Tag: Ailerons

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Wing fittings and aileron work

I’ve spent a couple hours this week getting bolt length sorted out and getting some of the wing fittings attached.

My strategy for the wing attach fittings was to make one of each type of fitting, pilot drill the holes with a 1/8″ bit, and use those to mark the location of the holes in the wing spars. Those holes got drilled on a drill press using Forstner bits. Then I cut the rest of the fittings, used the first ones as templates for drilling them, and figured all of the holes should line up.

Well – they’re close. I’m not a machinist, nor am I using tools techniques of suitable precision to produce perfect parts. For example, when looking at the CAW2A wing root mounting brackets, the holes are not perfectly aligned – so there’s a top and bottom to those, meaning until I figured that out it took a few tries to get everything lined up right. No big deal.

Then I discovered that one of the holes isn’t drilled perfectly square. It’s only off by maybe .010 total, but just enough that you can’t run a bolt through the forward bracket, the bushing, and the aft bracket without interference. If the bolts were just going through holes drilled in the wood of the spar, it would be fine – but the bushings are a snug fit, I had to do a little adjusting of that hole to get everything to fit properly.

We finally got the bottom of the aileron leading edge routed so that it’s now in its final state. When fitting the aileron and checking travel, I discovered that I’d messed up just a little when up finishing out the aileron bay. On the first wing, I’d positioned the top beveled strip with the aileron in place, and checking clearance per the plans. On this one, I just measured the first wing and matched it. I don’t have enough up travel on this aileron. After a little more investigation, it’s just the ends that interfere, so easily cleaned up with a couple minutes of work with the razor plane. I’ll need to pay closer attention on the next two wings. I’m thinking just use a length of 1/4″ shim stock to set the spacing with the aileron solidly fixed in its final location.

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Catching up

I’ve missed a couple of updates to work done on the plane over the past week or so. I got the second coat of varnish on the wing, including the aileron. I got all of the bushings in place, and started to attach the various attaching brackets… oops! No torque wrench. And, I can only find one CAW9 bracket. I think I ran out of 3/16″ x 1″ 2024 flat bar stock before I got them all made; I need to go hunting and gathering again. Once that’s done I can finish off the aileron (the lower leading edge needs a pass through the router for its radius) and move on to varnishing the other wing.

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Finishing out the aileron bay

Last session I cut and sanded everything to get the top of the aileron bay closed out. Well, not everything; after gluing in the CW37 piece I realized that there were some additional supports I hadn’t cut. As I was running short on time, though, I had to leave them for another day.

The fun part (and it actually was kind of fun) was cutting notches in CW37 for the ends of the rib caps. After marking the location of both sides of each rib. I cut a shallow slot with he razor saw, then used an X-Acto knife to gradually fit the depth of the notch to fit. In the end I got it in and clamped, then had to leave.

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Aileron skin

Over the past couple/few days I’ve glued the bottom skin on the aileron, then attacked the top nose skin. Trying to get the lower and rear edges of the skin glued down at the same time is, I have concluded, a fool’s errand. I ended up gluing it to the flat front portion, then doing the top edge separately using a long piece of flat board to clamp it to the tops of the ribs and the aileron spar. The front edge I’ll do separately as there’s not a good way to clamp it in place.

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A couple days’ work

Saturday: Ripped the CW37 parts down to the proper 1/4″ thickness. These are the strips with one beveled edge that go in the top and bottom of the aileron bay. The parts I got are 1/2″ thick, which won’t work anywhere. Ripped them all down to 1/4″ so I don’t have to do that again for the other two wings. With them cut to the right thickness, I cut one to length and glued it into the bottom of the aileron bay.

Then I discovered (or confirmed) that I’m an idiot… there were a couple of missing aileron pieces that I found in the bottom of the parts crate. Had I installed them in the first place, the little triangular braces would not have been needed. It’s no big deal; I was able to slot the nose skin support spar and get them glued in.

Today: Got the nose skin plywood glued onto the front of the wing. I think there are now about 70 or more clamps on the wing. I had planned to glue the top aileron nose skin in place, but that’s going to take some more work. I see no way to get that ply to stay attached all the way around without some sort of clamping jig. Stu and I figured out a good arrangement, but I’ll need to get some MDF, ply, or pine scrap to cut them out of. I need seven sets of clamping blocks for the nose and trailing edge, then I can use bar clamps to hold everything in place.

