The horizontal stab is complete!
Not too many problems here, except that I had to work a bit getting the remaining #30 rivets to fit in the frame. After some problems using the thin-nose no-hole yoke on the vertical stab, I seem to have mastered the art of using it.
Because the no-hole yoke is thinner, it flexes more as the squeezer ram develops more force when moving toward the end of its stroke. This flexing was causing slanted and/or cleated shop heads when I first used it on the vertical stab. By using a longer (1/2 inch) flush set the squeezer engages the rivet with slightly less force, not deflecting the no-hole yoke as much but still with enough force to form a good shop head.
Here’s another picture, this time without the blue plastic. Van’s recommends removing it to prevent corrosion…so I did.
And here’s one more picture…I like that shiny alclad!
With the first tech counselor visit complete, it was time to start on the horizontal again.
Whitney was looking for things to do, so I put her to work pulling clecos and inserting rivets. We got the top of one stabilizer riveted. Once again, the pneumatic squeezer came in handy. The only problem with using the squeezer is that a little finesse on the trigger is required. It’s very easy to slam the rivet in place rather than gently squeeze it. Also, an adjustable set is a must-have item for the squeezer.
One more thing…I’m just about ready to pitch my Avery rivet height gauge. The plans call for -3.5 rivets, which Avery’s gauge says is too short, i.e., not enough rivet shank protruding from the hole. I tried one -4 rivet which was the right length according to the gauge. That rivet was harder to set; the shop head tended to ‘cleat over’ and become lopsided. The rivets called out in the plans made almost perfect shop heads.
Lots of progress in the last week and a half…
After riveting a HS-707 nose rib in the left HS left skin, it was time to insert the entire front spar assembly. The plans call for riveting the nose rib in by itself, but it was much easier to keep the skin in place on that nose rib by clecoing in the center and end ribs. Thanks, Mike, for the tip.
I also ended up using one of the MK319-BS monel blind rivets that Van’s calls out as optional for attaching the nose rib. Even with the rib flanges spread a bit before riveting, the forward-most portion of the flange still didn’t lie flush against the skin. So rather than try to buck a rivet while holding the flange in place, I used the MK319-BS. Those of you who either (a) have done this before, or (b) are going for an award at Oshkosh may consider this a cop-out….well, have a nut. The blind rivet worked great, and looks ok too.
And here’s the left skin riveted on, with the exception of the end ribs and rear spar. I’m leaving the structure open until the first visit from my EAA Techincal Counselor. Ken Balch kindly volunteered to be my TC, and I’m really looking forward his first trip to the shop.
One other thing to note…Ellen did a great job with the rivet gun! After only a little practice on some scrap, she was wielding the 3X like she’d done it for a long time.
After repeating the process on the right side, here’s the almost-finished product. It’ll be completed after Ken’s visit…or else I’ll be drilling out a bunch of rivets!
The rear spar clecoed in place. This HS structure is pretty flimsy without the rear spar.
Not much time spent today, but we did get the first skin rivets in. One small step for the Mighty RV, one giant leap for Dave. I had a bit of a mental block about these rivets. But some practice and mental rehearsal paid off.
Just a few rivets done because it was getting too late to make a lot of noise with the rivet gun. But none of them had to be drilled out. Bonus!
Lots ‘o riveting going on in the last few days…and drilling out some rivets too.
I had to re-learn all those rivet bucking skills I had forgotten since the SportAir workshop. Ellen caught me in the midst of a hard-to-hit rivet. But the HS front spar is finally finished…
Here are the front and rear spars covered with spiffy yellow Super Koropon primer.
…and here’s everything clecoed together. Next task – practice flush riveting, then start putting the skins on.
HS parts are all alodined and primed. If you’re desperately interested in the whole process, go here.
Finally…some rivets squeezed! Constructed the horizontal stab rear spar and attached its elevator brackets. I had to drill out a few rivets, but didn’t make too much of a mess.
Here’s one rivet drilled out, and another ready for the punch. Once the rear spar was done, I started re-assembling the front spar in preparation for riveting.
The new HS-710 and -714 arrived last week. Trimming and finishing went quickly, and the new parts fit very well with the existing holes match-drilled in the HS-702s. Pre-punched parts are freakin’ great!
While preparing to countersink the VS spar doubler, I re-read Vans’ instructions on how to countersink. Turns out I used the wrong method on the HS-710 and -714 reinforcement angles – using a male dimple to check countersink depth makes for too deep a cut.
For a hole that will accept a dimpled skin, the current instructions call for countersinking the hole just enough to make a rivet sit flush, then going another 0.005″ (two countersink sink ‘clicks’). Well, mine were a lot deeper than that. According to Gus at Van’s, there are no structural issues since the holes weren’t countersunk all the way through. Riveting the hole could be difficult since the rivet shank will expand in the area between the countersink and the dimple, but the suggestion was to rivet them anyway – four sub-par rivets wouldn’t make that much difference.
Just to be on the safe side, though, I’ve ordered a new -710 and -714. The challenge will be to make the match-drilled holes line up on the other parts drilled in assembly with these two. If I can do that, I’ll use the new parts. If not, I’ll fall back on Vans’ suggestions.
Lots of things happened in the last three days. Once the skeleton was done, I prepped the right HS skin, sanding out interior scratches, trimming off blue plastic, and smoothing edges. I started dimpling with the pneumatic squeezer, and then Ellen and I continued with the DRDT-2.
Ok, here’s a quick quiz…what step didn’t I list above? That’s right, I forgot to debur the right HS skin rivet holes until we were about halfway through dimpling. Before doing any more, I called Van’s to see how bad I screwed up. Well, I lucked out – because the cure was simply to sandpaper the male side of the dimples to remove burrs. After reading some newsgroup posts on this problem I considered the possibility of structural problems – cracks, etc. – from dimpling with burrs, but Van’s wasn’t concerned. That’s good enough for me…but this is one mistake I’ll work hard to avoid in the future.
…and I didn’t make the same mistake on the left skin. It’s finished and the HS is done until the Super Koropon primer arrives, which I hope will be in the next week. Can somebody explain to me why it takes PRC-DeSoto a month to ship one 2-gallon kit of epoxy primer?
DVD of the day – ‘The Great Waldo Pepper’. A great, yet underappreciated movie – and in my opinion, some of the best flying scenes ever filmed.
I’ve gone awhile without an update – too much work stuff getting in the way of building! In the last week I finished match-drilling the left horizontal stab, then assembled the right horizontal stab frame and clecoed it to the skin. After prep work on the inboard ribs, I match-drilled them to the front and rear spar, again using a 12″ #30 bit. It worked even better this time than before.
Edge distances are muy bueno – I’m relieved. A screw-up here would mean redoing a lot of work.
After finishing up the right HS match-drilling, I disassembled everything. Had several kinds of fun finishing edges with the scotchbrite wheel, then deburring holes. Following that, dimpled the frame with the pneumatic squeezer – once again, the squeezer is one tool that’s worth the expense. The skins still require edge finishing, deburring and dimpling.
DVD of the day – ‘Monty Python’s Flying Circus, Volume 3’. The ‘Lumberjack Song’ really makes tedious work go faster.