Our RV-7 has a Name!

Registration number N49MS!

I was playing around with the FAA registration web site and decided to try a couple more combinations of what I thought would be a cool tail number for the RV. I had checked before and was a bit disheartened to learn that there are sleezy companies out there that snatch up all the small and cool tail numbers to re-sell them.

While some people might say that’s clever, I think it’s slimy. But that’s not what this post is about. I tried a number of “2×2” tail numbers just to find that they’re mostly all reserved (a few were actually assigned).

I did, however, come across 1 that was not yet snapped up by the sleazy businesses: N49MS. I immediately ran over to the wife to see what she thought. It consists of “49”, which reflects our 49-er spirit (since we’re Californians), and “MS”, which are our initials. Wow! I couldn’t think of a better way to personalize our airplane!

It costs $10/year to reserve an N-number. I’m hoping I’ll only have to spend $30 before I can turn the reservation into an actual registration. 🙂

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Bits and Bobs store

1/8″ diameter squeezer gap gauge

I’ve crafted a couple simple tools to help us with the assembly of the plane as we go along, and I’ve decided to share them with fellow builders, so I am putting up the 3D STL files on my Thingiverse page for people that have a 3D printer and would like to print them.

For those that don’t, I put together a little where you can purchase the designs I made which are printed or laser cut already. You can find my first design, a pneumatic squeezer gap gauge, on the Aviate.Org Online Store.

There’s also a donate button there if you’d like to buy us some coffee…or better yet…100 rivets!

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Replacing a couple rivets

Drilled out first bad rivet

I’m quite happy that after completing the reveting on the rear spar, there were only 3 rivets that I wanted to replace…2 of them for sure, and 1 that probably could have stayed. I ordered a rivet removal tool, which is specifically for universal rivets (round heads). It was another good buy!

Rivet removal tool

The tool attaches to a drill and has a drill bit which travels through the center. A spring keeps it retracted. The end of the tool has a recess that allows it to fit completely over the rivet head, and the drill bit travels through a hole in the end, thus keeping it centered on the rivet. Without this arrangement, it’d be very hard to drill perfectly in the center of the rivet (given the sloping head).

Drilling in the exact center is important, so that you don’t accidently drill and deform the underlying rivet hole. You can set the depth the drill bit extends through the end of the tool as well. The goal is to drill just beyond the surface of the skin. You then use a punch in the hole you just drill to snap off the head of the rivet, then punch out the bottom.

Another rivet out. the snapped-off head it just to the right of the hole.

Front Spar

On the front spar, we couldn’t use the pneumatic squeezer for the bulk of the rivets since they sat behind a rather tall set of angle brackets. So, I broke out the rivet gun and bucking bar, and went old school for most of them! They turned out better than I thought they would given I’ve been spoiled by using the pneumatic squeezer for most the riveting of the spars.

Bucking some rivets

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Wing kit ordered!

Now the clock starts! Fulfillment time currently is 14 weeks. I’m hoping that we’ll be done with the empennage just before the wing kit arrives. From the looks of it, 2 large crates comprise the thing, and there are a few of the larger fuselage pieces thrown in to take advantage of the room.

Tomorrow we’re going to have a nice chicken wing lunch to celebrate!

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Riveting hstab rear spar

Mike the Rivet Man

After sorting out the rear spar elevator notches, we started riveting using the NEW pneumatic riveter! It took a while to get here, but I’m really glad we spent the money for it. It made quick work of riveting the rear spare 603PPs to the reinforcing bars (609PPs).

The beauty of it is that all of the rivets look identical, and perfect!

Perfect rivets all in a row

Here you can see 8 rivets attaching a hinge to the spar. I’m holding a -4 rivet gauge over the shop head to check that it’s been compressed enough, which it has.

The reinforcing bar-to-spar work amounted to 124 rivets, mostly AN470AD4-6, with a few -7s and -5s thrown in. The plans called for -5’s for the 2 outer hinge attachments, but when I went to set the first one, it looked too long. Sure enough, it didn’t set properly, which means I’ll have to drill it out.

The 1 bad rivet…too long!

I changed to -4’s for the rest and it worked out just fine (the picture with the blue gauge shows one set of the hinges with the -4’s used).

The shop heads (front side of rivets) look really cool against the spars:

I think these were AN470AD4-7 rivets here. Empty hole is for attaching a rib later.

Overall it was a great afternoon riveting. We found that the riveting part is the quick part. It’s preparing all the pieces TO be riveted that takes a bulk of the time. Next up, we’ll be riveting the front spar of the horizontal stabilizer! But first, I have to order a rivet removal tool and a small torque wrench.

