Elevator tip rejection, tail light fitting

As per usual, plenty of stuff around the house to do today, but I did make some time in the evening to get in airplane work. I’d intended to get the elevator tips sanded down and see if they’d need some more filling, so the first step was to get them separated from the elevators. This was significantly tougher than when I did the similar gap-filling work on the rudder tip, and I guess I maybe should have scuffed the area around the tip recesses some more, because in a couple places the thin bead of cured micro stuck to the elevator instead of the tip. The end result was that my gap-filling was sort of a failure.

I did still go ahead and rough-sand the micro on the leading edges, but the more I looked at the gap fill and thought about stuff I’d done with these tips, the less I liked how everything was going. Unlike with the rudder, the excessive gaps here were caused by nothing more than me not having the tips completely flush while drilling the mount holes. I could possibly fill those holes with flox and re-drill, but at this point the original recess lines are lost.

Basically, I’ve decided to order a new pair of tips and start over again clean, and chalk these up to a learning experience. Some more careful fitting of the new tips may make it easier to match the contour of the stab tips as well.

In any case, for today I moved on to working on the rudder bottom instead. It was finally time to open up the mount hole for the tail light and figure out the mounting. It took a few different ideas to find a good way to mark the approximate center of the light pad, but that turned out to be sort of unnecessary. I didn’t have the right size hole saw for the light mount, so I decided to use a unibit instead, which wandered as units are wont to do. It ended up being a multi-stage process of opening the hole to a particular size, then using a sanding drum on the Dremel to massage the hole in a desired direction, then opening it up some more with the unibit, and so on.

The fun part is that the pattern in the Flyleds instructions is kinda incomplete – it says to make a 1” hole for the light, which is larger than the heat sink, but the wires for the light exit beside the sink, far enough out that a 1” hole isn’t big enough to accommodate them if it’s centered on the light itself. So after getting a nice round 1” hole, I proceeded to add a notch on one side with a file, then use the sanding drum to turn the whole thing into a sort of weird oblong hole.

Not that it matters, as the bezel for the light covers a lot. In fact, it covers the entire flat pad it’s mounted on, which is something worth noting when you consider the time I spent trying to carefully make this area super flat…in the end, absolutely none of it is visible. Now I’m sort of tempted to reshape the pad to better blend into the light, but that’s probably absurd overkill. Seems like it looks decent as-is:

Notably, those two mount screws are just loosely inserted, not attached to anything (more on that later). That nice shot belies the sorta ugly hole hiding behind it. But that’s why…it’s hidden:

The marker line seen above relates to the next bit, which is the attach bracket for the light. There’s a sort of semicircular aluminum piece with tapped screw holes, which is intended to be epoxied inside. Problem is, the inside of this fiberglass piece 1) isn’t super flat, and 2) doesn’t have a lot of room for this piece. I spent a fair amount of time tonight working on carefully removing material inside there (a challenging process in and of itself) and then removing material from the bracket as well. It still doesn’t fit perfectly flush, but I at least got it to the point where I could start the screws with it in place before calling it a night. More trial-and-error is in store for tomorrow.

Finally, before quitting, I decided to get ahead of other rudder bottom work. At the leading edge, the portion which extends ahead of the spar, I want to add a sort of “cap” on what would otherwise be an open end. This has a couple advantages: first, it looks nice, and second, it provides a place for me to add a grommet or other provision for routing the tail light wire inside. On that second note, I think I’m going to add a short bit of conduit in the leading edge area. This won’t extend all the way to the aft end of the tip, but only far enough to allow for directing the tail light wire from the vertical orientation (where it enters the tip) to a horizontal one, pointed at the trailing edge.

With this in place, I’ll feel confident riveting the bottom in place (vs using screws), knowing that if the rudder is removed, when it goes back the conduit should make it straightforward to feed the wire back towards the trailing edge for reinstallation, while also allowing for enough excess wire further back to allow for puling the light out and disconnecting it. For connections, I’m going to use knife splices and heat shrink, rather than something like a Molex connector.

Anyway, that was a roundabout preface for saying that I cut out three 5×5 squares of glass and did a flat layup with them. Once that’s cured, I’ll cut it down to size and get it epoxied into the bottom. It’ll probably make more sense when it’s done and there are pictures, vs me trying to explain it…

Posted in Electrical, Empennage, Fiberglass | Hours Logged: 2

Elevator tip filling

Short session tonight – I just mixed up a batch of micro to fill out the forward ends of the elevator tips. I did this with the tips clecoed in place, so I could also work micro into the gap between the tip and the skin, since that needed filling in a few places. I’d hoped to maybe do some filling on the horizontal stab tips, but by the time I finished working the micro into the seams it was starting to stiffen up pretty well, so I think I’d be better just doing those tips separately.

