Warning: This is a long post with lots of pictures. I’ll try to keep commentary to a minimum. (Oh, and I just took the pups for a run outside, and it was cold, so please excuse the typos…my fingers are still a little frozen.)
Well, today was a day off for me (New Year’s Day observed) where everyone else had to go to work, so I got a ton of work (on the airplane!) done. It was really cold last night (and today on our run…brrr), so as soon as I was ready to get out into the garage to work, I turned on my portable heater and turned right back around to go inside.
Hmm. I guess I can devinyl some leading edge skins while the garage heats up and I keep warm with coffee.
That was about an hour of devinyling, so when I took my leading edge skins outside, it was not too bad temperature-wise. Thanks portable heater!
Note: I am working a little out of order. Technically, I should be prepping the main ribs for priming, then riveting those ribs to the spars, then setting the wing stand up, and then adding the leading edge. Since I’m waiting on some scotchbrite wheels for the rib prep part, I’m jumping ahead to the leading edge stuff.
Here, I’ve got all of the right leading edge ribs (except the inboard, undrilled rib) clecoed into the leading edge skin. Many people have trouble here, but if you follow the directions (which I kind of did), you start from the front end of the rib, top and bottom, and then you are okay from there. The biggest trick I found was to push the rib forward (towards the nose) as you are maneuvering the rib into place. I have long arms, so I could see the holes line up from the back, then reach around and stick a cleco in.
Anyway, then I put the leading edge on the spar, and stood back in amazement. (Amazement at the size of the assembly, and that all the holes freakin’ line up! I know this is a prepunched kit, but still, everything just always lines up. Thank you Vans!)
The dogs must have sensed my excitement…they came out to see what was happening.
After playing for a few minutes, they went back inside (it turns out they came out to ask me to turn on the gas fireplace….okay, okay, I will).
After setting both leading edges on the spar (and securing them from beneath with some #30 clecos through the main spar), I noticed that the spar really needs to be straight and level to proceed, even though it’s not fully assembled yet.
So, even though I know I’m going to take this all down soon, I went ahead and leveled the spar using the trusty (and calibrate-able) iPhone app from Stanley.
Then, I needed to address the spar bowing in the middle from the weight of all the components. (Once the skins are on the wings, they provide that support, but until they are, there is no (what I’ll call) lateral rigidity.
Oh yeah, I snagged this picture to elaborate on the reason for the larger angle off the outboard rib from the other day. See how the skin overlaps the edge of the rib and spar? I won’t have to notch my support angle to accommodate the skin now.
Okay, time to remove the spar sag.
I tied a piece of string between the top edge of two clecos (actually, it didn’t need a knot…the cleco clamped the string enough).
Before removing the sag, you can see how much bow there is (look at the row of primed countersinks).
A few cranks of my adjustable homemade jack, and the middle of the spar shows the same distance with the string. This was equally as easy to dial in.
Then, with everything level, I clecoed the leading edge skins to the spar.
Now I can move on to the inboard leading edge rib. It comes undrilled, so first thing, I kind of held it in place and made little marks where the holes were going to go.
Then, back to the workbench for fluting (between the hole locations) and flange bending (to 90°).
Okay now I need the…what is it?
Okay where is it. I’m sure there are two of them, one for each wing…
[searching shop storage …hmmm…and the airplane room upstairs…hmm…]
Grrr. Where did they go?
Upon closer inspection of the plans…
I marked my half inch line and then pondered how I was going to fit this round (straight) peg into the square (rounded) hole.
[Many loud, frustrated grunting noises…]
Then, after careful measuring, checking, drilling, remeasuring, and rechecking, I had the right joint plate and inboard rib drilled.
This one turned out pretty good. 11/16″ all around. I repeated that exercise on the left wing.
It’s only 1/16″ short in some places. I’m assuming I can make it work with 10/16″, but if I can’t, I’ll just redrill a new joint plate.
Anyway, I was staring at the opening for the stall warning vane, so I got curious and fished out the (separately packed…not really part of the original wing kit) stall warning components. They have this doubler that fits in this hole, with a couple locator tabs (in case you are modifying an existing leading edge that was not prepunched with this access hole). Since mine already has the hole, I snipped off the tabs.
I definitely need the access plate doubler and cover no matter what, but I did give some thought to whether I am going to install the stall warning vane.
I am planning on using the Dynon AOA vane, which will give me good stall warning (I believe it is calibrated during some demonstrated stalls for the highest AOA seen during stall for any flap configuration). For awhile, I kept thinking that I won’t need the Van’s vane (and I was a little miffed that they cut a big hole in my leading edge!), but then the CFI in me woke up and thought of a few things.
Every once in awhile during a rotation or flare, I might get a little chirp of the stall warning. Everyone does, and it can’t hurt to have a small reminder, separate and therefore redundant from the Dynon Air Data Computers (ADCs…wait, I think dynon calls them ADAHRS…or air data, attitude and heading reference system) during slow speed maneuvering. The Dynon is based on pressure differential (between the front and the angled top of the pitot probe), and the other is based on direction of relative wind (the vane just lifts up and compresses a microswitch when the relative wind pushes up on it).
I’m going to go ahead and install all of the provisions for both. It will be pretty easy to get everything installed, and just leave the little vane out if I don’t want it in the end, but I have to fill all the rivet holes anyway, might as well not rule out any future decision changes.
I’ll probably install both; you can’t be too aware of low speeds, and frankly, it will probably help resale to have the more traditional stall warning.
Then, I found the leading edge vane support rib. They come as a pair of two; one for the RV-9, and one for the RV-7,8. It was obviously while holding it up to one of the leading edge ribs that the one with the sticker on it is the correct one.
So I wouldn’t forget, I tossed the other one in my scrap pile.
Whew. Good day. I’ve made good progress in the last few days. Tomorrow, back to work, but hopefully I can keep this up.
Oh, and for the record, I hardly had enough 3/32″ (silver) clecos to do both leading edges at the same time. I just ordered 100 more, but I am going to need way more that that to keep working on both wings at the same time. This might be a good time to work on one wing at a time…or break down and order the 500 or so that Vans suggests.