Today I’m continuing with building up the elevator trim tab. I’m starting by filing down the edges to get 3/32 inch clearance between the tab and the elevator.
Once I got the edges filed down, I started to work on the trim tab end ribs. The S-51 plans don’t provide much detail here so I’m going to wing it and use the tip of an old RV rib from the scrap pile. I figure this is a good way to repurpose the screwed up rib.
I began by just eyeballing up the rough size I’d need. The angle of the donor rib is pretty darn close.
As I’m fitting the trim tab end ribs, I’m also noticing another issue that I need to fix. The trim tab spar is a bit narrow in thickness for the skin of the tab to contour and match the trailing edge skins.
My solution is to make a tapered spacer. Of course this is strictly by trial and error, so there have been a few of these spacer pieces made to get the thickness and dimensions correct. This is one of the times that building the S-51 when it takes a lot of time to get things just right.
As shown in the picture below, you can see how the trim tab spar is not quite made to the right dimensions, in that it’s a bit thin.
Here’s another angle, as viewed from the side.
In the picture below, you can see the tapered shim and where it’s located.
Here you can see that I needed quite a bit of extra thickness to bring up the trim tab skin to match that of the elevator skin.
The tab is slowly coming together.
Then to finish off for today I ended with adding the skin filler strips on the top and bottom of the elevator.
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