Starting the rudder

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While the horizontal and vertical are awaiting inspection, I’ve started the rudder. I spent three hours or so studying the plans, then cutting stiffeners for the left rudder skin from the raw material provided.

Left rudder skin with stiffeners

I had to read through the plans a couple of times to properly interpret how cuts are made between the prepunched holes. A bandsaw and belt/disc sander really speed up the trimming/shaping process. I didn’t like the little half-hole left where the stiffener taper is cut, so I used the belt sander to round off the corner a bit.

Hitchhiker’s guide quote

One of my co-workers handed me this message today which he found in a piece of biscotti. I’ve never heard of “fortune biscotti” before, but it seems as though Mama has been reading “The Hitchiker’s Guide to the Galaxy.” This little tidbit had to get posted in the shop.

Horizontal and vertical stabs

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VS frame riveted to skin, spar clecoed in place

The horizontal and vertical stabs are mostly riveted, except for their rear spars. I’d like to leave the interior rivets exposed for a Tech Counselor visit, so the rear spars are only clecoed into place. Just had to have these two set up together for a motivational “looks like an airplane” picture.

Fun with the pneumatic squeezer

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VS frame riveted to skin, spar clecoed in place

VS frame riveted to skin, spar clecoed in place

Ellen and I riveted the VS frame into the skin, then came all sorts of fun with the pneumatic squeezer setting the root and tip rib rivets. Had to drill out a bunch of ’em…

…but the end result was good. Once I figured out how to handle the no-hole yoke, getting the tip rib rivets was easy. The aft spar will remain clecoed until my first EAA Tech Counselor inspection.

Motivation is going again!

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VS frame riveted and clecoed into its skin

I’ve been on travel for the last couple of weeks, but finally got back to the airplane. A trip to the annual EAA Chapter 486 RV Forum got my motivation going again!

VS nose rib scratches polished out

Riveting the root rib, nose rib and front spar together proved to be a problem for me. I was being a little too cautious in bending the nose rib out of the way, and thus cleated a couple of rivets. Considering using blind rivets, I called Van’s to find out which ones would work. Turns out that an LP4-3 would work fine, but I decided to give solid rivets one more try and everything worked ok except for…

…some scratches from the bucking bar. Some fine emery cloth and a scotchbrite pad polished ’em right out.

…back to the VS

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Just finished up the HS to the point of being ready for inspection. So…back to the VS.
The next step in VS construction was riveting the rear spar together. Not too many problems here; the pneumatic rivet squeezer proved its worth once again while squeezing all those -4 rivets.
Finally got some use out of the Avery back-riveting plate. The countersunk/dimpled rivets came out pretty well – or at least the camera makes ’em look good.
The frame is going together next. Here, the bottom rib/spar rivets are ready to be squeezed or bucked. I really need a thin-nose/no-hole yoke for the squeezer. It would really help here.

Lots of progress in the last week and a half…

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Lots of progress in the last week and a half…

After riveting a HS-707 nose rib in the left HS left skin, it was time to insert the entire front spar assembly. The plans call for riveting the nose rib in by itself, but it was much easier to keep the skin in place on that nose rib by clecoing in the center and end ribs. Thanks, Mike, for the tip.

I also ended up using one of the MK319-BS monel blind rivets that Van’s calls out as optional for attaching the nose rib. Even with the rib flanges spread a bit before riveting, the forward-most portion of the flange still didn’t lie flush against the skin. So rather than try to buck a rivet while holding the flange in place, I used the MK319-BS. Those of you who either (a) have done this before, or (b) are going for an award at Oshkosh may consider this a cop-out….well, have a nut. The blind rivet worked great, and looks ok too.

And here’s the left skin riveted on, with the exception of the end ribs and rear spar. I’m leaving the structure open until the first visit from my EAA Techincal Counselor. Ken Balch kindly volunteered to be my TC, and I’m really looking forward his first trip to the shop.

