I spent some time today getting the top rib riveted along with the skins to the main spar. The counterbalance rib was riveted on next. Then it was time to move onto the trailing edge of the rudder and riveting a “double flush” rivet. Essentially a normal flush rivet where the shop head is set in a dimple and set flush to the skin on both sides.
I ended up using my pneumatic squeezer to partially set each of the rivets along the trailing edge. Starting in the center and working towards the outside edges, I partially set every 10th rivet, then every 5th rivet. This kept on until all rivets were partially set. I then used a flush die set in a C-frame rivet set holder in my rivet gun to finish each shop head flush to the skin following the same pattern that was used to partially set them. All the while making sure that there was no bowing, hooking, or pillowing of the edge going on. An overview of the technique below:
I’m not 100% happy with how it turned out, but that’s just the perfectionist in me. The results were a relatively straight trailing edge.
Next up is rolling the leading edges. The idea here is to tape the metal to a rod and roll it upwards creating a nice even bend in the metal.
I recently read on Van’s Air Force a tool that Eric, a fellow RV-10 builder, had created to make this job easy. I decided to give it a try, so in preparation to do that, I spent some time fabricating this tool from some closet rod, two 3/8″ drive sockets, and JB Weld that I bought from Home Depot.
I had purchased 1.25″ diameter closet rod, as that is the size suggested in the RV-10 plans, and 7/8″ sockets, which fit perfectly inside. I cut the rod to match the length of each leading edge section to roll. I also drilled some holes in the closet rod end and also used the grinding wheel to scruff up the sockets for better adhesion of the sockets to the rod.
Once this dries overnight, the idea is to use two 3/8″ drive socket wrenches in each end to easily roll the metal taped to the rod.
The 3M VHB tape from Van’s showed up this week, so I was ready to start back on the rudder again. Thankfully, this time the tape VAN’s sent worked like a charm. This further validated that the tape I got from Amazon was junk. The night that the tape came in, I adhered it to the trailing edge wedge piece. Tonight I attached the wedge to the right skin which sits flat on the table. Clekos were installed from the underside of the skin in the trailing edge at the end of each stiffener. I then got my wife to help me as we rolled the left skin onto the right skin, stopping at each stiffener location to finish the internal riveting of the stiffeners and shear clips, peeling back the 3M tape on the top of the wedge piece as we went. Once this was done, I finished riveting the lower rib to the skin, and installed clekos in the rest of the holes of the trailing edge in an alternating fashion. I clamped a 6′ steel angle to the edge of the table to give a straight and uniform edge. Finally, I put a wide board over the skin with some weights on it to hold it down and let the surfaces bond to each other. I’ll leave it overnight like this. Good progress tonight!
Spent the day today riveting a good portion of the rudder.
First up was riveting the lower rib together, followed by adding a nutplate to the rudder horn, then riveting the horn to the bottom rib.
Then I riveted the stiffener plates and their associated nut plates onto the spar (no pictures of this)
Then we got to back riveting the stiffeners onto the skins. This went relatively easy.
Then I riveted on the bottom and top ribs along with the stiffener clips to the right side skin.
Then I came to the part where you bond the trailing edge of the rudder together. This is a relatively important step as getting a straight and true trailing edge is one of the more difficult things to do. The first step in the process is to bond the trailing edge together in prep for riveting. Bonding has helped a wide range of builders achieve good results. Traditionally, this bonding was done with Proseal; The messy fuel tank sealant material. Downside is it has a limited working time, is messy, and takes several days to cure before you can continue. VAN’s has suggested a new method using a double sided tape adhesive, namely 3M F9460PC VHB. I picked some up off of Amazon a couple weeks ago so I had it ready for when I came to this step. I prepped the surfaces to make sure they were clean, then made a couple of attempts of attaching the tape to the trailing edge wedge piece. I got frustrated rather quickly as the tape just didn’t seem to be cooperating. The adhesive had a tendency to stay stuck to the main roll of tape rather than staying on the piece I was pulling. If I got a good piece of tape going, it would quickly come to an end as the adhesive would start to stick to the main roll and pull off of the piece I was pulling, putting me back to square one. This left me with some areas that were fine, followed by area that had no adhesive at all. I got frustrated pretty quickly, and decided to call it a day after quite a bit of progress. I really don’t want to mess this step up and rush or do it half-assed without the proper materials. Pictures below show the adhesive (shiny material) completely left behind on the main roll of tape, as well as its tendency to pull off the piece I was working with and sticking to the main roll again…
So tomorrow I will see if Vans thinks this is a case of a bad batch (or past its shelf life) of tape and re-order some, and maybe even order a small amount of proseal as a backup depending on what they say. In the meantime, I can start riveting the initial pieces of the HS while I wait for something to ship.
Over the last week, I’ve managed to get the skins on the rudder, match drilled, everything taken apart and deburred. Today I was able to take all of the parts to the bath tub to prep them for priming. About 2.5 hours later, I was priming all the parts. I wasn’t that happy with the priming on the VS, it didn’t adhere real well in some spots. I made a point to scuff up the surfaces better this time, as I don’t think I did enough of that last time, and didn’t give a good surface for the primer to stick to. I also bought a case of better Scotchbrite pads from Amazon for the job, plus I only have a couple of maroon pads that came with my tool kit, so I’ll need more anyways. After the prep today all of my parts were dull looking, skuffed up pretty well, no shiny surfaces remained. We’ll see how this session of priming went and decide whether I need to buy some etching solution as an additional step prior to rinsing and priming the parts.
A couple of pics of the rudder as I was preparing to match drill all the holes common to the skin and the skeleton.
Like before, while waiting for the rudder parts to dry enough to flip and spray the other side, and dry again, I decided to start on section 8; The Horizontal Stabilizer.
I got the rear spar, stiffener, and Hinge Brackets deburred, match drilled, taken apart and holes deburred. I was rather surprised that at such an early stage (page 1, in fact) that the instructions tell you to prime the parts you just worked on, as we’re going to start riveting them already.. Okay… So I prepped the parts in the tub again, a bit of a challenge with the spar being so long (see the picture below), and let them dry as I took a break for dinner. I actually needed to butt the two work tables up against each other for the first time, as this is a pretty long part. The tables are 5 feet long each, so this part is a little over 10′ long.
A quick “selfie” in my garb after finishing the primer coat on the Horizontal Stabilizer Rear Spar.
Tomorrow I should be able to start riveting the Rudder together once the parts cure overnight.
This weekend I was able to prime all of the components of the VS as a final prep step prior to riveting it together.
The first step was to transport all of the metal upstairs to the bathtub. I then used a wet scotchbrite pad with a dusting of Bon Ami to scrub down each of the parts. The parts were then rinsed and wiped off dry. I let the parts sit for an hour or so for additional drying time.
Once back downstairs, I started by using some leftover plywood and particle board from bench construction to create a makeshift spray booth. I used some hooks to hang the ribs and other items from while spraying.
This being my first time using a spray gun, I’d say the parts came out okay. Some playing around with the quantity of liquid and spray pattern settings on the gun on the application to the back side of the parts proved to be a bit better. It was clear that I had too much volume the first time around, and with the primer being relatively thin, I got some dripping going on. I may do a quick touch up mid-week and apply a thin 2nd coat. It turned out decent overall, and like anything in this process, the second time you do something it’ll go faster and turn out better.
Between priming each side and also waiting for drying to happen, I decided to make use of the down time and start section 7, the rudder.
Lots of cutting to separate combined parts, trimming to spec, and deburring them all. It seemed to go pretty quickly and was able to start on getting the rudder horn attached to the main spar and match drilled.