Since I knew I was going to make some dust —of the worst kind (carbon fiber)— I started off this morning by taping up the canopy’s protective plastic cover to ensure no plexiglass was exposed. I also taped up the majority of the seams between canopy and airframe.
The layups I did last week on the inside front lip of the top cowling come into play here. And solves an issue that has been high on my list of things that were gnawing at me, since I saw it every time the top cowl was mounted in place: what I dubbed “10&2” on my lists (clock positions)… in homage to my high school driver’s education teacher always yelling at us that was the proper hand position when driving.
Looking from aft of the cowling, the less egregious was the 10 O’clock position shown below (pic 1) where it has a considerably higher elevation than the interfacing D-deck surface. I put the shop vac nozzle close by as I used the Dremel tool, belt sander, orbital sander, and then hand sanded down this protrusion to an acceptable level (pic 1). I could do this without cutting through the originally cowling with the extra plies on the INSIDE of the cowling to fill that gap, so in reality the layup and this cowl edge removal action is just that: a twofer!
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At the 2 O’clock position it was the same story, albeit even worse. I laid up 3 extra plies on this side, inside, again to not only back fill the air gap that was present from this extreme case of “oil canning,” (pic 1) but provide carbon fiber on the inside to allow me to grind down and remove the cowling’s original top surface (pic 2). Since I’ll be painting the top cowling, these 10&2 areas will be hidden by micro and paint. Yet another very fulfilling task complete!
Since I had my orbital sander and shop vac plugged in and at the ready, as well as my canopy covered and seams taped closed, I took the opportunity to do a good final sanding of the right strake’s top surface in prep for upcoming micro.
Another prerequisite task that needed to be completed before the actual microing up of the wings is the air gap on the outside front corner of top cowling, where it meets the wing. I had an aha moment the other day as I was pondering how exactly I was going to do this, since it would be easier with the wings off, but I don’t want to spend the sheer time and effort to remove the wings and remount them just for this. And clearly the wings need to be on during the finishing process to get them all even-steven and matched surface-wise with the strakes.
Here is the offending gap on the left (pic 1) and on the right (pic 2).
[In pic 1 note the crack in the wing flange at the corner about 1.5″ above the tip of the scribe… I discuss this in my next layup]
My eveel ingenious (that’s what I’m calling it… just go with it!) plan entailed simply floxing and glassing the strake’s cowl flange to the wing’s inside edge in situ, to then be cut after cure. To be clear, my plan involved layups on both the inside (underneath) and the topside, as I did in the pics below, but the wing is way thicker than the flange, so I’ll need to have good eyes-on and full access to work that… this should suffice for now: some flox in the gap and a ply of BID, peel plied of course.
To keep my topics straight, I’m jumping ahead in time with the layups cured, and peel ply pulled. Here we have my cut lines marked, which I will cut tomorrow after a good overnight cure.
Another layup task I completed in prep for finishing both the left wing and strake had a twofold purpose: 1) there was about an inch long crack on the wing-side flange at the very outboard edge/corner near the intersection of strake, top cowl and wing (closeup in pic above), and 2) when I set the wings in final position, the extra washers I placed on the left side wing bolts created a wider strake-wing intersection gap than the right side, and more than what I preferred.
So I laid up a single ply of BID, 1.5″ wide down the length and across the aft strake to wing intersection gap. This will allow me to cover and reinforce the cracked wing flange while also reestablishing a thin gap “kerf” between strake and wing, since I still have to do the backside (underside) reinforcement layups on both strake and wing intersection lips after wing removal.
Again, jumping ahead hours later this is after cure when I pulled the peel ply (I will recut the left strake-to-wing intersection gap line tomorrow).
My final layup task for the day, again in prep for slathering up the left wing and winglet with micro, was to repair a small divot at the very top aft inboard edge of the left winglet.
This was simply a very thin area of UNI that somewhat aggressive sanding in prep for micro exposed. You can see the spot where I cut away the dry, thin delam’d UNI where the light spot is from me reapplying micro, adding a very small patch of BID in the bare foam hole, then covering it with a ply of UNI.
On the aft 1/2″ TE depression I also added a postage stamp sized piece of BID both for transition at the depression for the overlying UNI (pic 1), but also to reinforce the aft top corner, which looked a bit rounded compared to its counterpart on the right wing. Which all can be seen after I pulled the peel ply and razor trimmed the glass (pic 2).
Yes, it was quite a long, busy day… I pulled the bottom cowling off to allow me to get the wing root heat shields out to subsequently get the ailerons pulled off the wings [this pic also has the right wing top and inboard winglet final sanded and prepped for micro… which was my last task of the evening].
I then micro’d up the bottom surfaces of the ailerons. Not shown is a pic where many hours later I cheese grated the micro-laden ailerons.
If you’re wondering why the right aileron (left in pic) is not fully covered in micro, it’s because when I skinned the bottom of the right wing many moons ago I followed some bad advice and immediately added some micro to the curing wing bottom skin. Thus I have a layer of micro that has already been sanded down and the middle area is fine. Just the overlapping BID on the forward edge and the trailing edge really needed it.
Also not shown was my using the orbital sanding to knock down the micro on the inboard side of the rudders about 80% to final. Time was getting away from me and I wanted to knock down the micro before it got too hard to “comfortably” sand, which honestly will be job #1 tomorrow when I get into the shop (sanding micro’d surfaces). Unfortunately it was very late, dark, and cold outside, so I sanded the rudders inside… yep, I broke the seal on getting dust everywhere! Thankfully the plastic sheets are containing it in large measure so that only everything inside the plastic walls is covered in micro dust (sheesh).
My major goal for tomorrow is to micro up the right wing top and inboard winglet.
Moving forward…