Katie's RV-3 Build Log: Progress at Last. 15/125 hours

I'll admit, I've been a little bit lazy with the blog lately. I've picked at the plane here and there over the past few weeks, but felt increasingly crappy about the project. The stab skins are thick, bulky, heavy, and put up a mental and physical fight with me every time I went into the garage. I made the plywood clamps like Van's specifies a couple weeks ago, but they suck. The skins flopped around and the clamps did not hold them anywhere near their final place, and to make matters worse, I thought I dented the skin with the hard edge of the plywood when I removed the big clamp the last time. Thank God the damn skin is so thick, it survived the blunder. I had an idea to clamp a pair of 2x4s to parallel the front spar, spreading out the clamping force along a straight line instead of over the airfoil shape, but 2x4s are really heavy and I didn't want to twist the skeleton. And who am I to make a jig better than Van? All the frickin woodworking, and visualizing, and plumb-bobbing, and slooooow progress had me wondering whether I even had the skills for this. It didn't help that the RV-12 we are building at work goes together like a kid's jigsaw puzzle, and Possum and Pete are finishing components faster than I can take pictures of it.

Widely-bent .032 skin with the dreadful plywood clamps on the floor beneath the jig

But finally this weekend, I had a sort of breakthrough revelation. Suddenly I told myself:

1. You are not too good for duct tape. The shit's marvelous, and you have a mile of it in your tool box.
2. Don't spend too much time visualizing and pre-planning how you are to do a task. You don't have enough building experience for that yet, so there is a very good chance that your plan won't work, and all the time you spend visualizing is a waste. Get out there, handle the parts and let the airplane help you figure out how to execute each task.
3. Van's instructions are a simple read, but deep in intention. Sometimes it takes several readings over several days before the best way to do a thing sinks in.
4. Use the experience learned from scratch-building the CX4 tail to lead you.
5. You can drill a 3-foot rivet line with variation less than a thin sharpie line wide. That rivet line is not perfect like a pre-punched skin. This airplane is DIFFERENT from every other. It's organic, much like an impressionist painter's brush stroke or a freckled face. Its beauty will be in its character. Do your best to build a clean, straight airplane, but it won't look like a CAD punched premanufactured kit, so quit obsessing over it. Its character is something to embrace, not defeat. It may not win any shows, but that's OK, as long as YOU are proud of it!

With that, I was able to loosen up a bit and free my mind of the fear of screwing up. I was able to take control of the unruly skins by using whatever amount of duct tape I needed to get them in their place. Finally, after the misery of the plywood clamps, I decided to try the 2x4 idea, only using lighter-weight 1x2s. Found some at work in the junk (hee hee, free stuff!) and tried it on Saturday. Took some fiddling & enlarging of the bolt holes to get them to go on easily, but BINGO, they worked like a freakin charm. A long 1/4" carriage bolt in each end made it really easy to get the skin to set down flat along the entire length of the stab, and adjust the tension when necessary. I probably should have put wing nuts on them to make it ridiculously easy to adjust. The best part is, it was entirely my idea. Ben had nothin to do with it!

Skin in place with copious duct tape, 1x2 clamps, and calibrated blocks under the TE.

After initial fitting, I was going to trim the trailing edge to an angle that made the tip rib fit the LE better, but Ben talked me out of it. (again, trust Van's instructions that said NOTHING about trimming the TE, just the ends.) Instead I blocked up the TE by trimming a pair of 2x4 blocks to sit on the jig crosspiece, with the top surface exactly 3/16" below the spar, to allow gravity to give me the required skin overhang aft of the rear spar. (Why fight gravity with clamps when you can harness it?) This set up a baseline location for the skin. Once the skin was clamped in place solidly onto the skeleton, I transferred the locations of the spars and ribs to the skin via sharpie.

One major thing I did change from Van's instructions was that I did not want to drill the rivet holes blindly through the skin, into the skeleton. I've spent WAY too much time on that damn thing to risk running a rivet line off an edge. Plus, my drill control is not quite steady enough to make a straight rivet line in mid-air. Instead, I transferred all the rivet lines and pitfalls like flutes and relief holes onto the insides of the skin. Then, I laid out the rivet spacing, center punched, and drilled the skin on the workbench. After that, it was pretty easy to reclamp the skin to the skeleton and match drill the skeleton to the skin. I may have enlarged the skin holes just a micro bit, but I think it was a good tradeoff, since I ended up drilling nearly perfectly centered and straight rivet lines. :-D I used a #41 bit, so the holes are slightly undersized anyway.

My hand's a little sore from 108 rivet holes per side-- each one center punched, drilled, match drilled and clecoed today. Add that up, -12 builders! :-P