Good Night, Beautiful

Well, well. It’s like Deja Vu all over again.

When my previous RV-8 kit’s progress ground to a halt, I had bills to pay and kids to educate and weddings to pay for; so the kit was sold to a good guy who finished her. Sadly, my second attempt at finishing an RV-8 has also ground to a halt; this time due to family circumstances changing which will require me to re-locate. Any workspace quickly becomes a very organic place with memories and nooks and crannies; it breathes as new bits are introduces and completed assemblies are set aside. I’m dreading having to disassemble everything and put it into storage hoping to re-establish another work place at an undetermined location and at an unspecified time in the future; but that’s what I’m going to do.

So, good night my Beautiful Daemon, rest easy. You’ll wake up in a better time and in a better place where we can get back to the business at hand; helping us both take wing.

Tanks. Tanks a lot.

Ahhh. Fuel tanks. With the empennage finished, it’s time to move on, and we’re moving on to fuel tanks next. Most of the construction is done, most of the seams and rivets are sealed. All that remains is the aft end of the tank, called the baffle. It’s relatively easy to do, but it’s also where nearly all the leaks come from, so it’s worth spending some time to do right.

One of the really nice things about aluminum construction is that it’s a fairly clean process; there are few odd smells or sticky goopey messes – but the sealant that gets smeared around the seams of the tank are the exception to both of these generalities. The sealant is called “Proseal” and if applied correctly, it makes a permanent seal and you never have to worry about the tanks again. “…if applied correctly…” is a big caveat.

I’ll get some pics soon and fill out this post so you can see what I’m talking about.

Pop!

OMG. The control surfaces don’t end with a whimper, they end with a POP!

Those “rolled” leading edges are finally finished. Since the completed leading edge isn’t a structural part of the surface, just an aerodynamic nicety, they’re finished with simple blind, or “pop” rivets.

Quick run through, I know, but I’m anxious to move on. I’m still collecting many of the nearly complete portions of this kit, hoping to make things simpler and easier to pack up and protect for relocation.

Rolling, rolling, rolling…

(cue the Blues Brothers “Rawhide” theme)

With all the metal work that goes into building an RV, you might not think that simply bending aluminum skin into a generally rounded shape would keep people up at night with stress, but it does.

The Rudder and elevators “nest” into the aft end of the Vertical and Horizontal Stabilizers. The Rudders and elevators rotate as well, so to always have a smooth transition from Stabilizer to control surface, the leading edge of the Rudders and elevators must be “rolled” to a semi-circle. Sounds easy, but it ain’t. Here you are looking up what will become the leading edge of the Rudder, and you can see both ends of the skin extending straight forward (to the left) beyond the yellow/green zinc chromated Rudder spar. There’s a section of 1/2″ conduit restrained by some eye bolts and you can see the all important duct tape applied to one side of the skin.

Roll that tape around the conduit, put a set of Vise Grip pliers on it and roll and you’ll end up with one side set into a curve. You can see the side against the carpet (placed on the work bench to minimize scratches) hasn’t been rolled yet.

Doing the same operation on the other side is a bit trickier since there’s less free room; as you roll it up, the other already rolled curve gets in the way (Oh poor me), but we struggle on…

These two edges will eventually be riveted together, however since they’ve just been introduced, I’m going to give them some time to become friends and adapt to their new shape, so I’m just clecoing the edges together for the time being.

It’s not really hard, and the good news is the final seam and rivets will be almost invisible once installed, but struggling to close that gap and maintain a nice curve is hard, especially as the opposite side is just waiting to catch your knuckles and give you a really nice metal cut; guess how I know this?

Moving forward again

OK, I’ve licked my wounds, my “Exit Wounds” and I’m back to work. Time to make some progress and have a happy moment. I finished the Rudder!

The skin had been carefully prepared, primed internally, stiffeners riveted in place and the original underlying structure was waiting. Time to get back on the horse. The skin was bent so the trailing edge has a smooth and straight bend and would fit closely on the structure.

