Saturday, January 2, 2010

Cold Weather Operations

It has always been the plan to build the larger portions of the plane in the hangar. Well, maybe not always. At first I had hoped that I could do the whole thing in my basement, but the door and stairs from my basement to the back yard aren't wide enough for the tail cone to fit through once its assembled. I had designs on the garage, but after nearly two decades of marriage I knew better than to even broach the subject of cars being relegated to the driveway during the winter season. There are a number of strategies to keeping the family happy when undertaking a project of this scope and magnitude, and making them scrape ice off of the car early in the morning is most assuredly not one of them.

Knowing as early as October that I'd be needing some room in the back of the hangar to act as a remote shop, I started planning for the eventual move out there by cleaning out some of the accumulated junk that has been lining the back wall of the hangar for time immemorial. Or at least since we moved to the house near the airport six years ago - that's when it really started to build up. There were things that the movers wouldn't move and that I didn't necessarily want cluttering up the new house, so they went to the hangar. Most of it was just junk, but it's hard to throw a lot of stuff away when you live in the city. We only get one trash can per week, so the temporary storage of junk in the hangar inevitably ends up the same way as temporary taxes do: it quite easily becomes permanent.

Once it became apparent that the boxes were going to have to go, I started watching the local waste transfer station for one of their periodic amnesty days. These are scheduled days when hazardous trash can be dropped off free of charge. One of the larger boxes stored in the hangar was full of stuff that the movers had considered to fit that bill, which is to say anything that looked like it might be a chemical. When the first chance came around to get rid of that box, I jumped at the chance.

As this transfer station is very close to Bolton, I had often seen the long lines that form when amnesty days come along. Naturally I decided an early start would ensure that I was somewhere near the front of the line, me being of the sort that hates to wait. I was a little late getting started, so I was in a bit of a hurry when I got to the hangar to retrieve the box of chemicals. That might not be the sole reason that I failed to adequately secure the bottom of the dessicated and decrepit old box, but it was a contributing factor. Predictably, the bottom fell out of the box precisely underneath a nearly full plastic quart bottle of charcoal lighter fluid, which bottle too was dried and brittle with age. It split into at least four pieces when it hit the floor and the lighter fluid, as can be expected of any fluid held hostage for that long, made a break for it.

So, it was a bit of a quandary. Go to the transfer station and dump the rest of the stuff before the line got too long, or go to the local grocery store for some kitty litter to dry up the ever expanding puddle of smelly fluid? I decided to go to the store first, but as I drove past the transfer station I could see that there were only two other vehicles in line. I decided to just get that part done with. It's a very professionally done operation, so I was in and out in just a few minutes. It seemed longer as I kept looking towards the airport hoping not to see a large, black, oily cloud growing over the general vicinity of my hangar. That stuff is lousy for lighting charcoal, but with my luck it would be a fantastic job of burning down an airport.

I'm sure the wild-eyed guy at the grocery store hurriedly buying nothing but 40 pounds of non-clumping cat litter raised some eyebrows and perhaps even had the store manager desperately checking the internet to see what kind of WMD can be formed from cat litter. No one asked me anything about it, though, and I was able to get back to clean up the spill before the dreaded conflagration erupted.

Shop preparations tapered off significantly after that ignominious start.

There's no choice now. Winter is fully upon us and the tail cone is either going to have to be done in the cold or it is going to have to wait for more clement weather. I have it on good authority that RV builders in states like Minnesota routinely work in sub-zero temperatures (and that's in July/August. I don't know what they do in the winter when it gets really cold!!) so I ought to be able to handle a comparatively tropical 15 degrees.

I tried it for the first time yesterday when I decided to finish up the job of cleaning out the junk from the hangar, and if I was still not suffering from the early onset of hypothermia, finally assemble the new sawhorses I had picked up at Harbor Freight. Loading the boxes into the Subaru was easy enough, although there was a situation with a trash bag that not only contained 40 pounds of oil-soaked cat litter but a few hundred blind rivet nails from the riveting of the vertical and horizontal stabs bursting open and dumping half of its contents out in front of the hangar. Yep, right out there where the wind chill had the temps down to the average ambient of a Minnesota spring day. Which is to say, COLD! If degrees Fahrenheit were playing cards, you wouldn't have enough for three of a kind. It was no fun cleaning that up! Although, as a newly minted airplane builder, I'm somewhat proud of the fix I applied to the ruptured trash bag: I twisted up the area around the breach and secured it with a tie wrap. I considered rivets, but...

The sawhorse assembly went pretty much like the assembly of the typical Harbor Freight purchase goes. It's the opposite of the RV-12 assembly rule: if it doesn't look like the parts are fitting right, it means that you're just not trying hard enough. Working in the hangar wasn't too cold in general, but trying to get 16 tiny little nuts onto 16 tiny little bolts was a lot harder to do with frozen fingers than it normally would have been. I realized that I was going to have to pull out my old propane heater if I expected to be able to work there for any length time.