One thing I did differently from the rudder tip – I didn’t temporarily pop rivet the tips in place. Getting the cheap rivets out was more annoying than I liked, so I decided to dispense with that step. It was a little more tedious to work around the cloches, but overall not bad at all.

Of course, as is the case with micro, currently thing looks pretty nasty, but with sanding they should shape up pretty nicely. We’ll see how that goes tomorrow.

Posted in Empennage, Fiberglass | Hours Logged: 1

Elevator tip shaping

The day after doing a layup is always fun – it’s time to rip off the peel ply and see if you did something right, or if it’s gonna be do-over city again. In my case, there was the additional mild concern that I’d epoxied the tips to the elevator in spite of taping up, but once again both tips popped right off with no drama. After removing the peel ply and putting them back in place, the front-end profile matches up far better than last time:

Next up was cleaning things up. The ragged edge where I cut the wet cloth got sanded to a nice straight line, and then I went to work sanding along the joint to remove the excess cloth and make a nice smooth scarf joint. With that done, the tips look a lot better already:

The next step is to slop on some micro and work on the final contour for these guys. Most of this will involve shaping the front end I glassed over, but I also want to fill the gap between the fiberglass tip and the aluminum skin. The photo above in particular shows one of the unsightly gaps that I want to take care of. Before doing this, though, I wanted to tighten up the glass-aluminum interface; right now the edge of the elevator skins want to curl up a bit. That just required a bit of work with a hand seamer, and eventually things were looking much more flush, and thus conducive to adding micro.

I also temporarily added the stab tips to get an idea how things will line up. Interestingly, whereas on the vertical the rudder tip needed to be built up to match the stab, here I have the opposite problem; I’ll need to build up the stab tips a bit to match the elevator. I’ve also got a bit of refinement to do between the tip and skin contour there, so overall there’s gonna be a decent amount of micro applied, which in turn means a good bit of sanding.

Initially I’d thought I might get to doing micro tonight but I ended up just doing prep work instead. I sanded all the tip pieces down to remove the gloss from the gel coat and promote adhesion when I add micro. I also sanded the epoxy skim coat on the rudder bottom that I added previously, so that piece should be ready for primer once I get the tail light fitted. Though as I type this I’m remembering my intent to add some more glass to the open part of the front end, so never mind that last part…

Posted in Empennage, Fiberglass | Hours Logged: 1.5

Glassing over the elevator counterweights…again

Not a lot to report tonight. I finished taping up the elevators after running out for more packing tape, got the tips clecoed in place, and laid up two layers of glass over each counterweight. I decided to trim the glass plies immediately rather than waiting for them to cure partially, since the goal was to make sure they were pulled in tight against the counterweights. I figured they’d be more likely to sit proud if I waited.

I think this was a good idea, but making it happen was somewhat annoying. At first I tried using a razor to cut the glass, but even something that sharp was more likely to drag the cloth than cut it. I ended up using my little pizza-cutter type thing that I use for cutting raw glass cloth, which did the trick but then was a lot of fun to clean up.

From the looks of things I’ll have much better results than last time; tomorrow we’ll get to find out if my optimism is merited. In the meantime, here’s another photo of wet glass and peel ply:

Posted in Empennage, Fiberglass | Hours Logged: 1.5

Redoing the elevator counterweight glass

Well, it looks like the theme of doing fiberglass stuff repeatedly is sticking around. Last week, the day after adding the glass, I took a deep breath and tried popping the tips off. I was happy when both came off with no drama at all. Next, I got to work on one tip, blending the nee glass into the old tip to complete the scarf joint, then trimming the overhang to fit.

It was about this time I discovered an issue: the glass around the front of the counterweight sat very proud of the adjacent counterweight skin. I’d thought that my glass would have a nice little lip that I could sand flush to the skin, but nope, wasn’t going to work that way. Basically, there were a few different problems that came together here. First, the tiny bit the counterweight was inset compared to the skin wasn’t enough to accommodate the glass wrap. Second, three plies of glass was probably way more than I needed. Third, I think my layups were way wetter than they needed to be, exacerbating the excess thickness of the glass.

The fix for this was pretty obvious: I needed the counterweight set back further from the skin. That meant spending some more time sculpting the front of the counterweights, to provide more room for the glass wrap, plus cutting the glass off and redoing that entire area.

