Even more forward bottom skin stuff

So yeah…it’s been hot. Hot enough that I haven’t been working, in case the long dry spell wasn’t already self-evident. I did actually construct what I intended to be an air-conditioned cubicle around the fuselage a couple months ago – basically just a PVC pipe frame with plastic sheeting draped over it – and I even tried it out once or twice, but still, yeah, nothing got done.

Fortunately, this weekend it’s finally not-hot enough (notice I did not say “cool”) for me to be OK spending time in the hangar, and as a bonus I didn’t have a weekend full of stuff to distract me. And I’ve already been getting back into the building mindset the last few days, so yeah, I finally did stuff again.

Unfortunately, I got off to a rocky start. First order of business was to debar the edges of the left and right bottom skins, which I did on the bench grinder. For straight pieces, this is easy – just run the edge along one of the grooves I’ve worn in the Scotchbrite wheel. For curvy stuff (like these skins), I tend to run the edge laterally across the wheel, working each side of the edge in turn. Well, I guess it’s been so long since I did this that I forgot that doing this with the skin angled *towards* the direction the wheel is spinning is Bad. So yeah, I barely got anything done on Skin #1 when the wheel caught it and put a beautiful little bulge in the edge of my nice skin. Cue lots of grumpiness.

Once I got pas the usual initial THIS PART IS RUINED NOW freakout, I decided to see if I could take the bulge out a bit. A little bit of work with a mallet, and I made it, well, better, but not perfect by a long shot. But the skin still fit OK in place on the plane, albeit with a bit of oil-canning between rivets, but a bit more work on the edge made that better. There’s no structural problem here, just a mild cosmetic one, and it won’t be in a super obvious place, so I decided to build on.

I finished my deburring (much more carefully, you bet), dimpled a bunch of rivet holes, and the skins were all ready to go. Next up, the forward gear crossmember needed some attention – this is the part I had to replace a while back because I prematurely riveted it to the floor and munged up the old one removing it. Both crossmembers needed to be countersunk for the  skin rivet holes, and once that was done, I scuffed, cleaned, and primed the new forward crossmember.

In between all that, I cleaned off all the stuff I’d had sitting on top of the inverted fuselage (following the any-flat-surface-becomes-a-table theorem) so I could put it back on the rotisserie setup and flip it over again. I wanted to get a look at the brake lines in the gear towers – I’m planning on remaking those so they come out of the floor ahead of the gear leg mounts, instead of behind, which will simplify plumbing the short lines from the bulkhead fittings to the gear legs.

My original line of thinking had been to address the brake lines prior to starting to rivet on the bottom skins, but after a second look, I don’t think having them in place will complicate the brake line issue at all – at least not compared to working inside the gear towers themselves. So I’m going to hold off on remaking those, until I get to the point of actually mounting the gear legs. I figure I’ll be able to make a better decision about redoing the lines at that point. (this is provided that I mount the legs prior to putting on the forward top skin, which will definitely make doing the brake lines harder…but hey, I can still punt for now)

Anyway, that was the sum total of work for the day. From here, I get to start riveting these skins in place, which should be interesting given the kinda limited access between the bottom skins and the floor. Still, the procedure in the construction manual sounds like it’ll make it not too bad – in any case, it doesn’t look any more obnoxious than shooting the rivets in the flaps. Shooting rivets will probably have to wait till next weekend though – I get home from work kinda late, and by the time I’ve had dinner, I’m thinking it’ll be at an hour where banging rivets will not endear me to my neighbors (especially the ones with a newborn). I’m sure I can find something else to do – assuming, of course, I can successfully get my weekday work sessions going again.

Hey, maybe I’ll even take some pictures next time!

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