Oct 12, 2005     Glassing the Sides - (9 hours)       Category: C07 Fuse Ext

10/06/2005 (4 hours):

I tried something new today. For a while, I've been using just a brush to wet out cloth. I use it to brush on the epoxy, stipple it into the surface, then work out air bubbles. This works very well, but takes a LONG time and is hard on the wrists. I have arthritis, so things that are hard on the wrists are things I usually like to avoid. I've now gone back to the squeegee - it's much faster. The critical factor is using MEK to clean the squeegee. I avoided it in the past, and frustrating with vinegar, cider vinegar, and isopropyl alcohol led to me all-disposable products. MEK is a totally different story. I haven't figured out how to dispose of it in an eco-friendly way yet, so I'm reusing the same batch in a coffee can. You get some mileage out of it.

I may need a slower hardener mix, though. I've been on a 50/50 mix, and that has worked well because I usually dealt with small areas at a time. That was before I decided to peel-ply all of my layups. I had trouble getting it all wet out when I laid up the first of the two sides. I didn't want to just dump new epoxy on it to wet it out, since the stuff underneath was almost cured, so I may have a mix of peel-plied and non-peel-plied areas. I'll deal with it. One side is done; I'll do the other tomorrow.

10/11/2005 (2 hours):

Today I prepped the second side for its layup. I'm not installing the plans step so I skipped that section. I also pre-cut all of the cloth pieces, the peel ply, and so on.

10/12/2005 (3 hours):

This didn't take as long as I expected. I did a better job with the peel ply, although still not perfect, and I apparently still have a few bubbles. It takes time to get back into the swing of things. I'm not going to fix the bubbles now. I'll wait until I have more of the superstructure together, then one day I'll go around and inject epoxy into all of them at the same time.

The tub is done!

  Oct 05, 2005     Contouring the Sides - (2.5 hours)       Category: C07 Fuse Ext

10/04/2005 (1 hours):

Cut the notch where the canard will sit, and shaped about half the fuse. This went a lot faster than I expected.

10/05/2005 (1.5 hours):

Looks like I overestimated this step. Better than the other way around. The shaping actually went pretty quickly. I used a belt sander to shape the blue foam and longerons, since those would otherwise have taken a long time to sand by hand. I did the urethane with a hand sanding block, just an 11-in board with sandpaper on it. Quick work.

The only problem I had was with the fuel sight gauges. In Chapter 5, I messed up how these were supposed to be installed. I bought the lighted replacement sight gauges, which look great. However, their documentation was a little confusing to me, without being able to picture the strake. I just cut out the general opening and left it as-is for now. I'll fix/change this when it comes time to start building the strake, when it's obvious where the strake floor will be.

Finally, I cut a few foam plugs for holes left when the sides were removed from their forms. You can fill these with dry micro, instead, but the foam is lighter because only a little micro is used to hold the plugs in place. Once the project is done, nobody will ever know, but since I made some mistakes in various sections that have added weight, I decided it wouldn't be the worst idea in the world to do some weight-removal things, too.

  Sep 30, 2005     Glassing the Bottom - (8 hours) Category: C07 Fuse Ext

The plans say three hours. I allowed six. It took eight. At least it's done.

This was a messy step for me because I got interrupted by an emergency at work. I ended up having to save a portion (glassing the area between the firewall and rear LG bulkhead, and installing the UNI reinforcements) for later, which was a mess because some of the glass pulled away from the firewall/bulkheads as it cured.

Before it was completely cured, I used some clamps and boards wrapped in plastic to force the edges against the firewall and rear bulkhead. Unfortunately, THIS caused a crinkle where it wrapped around, which reduces the strength of the layup. Fortunately, it didn't happen around the reinforcements, so it shouldn't cause too much trouble. I'll fix it later, when it comes time to build the fear cover.

I also learned a valuable lesson about layup quality. I only used peel ply where the plans call for it - along areas where there will be future joins (for the sides and around the bulkheads and firewall) and anywhere there was a current join (between the pieces of UNI). Well, those areas look great, and the rest is mediocre. There's no problem with the actual workmanship, but the areas that I used peel ply on look a lot better. I know this is going to get covered up in finishing, but it also means more sanding later, when it comes time for that step.

