Candle Making

One of the things Van's (surprisingly) doesn't tell us to do as part of the RV-12 build is to leak test the fuel lines before covering them up with a bunch of airplane. I'm not the first person to figure out that it makes a lot more sense to test the lines now, when all of the irritating obstructions are still sitting on the shelf, rather than later when the fuel lines are not only blocked but also inconveniently populated with fuel. Because Van's (surprisingly) doesn't advocate this kind of testing, they provide no mechanism for doing so. The kind of people that are attracted to the idea of building their own airplanes are (not surprisingly) somewhat industrious in nature, so (not surprisingly) there have been a number of testing methods developed by those that have gone before me.

The most popular way seems to be to employ a user-fabricated stand pipe made out of leftover fuel line, a brass T-fitting, a Schrader valve, a rubber hose to act as a proxy for the pressure-sensitive fuel tank, and last but by no means least, the diligence required to gather all of that stuff up. I was lacking in every single one of those things. Fortunately, RV-12 building compatriot Torsten is not only far more energetic than I am, but also far more generous. He kindly sent me his test kit to use. He didn't actually send the faux fuel tank rubber hose - I purloined that from the local mechanic at the airport.

The fuel that will be pushed through the fuel lines will only exceed 5 PSI through some kind of miraculous pump failure mode in which it actually works harder than normal as it dies, but I still decided to test at a hefty 20 PSI.

Here's the faux fuel tank closing the fuel system:

And here is the fuel leak that I detected by brushing on some of the bubble-blowing liquid that kids know and love:

The leak was (not surprisingly) in the second worst possible place for it. Actually, that ranking could be argued - the only potentially worse place would be where the return line passes through the firewall shelf. That would be hard to get too, of course, but the leak at the bottom of the fuel shutoff valve actually required the entire valve to be removed in order to tighten the fitting. And by "removed," I mean "the rivets that hold it in drilled out."

Here it is after the fix and 20 new PSIs stuffed in to replace the previous twenty that escaped when I loosened the fittings in order to remove the valve. No more bubbles!

That all took a few hours of sporadic effort; the remainder of the time was spent making some yard long candles.

Well, no, they aren't actually candles. Those are the pushrods that will be attached to the oddly shaped assembly of metal that rocks left and right as the control sticks are moved. These rods will convert that lef/right action to forward/aft motion in order to transfer it further back in the fuselage. They will attach to a couple of rotating columns that will transfer torque forces out to the flaperons. Or, in easier to elucidate terms, these control rods will help the airplane remain right side up, and turn it on demand from the pilot or autopilot.

The fabrication of the two pushrods was a matter of cutting one long aluminum tube into two equal length shorter tubes and a third very short tube that ended up in the scrap box. Being that the two shorter (but not shortest) tubes are almost a yard long, the first cut had to be done with my old friend, the hacksaw. The throat of the band saw is nowhere near big enough to swallow that much tube.

Once cut, each tube end had four holes drilled through the both the tube wall and a brass(?) threaded fitting, with the intention of providing holes to allow the riveting of said threaded fitting into the control rod ends.

It was humid today and that, combined with the fact that I put three coats of paint on the control rods all at once, means that the rods need a good 24 hours to dry. In the meantime, we prepared the torque tubes that will convert the forward/aft motion of the control rods into, well, torque. By "prepare" I mean "remembered that powder-coated parts need to have the bolt holes drilled to final size before expending great effort getting them into the tight and confined place that they need to go, only to find that they need to be removed to drill out the bolt holes."

That didn't take long, mostly because I beat the long odds and managed to not lose anything.

While I was doing that, Cadillac Pete was gathering up the parts for the next thing to do. These are the parts that will complete the flap handle. The tube will get the silver knob-looking thing attached to it to give the pilot a place to press with his thumb. The spring will go into the flap handle tube before the new tube and force the tube back after the pilot releases the thumb pressy-on-thingy. The idea behind this pressing and releasing is to move a clevis pin in and out of the teeth on the part that has the three notches that look as if they were sized specifically to the correct width required to absorb a clevis pin.

