RV-14 Build

Today I riveted the vertical stabilizer skin to the forward spar and ribs, clecoed on the rear spar, and started riveting the skin to the rear spar. It was getting late and I was tired, so I decided to stop before I started making mistakes.

First, each family member signed one of the inside skins, leaving a few secret messages.

Then I started with some more experimenting with my adjustable squeezer set, and with some practice parts to get my rivet bucking skills somewhat current. I set up a cradle of cardboard and clean rags to keep the VS on it’s edge, which seemed like the best approach for bucking rivets.

Overall, I was happy with the way everything turned out. I had to drill out two rivets, both times the bucking bar slipped off the rivet. I was able to remove both without enlarging the hole, so replaced with the same sized rivet. The second rivet was annoying, as I somehow put a minor dent in the rib and skin when the bar slipped. I’m not sure how it happened, but the result is a slight bump in the skin near the rivet. The main thing is that the rivet set well the second time. You can see how the light is slightly distorted around the middle rivet in the picture below.

I was able to squeeze rivets along the edges of the skins, even the most forward holes on the top rib.

I can see why the plans recommend setting the manufactured heads aft on the rear spar. There is very little room to get at the skins rivets along the rear spar. I did the easy rivets with the squeezer, but I didn’t want to tackle those with less clearance tonight. I’ll try to finish up the remaining rivets on this piece tomorrow.

Tonight I received my adjustable set for the pneumatic squeezer, along with some scrap aluminum. I spent an hour drilling, counter-sinking and riveting some practice pieces, and documenting the settings needed for each length rivet. Then I re-squeezed all of the rivets on the VS spars and ribs, and they all came out great. The hardest three rivets are where the root ribs meet the front spar. There isn’t much room, and the ribs aren’t square to the spar. I had to switch to my rivet gun with a double offset piece to finally get those done.

With the rivets done, I can finally complete the Vertical Stabilizer. I clecoed the frame to one side of the skin in preparation for riveting. But it’s a bit late in the evening now to start riveting. I’ll try to knock it out tomorrow.

With the primer coat looking ok, I proceeded to start riveting parts together. First up was the doubler plate on the front spar, then the rear spar doubler and hinge attach brackets. For the front spar plate I used the pneumatic squeezer. For the rear spar, the pneumatic squeezer wasn’t viable. The -6 and -7 rivets were too long for the pneumatic squeezer with the yokes I have, and the squeezer couldn’t develop enough power to squeeze the rivets. I need a yoke with a wider throat to allow me to use it with those longer rivets. So I used the hand squeezer to do all the rear spar rivets. It came out looking good.

Earlier this week I decided to hold off on priming parts until I have a few more tools. I ordered a new spray gun, some towels, some spray bottles, and once that arrived tomorrow I should be ready to prime parts. I spent some time tidying up the garage tonight, and installed an air filter on my bench to ensure I have clean and dry air going to my tools. I also took the opportunity to redimple the other side of the vertical stabilizer skin. The dimples are slightly crisper now and I feel more comfortable with the end result. Next time I dimple, I’ll have a better idea of the pressure I need to be using.

In was in and out of the garage today, but managed to get the rear spa doubler counter sunk, and the spar dimpled to match. I started with a practice piece to get my counter sink cage set correctly, and after a little experimenting had it dialed in to where I was happy. With a rivet in the hole, it sits just shy of the lip, by perhaps a couple hundredths of an inch. The reason for the slightly deeper hole is that the dimpled spar needs to sit inside the countersunk hole, which obviously takes up more space than the rivet itself. The challenge is figuring out exactly how deep to go. I’m going to start with what I have, and can always deepen the cut if needed, but I have a feeling it’s right where it needs to be.

As I dimpled the holes and compared to the skin dimpling I did last night, I’m concerned my skin dimples are not crisp enough. The skin is actually quite thick, thicker than the ribs and spar, and I may need more tension in my dimpled to really form the dimple well. I clecoed the top rib to the skin on one side to see how snug the fit was. It’s hard to see in the photo, but there is slight gap between the rib and the skin. There are larger gaps where I fluted the rib, but the worrying area is where the clecos are inserted. If I haven’t formed a totally clean dimple, there will be a problem when it’s time to rivet to the ribs, the skin will not sit flush with the ribs, and the skin will develop waves. I decided to adjust my DRDT-2 dimpler and to try redoing a couple of dimples and compare the results. With some more tension, the dimple was definitely crisper, and there was more scuffing of metal around the dimple. At one point I put too much tension in the dimpled, and there was a very slight depression formed where the female die depressed the skin. I adjusted back a little and ended up with what I thought was a good amount of pressure. I kept going, re-dimpling one entire side of the skin. It was very hard to tell the difference besides the scuffing marks. Using the reflection test (seeing how reflected light bends around the dimple), there was no appreciable difference. For both the original and the re-dimpled holes, there is no bending of light until inside the ring around the dimpled hole. I did break out the squeezer and redid the tightest 3 dimples on each side. Continuing to the other side of the skin and redoing all the dimples just doesn’t seem worth it. I think what I have is definitely sufficient, and redoing the dimples is just risking a mistake, and probably enlarging the hole as the dimple sets in a slightly different way the second time. The pics below are of the two sides of the skin, one side has been redinpled, the other hasn’t. But which is which? The second pic is of the redimpled holes. You can see slightly crisper edges

With the dimpling all done, it’s time to prime and then start riveting.

In other news, I am hoping to connect with my tech councilor next week before he heads to Oshkosh. And a letter arrived from Vans with my two missing washers. I added them to the appropriate bag and marked the inventory list, which is now complete.