RV7-Factory

Took a couple of days off this week to spend time with the kids on summer break. Aka, snagged one and knocked out riveting the top skins on the left wing. Pretty straight forward process really. The spar to skin rivets we did traditional. I trained my eldest on how to give me bursts on the gun in various lengths. Per the manual, we started with the center rib and worked our way out and down. First completed the inboard skin, then the outboard. Took a day and a half. I stayed on the underside, and Taylor stayed on the top side.

Here were our friends for the task. Top is the Cleaveland Back Riveting Bucking Bar. While any bar “could” work, this one makes it pretty simple for an inexperienced buddy. It’s comfortable and simple to make sure is flush against the skin. Just below it is the 12″ Long Double Offset Back Rivet Set also from Cleaveland (actually Avery Tools). Now, here’s the tip of the day: Set your 3X gun to 80 psi when using this set. It sounds like a lot, but with all the mass you’re moving, it’s not like your short, straight back rivet set. As with anything, practice makes perfect, so practice.

As you can see from the top photo, the result we got on the skins was fantastic. We did have some to drill out when focus was lost momentarily, but overall, it went pretty smooth. It was a lot of rivets, but worth it.

Something about being able to stand back and look at something this big and not see any clecos in it. The manual says it is now ridged enough to remove from the stands. After taking off the lower C-clamps and seeing it not move at all, it’s definitely ridged.

Next up will be a total repeat on the right wing.

Now that the left tank has passed the leak test, I decided to mount it to the wing in preparation for riveting the skins on. I was pleased to find it generally fit well with no interference issues with the leading edge section.

There was one spot that makes me a little pause, but I am not sure I could do much about it. I tried to massage the skin of the leading edge some and considered making a small splice piece or some way to capture the skin from the tank, but in the end, opted to let it go for now.

At this stage, I was at a cross road. I need a helper or two to rivet the top skins on, but did not have access to any for the rest of the day. So I went back to doing tasks I could accomplish solo. One of those was mounting the SafeAir pitot mast to the underside of the left wing. I prepped the template and then worked to get it placed, marked, and cut out. I have chosen to place my pitot just outside the outboard inspection plate. while this does require some additional attention when routing pitot tubing past the aileron bell crank, I think it’s a better location overall. Will provide good access from the inspection hole if needed and the web of the rib will help in making the mount more ridged. I’ve heard good reports by other builders that more outboard has worked well for them.

Here you can see the SafeAir mast placed and installed. As you can see, it sits against the side of the rib nicely. Now I can fabricate a small angle that will then attach to the rib and the mast, providing some good support for the mast. This not only give the mast an additional attach point, but reduces the stresses on the skin. May not really be necessary, but seeing how flimsy the attachment of the pitot on my certified Beech Sundowner, I wanted something more.

This was after many attempts at fitting, but with a little patience and filing, it fits very well through the skin.

 

As you can see here, I took some stiffener scrap (likely from the tanks or elevator/rudder and fabricated a simple bracket that I riveted to the mast base with platenuts where screws will then attach the mast to the adjacent rib. This configuration is pretty dang solid once cleco’d in place. I am debating on placing platenuts on the remaining holes, including the spar holes, to make the mast completely removable, or simply riveting it to the spar and skin and if needed, drill out the rivets if maintenance requires it. Guess we’ll see once we get to the bottom skins where I land.

So I decided to use the manometer method to test the tanks for leaks. Word of warning, this method is dang sensitive. Slight temperature and pressure changes throughout the day can have you chasing your tail and creating false alarms. I see the wisdom in balloon method…as it gives a good indication of success without giving the builder a scare if he’s an over thinker. The other way is to make sure you have an accurate means of measuring all the other factors at the same time as looking at the column of water. It’s repetitive math, but it can give you a dang accurate look at your success.

As it stands, my column of water shows a leak free tank after 4 days since starting the experiment. 1 down, 1 to go.

Took advantage of the the nice calm sunny afternoon and scuffed, washed, and primed the left top skins.

Here they are baking in the sun. Bella did a good job of staying down wind while they dried. Can you imagine all the hair she could introduce into that primer?

Once the primer was dry, I hung the parts on the wing and then rechecked the assembly for square. I kinda dig that olive green color on the inside. I sure hope it’s worth all the work/weigh (though minor) in the end.

Next up will be the final riveting.

After the excellent build day last Saturday, I wanted to continue the pace. So today I set out to prep the top skins as much as I could. I deburred the already match drilled holes and then grabbed my daughter to assist holding the large skins while I hit each with the dimple dies. She actually said she enjoyed helping and talking (and talking 😉 ).

We repeated the process on the inboard top skin. I could really feel the difference in the skins due to the thickness.