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Dreaded notches!

Hidden notches!

Early on in the process, I noticed this note on the plans, which calls for trimming a couple notches out of the rear spars in order to give the elevator horns enough room to move to their bottom stops. This wasn’t called out in the instructions at all, but I made a mental note to make sure I cut them out before priming.

Well, guess what happened?

I dropped Van’s an email and asked if I should do this trimming now, or if I could wait until I actually got the elevator horns (which were on back order initially) installed in a later step. They suggested that it’s best to cut the nothes now, since damaging the 609PPs in any way would be a bad thing. Since the notches come close to the bars, it was prudent to cut them out before we started riveting.

I’ve been dreading this step because the last time I had to cut a large-diameter hole I made a mess of it (didn’t practice at all with the step drill). Also, I didn’t feel I had the proper tools for cutting the notches out. So, I swung by Harbor Freight and picked up a pair of air shears after watching a number of YouTube videos about them. After a few tries, I committed to doing it.

The notches, side by side

In retrospect, I should have lined the spars up first and drew the lower line across both. I marked them up separately, so they’re not even. It’s not a bad thing, just an O/C thing. 🙂

One of the other RV builders at the airport dropped by, and I showed him my conundrum. He thought maybe I was overthinking the issue, and I agree. It all ended up fine. Build on!

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Finally got some painting done!

Shooting the Green!

Finally! FINALLY!!

We finally got to a point in the project where the next step was,

“Prime, if desired…”

I’ve been a bit apprehensive about spray painting. First off, I’ve never done it before. Secondly, I’m using a particularly toxic primer. These two sticking points perhaps contributed to the long wait. The weather hasn’t been helping out, either. Lately the daily high temperatures have dipped below 60, which is about the lowest temp you want to have for spraying AKZO.

I had several potential approaches to priming. First off, I was hoping to be able to prime at the hangar by building a small paint booth. I asked the airport manager about it and she was fairly sure it wasn’t a good idea (overspray, flammability, etc.)

The next two possibile solutions were to build a small paint booth at home, inside the garage. To that end, I invested in a 10″ “explosion proof” fan, and 25′ of duct, which I’ll use to vent the fumes and spray from inside the paint booth. I’ve watched a number of really decent project videos on YouTube on this, and I think I’ll invest the time and effort to do so.

However, time is of the essence! I need to order the wing kit soon so that we can move smoothly from the empennage into the wings without waiting too long. Currently it’s about a 14 week lead time.

So, the last solution is to just spray these first parts outside in the backyard, where the overspray will quickly dry and float away without causing any damage. I assembled the parts and built a low table with chicken wire for a top, ordered the AKZO primer paint, a good 3M repirator, and all the other accoutrement required to do the job.

After several days of rain, today was forecast to be partly cloudy and 61°, which was right at the low point for spraying (although I’ve read that several have sprayed AKZO at 55 and even 45 degrees). So, I brought all the pieces-parts up from the hangar and started the process of preparing them

Step 1: scuff and clean

The first step is to scuff all the parts to remove the protective ALCLAD cladding in order to give the paint better adhesion. Next was to clean the surfaces from any oil/grease. I did this with denatured alcohol.

Next up was preparing the paint. Mixing the AKZO was interesting. As mentioned before, the paint came in gallon cans that were pretty bashed up when they arrived. Fearing a leak would start at some point, I went out and bought 2 empty gallon paint cans and set about transferring the paint.

The first can was the curing agent, which is a clear liquid with a slight yellow cast and a consistency of light syrup. I snapped on one of these paint can pour spouts and made the transfer easily. I then topped that can with a Rockler paint topper (with built-in paint mixer!).

The paint itself was a different story. The solids had settled and coalesced at the bottom of the original can. I started by first shaking the can a bit to mix it, but gently since the can was damaged. After pouring half of it I saw the solids had gelled at the bottom. THICK solids! I decided to pour back some of the liquid and try shaking some more, then stirring with a paint stick. Still, some of the goop was like silly putty! I finally got most all the goop reincorporated with the liquid and scraped the rest into the new can. After inserting the Rockler top I was able to stir it easily.

Transferring paint to new can. Rockler top is behind

After transferring the paint to their new cans, I mixed the Component A (paint) for a couple minutes, then poured out equal parts of Comp A and B into a mixing cup and stirred it up good.

mix mix mix!

Next, the paint was pouted through a filter cone into the spray gun’s hopper, and off I went!