So today I did the cutting on the tips, along with the drudgery of sanding a taper into the edge yet again to allow for the scarf joint. Then I got to the fun part of the program, working on the those counterweights. This time I tried a different technique for the shaping; last time I did all the work with files, but found that to be pretty tedious. This time, I decided to try using a sharp (but not valued) knife to shave bits of lead off, and it worked pretty well for rough shaping. The knife also gave me a decent way to shape the lead near the skin without damaging the skin – much easier than when using a file. After roughing with the knife, I did still use files to finish and smooth things out, and especially to round the corners off.

In the end this amounted to carefully shaving about 1/16” off the front of the counterweight. This should provide me enough room to get a thin glass wrap around the front; when I do the next layup, I’m only going to add two layers instead of three, and make sure to do better at squeezing out excess epoxy. Another thing I’m going to do differently is to trim the glass at the counterweight-skin junction (after giving it some time to partially cure); this way I can tuck the edge of the glass into the inside corner between the weight and skin, which should help prevent it ending up proud when it cures.

My intent tonight was to finish re-taping the counterweights to be ready for laying up tomorrow, but…I ran out of packing tape. Guess I’ll run out tomorrow and pick up some more, I’d like to get working on this layup pretty quickly after work tomorrow.

In other news today, I decided to pick up on the rudder bottom cap again too. Come to think of it, I think that was the part that got me started on doing fiberglass in the first place. For that, I just mixed up some of the System Three epoxy I bought, and added a skim coat over the area of the taillight that I reshaped previously. That should take care of any pinholes from the micro, and get me in pretty good shape to go ahead and cut the hole for the taillight and get the bracket epoxied in place inside. Then hopefully I’ll just need a few coats of primer to get rid of any remaining imperfections, and that piece will be ready to install.

Posted in Uncategorized | Hours Logged: 4

Glassing over the elevator counterweights

OK, back at it again. Hopefully we’re at the point where it’s not gonna get too cold for fiberglass any more this year. One thing I see from looking back is that I never wrote up a short build session from about a week ago, when I added micro to the closeouts on the h-stab tips that I’d previously closed in.

Tonight, though, it was time for the real fun – that is, adding glass to the forward edge of the elevator tips to enclose the counterweights. For this work, I’m basically just doing the work in place, using the counterweights themselves as my “mold.” So the first step is to cover everything in the area with clear packing tape to act as a mold release:

Then, it’s just a matter of adding plies of glass cloth. Before doing anything, I wanted to evaluate whether I could use single pieces of glass for each layer, or if I’d have to get creative with shapes to conform to the curvature here. The glass cloth I have is really good at conforming, but I decided to try test-fitting a piece of dry cloth beforehand just to get an idea. Not only did this show me that it would conform, but it also gave me a good idea of what I’d need to do with the wet cloth to get the conformation to happen – much better than figuring that out with wet plies.

For this task, I used the helpful tip of putting the cloth between two pieces of plastic, and working the epoxy around with a squeegee to get everything saturated. This is especially helpful with this cloth, since it’ll deform really easily. This way, the cloth retains its shape while being wetted out, and I can cut out each piece, plastic and all, and only peel the plastic off when I’m ready to apply. This also makes it really easy to cut out nice regular size/shape plies.

There’s not really a lot more to say, but here’s that same elevator tip after adding three plies and then topping it all off with peel ply. Tomorrow’s the really big day, when I get to find out if I did a good enough job with my packing tape…hopefully these tips don’t end up bonded to the aluminum….

Posted in Empennage, Fiberglass | Hours Logged: 2.5

Vertical done-ish, closing out horizontal tips

Well, I almost talked myself out of working on the horizontal tips tonight, since it’s dropping into the 40s later, but eventually I decided to do it, and just bring the heat lamp into play if necessary. First up, I actually needed to fine-tune my balsa inserts a bit more. One thing I noticed as I was finishing up last night was that the horizontal tip profile didn’t match the elevators very well – it was a bit fatter not too far from where it joined the stab.

One thing I’ve learned is that these gelcoat pieces can be coaxed into a more permanent shape change by stressing them and leaving them that way for a bit. This is, in fact, how I handled these same pieces not fitting the stab curve very well – I stuck little popsicle-stick spacers in to spread the pieces to fit, and found that after a few days they were staying in that shape.