From that point, it was a relatively simple matter of slipping the skin over the structure, match-drilling the few holes that hadn’t been drilled and riveting together, probably 3 hours work.

Finally with a few blind rivets and some tight squeezer moves inside the rudder horn, the rudder is finished!

Well, finished except for rolling the leading edge. More on that to come

Exit Wound

Well…well…well. I’m sad to report that my best efforts to comply with the Service Bulletin on the Horizontal Stabilizer for my kit has finally come completely undone. I’d spent many hours and not a few dollars getting parts and more parts and MORE parts to make this work, but in the end my own faulty workmanship sunk me. To recap: In order to put in place a fix to a potential weakness of the Horizontal Stabilizer, a significant amount of work was called for to disassemble the HS, add and delete some parts and then put the entire thing back together again. This part of the kit was never intended to be re-done, it’s not held together with zippers or screws: it was all done right with solid rivets for once and for all. A few odd kit issues and tight spaces contributed to my causing damage to more and more parts until there was more damage than could be easily managed. The final blow was a hole I drilled incorrectly.

Right in the center of the picture, you can see a fresh hole drilled above and to the left of where it should have been; somehow the drill slipped after I had set it to the intended spot and when I looked at my work after the bit went thru the material, well, it wasn’t a good feeling. Three more significantly damaged parts which would require replacement and significant disassembly and reassembly do be done. I threw in the towel and have ordered and received an entire new Horizontal Stabilizer kit which has been updated to include the SB repair. I’m sad to let this old part go and I’m very frustrated that I screwed it up, but now it’s time to be honest and move on.

Builders: If you’re reading this blog to assist you in your own RV project and you’re facing this SB 14-01-31 repair, let me give you some guidance. The complexity and challenge here is totally dependent on which way the original rivets were set when you built your Horizontal Stab. Check out your construction photos. If the AN-470 rivets holding the Splice and Reinforcement angles were done so the Manufacturer’s Head (the rounded end) is on the aft side of the Spar web, then you’re in luck and you’re job will be relatively easy complying with the SB because you’ll be working from the aft side of the Spar where there’s a lot of room to get access. If those rivets have the round head on the forward side of the spar, then it’s MUCH tougher to get access to drill them out since you’ll be working within the leading edge of the HS. Knowing what I know now, I’d NEVER have done this SB on an unassembled and never flown kit with the Man Heads forward. Man Heads facing aft? Yea, go for it. I learned a hard one here; a new HS kit is about $800! Good luck out there.

Doubler, or nothing

Seems like it’s always, put up, or shut up with building a plane. This is a simple and clean and very real business. There’s no way to fake your way through this, appearances don’t count for anything. It’s a reality check from start to finish. So, today I was putting up with continuing the SB 14-01-31 process of rebuilding the Horizontal Stabilizer. It’s time to fit the doublers. A “doubler” is exactly what it sounds like, a double layer of aluminum intended to approximately double the strength of a piece. So, really I’m adding a piece which wasn’t part of the original kit, or the original plans. This new part wasn’t expected, so there is no space made for it, no holes drilled for it. For once, this construction is quite a bit more art than science. This piece is positioned by quite alot of “That looks about right”, aka T.L.A.R. In the first picture, you’ll see some overlapping blue circles drawn in place, that resulted from several attempts to position this new part and draw in where these new and unexpected holes were to go.

The photo on the right shows where I was finally able to find a place I liked; these holes were drilled along with the doubler and the new piece was installed:

The new pieces are still shiny and new and un-primed, that won’t last long! Another part of this is some heavier angle pieces of aluminum, they get a little shaping in my hands and then they’ll take their place in the center of the Horizontal Stabilizer and transfer stresses and loads across the Stabilizer and from the stabilizer to the rest of the plane. Again, the unpainted one is the new one, the yellow primed one was removed and will now be put out to pasture and stud so the world can have some new and adorable angles in the future!