From now on, I will peel ply everything, unless it's totally irrelevant. I have a 38-yard roll of 60-in wide peel ply, and I'll order another shortly. This stuff seems expensive at first. If you order it from an aircraft supplier it costs almost as much as fiberglass cloth. However, you don't use nearly as much of it as you use of the fiberglass, so its cost impact isn't all that significant. You can also get it on the cheap from fabric supply stores, if you know what to look for.

There is a great debate about the "sizing" that manufacturers apply to the cloth you'd find in a fabric store - some say this can leach into the layup and weaken it. I have some doubt as to whether this matters. Even a weak layup is still immensely strong, and you don't use peel ply between every layer. I tried a few tests with store-bought stuff, and while not very scientific, I couldn't detect any significant strength difference. I suspect the difference is probably a small or moderate effect, and you get a better bond between layups that have been peel-plied than you would if you had sanded them. Since sanding is also an acceptable joint prep method, I suspect this probably works out close to even in the end. Oh well. I have the funds to stick with aircraft suppliers, so I'll do that just to be on the safe side.

Word of caution. If you do go with stuff from a fabric store, buy some real peel ply first, to compare it. The stuff I first bought was much too gauzy. Real peel ply is thick and dense enough that you can't see through it. Think of a white cotton bed sheet, but made of polyester.

  Sep 28, 2005     Contouring the Bottom - (9.8 hours)       Category: C07 Fuse Ext

06/16/2004 (2 hours):

I've been getting less working time lately, because I'm changing jobs and addressing my outstanding obligations has been a bit of a headache. Also, Elliott's sleep cycle has changed and has required more of my attention at night, so I'm just not getting as much Cozy time. Life goes on. I did manage to take a few hours this evening to use my new belt sander to make the 45- degree angle bevel on the lower longerons from F22 back to the landing brake. I first cut the foam down to the edge of the longeron with a coping saw, then sanded the longeron to a 1/4" wide exposure.

06/24/2004 (1.25 hours):

Another short day, but I'm feeling the building-bug kicking back in, finally. Tonight I cut the bottom contour guide and started in on rounding the bottom. I'll probably have a little bit of retouching to do around F22 but I'll address that later. In the first picture below you can see the tools of the trade. I use the saw and Surform plane to do the rough shaping. The Surform also does an amazing job of cutting through the micro without making little chunks that gouge the urethane spacers. I use the brush frequently to keep the sanding area clear, and I've basically been doing the rest via good, old-fashioned hand sanding, both with the block you can see in the picture and with the 2x4 jointer sander you make for sanding the NACA scoop.

09/26/2005 (4.5 hours):

For the past few days, I've put several hours into finishing the shaping of the fuselage bottom. I've repaired most of my errors at this point, and I'm working my way up to glassing the bottom. Hopefully I'll be glassing by the end of the week. It's good to get back into the project!

09/27/2005 (2 hours):

Today I sanded the recess around the landing brake, and built up the duct-tape layers around it. The duct tape edges are a little ragged, but it looks OK. I also skipped the installation of the wood block for the step. I've seen and used Marc Zeitlin's retractable step, and much prefer it to the plans design.

It didn't take as long as I'd thought to shape the bottom, although I may have lost track of a few hours from before the move. I think I set the estimate based on doing all of the contours at once. The plans call for the upper section contouring to be done after the first layer of glass is down on the bottom.

  Sep 27, 2005     Install Antennae - (2.5 hours) Category: C07 Fuse Ext

09/26/2005 (2 hours):

There are a variety of locations to install antennae in a Cozy, and no "right" way to do it. The winglets are almost ideal for the COM antennae, the NAV can go in the canard/wing, and the transponder and GPS can go in the nose. This left me with the glideslope and marker beacon. I may never use these, but installing them is good practice for the more critical antennae installations, so I went ahead with them anyway.

Installation was relatively straightforward once I puzzled out RST Engineering's documentation. The only problem that I had was the toroids. For the glideslope these ended up along the centerline, which was fine - there's a thick layer of foam to dig into there. But for the marker beacon, the toroids do stick out above the foam a slight bit. I haven't figured out what to do about this yet, but the bump is very slight, and I suspect I can probably just fair it into the fuse bottom and call it a day. After all, some people actually hang external antennae on their birds!

I routed both lines away from the antennae fo 6 inches per RST's recommendations, then ran them together to the rear of the instrument panel, just to the pilot's side of the heat duct. This, again, is an area where there's no clear guidance from the plans, but it seemed like a good spot. Hopefully this won't be in the way of anything important. I actually drilled two separate holes to make the wires easier to identify later. Finally, I used flox, plastic sheeting, and weights to fix the coaxial antennae leads into the channels I prepared.

