Blind Spots

Some lessons just need to be learned over and over and over, or so it would seem. I thought I had a pretty good handle on my propensity to develop blind spots. As evidence I point to the fact that despite taking the sixteen hour course that will permit me to sign off the annual condition inspections on N284DG, I intend to continue the practice of paying a local AP/IA to take a look at it once a year just as I've done every year that I've owned the RV-6. I think this is a prudent thing to do, especially after he found a crack in the elevator trim tab that I had to have looked at hundreds of times, but never saw.

It happened again with the CHT problem. After getting some hints from Van's on what to look for in my quest to isolate the problem, I asked Pete to come down to the hangar and help out. It's much easier to trouble shoot wiring when there are a couple of people working on it - someone has to hold a multi-meter probe at each end of the questionable wire and with a long wire, that can be difficult to do alone.

As we were looking around at various wires to test, Pete asked about a PURPLE/YELLOW wire that was hanging loose from the wire bundle. I had seen that wire before, but because I was looking for a PURPLE/BLUE wire, and because it is not uncommon to have cut/stubbed wires on a Dynon D-180 to Skyview conversion, I ignored it. I ignored it even after learning from the wiring diagram that I was, in fact, very interested in the condition of PURPLE/YELLOW wires. In other words, I was looking right at the problem, but a blind spot that I had developed it was precluding me from actually seeing the problem.

Sure enough, fixing that broken wire fixed the CHT problem.

Man, did I ever feel like an idiot!

It's fixed now, though, and we can press on with the next items on the to-do list.

I'm not sure why the wire broke in the first place, and that's going to nag at me for awhile. I do have a theory: that particular bundle is the only one that doesn't seem to have enough slack. In fact, it seems that there is quite a bit of stress on it. I think it's possible that starting the engine introduced enough vibration to simply rend the wire in half.  I'm going to have to find a way to relieve the stress on the bundle so this doesn't happen again.

Getting back to work

I'm sure you've been wondering... 

Why haven't I been posting updates on my progress? Because there really hasn't been much. There are a number of reasons for that.

The weather has, of course, been miserable, and so have I. Regarding the weather, I really shouldn't complain. Yes, it's been cold and windy, and it's getting dark ever-so-early these days. Yes, I am frustrated that young Cabot Bennett, of whom I do not expect a tremendous amount of intellectual acumen, remains convinced that I can summon forth light and heat at will (and to be fair, from his inside-the-house perspective, I can!) so that we can go outside and play but simply choose not to.  He is immutable in his belief that if he stares at me with big, sad, plaintive eyes long enough, I will exercise my god-like light-creating gifts and we can go outside for some fetch.  Yes, these are weather-ish frustrations, but they are nothing compared to what's happening out east.

But still, they are my frustrations. So, they matter.

Nor did it help that I somehow ended up with godawful muscle spasms in my neck and shoulder.  Bad, they were, and not conducive to any productive activities (such as throwing a ball for the dog). They were far more conducive, as it turns out, to sleepless nights and an extremely edgy mood. ("Go AWAY, Cabot!!")

This continued well into the work week.  I finally broke down and made an appointment with my chiropractor. I have to say, I think I really impressed him this time. He poked and prodded around the neck/shoulder area for longer than usual, and finally proclaimed his diagnosis:

"Oh, my!"

Yeah, tell me about it! He did what he does to get the bones back into their proper places ("Two vertebrae and a couple of ribs - what did you DO??") and started trying to work the knots out of the spasming muscles. He found one particularly bad spot (I can how badly the muscle is clenched  by how much it hurts when he presses on a spot , and this one hurt a lot!) that he started working on. 

"It feels like you swallowed a golf ball!"

I should be so lucky. Ipecac is dirt cheap compared to this guy.

After a better night's sleep and a dose of muscle relaxant, I was pretty much, almost, more or less, maybe, back to my normal contumacious and surly self.  For awhile. Things are pretty weird at the office, though, and I'm in one of those phases where everything I touch turns to, well, something worse than when I started.

