Stjohn's RV-7

Finished dimpling/deburring the HS. Not without a couple of glitches (Cframe == evil), but that section’s done. time to prime the primable parts.
Or maybe not.
It looks to me like priming is a huge pain in the ass, and I don’t really have the talent or the facilities for it, except in the most makeshift way. I don’t want to spend any longer on it than I have to, but I definitely want to break out the flea-market HVLP gun and see what I can do. So my plan is this: do the VS assembly/drilling/deburring/prepping, then prime the HS and VS at the same time. I’m not going to prime the skins. All I really care about is priming the vulnerable stuff, like the reinforcing angles and maybe the VS doubler. I’m not terribly worried about where I drilled the holes for the skin rivets because a rivet is going to seal up that metal better any any coat of paint.
So that’s what I did today: edge-prepped the VS spars and ribs.
I know this is building out of sequence, but unless the work takes more time than the prep and cleanup, it offends my sense of efficiency. As it is, shooting paint will be the least part of it, but I want to spend as little time doing it as possible.

8 hours.
Managed to get a dimpled skin and some ribs out of it.

Whole lot of building and not a lot of photography today. Drilled, disassembled, deburred, and dimpled right side HS today. I got to use my pneumatic squeezer. A lot. I clamped it in the vise for a little improv bench squeezer action. Ribs and spars ar a lot lighter than the squeezer, so this make things pretty easy.

I also dimpled the HS601PP skin using the squeezer freehand, but had to go to the C-Frame for the deep-reach stuff. I have to tell you, using that C-frame dimpler is a royal pain in the ass. The DRDT-2 is the way to go, or just welding up a big box-tube copy of it and finishing it in such a way that you can use the squeezer for the dimpler’s motive power. I have a design in my head, but I don’t need to go into it here since I can’t weld and I’m going to get all the mileage out of this Avery C-frame that I can. However, if you don’t position your workpiece correctly or you take your eye off it for the amount of time it takes to line up the hammer blow, your skin could jump off the dimple punch and put a hole somewhere in the vicinity of the one you actually want to dimple. Like so:

Well, that totally sucked. Not replace-the-skin sucked, though. The rivet is on the bottom side of the HS, and I did manage to drill it out to 1/8 and I’m hoping the rivet seats and covers up the slight elongation of the hole.
Eventually I got all the ribs and skin dimpled for the right HS. Deburring was not bad, just tedious, made even more so by this:

The black probelike thing is a Cogsdill Burraway, .093 size. The little silver sliver next to it is the blade. The idea behind this tool is you put it in a drill motor and run it through the hole you want to deburr. The little blade sticks out to the side of the shaft and deburrs the hole in one pass, outside on the way in, inside on the way out. In theory. Problem is, the .093 is just a wee bit too small to be effective on #40 holes, especially ones that are a little on the big side. This led me to try to adjust the blade tension. I subsequently broke it. So now, I have to find a frigging watchmaker to replace this blade. This tool is so small, it’s impossible to modify with the stuff I have. This pic was shot through my magnifying-glass desk lamp out on the workbench. However, the 1/8 size Burraway is great. Go Cogsdill! What I need to do now is get online to MSC and order a new retaining pin, and a bigger blade, if they have it. This little bastard was $55 bucks, so I’d hate to think it’s useless. Tomorrow we make sure all the edges are done (sometimes I miss things) and move on to the Left side HS.

4 hours
Took apart the HS assembly, got HS 710 and HS714 out of the mix. Didn’t have to drill the outboard-most holes of those two, because I foolishly did it earlier, when assembling the skeleton. Yer not supposed ta. But, because my angle measurements were dead-on-balls-accurate (and this is an amazing kit and I am extraordinarily lucky) everything is just fine. So you see here before you, the left side HS, final-drilled and clecoed together.

But of course, yours truly didn’t read the friggin directions again where it says to leave the Emp fairing holes undrilled. I’ll deal with that later.
That brings us to the next phase, which is “Repeat the above steps for the other side HS.” The best part about that is, I got from zilch to this:

to this:

in about two hours. Things go a lot faster when you know what you’re doing, or you’re at least sure you’re not messing it up badly enough to warrant a redo.
So that’s where it stands at the moment, folks. Have to final drill and deburr the right side (or left, that detail on DWG3 confuses me when it points left and says “right”) and then agonize over primer, MEK, scotchbrite pads, and go through the learning curve of my flea-market HVLP sprayer.