Once bitten, twice shy

Time to get back on the bicycle: time to build a new rudder. The new skin had arrived, been drilled out with the stiffeners, been primed and dimpled; time to put it all together again. Having ruined the last one by too cavalierly riveting right off the edge of the back rivet plate, I was extra careful and extra slow this time. And, it all went well, just as it should go. This isn’t a hard bit to do, but having botched the last one through simple carelessness; I was over careful this time. To recap:

Skin primed where the stiffeners will be attached, stiffeners primed where they will be in contact with the skin.

Tape a row of rivets in place, flip it over and place the stiffener in place, then rivet it all together:

Looks easy, and it is, but heart stopping nerves this time! Now, proceeding, I clecoed the skin to the underlying structure to begin to bend the trailing edge to it’s acute angle. The final sharp bend will be accomplished after the skin has gently adjusted to it’s new shape.

Thank God that’s done!

My problem with ED

While the little blue pill is all the rage, sadly my problem isn’t as easy to cure. In my case, ED refers to “edge distance” and it’s the current bug-a-boo of my airplane building life. Assembling an airplane is simply a matter of holding many pieces of aluminum together so that they act as one big piece of aluminum. The things holding all this together are rivets, and rivets can only hold things together if they’ve got a tight grip on sturdy pieces of aluminum. If a rivet is too close to the edge of a part, that rivet can easily rip out when stressed, so maintaining sufficient “edge distance” is important.

In complying with the Service Bulletin 14-01-31, I’ve had to replace some parts and add new parts and in two specific cases my ED is a problem. Firstly, after buggering up the HS-814 Splice Angle, I bought a replacement only to find that it’s holes didn’t match the holes in the HS-814 I removed. The new piece’s holes were barely different, but that brought the whole ED issue out; there was insufficient distance between these relocated holes and the original holes already in place.

You can see that the holes in the silver piece on the left are staggered a bit while the holes drilled along the bottom edge in the right picture are aligned. The small blue sharpie marks adjacent to the two outer holes and the two inner holes along the bottom edge are where the new piece requires rivets. Def no good. It took a while, but I’ve just heard back from Van’s Aircraft that actually my kit wasn’t supplied with an HS-814 piece; it had to be fabricated from instructions and the instructions wanted all holes in a row! Hooray! Now I just have to make a new “old” part and I’m back in the game; no ED issues!

Oh, well, except for this one. Again, the SB I’m working on has modified parts of the existing Horizontal Stabilizer and added new parts, and things are getting pretty close. Two holes to be drilled as part of this procedure come very close to a Notch I was instructed to make in a part, so again: ED issue!

Just to the left of the “1” on the ruler in the picture on the left is a small blue circle, and it’s practically next to that nice rounded notch I made. The photo on the right shows the top and bottom notch with the small blue circle right next door! Again, this would normally be considered too close, but because this is a modification of an existing part, this closeness was unavoidable and while it looks bad, it’s considered “acceptable” in the circumstances of overall adding strength. Net – net it’s an improvement. While I’m generally smart, they’re very technically and specifically smart about such things. They have the physics and computer models to analyze such things and they say it’s OK, so on we go.

I feel like I’ve gotten all the answers I need to proceed, so back to the dungeon!

Third time’s the charm?

OK, so, the original rudder of this kit was crunched during transportation due to poor packing on my part. I got replacement pieces and was just about done building a replacement when I back-riveted right off the side of the back rivet plate. There are no words, other than four letter words that can describe how pissed I was the moment I realized I’d ruined the part.

Building airplanes is really just the summation of thousands of small actions, but (like the animals in “Animal Farm”) some actions are more equal than others.  This one small action of back-riveting with no back rivet plate in place irrevocably ruined the skin of the rudder and the skin is one big piece; so one small accident ruined one large part. Bummer doesn’t begin to sum it up.

So, once more into the breach, dear friends.

Cut out the stiffeners from their original state and then shape and deburr their edges until they’re nice and smooth and ready to be installed:

Cleco the stiffeners in place, then drill them to the skin:

Finally, take it all apart again and prepare to dimple all the holes in preparation for priming and riveting.

This sort of think REALLY keeps one humble! Personally, I thought I had enough humility, but it seems my Higher Power has other thoughts and plans in store for me.