Since it was a weeknight, time was short, so I ended with completing the scarf joint where the leading edges of the skins overlap. I’ve heard where some got after this too aggressively and had to replace skins. Mine may keep my finished airplane from being an award winner, but the overlap looked pretty good with the tank on, providing a pretty good flush transition, so I called it good. I then finished the last few dimples (as I didn’t dimple the overlap at the corners until the scarf was done). At this point, the skins can be primed and riveted on.

Saturdays are always a good day in the shop. Both therapeutic and productive. I set out with the goal of knocking out a ton of work. Started the morning by riveting all the ribs to the skin. I actually enjoyed the solo riveting. Only had to drill out two. The swivel head flush set and tungsten bucking bar make setting AD3’s a breeze. You do have to be very careful not to drop the tungsten bar, is it will dent anything it hits with very little effort. Lay a foam pad or something thick and soft below where you are riveting just in case. I fortunately had no drops…but I have heard of others not being as lucky.

Here is a good shot of the leading edge out of the cradle post completing the ribs. I’ve heard others say that the Wings are fun because you really get the sense of building something big as you complete sections. I agree.

Once all the riveting was done, I quickly set out to cut a big hole in it. I was surprised how much mental effort it took to convince myself to start drilling and cutting. After all, I had just completed the assembly to near perfection in my mind. No matter, I committed.

I first marked locations to use my step bit and get 3/4″ to 1″ holes near the corners. From there I used a Dremmel and a cut off wheel to connect the holes as close to the template line as possible. From there it was simply a matter of filing to final shape. Take your time here and be patient. Once the hole was done to my satisfaction, I moved to marking, drilling, and dimpling the holes for the lens screws per the template.

Here you see the cutout complete and ready to accept the Plexi lens.

The Duckworks lens is a bit of fun, work, and scare. Unless you have worked with Plexiglas before, it can bite you fast. Fortunately, I did a bit of Plexiglas work in High School years ago, and I remembered how finicky it can be. First, take your time. Remove ALL nicks and burrs on the edges. Drill very slow and polish the edges to a near clear appearance. Make sure you mask the edge before you polish…or you will ruin the field of the lens in a heartbeat. All holes must be deburred or you will crack it.

The above shows the lens after all the work to trim the raw (but properly molded leading edge shape).

Here is the lens after attaching the doublers with platenuts.

After all the Duckworks kit work, it was time to see if the lens fit. It appears to fit nicely and as tight as one can get it with the gasket they provide.

 

 

 

Since I was clipping along for the day, I figured I’d test fit the leading edge to the spar. Looked good, so I set out to rivet it on with the pneumatic squeezer. This made quick work of both the top and bottom rows.

What a great sight. No clecos on the entire leading edge of one wing.

I was getting late, but I wanted to get a couple more items done if I could. So I set out to dimple the entire substructure of the left wing. I cannot imagine what my neighbors thought was going on at 2200 hours each time that squeezer slapped those dies crisply together. Rang like a bell. Fortunately, the shop is well insulated, so hopefully, they didn’t even know. After an hour of that however, all I heard was a distinctive “Thwang” ringing.

Once dimpled, I went to do as the instructions said and cleaned out the rear spar holes with a couple of light turns with a deburring bit. This insures that the skin dimples will sit nicely in them. I think it helps solve the “ski-jump” problem that I’ve read about on VAF, as well as compensate for the fact you are dimpling a much thicker piece of metal.

Ever get in a groove and just want to keep going? It was 2330 and I was in one. So I dimpled the wing walk doubler, prepped it for primer, then mounted it. Fit like a glove.

Today was a good 16+ hour day in the shop. At this point it was time to call it good for the week.

After calling it a late night yesterday, I went into the shop and realized I had forgotten to prep the outboard ribs for the platenuts needed to do the Duckworks light kit I planned to install. I made quick work of making up my template for hole locations and went to marking, drilling, and dimpling the holes as needed. Once complete, I primed all the ribs and skin.

After letting the primer dry enough, I set out to rivet in the doubler for the stall warner to the skin. Easy job with the pneumatic squeezer.

Figured I’d just install the plate too.

Time was running short for the night, so I quickly assembled and cleco’d all the ribs and skin together in the cradle. It’s now ready to rivet. It’s fun to see all the parts come together for the last time. It’s even more fun to remove clecos knowing you’ll never be putting one back in those holes again.

Nothing spectacular to report other than spent the evening prepping the left leading edge skins and ribs for primer. Once all the scuffing was done, I gave all the parts a good bath in Dawn Soap and water followed up by a wipe down of MEK. Hopefully can shoot the primer tomorrow.

