wednesday, but I’ll be out of town until next weekend.

I took the wrap off all the components, labeled them, then started to debur the ribs, doublers, and stringers.

I built a rack to store the VS and Rudder out of the way while I continue working on the other parts. I managed to find a good spot up high, with (just) enough room to maneuver the parts. I may need to add some padding and some kind of earth-quake safety strap, although I think they are quite secure as-is.

With these tucked away safely, i took the opportunity to tidy up the garage. Then I opened up the crate and pulled out the spars for the Horizontal Stabilizer. These things are long! Here are all the parts for the Horizontal Stabilizer, except the skins which are stashed away safely in the back of a cupboard.

Step 1 was to finish straighten up the spar doublers, which I was able to do easily enough. I peeled the vinyl off the rear spar and doubler in preparation for deburring, then final/match drilling.