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David Paule 07-06-2018 06:38 PM

Belly Rivets
Riveted the seat belly skins and the belly skin that’s immediately aft of the firewall. The Titanium overlay did not get riveted on at this stage. Since the fuselage is still upside down in the jig, I bucked the rivets from underneath, while my helper, Glenn Potter, drove them from above. It was a hot day and it got hotter inside the fuselage. But the worst part was that my close-work reading glasses would fog up, and that, combined with the relatively poor lighting, made my share difficult.

We lost some time on the first afternoon when I learned that Glenn, instead of merely being late at the shop at my home, had showed up early out at the hangar. He ignored the fact that every bit of work he’d done so far on the RV-3B was at my shop here at the house, 15 miles away, and was waiting patiently for me to appear at the hangar. Good thing cell phones have been invented or he’d have had a long wait; I wasn’t planning to stop by the hangar until the next day.

The riveting took three afternoons. It cooled off and I set up a fan; things improved.

The red tape marks rivet holes for the Titanium, which get riveted at a later stage.

Here’s the proof - no clecos on the belly!

This job took some figuring out since I seemed to need one or two more bucking bars than we had on hand. Plus, my drop light died and I had to use a flashlight. Primitive, eh? Always one thing or another. But now, done.

This and the previous post above kind of brings home to me how much my friends are helping me build this one-seat airplane. Couldn't do it without them.

The photos are also lurking here and here.


Larry DeCamp 07-06-2018 06:53 PM

David, I admire your work 👍
If you are ever the mood to sell, please put me first on your call list..Larry

David Paule 07-21-2018 02:27 PM

Before I can glue the forward side skins on, the tunnels have to go on, at least where they fit in between the side skin and the lower longeron. Since I did a poor job on the left one, it’s on order and I’m working on the right one.

Both the forward tunnel bulkheads are riveted to the belly skin.

I’d planned to install the Fiberfrax and titanium underlay (overlay?) at a later stage in the assembly, but a trial fit proved that the titanium would not go under the tunnel inboard flanges then. I need to install the titanium before the tunnels go in. This meant that today’s job was fitting the Fiberfrax and locating it.

I trimmed it to size, adjust a little to suit, and then pressed it into the spacers along the belly skin. Here the Fiberfrax is cut out for the first one. The Fiberfrax is so soft that it’s easy to do this just by feel.

As shown, I used an Xacto knife with a #2 blade. Proceeding right along, shortly the Fiberfrax fit fine.

My original plan was to lay some 3M Fire Barrier 2000+ down on the belly to hold the Fiberfrax in place, but I soon realized that this batch of Fiberfrax was the sedentary kind; it didn’t want to get up and wander around. Those spacers hold it just fine. Just as well, the local stores are out of the Fire Barrier and my previous tube is clogged with cured stuff.

But there were two places where I wanted to add some anyway, so I cut the tube spout open and was able to put some into a syringe left over from the tank sealant days. I used this to caulk the seam at the firewall flange. The only reason was to help preclude exhaust leaks there, and yes, the titanium goes over that too. And I had one rivet hole the I drilled for the titanium which was in a poor location and which I intend to leave unfilled. I caulked that with the Fire Barrier, too.

I’ll have to get a tube later in the game, though.

Worth noting is that Fiberfrax is an aggressive collector of dirt and dust. I've never seen anything like it. When I wasn't working on it I laid a sheet of .010 polycarbonate over it to cover it. Nothing special about the plastic, it was handy and cut easily with scissors.

After the usual prep work, I was able to glue the titanium underlay to the forward belly skin. The prep work took less time than normal since the titanium with the .040 belly skin is stiff enough not to need an exoskeleton. Plus skin-to-skin joints generally don’t need one.

I’ll leave most of the clecos in until the rivets go in, since I’m not sure how well the titanium adheres.

Question for English majors - is Titanium or titanium the preferred spelling? Seems to me that since aluminum and steel aren’t capitalized, that there’s no reason for titanium to be, either. The names all describe elements, even though we use alloys of them rather than the pure forms. I haven’t been consistent before with capitalizing them. What do you think?

The next step was to glue the right hand tunnel on, since it’s inboard flange goes over (under?) the titanium. The glue is now curing. This inboard row of rivets can’t be bucked. I nearly wrote “nearly can’t” but with the forward bulkhead riveted in place like it is, it’s impossible. Fortunately, it uses blind rivets. When the glue’s thoroughly cured I’ll drill those holes to final size and install them.

Back to the RH side skin. The frame prep work is nearly done. You’ll see that there are no rivet holes yet through the firewall; the strips that attach to the inboard side of the firewall flanges haven’t arrived yet. Ideally, I’d dimple the side skins and firewall flanges, and maybe I’ll get to do that.