09/27/2005 (1 hours):

I did this only at select spots - the rest of the space will be filled with micro prior to glassing, which is lighter. There's no need for massive strength here. I potted the toroids in flox, too, and soldered the leads to the tapes. Tomorrow, I'll pot the leads in flox, too, to provide some rigidity around the critical solder connections.

  Jun 08, 2004     NACA Scoop - (31 hours)       Category: C07 Fuse Ext

05/25/04 (2.25 hours):

Cutting the blocks for the NACA scoop was easy enough, but I screwed up cutting the 2" foam efficiently - I went the long way, not the short way, thinking only one block was to be cut. I just know I'll pay for that move later, but fortunately a sheet of 2" thick urethane is only about $14. I'll order an extra sheet with my next parts order. In the picture below you can see my trust bandsaw (snicker) but it works very well. Even if I had a bandsaw, I could still have made these cuts faster with the coping saw than walking over to a floor machine. When shaping urethane, power tools are just irrelevant. The second photo shows all the bricks it took to get the blocks to conform to the fuse bottom. The bricks on the 1" foam are just for good measure - it bent pretty easily - but the 2" foam is pretty stiff and needed lots of weight to get it to curve.

05/26/04 (3 hours):

Although it doesn't seem like much progress for this amount of time, I got the small triangles floxed into place between the landing gear bulkheads tonight. I spent some time getting things laid out just so, and puzzling out exactly how they would fit. I also cut the C and D pieces as well, although I didn't mount them yet. I have some untrimmed excess flox to remove before I can do that, so I'll save it for the next day.

05/27/04 (4 hours):

Tonight I fitted supports C and D. It took a bit of figuring out and I have a slight gap that I'll have to fill with foam or micro at some point, but otherwise this bit was fairly straightforward. As you move along here you start to see the progression - everything gets filled with urethane to or above the level of the bulkheads so when you're done sanding you have a perfectly smooth surface. Neat.

05/28/04-05/29/04 (3.5 hours):

Funny story, or at least it will be when I look back in a year or two. I spent some time putting together the 3/8" foam pieces between the aft LG bulkhead and the firewall. In the process I screwed up the long horizontal piece, cutting it too narrow fore-to-aft to sit in the hole without support. So I cut another, and began assembly.

Composite construction has a way of reminding you to not get cocky, and I certainly did here. I mixed up a moderately sized batch of flox using all Fast hardener, and got to work sans gloves because I've been pretty successful at keeping my hands clean on "minor" flox and micro work like this, so I'm mainly wearing the full getup when doing large layups, or working with fabric. (Fiberglass itches!) So here I am gluing the foam pieces in and my flox starts to exotherm. Only, I'm not holding the cup so I don't realize it - flox just gets easier to spread when the runaway heat buildup first starts. At this point I had the two side pieces installed, and I've got flox almost completely spread on the large horizontal bit.

The smell and sizzle awoke me to the pending issue, but I figure, hey, I'm basically done here so no big deal, right? I quickly spread a thin layer of flox on the rest of the edges, knowing I can always fix it later - grind a bit off if it sticks up, squirt some new flox into any gaps, etc. I start putting the piece in and realize that because it's so tight I can't get it in at all. Now I've rubbed exotherming-flox all over the place, I have it on my hands, all over the various foam and bulkhead pieces, etc.

I did the right thing, and yanked that piece of foam out of there before it could become permanently installed at an awkward angle. I then spent some time cleaning flox off the bulkheads and properly installed foam side pieces before it could completely harden, cleaned my tools and hands (which itself took time) and quit for the night, frustrated but at least accepting my fate. Remember that undersized piece of foam? The next day I arranged some supports on the insides of the bulkheads to hold it in position, mixed up a fresh batch of flox and put it in a plastic baggie. I cut off the corner and used this to squirt it into the thin gaps I had previously been worried about, and in 10 minutes I had the "bad" panel installed, perfectly. Live and learn. It's not even worth the effort to clean the flox off the old piece. I'll just cut the edges off and use it as scrap material for future work, if I need it.

