Oct 15, 2023     wing finishing & attach - (12 hours)       Category: C19 Wing+Ail

Filling, sanding and finishing the wings is a lot of work. I enjoy the scrounging and improvization aspects of plans built, but it takes a lot of time that I could have spent completing the project ahead of life's unexpected events. _Don't_ take my route of slow & cheap - buy the Durabond boards and/or 3M Cubitron paper.

This is also a spot to store the instructions on attaching the wings - plan on buying the bolts in several sizes so that you don;t have to measure, then wait for delivery of the correct ones.

  Apr 01, 2006     Attachment, Wing to Center Spar - (6.5 hours) Category: C19 Wing+Ail

Because I bought my wings and spar together from Dennis Oelmann, he match-drilled them for me. Attaching them is thus a piece of cake. That's a fair bit of tedious work saved!

  Dec 23, 2005     Controls - (7 hours) Category: C19 Wing+Ail

12/23/2005:

Not great notes here, either, but the job got done. This entry is a placeholder for the items I haven't done. I didn't finish this step because I intend to install spherical bearings for the aileron torque tube, and I don't have them yet. I used an FMN10 temporarily to test things out, but I didn't set the final position of things because I don't have the spherical bearings quite yet. Here's what I have left to do for the left wing:

1. Install the spherical bearing for the torque tube. 2. Adjust the CS127 brackets to their final positions.

3. Fill a small air gap under the bracket shoulders with flox.

I also have not jigged the wing to the spar, obviously, because I haven't finished the right wing.

Oh, and I haven't made the spar. =)

  Sep 11, 2011     Aileron Mounting - (2.5 hours)       Category: C19 Wing+Ail

This step shouldn't have taken 2+ hours, but it's been so long since I've driven a rivet that I put them in upside down and had to drill them out because they didn't have enough clearance! That done, the ailerons went in smoothly and the counterweight hangs them just where it should. (The photo here looks like it's trailing-edge-high here - it is! That's because the wing is angled on the foam blocks I have it resting on.)

  Nov 25, 2005     Top Skin - (12 hours)       Category: C19 Wing+Ail

11/25/2005

I plan on installing the hidden rudder belhorns, and a kind fellow builder was nice enough to send me a digital copy of the plans while I waited for mine to arrive in the mail. The only part I needed from those for now was the routing of the rudder cable conduit, which is pretty straightforward - you just run it straight from the entrance location in the wing root to 1.2" in from the trailing edge at WL169. It should come just to the corner of the aileron cutout without actually touching it.

11/23/2005 (4.5 hours):

To prepare for glassing the top skin, I installed the rudder cable conduit and cleaned up the leading and trailing edges. I also cut the notch for the flox corner around the attach bolt access hole. Finally, I sanded the spar cap flush with the top of the wing. I definitely need to get a new belt sander - this took 3.5 hours to do with my piece of trash. The spar cap wasn't bad, just a little proud in spots.

11/25/2005 (5.5 hours):

This step was fairly straightforward, just time-consuming. I took a little longer wetting out the glass than when I did the bottom, because I had to use the brush a lot more. "Dump and run" isn't well suited to steep curves or vertical surfaces, and the leading edge is much more curved on the top than the bottom (naturally). Anyway, no surprises - micro, fabric, epoxy, squeegee, peel ply, plastic, and squeegee with hair dryer.

I clamped an aluminum straight-edge on the trailing edge. The extrusion John Slade and I bought when he was here didn't work out - it got covered with epoxy and I didn't have time to clean it off completely. I bought some replacements, just right-angle aluminum extrusion. I used spring clamps and clothespins to hold them onto the trailing edge and keep it perfectly straight. Should do the trick.

12/6/2005 (2 hours):

I had neglected to install all of the reinforcing layups, so today I took care of those. These included the BID triangle at the outboard edge, the two UNI pieces near the outboard attach bolt, and the three UNI strips over the inboard attach bolt and onto the top of the wing. I also installed the two 2-ply UNI strips that make a "V" from the outboard attach bolt onto the top of the wing. These are actually from step 9, but since I was here it made sense to just do them all at the same time.