With the tanks now fully sealed, it’s time to get back to finishing up the major wing portions. First up is prepping the splice strips, which hold the tank to the leading edges, dimpled, nut plates attached, and primed. I dimpled the screw holes first, then clecoed on the platenut. Once lined up to my satisfaction, I drilled one ear of each platenut and then clecoed through each drilled hole. I was then able to drill the other ear and remove the platenuts, debur, and then dimple the all the #40 holes. It was good to get back to part fabrication after the tanks. Stuff moves soooo much faster without all that sealant business. I did have to remember what tools I had in the shop though. Since the center holes are already dimpled for the screw, it’s very hard to use standard dimple dies for doing the platenut mounting holes as you could smash the screw dimple back unless…you have a small diameter female dimple die from Cleaveland Tool…which I do. I just had to remember I did after a short panic of the “oh no, how will I get these” moment. I also dimpled the ears of each platenut for a perfect fit.

Once all the holes were properly dimpled, I primed both strips and then cleaned up the shop a bit. Once dry, I proceeded to rivet on the platenuts. I found using the pneumatic squeezer to be very therapeutic.

After the leading edge splice strips were done, I removed the left leading edge assembly off the spar/stand. I then went about prepping the parts for the Stall Warning kit that my wing shipped with. For older (I use the term loosely here) kits, Van’s makes this an option for builders to retrofit. My wings are still new enough that it’s standard. I will be installing an Angle of Attack indication system, but since it’s included, I will add this other “safety feature” as well. You can’t have too many ways for the plane to tell you that you’re approaching a stall, can you?

I removed the doubler from the skin, which I had added a long time ago from the kit parts. I had match drilled it way back when I installed it. I deburred and then dimpled it, much like the splice strips, to mount the platenuts and where it will be attached to the skin. Primed it, then moved on to disassembling the remaining parts of the leading edge. Once dry, I installed the platenuts and then for some reason, clecoed it back onto the skin.

Once I realized it had to come off again, I removed it, leaving some primer on the skin. It won’t make a difference once final riveted onto the skin in the end.

Here is the skin in the cradle. I need to remove the vinyl from at least the rivet lines, debur, and then dimple. Once there, will scuff, prime, and then be ready to final rivet. What you can’t see in this photo is the slot that is drilled and cut for the stall warning metal vane that sticks out from the leading edge. I final drilled and connected the holes that where already pre-punched.

I was on a roll for the day…so I prepped the parts for the warning micro-switch cage. You have to countersink for several screws and rivets. I also had to clean up the vane some…as it was roughly welded and had some sharp bits still attached on it. It’s made of stainless steel, so it took some good filing to get it right. Once all the aluminum parts were prepped and ready, I shot them with primer.

Here is a shot of all the parts of the Stall Warning assembly together. I will be riveting in the nose rib along with all the other ribs when the time arrives, but as it stands, the subassembly is done and ready to go in the wing. I presume that the vane will rest on the bottom of the slot in its resting state, as there is NO other stop, other than the rivet head just below it for the platenut that stops its travel down. I don’t recall that being the case on those flying/finished aircraft, but I could have missed it. It will take some adjustment to get it right and working when flying, so we’ll see how all that works later.

Once all the parts were ready to go in final, I called it a night. You can see in the above picture, I did leave the primer off around the lower hole. That’s intentional, so as to give the ground lead from the switch a good, clean contact. Next up is the deburring and dimpling of the full left leading edge skins and ribs. Then final assembly and install permanently onto the wing. Nice to make a post NOT about the tanks!

Had another GREAT day getting the last of the last of the sealant tasks for the tanks done. As you can see above, I sealed the right tank pickup and cover plate on. I opted to NOT use the cork gasket as many other builders have done. I also replaced the standard 8/32 x 1/” Phillips head screws with Stainless Allen cap screws and washers instead. IF I ever need to remove these covers while the tank is mounted to the air frame/wings, I can use a hex key rather than a screw driver. A provision that I hope to never have to use, but one that was cheap and easy to do, just in case.

Here you can see both, side by side, fully sealed. I did make a good fillet around each screw head with sealant after dipping each screw in sealant before installing them. Just extra hopeful leak free insurance. I also did a little fillet around the BNC connectors for the capacitive fuel senders, also just in case.

Here is a close up. The sealant is about the nastiest stuff made to man…other than used baby diaper deposits. I plan to let these sit for a week, then I’ll be able to pressure/leak test. If all goes well, we may be able to claim success. I was able to get these done about mid-day…which meant I could now move on. I was able to do just that. Until the pressure/leak check, I’m moving back over to the Wings. Hears hoping…no more sealant for a LONG time!