3.5 hours
Last time, I was freaking out about edge clearance in a few places and also freaking out that drilling my inboard ribs out of sequence was going to totally hose me. Van’s tech support talked me down off the tower and explained that my hole in HS710 is close enough and if the ribs fit, they fit. So that greenlit the next move which resulted in this:

I managed to cleco the skins on, but the ship has drawn first blood. A subtle way of telling me to deburr edges before trying to finagle a fit in tight places. This was about an hour before the above pic, where I was trying to cleco the skin to HS708. So everything had to come apart, I rechecked all my edges and beat down the offending ones with the scotchbrite wheel. But after that little fracas, the skin went back on, and without too much scratching of the metal. You can see here that I’ve kept all the blue stuff on my skins while I’m learning how to keep from scratching it so much that I’ll actually have to paint the airplane. Speaking of which, is there a color called “TIE Fighter White?”
Here are a couple of shots of the ribs vs the edge of the skin. Not bad, but I got them a lot more lined up before I did any drilling.


And here’s the first noticeably airplane-looking thing I’ve done so far:

First off, I have to say that this will probably go down as expensive mistake #1, since it’s probably going to involve a new HS710, HS714, and 2 HS702’s. I might be able to save them, but only if the skins fit.
So if you look at where the end of the ruler is,
the distance from the center of that hole to the edge of HS710 might not actually be 1/4 inch. it’s close, damn close, like just outside of 1.5D.

The other thing is, yours truly has committed the sin of building out of sequence. You’re supposed to take all this stuff apart and work with one side of the spars, and fit HS405 and HS708 (inboard main and nose ribs) with the skin clecoed on to the outboard ribs and HS702/HS 603. I did not do this. So what I hope now is that when I actually strip this thing and cleco it up correctly, the places where I’ve put the ribs (based on the 5-3/16 dimension in the plans) will allow me to matchdrill the skin to the ribs with no trouble. If not, well, I order some new parts and shave a lot less metal off this time. What happened was, I drilled the inboard main rib to HS702 before test-fitting the skin to make sure I had enough edge distance on the angle splices and the rib flange. But now if I don’t have enough edge distance on the inboard edge of the skin, I’m screwed. All I know is I’m not drilling anything else until I complete the skin-fit.

Mostly. I’ve edge-prepped the inboard main and nose ribs (don’t remember the part numbers, and I’m at work) and I’m now trying to measure twice, three times, four times on where to put the holes in the main ribs so that the 2D rule is met for both the ribs and the splice angles. If you’ll remember from last time, there was some concern about being wide of the mark with the flange trimming of HS702 and it looks like the relief holes are a little bigger than they ought to be. what this means is that there’s a very narrow tolerance of where I can drill the HS405 rib to meet the 2D requirements. I’ve been agonizing over it for a couple of hours, and I think it’s still viable, although I can’t be sure.. The safest way to proceed is to replace the part. Duh. Any moron with a fat wallet and a lot of spare time can go through life this way, but I think if the part is still within limits, why not go for it? so that’s what’s going to happen. The 2D rule (guideline) might be smudged by about 1/32 of an inch (on the splice angle, not the rib), but if I put that hole in exactly the right spot, it will probably work fine.
I have a bunch of pictures on the camera, but I have yet to upload them. This will happen soon, I promise.

3.5 hours
Well, after much sweating, looking up parts and gnashing of teeth, it looks like my HS-702 isn’t hosed after all.. The relief notch is in, all the corners are rounded, and all the parts fit together.
Finished trimming HS702’s, double checked angle on the reinforcement brackets on the forward spar, drilled out the last 3 holes on each one after the angle was done.
Countersunk angles, dimpled HS-702’s, then trimmed HS404 (or was it HS408?) ribs. The inboard ones forward of the forward spar. Broke edges (need to find a good deburring thing for tight spots), and stopped. Getting tired.
Next is to finish prepping the ribs, then begin the drillfest.

2.5 hours
unclecoed HS aft spar, started on forward spar. Cut tapers for splice angles. worked out OK. It’s not pretty, but it’s within limits.
Lesson learned: when using the bandsaw, leave extra metal, IE, cut outside the sharpie line. The bandsaw takes off a lot of metal, the scotchbrite wheel takes off even more.
Need to go get a vise from Home Depot so I can make the bends in the angles and HS702’s.

OK, so one thing to know: bad rivets on a small part sucks to deal with. used the squeezer, had a bunch of bad rivets, so I drilled them out and started over. Didn’t turn out too bad, but there’s a technique to a squeezer too. If the initial point of contact is off, you get an angled shop head. Not a no-go, but something to think about. the lesson? Clamp everything.

Gotta get a #19 and a #12 drill bit. Also need to find a way to add up hours in a sentient fashion.
Drilled out HS spar and reinforcing bars, but need to round off the edges of the bars a little more.. the detail calls for 1/32 radius, which is friggin’ small, but bigger than what i’ve got.. No prob.. Scotcbrite wheel to the rescue.
tonight: 1.2 hours