Today I was soundly beaten by the Houston heat. I got some work done in the morning before going across the runway for coffee, but after that I just wasn’t up for dealing with it.
During that single hour, I deburred the canopy receptacle and got it clecoed in place and match-drilled. Then I ended up doing some trimming on the gussets I put in place yesterday. They didn’t fit well against the bend radius of the bulkhead, and the wouldn’t sit flush, so I had to remove some material from the corners.
The next step would be to get the actual skin deburred and put in place, which can maybe be a task for tomorrow. A more pressing thing I’m thinking about is the two shoulder harness anchors. These are riveted to the top skin and the second bulkhead back from the rear seat, and are made out of thick alclad sheet. What’s interesting is that they need to sit flush against the skin, but also need to be relieved for the additional thickness of the bulkhead flanges.
By the plans, you’re supposed to file this area down to fit, but that seems like an unpleasant way to deal with this. First of all, this fitting has to be done with the skin in place, which means working inside the tailcone, which is already not fun. It’d be even less fun with the trial-and-error that comes with fitting work like this.
So I’m entertaining a different option – rather than filing the anchors down to allow for the bulkhead, why not instead make shims out of .032” sheet (same thickness as the bulkhead) to go between the anchors and the top skin? This seems like it’d achieve the same goal of ensuring the anchors sit flush, without the filing and trial-and-error. The only issue I can think of is that the additional material might make the joint a bit less strong in shear, which would be the expected loading if the harness was ever asked to do its job.
I’ve asked this question on the Van’s forums; it’ll be interesting to see what kind of responses I get. There are some good engineering types in there that ought to be able to point out any horrible flaws in this plane.
It also occurs to me that I could possibly do the filing of the anchors (per plans) without the repeated fitting if I use my .032” stock as a guide, which makes it a little less unpleasant. It still puts the onus on me to do some very precise removal of material, though.
Anyway, that’s it for today. It remains to be seen how much I get done this week, as it’s supposed to stay hot about all week. At least I’m still getting small things done from time to time…