I also found that a few batches of glue I mixed up over the past week or two were probably not the greatest. My T88 had started getting cloudy — a sign that the resin is starting to crystallize. Some of my test pieces failed at the glue joint, albeit with a lot of force required, instead of the wood failing before the joint. I’m not really concerned about this. All of the affected glue was used for either the wing walk or adding corner blocking and gussets to the wingtip bow. The wing walk pieces are fully supported and there will be no bending, twisting, or pulling loads applied. The glue is strong, just not AS strong as what I’ve used everywhere else.

I have since tossed the syringe of clouded resin, warmed the rest of my resin supply until it’s crystal clear, and verified that test pieces now all break well into the wood rather than at the glue line. I’ve tried spruce to spruce, which tore apart well into the wood, and spruce to plywood which ripped the plywood apart.

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Bracing and gusseting

I got all the clamps off of the aileron this afternoon. Everything looks pretty good. Due to the way I had to cut the thin nose skin spar, I felt it best to install some bracing for it. These are just little half inch right triangles that I glued in to keep it straight.

With that done, I removed the clamps from the wingtip bow and sanded down the gussets I’d installed last time. I won’t know if they require any “fine tuning” until I have a chance to get some fabric on it, but I think they’re good to go.

I flipped the wing on its top surface and added some more blocking under the ends of the wing walk. These are just regular corner block stock to tie the plywood to the spar caps. I think everything looks pretty sturdy there now.

With some time and glue left, I sanded down the corner blocks on the underside of the wingtip bow supports. I cut, glued, and clamped the gussets in place and called it a day.

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On a roll!

Today I did some work with the razor plane and a new sanding block to get the aileron spar and other bits to their final dimensions. I got the top side geodetic braces cut and glued in place on the aileron. Then I glued the lower aileron nose skin in place – the aileron now has, I think, the maximum possible number of clamps on it.

With that done, I got the blocking sanded down on the wingtip bow supports, and cut and glued the top gussets in place. Only eight clamps there, but I think it’s still feeling the love.

And if you’re a Star Trek: Voyager fan, this makes Seven of Nine days in September that I’ve worked on the plane.

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Aileron work

I removed the clamps from the wing walk skins; all looks good. Once I have the wing flipped upside-down again I’ll have a look at the underside and see if there are any additional opportunities to put in more support for the structure, but I think it’s about as good as it’s going to get.

I cut and installed the lower geodetic braces in the aileron, as well as the aileron skin support (not sure if the plans refer to it as a spar or not). I’m pretty happy with how this one is coming together, especially considering the angst the first one caused.

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Wing walk skins down

Today I went through more epoxy than I have since gluing the spar caps. After some sanding and test fitting, I pre-glued the wing wall structure and the two plywood skins. Then Stu helped me clamp the edges down, and pinned down any spots that weren’t firmly in place.

As planned, I used some scrap lumber to make clamping bars. I used strips of geodetic material between them and the skins to ensure good pressure and clamped everything together with bar clamps.

With some epoxy left over, I glued the nose spar onto the aileron and did a little more corner blocking on the wingtip bow supports. With all that clamped, pinned, and taped in place it was time for lunch!

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Aileron freedom – and wing walk work

Today I located and temporarily screwed the bearing blocks in, and cut the aileron free from the wing.

With that done, I decided to have another look at the wing walk situation. I don’t know why the support bits were the way they were, but I decided to just get on with making them work. When I look at the plans, especially the oblique view, indicate that the parts may have been cut in an attempt to match a much earlier version of the wing without much of the reinforcement at the main spar root. Anyway… Two of them had the aft end cut well enough to work at the rear spar. The inboard support needed to be trimmed at both ends. All had to be modified to fit the main spar.

In the end I got all three to fit, though I’m not terribly thrilled with the lack of good options for supporting and blocking the ends.

Next up were the notches for the cross braces. Most were too shallow and look to have been cut out with an end mill or router; the corners were rounded. I used a file to square up the corners and deepen the notches to fit the 1/2 x 3/4 pieces.

I figure I’ve got another hour or so of work to get all of the blocking and support in place before mixing epoxy. Probably more; I still haven’t figured out what I’m going to do about the extension of the walk forward of the main spar. If I build it to plans I’ll need to remove or hack up the first false rib. And of course the plywood pieces require significant modification.

On the bright side, the plywood skin for the wing walk curves nicely and won’t be a problem to get glued down. I’d been worried about that, and had visions of needing to make my own laminated piece there, but it’s fine.