And by "old," I mean so old that the fitting wouldn't work with the new(ish) style propane tanks. Decades old. And, unfortunately, useless. It never really worked very well anyway.

Today, then, I would have to buy a new heater. I'd do that right after taking Co-pilot Egg for her driving test. What I failed to account for was the possibility that she'd fail the test and be in no emotional condition for a trip to Lowes. Oh well, it's not like I normally plan stuff all that well anyway, and she was pretty much dried up by the time we got to Lowes anyway. The things she did wrong on her checkride are easily fixed; she'll get it next time.

Once she was dropped off at home, I went back to the hangar to start doing some actual airplane work. It only reached 15 degrees today, but the heater makes all the difference! I had been wearing my Walmartt's (cuz I can't afford Carhartt's), but they're pretty restrictive when moving around and eventually get uncomfortable. With the heater going full blast it wasn't long before I was able to just take them off and work in jeans and a sweatshirt. A second pair of socks still helps quite a bit, though, as does something to cover the ears.

With the shop made habitable, it was time to start the actual assembly of the tail cone. There was one step that I should have done back in the basement that involved removing some extraneous metal from one of the bottom skins, and another step that required match drilling and riveting the F1283 J Channels to the bottom skins, but it only took a few minutes to knock those out. The two bottom skins are then to be placed upside down on a pair of sawhorses that stand "at least 38 inches high."

Mine don't. I blame Harbor Freight.

I pressed on anyway and it didn't seem to matter very much. With the two bottom skins sitting on the sawhorses, the "hoops" (the three fuselage frames) get slid onto the J Channels on the bottoms skins and clecoed into place:

That was pretty easy, but it quickly started getting trickier. The next step is to attach the lower left and lower right corner skins. The problem is that the platform of the sawhorse gets in the way since the assembly is still upside down and the inner radius of the long skins keeps them from reaching the bottom skins. I had to move the assembly right over to the edge of the sawhorse:

It seemed that the assembly had a tenuous grip on the sawhorses (or vice versa) at best, so I had to be extra careful not to accidentally dump the whole load onto the unforgiving floor. Which, as it turns out, was the least of my worries. There are certain times when getting skins to fit onto the underlying structure is a battle of wills, and this was certainly one of them. The strategy that I have adopted for situations like this is to find one hole that will take a cleco and get a foothold. From there, I sneak up on the more recalcitrant holes a hole or two at a time.

Here's the beachhead I found for these skins:

From there I found that I could start a flanking maneuver by getting the lower three holes of the skins to fit up against the fuselage frames:

With those troops positioned on the flanks, down low where the guards couldn't see them, I made a tactical retreat back to the beachhead and used a cleco-wave attack to get the front stabilized:

From there it was hand-to-hand trench fighting to win every inch of ground. Once you get one hole clecoed, the next in line will generally shift into place enough that you can convince it to accept a cleco, although it may take some wiggling and pushing. When the going gets tough, it can be dozens of holes that have to be done in a row. As you leave a string of clecos in your wake, most of them with more than a little shear on them, they will start to "pop" as the skins shift and the shear force is removed. The pop comes from some of them having had so much much force on them that they didn't fully retract when the cleco pliers were removed.

With patience, the battle is eventually won:

In order to stay close to the heater, I turned the whole assembly around before starting on the other side. The same strategy was employed:

It was tough going for awhile. The mystery as to why the second side was going so much harder than the first side had (and that's really saying something!) was solved when I realized that I had left a guard in place that was preventing the skin from settling down:

I do stuff like that just to keep it challenging.

And if that wasn't enough, I soon reminded myself why I don't leave that blue plastic coating on the skins. Because, you see, there might come a day when I forget to remove it and it gets trapped between a couple of pieces that I had had to fight to get together in the first place:

Which means removing the clecos in order to pull the blue stuff off. And that blue stuff that's hard to remove in the comfort of a heated house? Not even that easy in a cold hangar:

"So," you say, "doesn't the once-defeated aluminum just fall right back into place?"

Well, no. Aluminum could teach your typical spurned, grudge-holding woman a few things about getting even. Talk about your long memories...

Still, I did get it all clecoed up and ready to rivet. There are a few warnings in the plans regarding holes that are not to be riveted. Two of the areas not to be riveted are quite plainly stated, and I masked over them as directed:

The last set of holes not to be riveted aren't called out as explicitly. Instead, the plans say to rivet the left and right bottom corner skins only to the left and right bottom skins. By inference I take this to mean don't rivet them to the fuselage frames. I masked accordingly:

I'll find out tomorrow when I do the riveting whether I interpreted that correctly or not.

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