So last night, before quitting, I put a clamp on each stab tip to squeeze the open end to better match the elevator, and left those overnight. Today when I removed the clamps the tips stayed where they were, and matched the elevator profile much better. But that did change the shape of the open end, so I had to tweak the balsa plugs a bit.

After that was done, I got to work bonding the plugs into place. One thing I learned after closing the vertical stab tip was that it would have been better to lay up the glass cloth reinforcement over the wet flox mixture, rather than doing two separate work sessions. Makes sense – having the still-runny flox mixture under the glass means it’ll make much better contact, rather than trying to shape it around dried flox.

The concern I had with this was that without the plugs bonded in place, I was worried they’d move around as I was working the glass plies into place and wetting them out. That was easily solved by using a spring clamp on the open end of each tip after placing the plugs with the flox around them. The clamp also provided a handy handle while working with the pieces:

The fun part about working inside these tips is trying to wet the glass out without making too big of a mess. It seemed unavoidable to have an excess of epoxy end up inside, even when I tried hard to use the excess for wetting out. If I’d let the tips cure in the position shown above, that wouldn’t have been too bad, just a bit of extra epoxy weight – but these needed to be clecoed to the elevator while curing, to ensure that the whole assembly cured up nice and square. The last thing I wanted was epoxy running out for the tips and gluing these unfinished tips to the stab, which is why I topped everything with the peel ply. This isn’t really required here but it’ll help keep the excess epoxy from going anywhere it’s not supposed to.

The last step for the tips was to clamp the open ends again just to make sure they held snug against the plugs while curing:

With that done, I moved on to permanently mounting the (finally) finished vertical stab and rudder tips. These needed to be clecoed in, the mount holes drilled up to #30, then everything dimpled or countersunk as appropriate. Once that was done, the tips went back on one last time, and I went to town with the blind rivets. In spite of a weird hangup partway through – the pop rivet tool I was using spontaneously disassembled itself – I still got it done. Good thing I have two pop rivet tools, I guess.

Anyway, it’s been a long road but now I have the vertical closed out. Well mostly..there’s still the rudder bottom cap to finish out and put in place. But that needs far less work than the tips, so hopefully it’ll go a lot quicker…

Posted in Empennage, Fiberglass | Hours Logged: 3

Continuing with the horizontal tips

That title’s not entirely accurate, or at least it’s not the full story, but hey, it captures the broad strokes. I started off giving the vertical tips some attention again, giving them a good sanding to remove the last few imperfections, then shooting some more primer. For once, I didn’t immediately see a new flaw with fresh primer, so I think that odyssey is finally coming to an end. Once the primer has had a day or two to cure, I’ll drill the mount holes to final size, dimple and countersink as needed, and get the blind riveting done.

But the real work tonight was on the horizontal tips. First, I turned my attention to the gap issues I mentioned last night. Rather than simply sand the horizontal tips to match, I decided to take a close look at the elevator counterweights. I used a square to evaluate how well the counterweights matched the profile of the counterweight skins, and there were some irregularities. This probably isn’t too surprising, as the lead weights don’t exactly seem to be precision cast or anything.

Anyway, I ended up doing some more filing on the weights to shape them more to my liking, both getting the profiles to match and rounding the edges a bit more. Once I was satisfied with those, only then did I sand the horizontal tips a bit more to get the gaps nice and even. It’s also worth noting that this sanding still won’t be setting the final gap. As I did with the vertical, once I’ve built up the elevator tips and closed out the stab tips, I’ll wrap sandpaper along with gradually increasing backer material around the front of the elevator, and swing the elevator to get a really nice and even gap, as well as a slight concave profile to the back of the stab tip.

That’s down the road, though, for now I have a nice-looking gap as things sit:

Also visible in this photo are clecos in the elevator tip. I clamped those and drilled the initial mount holes tonight as well. For the most part I’m OK with the gap at the base of the tip, but I think I’m still going to add some micro along the interfaces to make things nice and tight. it also looks like I’ll need to work the elevator skins a bit to get them to mate better with the tips.

It was still too cold to really do any glass work tonight, but I did decide to go ahead and make the balsa inserts that will close out the stab tips. I discovered that, while folks seem to recommend cutting balsa wood with a hobby knife, in fact a metal blade on the bandsaw does a much nicer job. As before, after rough cutting the pieces it just took some trial and error, removing material with 40-grit sandpaper, to get a nice snug fit. Hopefully tomorrow it’ll be nice enough that I can get these closeout pieces bonded into the tips.

