Sunday, October 3, 2010

Fall Weekend

Rainy, chilly, fall weekends are perfect for two things: football and airplane building. Unless you live here, you probably don't realize that Columbus is a college town. Not so much a college town as one in which the university itself is almost the raison d'etre for the town itself, though. No, Columbus is a college town for only a handful of days all year. Those days are known as "game days." Weddings are scheduled around game days, and I suspect that more than one funeral has been delayed by a day now and then, depending on the quality of the scheduled opponent. I can state this unequivocal fact: the timing of the game this week had a direct bearing on when I worked on the plane.

Knowing that I only had until noon if I wanted to get any work done by kickoff, I headed out to the hangar pretty early in the morning. I only had a few hours to get the roll bar disassembled, deburred, primed, and put back together again. Deburring was going along just fine. It's easy as can be when I can use the deburring tool in the electric drill.

I knew that the battery in the drill was getting low on juice on Friday night, so I had plugged the spare battery into the charger before I left for the night. Sure enough, the battery died about halfway through the job. I retrieved the newly charged battery, slapped it into the drill, and.... nothing happened. I apparently hadn't gotten the battery all the way down into the charging cradle. It too was dead. Nothing for it but to proceed by hand.

That slowed me down considerably. I only had enough time to get the deburring done and the first coat of primer painted on.

While the primer was drying, I went ahead and prepped the roll bar braces so they'd be ready on Sunday.

I also still had enough time to gather up the roll bar mounts. They're pretty solid looking milled aluminum.

They get bolted onto the fuselage. I thought it odd that bolts were used since the roll bar won't actually be removable; I figure it must be a strength issue.

They look pretty professional, don't they?

As things worked out, I would have just enough time to finish the page since the last step was a simple locate & separate operation.

It all kind of fell apart on the "locate" phase. I looked and looked, and I could not find that big part! At this point the parts shelf is looking pretty barren, so I couldn't figure out how I could not find a big part like that. I eventually realized that the parts had already been separated. That's passingly odd; Van's is a lot like a teenager in that they don't do much of anything for you unless they absolutely have to. I couldn't figure out why they would have started separating a part at the factory that they apparently had never intended to.

Maybe its because it wouldn't have fit through the band saw.

Nah, that can't be it. That's never bothered them before!

Time was up and I had to run home for the game. We all take it pretty seriously!

Back in the shop this morning, I was able to get a running start on a new page in the plans. The bulkhead parts were to be clecoed into the tail cone, and I was then to mark a centerline on the tail cone pieces behind them in order to make sure the holes I was about to drill through them were on the centerline. I had to think about that: Step 1, cleco these things in place. Step 2, draw a line on two parts that were now blocked by the parts that I had just clecoed it. No way that was going to work; I did step 2 first.

That worked a lot better. Doing it that way, the marks were visible after clecoing on the bulkheads. A quick match drilling operation later, the bulkheads were taken back off.

Rather full of myself after my intellectual win over the guy that wrote the directions, I moved right into riveting on some kind of canopy hook thingy.

I then immediately drilled the rivets back out, having noticed too late that they were supposed to be LP4-4, not LP4-3 rivets. Short lived victory, that.

Oh, lest I forget, there was also a lot of countersinking and riveting to get the roll bar parts all assembled. The countersinking was done with the special 120 degree countersink because the outer side of the roll bar assembly uses the CS4-4 flush rivets. I also had to stare at the drawing for quite awhile to make sure I was getting the right rivets in all of the other areas, and that I had correctly marked the holes that weren't to be riveted yet.

Once it's all put together, it gets installed over those nifty aluminum mounts. It's a bit of a tight fit, and it wasn't particularly easy to do alone. At one point I had one end in and was walking around the back of the fuselage to try to get the other side in when the whole thing popped out and just missed landing on my head. That would have stung!

This is only a temporary installation until the matching holes are drilled into the mounts. The plans call for having a couple of braces installed during the drilling, presumably to make sure everything is aligned correctly.

It isn't.

That gap shouldn't be there, and I have no idea how to make it go away. The mounts are extremely solid and there is no way to adjust them. It seems that I have a somewhat crooked airplane.

I'll have to poke around on the internet and see if anyone else has had this problem.

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