The next step on the rear spars is to trip the W-707D and W-707G Rear Spar Doubler and Reinforcement Fork to size.
These parts are shared between the RV-7 and RV-8 (and maybe more, I’m not sure), and must be trimmed if you are building the -7.
This is a tricky trim job, though, because many people have future troubles with drilling the rear spar to the fuselage and maintaining the required edge distance for the hole in THESE PIECES.
It would be best not to overtrim, and leave even less margin than what is already there.
The plans and construction manual both point to Dwg 38, which is of course not included as a full-scale sheet in the wing kit, so I got out my preview plans and started staring.
Even though I’m only working on the right side for now (will bring the left wing up to the right side’s progress when I get the replacement spar from vans), I’m going to do both sides of this now while I’m all mind-prepped to do it.
Keep in mind here that you measure from the edge you are about to start cutting away, so once you start cutting there is no double-checking your measurements.
I decided to cleco the two smaller pieces together first, then transfer the lines to the bigger forks, and do those separately.
Of course, I didn’t get any in-progress shots of the fork cutting, but it went well. I then clecoed the left and right assemblies together and grabbed this shot after a few passes on the scotchbrite wheel.
After some time on the scotchbrite wheel, I have two ready-to-cleco parts.
Then, I clecoed the doubler plate and reinforcement fork to the right rear spar and started matchdrilling.
I had a hard time deciding if I should enlarge some of the rib attachment holes in the fork and doubler plate to final size, and I decided I would. I couldn’t find anyone who said it would be a bad idea, and now I’ll get to deburr and prime all of the rear spar components.
I did leave the majority of the rear spar “future” holes alone, though. I guess per the directions (indirectly, just in step order), I’ll drill those after priming the rear spar.
Of course, I was careful to mark and enlarge to #40 the flange holes that need to be dimpled now (the reinforcement fork prevents the female side of the dimple die from getting behind these holes).
After taking everything apart and deburring holes, I have a few pieces ready for priming, and a rear spar with some remaining deburring before priming.
Today’s hour was a good one; a few things ready to prime, and just one deburring and priming session away from being able to rivet the rear spar assembly together.
I need to go buy some more Napa 7220 Self-Etching Primer.