Posted in Empennage, Fiberglass | Hours Logged: 3

Getting going on the horizontal tips

So it’s been another batch of cold days, which has kept me from really getting into any work, but I did find time a couple nights ago to pick up some actual body filler to use for pinhole filling and other minor touch-up work. Tonight I made the first use of that by mixing up a small batch and using it to restore that groove I accidentally cut in the rudder tip. Also, another nice touch with the filler is that it sets up a lot faster than micro – the touch-up I did was sandal within an hour or two. That, in turn, allowed me to get my sanding done a lot sooner, and I even shot a light coat of primer just to get a better look at any imperfections. The whole piece needs maybe one more overall sanding and another coat of high-build, but I think at that point these will finally be ready to rivet.

In the meantime, I got back to work on the horizontal tips. The stab tips that I drilled last time needed to be trimmed to length; I made some starting marks last session and tonight extended those around the pieces and got them rough-trimmed and sanded to shape. A test-fit on the actual stab allowed me to finalize the shape and check fit against the elevator tips as well.

Next I worked on cleaning up the elevator counterweights. These are going to get wrapped in fiberglass, but before that can be done the shape needs some fine-tuning to match the counterweight skin. I spent some time working on those with a file, giving them some nice rounded edges, as well as a little inset compared to the counterweight skins, to allow for the eventual glass layup.

Then it was time to prep the elevator tips for glassing in the counterweights. As provided, these pieces are a bit long, actually extending past the counterweight itself. Some trimming is required here before getting to the glassing; here you can see the mark I made about 1/4” back to use as a trim reference:

After extending that line all the way around, I trimmed the tips, then went to work sanding a nice taper to the cut edge. This taper will allow for a good solid scarf joint with the glass plies I’ll be adding:

Now that the counterweight is exposed, I can also see that I’m going to want to work on the stab tips a bit too. The gap is nice in the skin area, but tapers a bit with where the actual weight is. I suppose I could trim the counterweight a bit, but I think it’ll be easier to get a nice edge by working on the tip instead. I’ll be wanting to get that done before I go to work adding glass here.

Also, I still need to drill the elevator tips to the elevators; obviously I’m going to want those clecoed in place before I start adding glass plies. Having the whole thing move around wouldn’t exactly make for a nice shape…

The good news is that it’s warming up again this week, so the weather should be good for getting this glass work done.

Posted in Empennage, Fiberglass | Hours Logged: 2.5

More rudder tip. Also starting on the horizontal tips

Notably, this entry actually covers work done over a couple days – I did bits of work on the rudder tip over the weekend, but at some point it seems absurd to keep making short entries and having to invent new title variations. Hence me combining them instead.

After sanding the epoxy skim coat, I shot filler primer on the tips once again. This revealed a few remaining pinholes in both pieces, but this time, instead of doing a big sand-down operation, I mixed slightly wetter micro and worked it into each pinhole just using a finger, leaving a bit of excess around each spot. After that cured for a day, a quick bit of sanding smoothed everything out, and I shot primer yet again. Finally, at this point, the vertical stab tip was pinhole-free, but I found a few more stragglers on the rudder tip, so I repeated the same procedure again.

As of tonight, the rudder tip was also pinhole-free, but I wanted to do a bit of touch-up on the flanges. The “step” where the flanges begin was uneven in some spots due to buildup from my multiple epoxy coat applications, so I went to work with a bit of 120-grit on a popsicle stick to clean those up a bit and make sure the flanges were nice and crisp. With that done, I shot primer…yet again.

As primer tends to do, it highlighted a new problem I created during my flange work. Looks like I got a little overzealous with the paper here, and now I’ve got a new groove to deal with:

That’s probably fixable with a touch of micro – or maybe I should just go ahead and get some regular old filler for this stuff instead of continuing to make batches of micro and then throwing away 99% of them. Anyway, the rudder trip farce keeps going…

On the other hand, I’m feeling good enough about my fiberglass learning to get going on the horizontal tips. I laid out the rivet holes on the stab and got those drilled in assembly with the tip pieces. For the most part, they seem to fit pretty decently with just the cloches holding them in place, but I think I’m still going to end up adding some support further forward to help them conform a bit better. I also expect that I’ll end up building them up a bit to get a nice smooth transition from fiberglass to aluminum…here’s hoping that process goes a lot more smoothly than the vertical stuff.

Next up will be trimming the horizontal tips and adding the closeouts on the aft ends…then there’s glassing in the elevator counterweights…plus continuing to bang on that rudder tip…

Posted in Empennage, Fiberglass | Hours Logged: 3.5