The RH side skin itself is nearly ready, but whoa! The zinc chromate primer is way to rough to the touch. It’s unacceptable. Then I remembered that I had planned to paint over that with a color coat anyway, and decided to remove the zinc chromate. That was a messy job. I’d pour lacquer thinner on, let it rest for a few minutes and scrape it off, using a plastic scraper so that I wouldn’t scratch the skin. I’ll have to do more on another day, there’s more to go.

That’s it for this episode.

The photos also reside here, here, here, here, and here.


David Paule 08-06-2018 08:35 PM

Well, with a bit of help from Sam Ritchie, local RV-10 builder, we glued the RH forward side skin on today. This is the cockpit side. This was the culmination of considerably more effort than had been apparent. Among the things that delayed this were:

The skin had been primed. The paint job turned out to be extremely rough, so I removed it completely, as I've mentioned.

With all the various overlaps of the construction, I had to add a lot of shims in a number of places. You may have noticed that.

I had to decide what I was going to do about the forward turtledeck later one. This is the one that goes between the firewall and the panel on top. According to the plans this overlaps the side skins and is attached with #8 screws and I believe the RV-4 is similar. If I were going to accept the overlap there, I’d have to fit those #8 holes in between the -4 rivets at the forward end and those rivets are spaced about 3/4” apart while the screws are roughly 2.5” apart. Worse, I’d have to drill, countersink the longeron and dimple the skin. That would only add a day’s delay. Still, the panel attachment meant that the position of the screws at the aft end would need to be a SWAG and the integration of the cowl cheek flanges would not happen for a considerable time down the road.

Or I could glue the skin on and countersink right through the skin, a less-desirable alternative but marginally acceptable.

Or I could install an angle on top of the longeron and screw the turtledeck skin to that. This offered a few advantages at the cost of a little weight and slightly reduced access to the forward equipment bay. And this is the option I’m choosing.

With all the various options and issues, actual thinking was required. Whatever else you can say about building an RV-3B, one tool is absolutely essential: an operable brain. I called my mentor; he has one of those. He outlined several of the conflicts inherent in this area, a good briefing.

Yes, I checked that I indeed have a #8 dimple die set on hand for when I need it. It seems that I needed that already for the tanks and there it was, right where it should have been.

Here’s the skin still clecoed with the exoskeleton in place, while the glue was curing.

You can see the the exoskeleton for the top longeron is bent. I used the stretcher to do this. I'm finding it to be a handy tool that I should have gotten earlier. It's too late in the construction to get much use now, but it still has its moments.

Also that the forward edge at the firewall flange is clamped but not clecoed. I’ll drill those rivet holes later, probably when I install the cowl cheek bulkhead and the back-up strip for the quarter-turn fasteners.

Then on to the left side. I’d had to replace the original tunnel side so I started hacking at the new one. I needed to shorten it and recess the turned-in flange and that’s as far as I got today.

The pics are also hosted here and here.


David Paule 08-12-2018 09:03 PM

Here?s a photo of the RH Side, glued but with the clecos removed.

Once the tunnel side was useable, I removed it and started drilling and checking the LH cockpit side skin. But first I took a few moments (that is, something over an hour - this is an RV-3B, after all) to go back to kindergarten to make some simulators for the systems boxes I don?t have yet. These boxes will all go somewhere but I?ll have to figure out where later and that?s what these are for. I?ve got most of the others on hand and can use actual components once I have good access to the interior.

Step one was to mark and cut out the cardboard.

Step two was to tape the boxes to shape. These represent only the outermost envelope of their volume and make no attempt to conform to their real shape.

Worth noting is that except for the empennage, virtually all the exterior skins that came formed, came mis-formed. They all, without exception, required some tweaking. Some took more than others but I had to rebend every one of them. This is apparently an RV-3B thing, but if you?re thinking of building one of these airplanes, consider this, too.

Here?s an alternate host for the photos:here, here, and here.


RWoodard 08-13-2018 10:49 AM


Originally Posted by David Paule (Post 1280318)

Worth noting is that except for the empennage, virtually all the exterior skins that came formed, came mis-formed. They all, without exception, required some tweaking. Some took more than others but I had to rebend every one of them. This is apparently an RV-3B thing, but if you?re thinking of building one of these airplanes, consider this, too.


You made me laugh out loud with this statement!

Thanks for reinforcing my decision to sell my RV3 kit!

I?ll be in Boulder sometime over the next 10 days or so helping my niece settle into her rented condo at Gold Run. I?ll give you a call and try to stop by. Always enjoy reading your updates.

David Paule 08-13-2018 08:51 PM

Missing Photos?
I discovered that some of the images, hosted by, have apparently gone missing or at any rate fail to download on my computer. I'm replacing them as I find them and have time.

