Month: November 2019

Today I had a few hours in the garage, and was able to get through a number of steps. I started by countersinking the trailing edge wedges, then countersinking the left rear spar, then dimpled a bunch of parts.

I used the Cleveland Tools wedge drilling jig, which made this a painless operation.

On the last hole of the right elevator wedge, I applied too much pressure and slightly elongated the hole. I’m going to leave it and build on, since all the other holes are good.

Countersinking the rear spar for the trim tab hinge was also quite easy. I clamped down the spar and went slowly. Because the spar is sandwiched between the skin and the hinge, countersinking the thin material is acceptable. The holes become slightly elongated, and there is a knife edge, but that is by design in this case. I deburred the holes carefully, trying to round the knife edge just slightly.

Then it was a few hours of dimpling; spars, ribs, shear clips, plates… basically every part that needs a dimple is now dimpled. A couple of holes were hard to reach, and I ended up using my vice grip dimpling tool, including the forward flange of this rib.

Next step is to rivet some nut plates to the inspection plate doubler.

Tonight I started dimpling parts. I made it through the counterweight skins and the four elevator skins. It’s a satisfying job, and so easy with the DRDT-2, I don’t know how others manage with a c-frame and mallet.

I started by breaking the trailing edges of the skins, so they will lay flat when riveted in the final step. I used my hand roller tool, which was way better than fiddling around with the hand seamers. The tool has two small wheels, and is clamped to the edge, one on each side. One is set to a slight angle. You clamp it to the edge, then draw it along, and the edge bends slightly. I wish I had used this on the rudder, it would have saved me some time.

Dimpling the skins is pretty standard stuff. However, the trailing edges require a narrow die, which I had purchased some time ago. The training edge is bent to fit flush with the trailing edge wedge, and the regular dimple die would interfere with the bend. The narrow die is ground down towards the tip, so it can dimple in some tighter places.

Tonight I completed the last few things I wanted to do before priming all the elevator parts. I shaped the outboard edge of the right elevator trailing edge wedge using the belt sander. Then I deburred the spar doublers, then trimmed and deburred the last couple of brackets. I have a big pile of smooth parts ready to be cleaned, etched, then primed.

I trimmed my replacement rear spar, then deburred it. I used a hacksaw to cut off the excess 11/16 of an inch, and then filed it down to final shape.

Then I was able to assemble the right elevator and final drill the few holes that need it. These are the gusset that joins the rear spar to the inboard rib, the tip rib web to main spar flange holes, and then the elevator horn holes. I also measured and trimmed the trailing edge wedge, using a hack saw and then filing down to final size with the vixen file.

The next step is to sand the outboard trailing edge wedge to match the shape of the fiberglass tip. Then I’ll disassemble the right elevator, and debur the few remaining parts. That should set me up for priming this weekend, then it will be on to dimpling.

Deburred skins today, then separated the three pieces of the trim tab pushrod and deburred them. This was a skip ahead, but wanted to get this done so I can prime it along with the other parts. The pushrod is made up of three pieces that are riveted together, here’s a picture of the right hand side piece. They are fairly small pieces, and eventually need to be countersunk.

Last night and tonight I spent several hours deburring the left and right elevator parts.

To finish up the left elevator deburring, I used my vixen file to clean up the edges of the spars, then used some scotch brite on the holes, and around the ends.

Then it was onto the skins again, both right and left elevators. For the skins I’m just using the edge deburring tool to knock off the edge burrs and at times my small files to clean up corners.

And then back to the ribs and spars for the right elevator, for which I followed the same process.

At this point I have a few pieces left to debur; right elevator skin, right elevator rear spar, spar doublers, the trim tab actuator arm, the right elevator tip ribs, and right counterweight skin.

My goal is to have everything ready so I can prime this weekend.

My replacement rib arrived today, and I trimmed and deburred it along with the other parts of the left elevator. Tomorrow I’m hoping to wrap up the deburring and move on to the right elevator.

The last couple of evenings I managed to spend a couple of hours deburring parts for the left elevator. The ribs are thin and intricate, and the most time consuming part, but progress is being made.

To debur holes, I’m using a deburring tool with a countersink bit, and the edge removal tool for all edges. For tight corners like those between flanges, I’m using a set of small files, one round and one flat. Then as a final step I’m using scotch brite to smooth out all edges and holes as needed.

I did manage to damage a rib when I made a stupid mistake. To remove some excess aluminum left over from when I separated the ribs, I tried using the scotch brite wheel. It did a great job, but also removed a bunch from the adjacent edge, which I didn’t notice in time. Another part replacement order, $5 from Vans.

In other news, my replacement rear spar arrived, along with some tank sealant that I need to secure the trailing edges.

I’m heading to San Diego for work, but will be back for the weekend.

I shaped the left elevator trailing edge end, drilled the left elevator close out tabs, then drilled the remaining holes around the inboard rib.

I spent some time setting up my belt sander, which I had bought months ago but hasn’t really needed until now. I tested it out on some blocks of wood and some scrap aluminum before using it to shape the outboard end of the trailing edge wedge. It was a bit of trial and error to shape this piece, and to be honest I’m not convinced I’ve got it exactly right. There will be a notch cut out of the back of the fairing, and until I do that step (months from now), it’ll be hard to know if I have this exactly right. Eventually I decided it was good, and moved on.

To help align the close out flange holes, one of the foam ribs is temporarily taped into position behind the flanges. I left a small gap so I wouldn’t drill into the foam block. With the trailing edge wedge in position, and all of this clecoed shut I drilled the three holes with a sharp new drill bit.

Shot of the three holes after drilling. Not sure why I bothered putting the third cleco in after it was drilled, but anyway. I used a clamp to gentry press the skins against the foam rib while drilling. I think it worked out nicely.

It felt great to cleco on the elevator horn and final drill this piece. With this in position, the whole left elevator was assembled, and it looked great.

The next step is to debur all of the parts and start dimpling and countersinking. So after admiring the left elevator for a minute, I disassembled everything and started deburring parts. Deburring seems to be one of the most time consuming tasks, especially when there are complex parts with a lot of corners. But it’s a good chance to really “get to know” the pieces, exploring every edge, surface and hole. At the end of each session I notice my fingers often have shallow cuts from running my fingers over edges. I never notice them in the garage while working. It’s rewarding to feel a nice smooth edge when the part is done, and like all of these tasks, it is becoming easier and faster.