Monday, January 14, 2013

Carb Syncing

So, here we are right smack in the middle of January, suffering through the season of... wait, what? Sixty-plus degree days?? Well, that isn't so bad!  Sure, the day job is fraught with stress and peril, what with corporate office auditors in the house for the next month or so (and hey, when did audits go from being 100% shouldered by the finance folks to them only getting 20% of the attention and the poor IT Director getting 80%???), but the clement outside temperatures are sure coming in handy. This is their first day here and I'm kind of on call, but they've disappeared for lunch. I figured I'd fill the time waiting for them to come back by writing a little update.

The unexpectedly warm weather is very welcome as I had been mortally terrified of standing behind a propeller turning at 4,000 RPM and producing a wind chill of something like minus two hundred degrees while trying to make small adjustments to a throttle cable, but as it turns out I worried needlessly. First of all because of the temperate climate, and second of all because I was able to foist that job off onto someone else. Well, to be fair, he really knew how to do it, having done it once already, and I had no clue at all, so it made perfect sense. But still, there I was sitting in the warm dry cockpit while he stood out in the elements (exacerbated by a touch of rain) adjusting the throttle cable -- it's hard not to feel at least a little bit guilty about that. That said, I'm doing an admirable job of it.

I suppose I ought to explain this whole carb syncing thing. As you may or may not know, there are two carburetors on the Rotax 912 engine. And, as I've always said, "My dad always told me to stay away from two things: blondes and carburetors."  He never actually said that, but that inconvenient little fact has never dissuaded me from sharing that little tidbit of parental wisdom. After all, it has been my life-long experience that he should have said it, even if he didn't.

The thing about having two carburetors is that they have to be very closely aligned with each other lest a dangerous vibration occur as a result of two cylinders receiving more or less fuel than the other two. This synchronization is achieved by inserting a pair of pressure sensors between the two carbs. That feat is performed by plugging a device containing the requisite pressure sensor/displays into the crossover tube that normally connects the two carbs. The answer to the now begged question of just why a crossover tube is needed to connect the two carbs is an exercise left for the reader, which is academia's way of saying, "Beats me."

And so it transpired that The Jackson Two, them having already performed this operation on their airplane in addition to having purchased a more expensive and more sophisticated electronic tool for the job than the mechanical version I bought, made the trek up north to assist in the synchronization effort. In the rain, as it so happens. Unfortunate, that, but probably more desirable than in the bitter cold. The view of it was terrific from my seat inside the airplane, and the wind was no bother at all.

This job quite naturally entailed the operation of the engine, a fact that forced me to get back out to the hangar and finish up a few outstanding jobs before getting the fuel tank back in and replacing some removed panels. I also finished up a few of the remaining items on the to-do list, chief amongst them being the torquing of the nosewheel nut. This nut is what holds the nosewheel fork to the nosewheel gear leg, but it also serves the purpose of putting a little resistance in the directional turning of the nosewheel itself. Without any such resistance,

[pause] The phone just rang.

"Dave Gamble" (my standard gruff greeting, used to discourage cold-calls)
"Hi, this is (mumble) calling. Have you had a chance to read through my emails yet?"

Now, this is a standard cold-caller tactic in IT. They send my emails trying to interest me in buying stuff that I have no use for. I just ignore them, hoping that they will get the hint, but sometimes that's not enough and they actually call.

"Well, which of the many people that send me emails are you?" I asked.

"I'm calling about your RV-10. Aren't you the guy with an RV-10?"

Ah, I see. It's someone calling about buying the RV-6! Yay!!!

"Well, no, I have an RV-6 for sale."

"No, I thought you wanted to have an RV-10 inspected," he replied.

"Ooooohhhh! You mean the RV-12!  Is this John W.?"

And it went on from there. So, the inspection is scheduled for Jan. 23rd, 9:30 am.

I originally had asked for Monday the 21st, but he informed me that the 21st is Martin Luther King day.  And as I've always said, if you find yourself in a hole, keep digging:

"Oh, you get that day off? I gotta get me a government job!"

I have that day off too, so I was just joking around. We had a nice chat and I'm now pretty clear on what I need to do to get ready for the inspection.

[end pause]

Without any such resistance, the nosewheel would shake and shimmy uncontrollably during takeoff and landing.  The nut gets tightened until it takes 26 lbs. of force to get it to swivel. That's pretty easily accomplished with this handy little scale I bought at Walmart.

I also updated my Skyview firmware to version 5.0. I had been putting that off out of fear that it would break something in the avionics, but I figured the plane is just sitting there anyway... it went without a hitch. Worth it, too. The moving map graphics are much, much nicer with version 5. As long as I was at it, I updated the aviation databases, something that we're supposed to do every 28 days. I never did with my Garmin because it was far too expensive, but the Dynon pricing is far better: $0.00.

With the carbs synced, there's nothing left to do but take all of the panels off again to give the inspectors something to look at. I'm pretty confident that there won't be any big issues, and I attribute that to the quality of the kit.  There really isn't much to do wrong enough to render it non-airworthy. I anticipate things more along the lines of "You ought to secure this little wire" and the like. All easily repaired.

I was worried that I would need to get the transponder checked before they could sign the plane off as airworthy so I asked about it, but he doesn't think it's necessary. I think avionics are pretty much out of his realm.

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