The first side done

I mixed another hopper of paint while the first side dried to tack (15 minutes). Then I carefully flipped everything over and sprayed the second side. Both times I lucked out and mixed just enough to finish each side!

Gotta love the booties

Overall, I’m happy with the results. I did forget a couple things while spraying, like giving the first batch of paint 30 minutes to be ready after mixing it. I also had a bit of trouble getting the proper fan pattern set, but after twiddling the knobs a bit it looked okay. I sprayed at 40psi, but probably could have turned the air down a bit more. Cleanup went okay, but I was pouring from a half-gallon can of solvent, and it got everywhere. There is a special solvent sprayer I need to pick up that makes it easier.

Unfortunately, I got started a bit late, as I had to run out to ACE hardware to pick up a connector for the spray gun to connect to the air hose. By the time I had finished spraying the second side, it was getting dark. I ended up cleaning up and bringing everything in well after sunset. All the parts were shuttled into the garage where they are currently drying.

So, I finally did it, and it wasn’t that bad. Tomorrow I spray the skins, then we can get back to work with riveting! Build on!

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Primer prepping

Paint table

It’s been kind of slow these past couple weeks. The weather is getting cooler, and weather is starting to become an issue. This past weekend I had planned to prime the parts we’ve been working on, but it turned out rainy and cool enough to dip below the minimum temperature for the AKZO paint.

I did, however, manage to complete a simple paint table, which I plan to use in the back yard to spray the parts we need to prime before we can start riveting the horizontal stabilzer. This one it temporary, and I’ll attach a 5′ x 5′ cloth paint tarp underneath so that it creates a trap for the paint overspray.

I’m still designing the paint booth that I’ll set up inside the garage so that I can spray during the winter, where I can keep it warm enough to spray. I have a 10″ exhaust fan and 25′ duct to take away the vapors and exhaust them outside.

Weather is improving, and I’m hopeful that during this week I can take some time to get some priming done.

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Primer has arrived!

AKZO Primer!

The primer’s here!

I ordered the AKZO military-green primer for the internal parts, which I intend on spraying on. I’ve been considering different options, but the AKZO primer has won out. Fortunately there are a lot of YouTube videos out there that not only go over how to apply it, but how to set up and use a paint gun…another skill I’ve yet to develop!

For the first run I think I’ll just spray out in the backyard, on a makeshift paint rack. I do have all the parts I’ll need to build a paint booth, but in order to get started quickly I’ll do what most others have done…paint outside…for now.

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New Dimpler

The new DRDT-2 dimpler TANK (I’ve yet to put it together)!

So last weekend we started dimpling the horizontal stabilizer skins with the Whack-a-Mole dimpler (C-frame dimpler). To be honest, I wasn’t happy with the results. To use it, you place the hole in the skin atop the male dimple die, then whack on a long pin, which then drives the female part of the die against the skin to make the dimple.

I discovered 2 things right away… unless you use the exact force each time you strike the pin, your dimples aren’t consistent. I also found it hard to tell if the dimple was set correctly until lifting the skin off the tool and checking it. As it turned out, the great majority of the dimples are under-done, which means I’ll have to go back and whack on them so more. The problem with that is, the more you deform a piece of metal, the weaker it gets. I found I had to strike the pin twice for each dimple near the end. No bueno.

Back when we first started the project, and when I was considering all the tools we had to buy, I had to decide between the C-frame and the DRDT-2. At the time the price of the DRDT-2 seemed excessive for what I needed it to do..produce dimples. Now I know that I not only need a tool that accomplishes this, but I need one that does it consistently, and with the least amount of potential damage to the skin (I have already had the skin jump off the small pin once as I was striking the pin, making a divot).

Anyhow, I bit the bullet and decided to invest in the DRDT-2 anyhow. So now I have 2 deep-reach dimplers…along with 3 or 4 other dimpling devices. For now I’ll keep both, but after re-reviewing the DRDT-2 I’m pretty sure it’s going to be the go-to dimpling device.

The difference between them is that the DRDT-2 is a compression dimpler, just like our hand squeezer, except it’s a giant, honking tank of a device (weights over 30#). One thing I like about the hand squeezer is that it was very easy to produce consistent results. The downside is that it’s tiring to use, requiring both hands and a good amount of force. The DRDT-2 has just one handle, and sits on the table.

Anyhow, so it now joins the other dimplers in the tool shed. I’m excited about it, actually.

Oh, on another note… I also bought a pneumatic squeezer/riveter…so that makes 5 or 6 suqeezers!

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