Where is the clevis pin?

Well...

Remember when I ordered all of those cotter pins to replace those lost when bag 2791 flew the coop? There's something I didn't tell you about that. You see, there was a clevis pin in that bag too and I failed to order it. I thought for sure that the act of ordering the cotter pins would be enough to convince the misbehaving bag 2791 to come out from hiding. As it turns out, fate will not be fooled by such transparent shenanigans.

I ordered the clevis pin this afternoon when I got back from the hangar.

I know when I'm beaten.

Having crapped out on assembling the inner guts of the flap handle, we pressed on with installing the torque tubes. That turned out to be another of those three-handed acts. One hand holding the bolt, the other handing holding the washer wrench, and the third hand (i.e. my teeth) holding the inspection mirror while trying to get the washer lined up with the bolt hole.

What can I say? I'm good with my teeth.

Compared to the control rods, the torque tubes were a piece of cake to install.

Hmmmm, cake. And I'm hungry. And there is a pristine cake sitting out in the kitchen.

That gives me an idea....

Meet David R. Copperfield

From Wiki:

David Copperfield (born David Seth Kotkin; September 16, 1956) is an American illusionist, described by Forbes in 2006 as the most commercially successful magician in history.[ Best known for his combination of storytelling and illusion, Copperfield has so far sold 40 million tickets and grossed over $1 billion.

Over $1 billion dollars, and his best known trick is making the Statue of Liberty "disappear." Pffft. I'm here to tell you, he ain't got nuthin' on me when it comes to making things disappear. But I'll get to that.

First, I have to provide an update on my EAA Chapter 9 hangar visit. You may remember that I attended a similar event last month when I went to see an RV-10 under construction. The RV-10 is similar to the RV-12 in that it is the only other Van's RV design that employs the new step-by-step builder's manual, but in all other ways they are polar opposites. While the RV-12 is essentially a simple enough airplane to be used as a trainer, the RV-10 is a fire-breathing, load-hauling, high end travelling machine. I'd be lying if I were to say that I didn't lust after an RV-10 myself, but an honest assessment of the types of trips I take and the palatability factor of the higher costs involved, plus the order of magnitude more difficult building process, puts me firmly in the RV-12 class.

So, back to the event. You also may remember that I was concerned about what kind of comestibles to provide. I didn't know how many folks to expect and bakery donuts at Krogers are only $3.49 a dozen... I bought three dozen. Fully half of those remained after all was done and said. Better too many than too few, although I feel somewhat bad for anyone that went to Krogers yesterday hoping to buy donuts. I had nearly all of them.

Most of the crowd arrived right around the advertised starting time of 10am. One of the earliest arrivals was the older gentleman that I am hoping to presume upon to paint my airplane. He arrived astride a beautifully restored Cushman scooter. Best known for their nearly ubiquitous golf carts, Cushman also produces small-ish gas, diesel, and electric trucks. The scooters were produced between 1936 to 1965. This is a 1963 model.

Pilots are a fickle sort. The scooter (not surprisingly) stole a little of my thunder.

Some folks even scored rides on it. I was busy acting the host, so I wasn't able to get in on that action, more's the pity.

With the RV-6 now moved into a new hangar, I have plenty of shop space again. Cadillac Pete helped me move the fuselage out towards the door where I get better light (and, as it turns out, a lot more heat when the afternoon sun is on the 'Broil' setting) to work with. There's no way my visitors would have been able to safely navigate their way trough the Byzantine labyrinth of parts, tools, benches, and airplanes that I was dealing with just last week. As with a goldfish whose habitat is a small bowl, the growth of my RV-12 was becoming severely restricted by the close confines. Now that it has a huge aquarium to live in, I expect much more rapid growth.