  Nov 21, 2005     Top Spar Cap - (6.5 hours) Category: C19 Wing+Ail

11/21/2005 (6.5 hours):

Next week I'll be going on vacation. I'm trying to get one wing glassed before I go, so today I prepped the top spar cap channel for glassing (1 hour) and came back to the office late to do the job (5.5 hours). It was quite an ordeal. It has three more layers than the bottom cap, but the channel doesn't APPEAR to be deeper (it is, it's just unnerving).

Worse still, a number of the threads in my spar cap tape had some type of contaminant, and picking them out and replacing them warped a lot of threads. I spent hours getting everything to lay flat and straight, and when I was done, no matter how hard I squeegeed, I still couldn't get all of the fibers to lay below the channel edges. I'll have some sanding work to do once the layup cures. Sigh.

I think in the future that I won't squeegee directly on the spar cap tape. I did this initially to press the fibers into the layers below, and to bring up excess epoxy. The problem is, it shifts the fibers around quite a bit, and makes the job MUCH harder.

It seems like my magic number is 3 - that's how many layers of tape I can successfully wet out at a time. I'll pre-cut a few 5" strips of plastic to lay in the channel. I'll lay down three layers of tape, get the center wet and lay down a bead of epoxy along the channel, then lay down the plastic. I'll squeegee through that, then lift it to lay down the next few layers. I think this will work better and shift the fibers around less. You definitely want to remove excess epoxy as you go. Otherwise it all ends up at the bottom, and you have a hell of a time getting the tape below the edges of the channel.

  Nov 18, 2005     Bottom Skin - (7.5 hours)       Category: C19 Wing+Ail

11/17/2005 (2 hours):

Today I finished prepping the bottom of the left wing for skinning. Hopefully I can get this done tomorrow. I made the channel for the flox corner around the wing attach bolt recess, and vacuumed the surface one more time for good measure, this time with my hand and arm encased in plastic to protect it from the loose fibers. I also installed the peel ply strips on the trailing edge and aileron cut line.

I used a slightly different method for this than called for in the plans. I tried small brads, but they dimpled the peel ply, and the plans specifically state that it must lay flat. I would have used staples, but I only had a few left and didn't want to run to the hardware store just for this. Instead, I put down small dabs of epoxy every 6" or so along the strips, let it soak in, and gave it a good stipple and wipe-down. I ended up with perfectly flat strips of peel ply. The only negative is that you have to wait a day for the epoxy to cure or the peel ply will come right off when you lay out the cloth, but that worked fine for my schedule.

11/18/2005 (5.5 hours):

Today I did some of my best work. Ever.

I started by installing plastic curtain rod covers to line the conduit hole, and a NAV antenna about midway down the wing. I had intended to do these steps yesterday to reduce the layup time, but forgot. I then micro'd the foam. In the future, I'll pre-fill low spots (like the electrical conduit hotwire entry slot) a day ahead of time, and allow to cure. That would make this step a bit faster, since micro takes time to settle into deep slots.

I then laid out all of my glass, both layers at once. Laying out one ply at a time is fine if you like 8- hour layups, but I'd like to fly some day. MGS wets out two layers of glass just as well as one. So, I got all of my cloth laid out perfectly as my first step. I then mixed LOTS of epoxy and wet out the entire surface, squeegeeing lightly to spread it around. I used a brush to touch up spots, especially around the LE and TE, and the 4" section over the shear web.

Once I had the glass fully wet out, I squeegeed lightly to remove the worst of the excess. I then peel plied the entire wing, and laid out my plastic sheeting. Finally, I very carefully squeegeed, using the hair dryer. I first worked along the spar cap, then from the spar cap to the LE and TE. I spent the most time on this step, making sure I was getting very consistent results so I won't have any thick (high) or thin (low) spots.

The hair dryer really makes or breaks the process of squeegeeing through the plastic. Yes, it helps liquify the epoxy again, but it also does something more important - it lets the plastic stretch evenly. This lets the plastic deal with compound curves without bunching up.