A couple of days ago I was frazzled from a morning of enduring the irritating shriek of those blasted motorized weed blowers that had been running outside my window all morning, I tried to escape for a little peace and quiet at a nearby Chinese restaurant, only to get to my pretty little car waiting for me in the parking lot and see its grill stuffed with hundreds of leaves blown there by the Professional Leaf Blowing Squad from South of the Border.

Grrr!

I got to the restaurant and settled into a booth. I was just getting started on reading my book (more on that later) when what do I hear? Yep, another trio of motorized leaf blowers working their way down the sidewalk outside the restaurant. Just as they reached the door, another pair of customers opened it to come inside. So in addition to now having to endure the unadulterated screaming of those cursed things, I also got to enjoy the cloud of noxious fumes that blew in with the recent arrivals. Who, as it turns out, sat down at a table right next to me and started to have a heated argument about the pros and cons of using the default record ID versus creating a proprietary new one.

In other words, geek talk.

Not just that, but heated geek talk.

“I would most wholeheartedly argue against that approach!” one of them said in what passes for vehemently in geek circles.

It was like overhearing a pair of ninety year old English butlers arguing over the merits of two-minute versus three-minute basted (“No, my illustrious friend, I will fight to the veritable death to prove that anything cooked longer than two minutes is poached!”) eggs.

As to the book. It is the story (told in first person) of a woman who has a friend who is having an affair and shares the secret with her. This causes her to reflect on her own comfortable yet unexciting marriage to (wait for it….) an IT geek. 

Hey, it was free.  You get what you pay for on Amazon. And it's supposed to be a murder mystery, but the only thing dying so far is my interest.

Anyway, she decides to “re-sexualize” their marriage, but continues to run into difficulties along the way, thus making her more and more frustrated. The husband has to work late and comes home too tired. He goes golfing in the morning and comes home in the afternoon, having invited another couple over for dinner. This naturally stymies her Saturday night plans for which she had gone to the pain of buying some nice, uh, intimate clothing at Victoria’s Secret. 

And somehow this is all his fault!! 

This bothers me no end. This is the biggest problem men have with women. Listen, we’re not fricking mind readers. We don’t have brain scan modules implanted in our frontal lobes moments after circumcision. If you want us to know something, TELL US!!! Especially if it's uh, you know, that kind of thing. Trust me, we're all ears when it comes to THAT!

And then…. A new arrival came through the door (quietly this time) and plopped down in the booth behind me, where he commenced to have a profanity-laced cell phone conversation. It finally wrapped up just as I was surrendering the game and getting ready to leave, figuring my office would be more relaxing than this had turned out to have been.

“Yeah, dude, we just gotta keep on keepin’ on.”
I wanted to shove my fortune cookie down his throat.

I did manage to get a couple of things knocked off of the RV-12 to-do list, though. First and foremost, the airplane moved under its own power for the first time!  I finally was able to re-do the engine run that I had to abort the last time I tried due to the loose valve covers. It was a little chillier this time around so I had a good ten minutes of sitting at idle waiting for the oil temperature to reach the requisite 122 degrees. While I was waiting, I spent a little time messing around in the Dynon SkyView EMS setup pages trying to get the fuel pressure gauge to work. The sensor mapping page showed the 'Kavlico 0-15 psi sensor' as having been detected and functional, but it was displayed in a bright red font. That font selection could only mean one thing: "SOMETHING IS WRONG!"  I noticed that the sensor didn't have a setting in the column next to it that displays what the SkyView thinks it should be doing with this sensor. I played around with the menus until it said 'PRESSURE', or something like that. I'll have to go back and get a picture of it. The net result was that the fuel pressure started indicating on the Dynon screen. Score a point for my side!!

The right side CHT was still showing a big red FAIL X, so it wasn't a complete victory.

The oil finally reached a decent operating temperature and Pete was not gesticulating wildly about anything amiss in the realm of leaking fluids, so I ran up the engine to wide open throttle. The RPM topped out at 4,750 rpm, so the prop angles will need to be adjusted to find an additional 200 RPM.  The good news here is that the brakes held the airplane at bay even at full grunt. That gets a checkmark on the acceptance test sheet. Figuring I had the motor warmed up and proven useful brakes, I had Pete pull the chocks so I could taxi around a little bit. It drives like a dream!