The weather was nice so a few of the visitors flew in. The unpainted plane in the foreground is a completed RV-12. As you look down the row, there are three more RVs. The plane at the end is a store-bought Piper, but I'm pretty sure the pilot of that one is building an RV-8.

After the guests departed, Pete and I decided that the pleasantly temperate weather warranted a little work on the airplane. I've been putting off the installation of the roll control rods for awhile because reports from the field indicate that they are an massive pain in the, uh, "sit-upon" to install. I'll cut to the chase: the reports are true.

The first obstacle arose immediately, just as if the starting gate of the Kentucky Derby was positioned backwards on the track. We didn't even get started before the race was blocked. The bolt wouldn't fit. This is nothing new; it is very, very common to have to final drill a bolt hole through a powder-coated steel part, but I didn't think to check these holes before installing the control sticks.

That's why I have an angle drill.

The beauty of the angle drill was that I could drill the hole without pulling out the control sticks. The sticks are only held in with one bolt, a washer, and a nut, but the nut takes a cotter pin. I didn't want to remove the cotter pin because 1) it's hard to do, and 2) I don't like to re-use them and I only have a limited number.

If I were to tell the truth, I'd have to share that I do in fact have twice the number of cotter pins that were included in the kit. That came about because I lost another bag of parts. In this case, it was a good bag to lose if I was going to have to lose a bag: the entire contents of the bag cost $.32. As we all know, the way to find a lost bag is to order replacements, but this time I thought I'd be clever and only pretend to order the parts. I loaded up my web-store virtual shopping cart at www.AircraftSpruce.com and waited for the magic to occur.

It didn't.

After a suitable percolating period still failed to produce the lost bag, I went ahead and placed the order. I don't have the bone in my wrist that will let me click my mouse on a Submit Order button for a collection of items whose total cost is less than the shipping charge, so I updated my order to include two of every cotter pin. Thus it is that I have spares.

But still, reason #1 was still in play and I was averse to the idea of removing the cotter pins.

With the holes drilled out to final size, I was ready to put the outboard bearing end of the control rods in place. Which would have been easy except for three things:

- 1, there is a little steel washer that goes between one of the control stick flanges and the control rod bearing.
- 2, there is a little steel washer that goes between the other control stick flange and the control rod bearing.
- 3, the control stick flanges are too close together for either of the washers to fit.

The only way to fix that problem was to remove the control sticks. So much for my efforts to preserve my limited number of cotter pins.

Even with the flanges bent out to provide more room, there was a problem with installing the washers. That problem was just like the risks associated with walking a tight rope strung over a bottomless pit: if a washer were to fall, it would drop all the way down into the guts of the fuselage.

The solution to that problem was simply to use a safety net, or in this case, a piece of paper.

Now, here's where I put Mr. Copperfield to shame. While attempting to get the fourth and last washer in place, some debit on my karmic balance sheet came due. It's as if the karmic bill collector suddenly appeared to collect the debt incurred from kicking a puppy or pushing a senior citizen aside in my fervor to collect three dozen donuts. I dropped the washer. Now you'd think that it would be a simple matter to find that washer. Surely it would be sitting right there on the paper safety net.

Nope.

Well then, it couldn't have gone far. Surely it would be somewhere down in the fuselage and, while tedious difficult, it should be possible to find it with an inspection mirror and a few degrees of patience.

Nope.

Well then, surely it just fell all the way through and would be somewhere on the floor in the vicinity of the fuselage.

Nope.

As we all know, time drags when you're becoming increasingly frustrated and perplexed in equal measure so I can't say exactly how long we looked for that washer, but it was at least fifteen minutes. It was long enough that I was harboring thoughts about just using one of the two remaining washers of that size and forgetting about the lost one, but the thought of paying the shipping charges on a $.03 washer quickly disabused me of that idea.

I finally turned to Pete and said, "You know, the only other place that washer could conceivably be is in the control stick."