For the curious, yes, I DID use my "dump and run" technique. Large, flat surfaces like the wing really benefit from this method. All this means is mixing very large cups of epoxy, and dumping it in a stream across a convenient relatively flat spot (like the spar cap area). You then squeegee lightly to spread it around in a thin layer, and move on to your next cup. The epoxy will wet out the cloth on its own. This produces some waste (I removed about 1.5 cup's worth during the squeegee stage, about 10 squirts) but you can do large layups like the wing VERY quickly. My time broke out as follows:

1 hour - Install conduit and NAV antenna

1 hour - Micro foam (next time pre-fill holes and let cure, would save time)

30 minutes - Lay out cloth, scissor trim.

1 hour - Wet out with epoxy

30 minutes - Lay out peel ply, stipple to mostly wet out, lay out plastic

1 hour - Squeegee

These are estimates. I think I actually spent more like 45 minutes wetting out, and 1.25 hours squeegeeing, but the numbers should be fairly close. In any case, I'm confident that if I come prepared with antennae already installed, and the slot pre-filled with cured dry micro, I can do the right wing's bottom skin in 3 hours using this technique. We'll see.

The best part of this whole process is that I no longer have any fear of large layups. It used to be a race to wet out and stipple before the entire thing started to gel, and it took a lot of stippling. That's hard on my hands and wrists - I have arthritis. Now, I hardly stipple at all. I only use one for touching up dry spots before squeegeeing, and painting vertical surfaces.

  Nov 14, 2005     Bottom Spar Cap - (21.5 hours)       Category: C19 Wing+Ail

A few comments.

First, box sealing tape is the WRONG choice for this area. The open pores of the foam allow epoxy to creep underneath the tape, where it sticks to the adhesive. This makes it very difficult to remove later. I don't have a great solution to this, actually, but at the very least use a thicker tape, like duct tape. Box tape tears when you take it off, and makes a godawful mess. I didn't want to leave any of it around, so it made for a lot of tedious sanding

Second, add a squeegee step an hour or so after you finish the layup. I had my spar cap on the left wing squeegeed perfectly level with the top of the trough. The next day, though, I discovered it had uncompressed slightly. It wasn't a huge rise, less than 1/16", but it made for a heck of a lot of sanding to bring it back to level. Better slightly low than slightly high - it's a lot easier to fill a slight outside skin depression with micro than to fair the entire wing into this area, and if you squeegee low, at least all the spar cap tape is there, and you aren't sanding any off.

Finally, PROTECT YOURSELF. I've sanded quite a bit so far, as you might imagine, but I never had a problem with it. I generally used the Fein, and was doing small areas at a time, either to rough up prior to a layup or to remove epoxy drips and the like. I'd get an itch or two, but was pretty careful, so it was never more than a minor irritation.

This time, whoah! I used the belt sander, and while "less than 1/16" doesn't sound like much, multiply it by the length of the spar cap, and you have a lot of fibers being removed. This stuff is VICIOUS. I probably would have been fine sanding - I got some dust on my hands, but not much worse than that. I wear a shop apron to protect my shirt and pants, and haven't had any issues until now. This spar cap stuff is MEAN when it's sanded. It produces long individual fibers that stick to everything. I was fine until I went to vacuum. The static from the vacuum pulled the stuff all the way up onto my arm. I've been itching all day, and probably will again tomorrow. Use protection!

11/16/2005 (2 hours):

More careful cleanup.

11/17/2005 (4 hours):

I got a little fed up with making aluminum parts piecemeal - sanding, alodining, etc. were all slowing me down because of the time involved in breaking the tools and chemicals out and putting them back. I thus spent some time making all of the aluminum parts I needed for the next month or so, which include the four seat belt brackets for Chapter 8, and all remaining LWA1-LWA6 pieces (three were already made). They're now alodined and ready to go. Hopefully this will save me some time in future steps.

The only thing I didn't make was the right wing's LWA18 cover plates, because I found it was easier to make these a little oversized and trim after trial fitting them. Getting the bend just right on the very end of the piece is tricky, so I just make it an inch further in, mark the exact edge where it meets the wing surface, and trim to that point. No point making and alodining something I'm just going to cut up...