05/31/04 (4.5 hours):

I had the day off today, but got very little done. I started cutting the aluminum hardpoints for the landing gear cover but cutting 1/4" aluminum is tough, and I got frustrated and stopped. I'll buy a bandsaw tomorrow and that should make short work of this job. I did manage to get the scoop sanded and shaped, though, so at least not all hope is lost. I also ordered Vance Atkinson's fuel sight gauges. Unlighted, since I don't feel the $30 price different for lighted gauges is justified - for $1 I'll add the LEDs myself. I don't actually care about sight gauges since I'll be using capacitive fuel senders, but I suppose it'll add to the value of the plane, and it's a nice backup.

06/01/04 (2 hours):

Today I shopped around and bought myself a bandsaw. Just a cheap 9" table-top unit, but it's actually pretty decent. I also bought a few additional blades, a metal-cutting blade among them. Band saws are amazing. Unlike a table saw, you can safely free-hand jobs through them, and they don't even know what you're cutting. They just go right through it. The blade doesn't even get warm. It took a bit of time to cut all 16 of the little metal hardpoints, but only because I wanted to be as safe as possible and arranged push sticks and guides to make sure my hands didn't get near the blade. The actual cutting took less than a minute. In contrast, it took nearly 10 minutes to cut JUST ONE by hand with a hacksaw.

06/03/04 (2.25 hours):

Yesterday I took a few minutes to alodine the landing gear cover hardpoints but didn't get any more done than that. Elliott hasn't been sleeping very well, waking every hour or two, and it's been torture for Nicole to deal with after she goes to bed. I put him back in the sling last night and he still woke up quite a bit but never for more than a few seconds, just to make sure he wasn't alone. He's not in any pain or discomfort so it's probably fear. We'll try putting him back in his cosleeper for a few weeks, and instead of having him sleep the whole night in his room, we'll have him sleep part of the time in each spot, then gradually phase him back to his room completely.

Anyway, because I had him in the sling I couldn't get anything done, but today I managed to take a few minutes over lunch to route out the holes they're installed in, fill with flox, hammer in the hardpoints, and smooth out the squeezed-out flox. I hammered one of them in slightly below the surface accidentally but I covered with flox and overall, I'm pleased with how it turned out.

Another builder pointed out to me that Wayne Hicks came up with an easier method. Instead of installing hardpoints and routing out a lip for the landing gear cover to sit ON, he installed tabs on the sides of his landing gear well (on the aft side of the forward LG bulkhead, and on the foreward side of the aft LG bulkhead). He then shaped his cover to fit INSIDE the well, with its top flush with the surface. This eliminates the need for the hardpoints (you install ClickBonds or similar on the tabs) and also the pain-in-the-keister 1/8" lip that is so hard to keep the glass lying flat in. Unfortunately, I had already routed this lip out when I was pointed to Wayne's site, so I went ahead with the plans method. But Wayne has had a number of good ideas (I used his upsidedown jigging method in Chapter 6, for instance) and I was kicking myself for not stopping by his site for tips and tricks before starting this chapter. Sigh.

06/08/2004 (2.5 hours):

It took some time to clean up the results after glassing. I had too much epoxy in the layup, and it started exotherming as I was laying down the peel ply. What came through the peel ply didn't want to peel off, so I had to sand that down. The Fein does wonders in that score - gets right down to the peel ply without harming the glass below - but it was still annoying. Anyway, moving on.

09/20 - 9/27/2005 (7 hours):

I did a poor job glassing the NACA scoop the first time around. I had a very difficult time getting the glass to lay into the joggles, had a few dry spots, and neglected to wrap the glass onto the bulkheads. I focused some attention on this area because the efficiency of the scoop will be critical to successfully cooling my rotary engine installation.

I started by sanding flush any rough areas, and sanding the entire area. I removed the dry glass sections. Then I filled the joggles back in with scraps of urethane. I will use Wayne Hicks' jogglefree concept for the landing gear cover: http://www.maddyhome.com/canardpages/pages/waynehicks/chapter_09_5.htm

I then re-glassed the area with two layers of BID. This means I actually have four layers, but it's not a huge area of glass, and the ounce or two I'd save by sanding it all down to foam wasn't work the time, energy, and risk of damage to the NACA scoop shape. I now have quality peel ply, and I applied this to the entire area. This both provided a good transition edge in those areas I had removed and helped the glass lay over onto the bulkheads.

I had one small area where the glass came off the firewall. A portion is still well attached, there's just an air bubble/curve where it comes around the corner. I'll fill this with some epoxy at a later step, probably when I glass the bottom.