So far, the second hosting by Imgur seems to be fine. Hosting by imagebam, though might not.

If you know of any, please PM or email me (via my username at the upper left) and I'll add that post to my list.


David Paule 08-20-2018 09:02 PM

Dallice Tylee came over to help me drill and cleco the LH cockpit side skin. At the aft end there?s a mild compound curvature that presses into position nicely but which I can?t quite manage by myself. This isn?t a kit flaw but a natural part of the design. She pressed a block of wood to the skin while I drilled from the inside, after which she put clecos in. Fortunately she?s both self-employed and a neighbor as well as a pilot, and was able to come over without a scheduling hassle.

The photo shows me yanking out some clecos to fit the LH tunnel side under the skin.

I also made a cardboard simulator for the compact EarthX battery for comparison. The previous one is common to the other sizes. Comparing these to the cowl cheek bulkhead and after locating the aft end of the cheek cone on a table, I soon found that neither battery would fit in the cheek in any orientation. The aft corners of the battery will protrude from the cheek, and no, I?m not going to have small streamlined bumps for them on the cheeks.

In fact, I?m a little surprised I even considered that.

That LH tunnel that's shown in my hand is now glued on and the side skin is removed for dimpling.

With both tunnels glued on, I decided that access to them is better with the LH cockpit side skin uninstalled, and took the opportunity to put in the LP4-3 blind rivets that go through the cockpit floor. Incidentally, don't believe the 2 1/2" dimensions shown in the plans. With the actual parts, decide for yourself what the spacing needs to be.

Additionally, I riveted the tunnel bulkheads to the shells. The rivets at the back end and the ones through the side skins remain to do.

The photos are now mostly hosted at But they are also hosted at

here and here for backup.


David Paule 08-29-2018 09:53 AM

Here?s a photo of the rivet holes in the side skin that are hidden by the wing. The row at the top of the photo doesn?t need to be flush. The plans are a bit vague about this area - I?m sure that other people have built their planes a little differently here. But for me the ease of riveting is more important than the extra work dimpling them. I could have gotten the AN442 flat protruding head rivets for this but I didn?t. Those are as easy to set as flush ones and are otherwise like universal-head rivets, but with a flat top. While we?re thinking of easy-to-set rivets, if you go back to reread that riveting spec MIL-R-47196 that?s on Van?s site, I?m pretty sure it says that flush rivet sets can be used on universal-head rivets. That?s also easy. But there?s a small dimensional window between a proper shop head and going too far squishing the factory head, so I haven?t been doing that.

The area outlined by the red dashed line will not be glued.

I rechecked the twist of the fuselage. Once the cockpit side skin goes on, no other tweaks can happen. This is it.

Here?s the longerons at the spar bulkhead:

And the longerons at the seat bulkhead:

I also checked the firewall and it?s aligned, too.

I was unable to check the aft end of the tailcone due mostly to not being able to see the level.

Rod Woodard dropped by the Boulder airport for a visit. It was great to see him again and to examine his new RV-3. It?s a very pretty airplane and I got to look at a number of things that I?d wondered - throttle quadrant location, seating height, fuel selector position, fuel vent position and configuration,, antenna locations, etc. Details.

Here, here, and here are the backup photos.


David Paule 09-04-2018 08:29 PM

Sunday before Labor Day was kind of a big deal. With the help of Charlie Stein and with Rod Woodard observing, we glued the LH side cockpit skin to the frame.

This marks the final skin while on the jig.

This skin, like the entire RH side, tailcone and cockpit sides, are as yet unriveted.

Rod Woodard took the first four photos.

The day was interesting and fortunately, uneventful. It went pretty much according to plan. It took 77 grams of mixed epoxy and there was a little left over. In the photo, the lids were ajar because I wasn’t sure if I’d need to mix another batch or not. As you can see from the cans, I’ve been using them.

I’d already put the tape on the inside of the skin.

Charlie Stein and me,

Once the exoskeleton and clecos were off, I stood back for a few minutes to look at it.

Incidentally, for this skin I countersunk the longerons .012 deep, using a rivet as a gauge. This gave me a noticeably smoother surface than the dimension of .007 that the factory recommends for non-glued joints. On the bulkheads I've been using the tank dimple dies and they work very nicely for glued joints.

Then I removed the front part of the jig that had supported the firewall. The plan was to install the engine mount and then the main gear legs, but the bottom front cross member of the jig isn’t removable and was in the way. Here’s the firewall without the jig obscuring it. Yes, I did remove that bump in the center of the cross member.

I also learned that, as I had rather thought, that the belly round-over will need trimming. Might even need removal but it’s too early to be sure.

The photos are also here, here, here, here, here, and yes, here too.


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