  Nov 07, 2005     Core Assembly and Web Layup - (14.3 hours) Category: C19 Wing+Ail

This took a little more time for the left wing than John Slade (who was up for the week helping me build the wings) and I expected. Mainly this was because of a few small alignment issues setting up the cores, but we wanted to get things perfect. Also, I caused us to take longer in the squeegee step by putting on too much epoxy by getting over-eager with my "dump and run" layup method. Still, the left wing joint is beautiful. We'll see if I can do the right wing just as well. When you cut the W18 cover plates that go over the wing attach bolt access holes, note that cutting per plans is unlikely to produce a good fit. A better way is to cut the plates slightly oversized, make the bend, then get the plates into position and scribe them to cut off the excess for a perfect fit. You only use an extra half inch of aluminum this way, and they look much better. Also, a comment on Alodine. I've had mixed success with this, so I thought I'd pass along a few tips that generally produce better results. The most important thing to know is that the qality of the Alodine step is almost entirely controlled by the cleanliness of the part. The Alumiprep can produce a part that looks clean, but once you alodine you see fingerprints and such left over. By then, it's too late to do anything, and that spot won't take the Alodine very well.

To make sure the parts are perfectly clean, first use some MEK or other cleaner to remove any micro or epoxy contamination that might be on the piece from setting it on a workbench, against a curing work piece while measuring, etc. The key to understanding what's happening is knowing what these chemicals actually do. Alumiprep will NOT remove this stuff - it's an acid, not a solvent. It's designed to react with corrosion and remove it, and etch off any other surface problems. But it only works against aluminum-related problems. So, after removing any epoxy issues, wash with clean water and a strong detergent to remove skin oils. Alumiprep will not remove all oils, just a few of them.

Next, know that the effectiveness of the reaction will be controlled by heat. You're suposed to dilute the Alumiprep, which is fine, but do it with warm water, not cold. You'll get a better reaction. Use a disposable brush to remove as much surface crap as possible. Then comes the key - use an abrasive Scotch Brite pad. (Use one without soap in it - Harbor Freight sells cheap but usable pads.) Get down into any scratches, which you ought to have - you did rough up the faces before glassing, right?

Finally, when Alodining, use a brush to make sure you have good coverage of the chemical. Some of the initial reaction may produce free converted material in a thin barrier liquid layer of used-up reagent on top of the piece. A brush will move this aside and allow the reaction to finish on the piece itself. I use small disposable acid brushes for this - you can get 36-packs cheaply. Don't forget to radius the corners of the wing attach hard points to match the foam, before installing them! And don't forget LWA2 and LWA3, which are described in Chapter 14. I missed mine for the left wing, and will fix this when it comes time to glass the bottom.

  Nov 04, 2005     Cutting Foam Cores - (17 hours) Category: C19 Wing+Ail

John Slade is up for the week helping me with the complex wing steps. That's not to say this chapter can't be done alone, but extra help sure makes the time go faster, especially if that help has made a wing him/herself. Hot-wiring does really take two people. I've heard of people cutting solo, using supports and other assistants to help hold the hot-wire cutting. I think it would be very challenging to get good, consistent cuts that way.

Making Templates. I'm bringing John Slade up to help me with hot-wiring cores and some other tricky steps. To save time, I'm preparing all of my templates at once. To make them, I bought the duplicate M drawings set from Aircraft Spruce, so I don't need to trace anything. I first rough cut the templates close to their lines. Then I spray melamine sheets with 3M adhesive and stick on the templates. I use a bandsaw to cut close to the lines, then a sander to finish the job. The job takes a while for each template, but it produces good results. If you follow this method, note that one template on the duplicate M drawing set has a slight offset in it that you'll want to correct. Other than that, it's straightforward work, just time consuming.