One other thing to note…Ellen did a great job with the rivet gun! After only a little practice on some scrap, she was wielding the 3X like she’d done it for a long time.

After repeating the process on the right side, here’s the almost-finished product. It’ll be completed after Ken’s visit…or else I’ll be drilling out a bunch of rivets!

The rear spar clecoed in place. This HS structure is pretty flimsy without the rear spar.

Skin rivets

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Not much time spent today, but we did get the first skin rivets in. One small step for the Mighty RV, one giant leap for Dave. I had a bit of a mental block about these rivets. But some practice and mental rehearsal paid off.

Just a few rivets done because it was getting too late to make a lot of noise with the rivet gun. But none of them had to be drilled out. Bonus!

Lots ‘o riveting going on

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Lots ‘o riveting going on in the last few days…and drilling out some rivets too.

I had to re-learn all those rivet bucking skills I had forgotten since the SportAir workshop. Ellen caught me in the midst of a hard-to-hit rivet. But the HS front spar is finally finished…

Here are the front and rear spars covered with spiffy yellow Super Koropon primer.

…and here’s everything clecoed together. Next task – practice flush riveting, then start putting the skins on.

HS parts are all alodined and primed

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HS parts are all alodined and primed. If you’re desperately interested in the whole process, go here.

Finally…some rivets squeezed! Constructed the horizontal stab rear spar and attached its elevator brackets. I had to drill out a few rivets, but didn’t make too much of a mess.

Here’s one rivet drilled out, and another ready for the punch. Once the rear spar was done, I started re-assembling the front spar in preparation for riveting.

Washed, prep-sol’d, etched, alodined and primed

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Over the last few days I washed, prep-sol’d, etched, alodined and primed all the horizontal and vertical stab parts. I must say that this whole process was a tremendous pain in the…uh, butt.

Here are the parts after washing with liquid dishwashing detergent, a wipe down with PrepAll (same stuff as PrepSol), and a scrubdown with DuPont 225S aluminum metal cleaner (same stuff as Alumiprep). Not too big a deal to do all this stuff, and a box of Scotchbrite pads came in handy. If you plan to do this process but haven’t yet, make sure you put a little extra effort into scrubbing the alclad parts. Swapping Scotchbrite pads frequently helps.

Next step was application of alodine. This was not fun. Ribs and other parts aren’t too tough, but spars are awkward and skins are even worse.

Here are the results. Ribs –

and a horizontal stab skin –

This step required a lot of cleanup. And the knowledge that chromate conversion processes like alodine use hexavalent chromium, a rather nasty carcinogen, is motivating me to consider a non-chromate conversion coating called PreKote. It’s non-toxic, non-hazardous, biodegradable, and can be applied with a hand sprayer and a fine (maroon) Scotchbrite pad. Unlike alodine, it doesn’t leave an anti-corrosive barrier and requires a chromated epoxy primer to provide corrosion protection. I’ve requested some information from the manufacturer, and we’ll see what happens.

And finally…priming. Because we live in metro Boston and are close to the Atlantic, I decided to use a fluid-resistant epoxy primer to provide an extra measure of corrosion protection. In particular, I’m using Super Koropon from PRC-DeSoto. It’s roughly equivalent to the Akzo Nobel epoxy primer that a lot of other builders seem to use. Here’s one horizontal stab skin –

and other assorted ribs and spars –

ike alodining, priming was a genuine pain and I’m glad it’s done for now.

My experience with applying this primer on the empennage is also causing me to consider how I’ll apply it in the future. Van’s rightly says that two-part epoxy primers are heavy. That’s true, but there is nothing better I’ve found for corrosion protection. On the wings and fuselage, I may choose only to apply it where it’s really needed – overlapping skins and skin-to-structure contact, anywhere that moisture can accumulate and promote corrosion. More to follow…

Now, it’s back to riveting the horizontal stab.