After the engine was shut down, I pulled the panel off of the avionics bay. Pete and I teamed up to test the continuity of the BLUE/PURPLE wire that runs from the CHT-R thermocouple post on the engine up to the Van's J-Box in the bay. Dead as Kodak's business model. Or so I thought. Pete took a look and pointed out that I was testing the wrong wire. I was testing the BLUE/PURPLE wire that comes out of the J-Box and plugs into the Dynon EMS module hanging on the firewall. As he pointed out, we really didn't know for sure if that was the correct wire. Just being the same color code should be enough to know, but given Van's demonstrated proclivity for practical jokes, it wasn't.  I removed the connector that provides the input to the J-Box and tested the wire there.

It was good.

Damn. That means the problem lies somewhere out of my purview.  It's either a Rotax, Dynon, or Vans problem, and of those three, Dynon is simultaneously the least likely to be the culprit and most likely to be helpful in troubleshooting. I decided to start with Vans.

As I sat on hold waiting for someone to answer, I couldn't help thinking "I hope it's not Ken. I hope it's not Ken." I'm still a little bitter after having to argue over whether or not they had sent me a $.75 adaptor plate. I said they hadn't, he said they had because "they made a pretty good guess as to who would need one."  He said that I probably had just lost it. Now, we all now that it is more then possible for me to lose something; history is on his side there. But here's the thing: I know when I've lost something. I remember actually having  had it, I just don't know where it is.

So, a few minutes later my call was answered. I explained the problem, I explained what I had already done to troubleshoot the problem, and I ended with, "I don't know what to do next."

"Neither do I," was the response.

Sigh.

Ken.

After a brief pause to swallow my first response, I said, "Well, why don't we try to figure it out together."

That worked. From that point on it was a professional and moderately helpful call. He suggested testing the continuity through the J-Box and up to the Dynon EMS module. To do so, he said, I should consult the wiring diagram on the Van's website.

Fair enough, but I couldn't help thinking that I already did that. Sort of, anyway.

So I pulled up the wiring diagram. I traced the BLUE/PURPLE wire up to the J-Box on the diagram. It was right next to the YELLOW/PURPLE wire that comes from the left side.  Coming out of the J-Box, the right side CHT is YELLOW/PURPLE, and the left side is BLUE/PURPLE.

Pete was right.

Again.

And so was I, in a way: another practical joke! What other explanation can there be for transposing those two wire colors??!

Hopefully I will be able to get out to the hangar while the good weather holds to check the rest of the continuity path. The goal at this point remains the same: figure out which of the four players owns this problem.

Cleaning up the rats nest

I spent a few hours working through the punch list. One of the first things I wanted to do was clean up the wiring. The stuff in the avionics bay wasn't bad, but could be better. The stuff in the tunnel was a nightmare. I got off to a slow start, though, when I couldn't find the step stool needed to get in and out of the plane when the wings aren't on. It didn't take long to find, but it did remind me that the actual steps were not yet installed. I took care of that, and will surely regret it as I begin the long, painful process of learning not to bark my shins with them.

I disconnected roughly half of the J-box connectors and re-routed some of them. There were still a couple of bundles that were in need of some tie wraps to keep them nicely collected. I gave myself a bit of a scare, though. I though it would be a good idea to turn the Skyview on when I was done to make sure that I hadn't broken anything.

 TRANSPONDER FAIL! Uh-oh!

I removed the transponder connector to make sure none of the pins had been bent. It looked fine. I tried re-seating it half a dozen times to no avail. Finally an inspiration struck me: how about trying it with the Avionics switch turned on? That did the trick. So, mental note: the transponder only works when the Avionics switch is turned on. Imagine that!

The tunnel was a much bigger job, due both to the extent of the mess and the awkwardly inconvenient work location. Just getting the various wires untangled enough to allow them to be bundled and restrained was a herculean task. It looks a lot better now, but at the end of the day I probably made it look better at the cost of having introduced a plethora of sources of the type of spurious electronic interference that will drive me nuts for the next five years.

I had hoped to get the throttle and choke controls installed, but by the time I got that *&^@#$ heater cable put back in I had had enough. I did manage to get the cables pushed through the panel and firewall, but the business ends of them are just dangling out over the engine.