We had some extra setup time because I saved some money. Wicks had a fire sale on foam, which normally runs $21 to $41 depending on block size. The stuff I bought was only $4.50 per block, a huge cost reduction, but it was only available in the smaller (7x14x41) size. To make up the difference, I bought 25 blocks, and we're cutting blocks to add to the ends of others. It adds time, and time is indeed valuable, but I'm happy we did this. The extra work with the blocks gave me time to adjust to block layout and hot-wiring, so I was much more prepared (and had gotten used to handling the saw) when it came time to do an actual airfoil cut. It wasn't really much extra work - just squaring the ends, and joining blocks to make them longer. The 3M 77 spray adhesive worked great here. Note to others - make sure your block faces are very clean when you join them. Even a slight amount of dust can prevent a good adhesive bond.

We learned a lot doing the hot-wiring steps, but we produced some absolutely beautiful cores. I've never seen anybody else's, but John seemed fairly impressed, and they look laser cut, so I'm happy. We used a couple of tricks that made the job even better, but there isn't room to document them here, so I wrote up a Hot Wire Guide to document them.

As part of this step, I finally got a chance to meet Stew Joslin, who has plans #1287. He lives in Coventry, CT, just three towns away from where I started my own build (Stafford Springs). Somehow before I moved we never had the chance to connect, but he was able to come down and meet John and I Friday night. It was good to have him, because we did the rest of the hotwiring job, and the micro bonding of the various bits and pieces to make the FC[1-5] cores, and the extra pair of hands was appreciated.

Do you live in the Northeast? I'm trying to organize local builders from New Jersey, New York, Connecticut, Rhode Island, Massachusetts, New Hampshire, Vermont, and Maine. Please use the link below to get in touch with me - I'd like to set up a fly-in, a build day, or something else. Builders in California, Texas, Florida, and the Midwest are much more organized than we are.

  Nov 05, 2005     Setting up the Jigs - (6.5 hours) Category: C19 Wing+Ail

Setting up the jigs was actually remarkably easy. I used a method I haven't seen documented elsewhere, but there isn't room to describe it here. I call it Jig Squares, and I wrote up a separate document describing it, with pictures. (Pulled from the Wayback Machine, https://web.archive.org/web/20070702153148/http://www.lucubration.com/greylady/jigsquares/)
___________________________________________________________
"Jig Squares
When it came time to do the wings, I spent some time setting up my jigs for Dust's Tee System. Essentially, this method uses a set of dados in each jig edge and "Tee" rails that fit them. This is a good system, but I scrapped it because I found a much faster easier way.

When it came time to set up the jigs, I used a square to draw lines at each jig's location along the table:


Then I used clamping squares to set up the jigs. These squares are guaranteed to be exactly 90 degrees. Don't buy cheap knockoffs. The good ones from Rockler can take 200 lbs of clamping pressure, and if you take the time to really torque down the clamps, there's no need to provide additional support for the jigs. They're incredibly stiff. To seal the deal, I used a pair of screws against (not in, just pressing against) the back of each jig to keep that side from shifting.


Five clamping squares are required, but I only had four. As a quick hack for Jig 5, I cut a hole in a sheet of plywood with two square faces. A clamp on each side had the same effect as a clamping square, and it was a quick, cheap solution. If you do this, use 3/4" plywood - anything thinner won't hold the clamp well enough to get good clamping pressure. (You can drill separate holes if you want more clamps.) Actually, it turned out that my plywood did NOT have a perfect 90-degree angle on it, so I glued on a thin wedge at the top, but it was not a big deal.


The end result is very satisfying. Setting up the jigs takes just a few minutes, and the results are perfectly square, very stiff, and the jig spacing is accurate. You'll notice that I had actually cut the Tee system dado slots already, so I went ahead and put a board in there. It doesn't add any support or alignment to the setup, but it does keep the jigs from falling while I clamp them down.


To each his own. The Tee system is a good recommendation, but if I did it all over again, I wouldn't bother with the slots. You need very good woodworking equipment for that method to work properly - you need the slots to be exactly the same distance from the edges of the jigs, or the Tees will actually misalign them. You also need very straight boards, or to rip plywood tongues very straight, because a slight warp there will also cause a misalignment. Over 128", even a very slight warp can be a big problem. Finally, preparing for the Tee system probably added two hours to my jig construction time, and the clamping squares did the same job with no possibility of error on my part.