I picked up the stick.

[rattle]

I turned over the stick and shook it.

The washer dropped right into the palm of my hand.

Let's see Mr. Copperfield do that trick!

But at the end of the day, the control rods are in (hopefully never to be removed) and the cotter pins replaced. Still no sign of the lost bag, though. That magic still isn't working.

Nuts!

A quick trip to Lowes to pick up the appropriately sized tap allowed me to continue on with the fabrication of the control pushrods. If you recall, they had been drilled out to #3 during the last work session and were ready to be tapped. The new Lowes tap worked better than the Harbor Freight tap (Harbor Freight: Home of Approximately Sized Wrenches and Soft Metal Taps) which had insisted on starting me out with a cross-threaded hole from the get-go rather than letting me create one myself later when I try to force a threaded bearing into it from an awkward angle.

Aw, come on. You know as well as I do that it's a distinct possibility, if not quite an inevitability.

I also like the tap driver that I picked up at Home Depot a lot better than the one that came in the Harbor Freight kit. I would have better luck driving a tap by stuffing it into a stick of butter held lengthwise than I ever did with that horrible tool. The beauty of the one I have now is that it will accept a ratchet wrench. Note that this requires a much higher level of patience and caution than would a normal tap driver because of the vastly increased leverage available from the ratchet wrench. I lubed the tap accordingly and used the searing heat of the aluminum tube to gauge when I needed to back the tap out for cleaning. I'm not kidding: that tube got hot!

I then ran into another of those inexplicable cases where the usually superb build manual really caused some head scratching when I tried to figure out why they had me do things in such an unproductive order. You may remember that I had been instructed to "temporarily" install the control sticks in order to complete the wiring for the push-to-talk (PTT) switches. Well, as it turns out the completion of the PTT wiring makes the installation of the control sticks anything but temporary. Unless you're willing to cut the wires, those sticks are in there to stay.

You may remember that I couldn't get the bolts to fit through the bushings, nor could I get the sticks to fit easily within the brackets. I decided to skip dealing with the bushings at the time since the sticks were only being installed "temporarily." I found out today that there was no hope of the bolts ever fitting through the bushings; the bushings had to be drilled out with a 1/4" bit. In the next step I found out that there wasn't much hope of the control sticks fitting into the brackets either since the plans required me to file down the bushings so that they would fit between the brackets, then file down the tubes on the control sticks such that the bushing was just a touch wider. It makes me wonder why all of this filing and fitting hadn't been done before the PTT wiring. I say "it makes me wonder" in a purely rhetorical sense: I know exactly why. Van's puts precedence on keeping jobs in logical sections of the manual rather that putting them in a logical order. The PTT wires had to go in the "Wiring" section, even if it made more sense to do it in the "Controls" section.

This is why they encourage you to read ahead. I have no one to blame but myself...

That said, note that when it comes to filing a steel tube, there are better locations to do it other than inside the guts of the airplane. I haven't thought it all the way through, but it seems to me that there had to have been a better order of progression that would have avoided this and it might have become apparent if I had read ahead. As it is, I had to resort to the Dremel tool to get the filing done.

Quite a bit of filing later, I had just a titch of bushing showing on each side of the control stick tubes.

I dug out the nuts and washers needed to bolt the sticks into place. Finished! All that was left to do was hoover up all of the nuts that I had dumped onto the work bench while searching for the correct sized nut (needle) in a bag full of dozens of other nuts (haystack). That's when I let my attention lapse. It wasn't much later that I realized my mistake: I had scooped up all of those nuts and dumped them into the washer bag.

This was a problem. I view nuts and washers like a horseman view colts and fillies: you really want to keep them separated until you have just the right pairing for them. There was nothing I could do but dump the whole mess out and sort the nuts out from the washers.

These are the completed pushrods. These will attach the pilot and passenger control sticks to the oddly shaped pieces that I installed last week and provide left/right input to the flaperons.