The full system requires five clamping squares and ten clamps. If you want to be cheap, you can skip the squares and just use pieces of plywood with perfect 90-degree corners, but check them to make sure you don't need a thin shim to make the angle perfect. Frankly, for $12 each, the clamping squares are worth it - there are a number of other places you can use them to good effect, and they save a lot of time and fiddling.
_____________________________________________________________________________________
Setting up the jigs goes by in minutes with this system. The time recorded here covers the actual creation of the jigs themselves. Note that I could have saved two hours by not cutting the dado slots, which I never used. Dust's Tee system is a very good option, it just wasn't my preference when it came time to actually set things up.

If you use plywood, and you care at all about wood, don't use epoxy for the jig cross pieces. Use wood glue. Not that massive strength is all that important here, but wood glue is always the right choice for a woodworking joint (off the plane). A good glue joint is stronger than the wood itself, and if a separation is forced, the wood around the joint will shatter before the joint lets go.

  Dec 07, 2005     Wing Ribs - (5 hours)       Category: C19 Wing+Ail

12/7/2005 (5 hours):

Removing the 0.7" of foam took a little longer than I expected. I don't know if there's a better way to do this, but I just used a Dremel cutting wheel, and carefully etched out the foam. It took two passes to get the final depth, but otherwise was fairly straightforward.

Removing the foam for the inboard rib didn't take longer than I expected - I expected it to take a long time, and it did. I had to re-read the plans and diagrams about 12 times to get it all figured out. In the process, I discovered that on my "make the aluminum parts" day I forgot to make the LWA7 pieces, so I made those and prepped/alodined them. Since nearly all of these parts are 2" wide, I've been cutting them out of some 2" bar stock. Hopefully I won't need a huge length of 2" bar stock later, or I'll have to re-order. This is a lot faster than cutting individual pieces out of sheets, since one dimension is already cut for you. You just cut the pieces to length.

  Nov 02, 2005     Building the Wing Jigs - (8 hours) Category: C19 Wing+Ail

This took a bit longer than I thought, and they aren't exactly beautiful, but I think it was worth the extra trouble. I made my jigs out of 3/4" plywood, which provides a lot of stiffness. However, the thickness makes it awkward to get the wings in, which are really at an angle to the jigs. To solve that problem, I chamfered the inside edges of the jigs so the actual contact surface of each jig is only 3/8" or so.

I also made dado cuts in each jig face a-la Dust's Tee System. By installing Tee segments made from poplar boards it becomes much easier to align the jigs when setting them up, and there's no need to Bondo them to the table.

PK note of 6/8/2020... there is a floating note in the Chad Robinson builders log:

"During a conversation on another topic, Dennis Oelmann mentioned to me that he had a wing and spar pair, completed and already match-drilled to one another. The price was reasonable and I had the money, so I jumped at the chance to save some build time here. Dennis does excellent work, often peel-plying and vacuum-bagging even very large parts. His parts are often ready to finish when they arrive.

"I still have the half-finished left wing, and the cores cut and waiting to lay up for the right wing. Occasionally in some pictures in this log you'll see them - the left wing is hanging on ropes in the hangar, and the right wing cores are on top of the wall cabinets. Hopefully one day they'll get some use."

I'm guessing that most of the early work in this section was never used, and the wings and spars are as purchased from Dennis Oelmann.

  Dec 31, 2005     Ailerons - (9 hours) Category: C19 Wing+Ail

Note from 12/31/05: I haven't taken very good notes of my progress each day, but I HAVE made a lot of progress. I produced the aileron, mounted it, and arranged the controls. I didn't do a great job of hinge placement on the left wing, so I'll try to be more careful on the right. As it is, everything moves smoothly, but I had to jimmy things a lot to get it all working perfectly.

PK note of 6/7/2020: Aileron finish and balancing is a challenge for Cozy builders. From Marc Zeitlan's comments, _most_ Cozy ailerons are out of balance and tail heavy. After prime and pre-paint, the balance tested good, being very slightly nose heavy. I am now putting final finish on the control surfaces and will show the results in the finishing section.