One Rivet At A Time

Welcome to Kevin Horton's RV-8 Project
Tuesday, March 03 2015 @ 07:37 AM EST

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Fibreglas - Done for the year, I think

Finishing Kit

I've made quite a bit of progress on the fibreglas in the last few days. Depending on how you count them, there are around 25 to 27 fibreglas parts on the RV-8. Starting this week, I had eight of them finished (empennage tips and empennage fairing), and I was working on another 13 parts (canopy skirt, upper and lower cowling, oil filler door, front and rear wheel pants halves for each side, gear leg fairings, spinner and wing tips.

The canopy skirt really came together over the weekend. I took Friday afternoon off, and got another round of sand and prime done. Once the primer went on I could see that I finally had the contours right, and that there were just a few minor rough spots to sort out. So one more minor round of fill, sand and prime, and it was ready of the silver paint this afternoon. It isn't perfect - there are still a few rough areas to sort out when it gets the real paint job someday, but it is more than good enough for now. I still have to run a small bead of sealant along the top edge of the canopy skirt.

I thought the upper and lower cowling were ready for the silver paint, but I can see that a few rivet heads can still be discerned under the primer, so I've got some more sanding and filling to do.

I haven't accomplished much this summer except fibreglas work. I need to get this aircraft flying, so I've decided that I won't shoot for perfection on every fibreglas part. I decided to focus on the parts that will be difficult or impossible to remove from the aircraft, as any future work on those parts would have to occur in the hangar. Parts that can be removed (e.g. cowling, wheel pants, etc) can be easily brought home to work on, even after the aircraft is flying. So, now that the canopy skirt is painted, I probably won't do any more significant fibreglas work except for the wing tips until after first flight.

I've got a lot of travel in the next two months, starting this week, so progress will pretty much stop until December or January.

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Fibreglas Update

Finishing Kit

I'm making good progress on the fibreglas, but there is still a depressing great deal of more to do on it.

All the empennage tips are done now, plus the empennage fairing. The upper and lower cowling are looking quite good, but there is still some work to do in the cooling air inlets to smooth out some rough spots. The second attempt at finishing the canopy skirt is looking much better than the first go, but there is still a lot to do there. Yesterday I started on the spinner and gear leg fairings, and today I put two coats of West Systems epoxy to seal the filler on the wing tips and wheel pants. I also put a layer of deck cloth over the Tinnerman washers that I had inserted in the wheel pants, as I was afraid that they would eventually come loose.

While working on the Engine Information System section of the POH, I realized that I should modify the format of one of the EIS pages. So today I dug back into the documentation to relearn how to configure the page formats. I updated the page format, and carefully recorded all the configuration and limits settings, so I have a good baseine.

Back to work tomorrow :(

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Fibreglas - slow progress

Finishing Kit

I took this week off, and I'll take most of next week off too. I've built up a lot of comp time from working extra hours, and I'm gradually using it up to get some time in on the project.

I've done three rounds of fill, sand and the cowling. It is looking a lot better. I probably get about 90-95% of the remaining pin holes with each round. I did have a minor set back mid-week - I had the upper cowling supported on two saw houses outside as I wet-sanded it. There was a bit of a wind from the west, and I knew there was a chance a gust could blow it off the saw horses. So I put the saw horses on the lawn on the east side of the drive way, figuring that the lawn would provide a soft landing spot if required. And I oriented the cowling with the open end facing east. Then it happened. I was coming out of the garage with a fresh piece of sandpaper, when there was a freak gust of wind from the east. 180 degrees from the prevailing wind. It blew into the open end of the cowling, picked it up and blew it across the driveway. The only good news is that it flipped 180 degrees and landed on the flat bottom, so it didn't ding any of the edges. It just put some nice gouges in the surface. Drat! That set me back a few days.

The rudder bottom an empennage fairing are almost done, but I still have a few pin holes and imperfections to fill. Hopefully this weekend I'll start putting on the temporary silver paint. Yesterday I put some West Systems filler on the top of the canopy skirt, and today I started sanding it down. So far, so good.

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Fibrelglas, with no end in sight...

Finishing Kit

I got an e-mail message from the wife of a local multiple RV builder about a week ago. She had been to me web site, and noted that I was using red Bondo glazing putty. She told me that they had used that stuff on their first RV. It looked great at first, but the paint started to bubble after a year. I was quite depressed, needless to say.

I posted questions on the RV-List and the Yahoo RV8 group. I got quite a few responses, both on and off the lists. The general consensus was that it was OK to use the red glazing putty, if a few precautions were taken. There was a risk of problems if it was not given enough time to cure before painting over it, in which case it would release solvents under the paint. But, there seemed to be a good history of no problems if only thin layers were used, and if it was allowed to cure for several days before painting it.

I've been making slow progress on the fibreglas parts. I riveted all the tail section tips, except one elevator (I have to dimple four holes) and the rudder bottom. I had a minor crisis when I riveted the left elevator tip on - I heard something moving around inside the elevator. I was afraid I would have to do some surgery to open the elevator up. I pulled the elevator off the aircraft so I could figure out what was going on. I eventually discovered that there were four washers loose inside the elevator. There was just enough open space in the trim tab area that I could get the washers out without drilling out any rivets.

The rudder bottom and empennage fairing are mostly pin hole free, but they need at least one or two more cycles of prime, sand, fill before they are done. The bottom 90% of the canopy skirt is looking great, but the lip that attaches to the canopy has too many wavy parts. I decided tonight that I needed to start over in that area. I sanded off the primer and glazing putty, and I'll put on a layer of West Systems epoxy and filler, then sand that down to get rid of the waves.

The cowling bottom has glazing putty curing in the pin holes - I'll sand it this weekend and prime it. The cowling top has a layer of primer, but I haven't had time to put any filler in the pin holes yet.

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And Even More Fibreglas ...

Finishing Kit

It's been a busy few days. A hole in my work travel schedule opened up, so I booked last week off before any other work commitments could get put in that week. I spent much of the week fighting with the fibreglas.

I finally got all the tail surface tips in good enough shape for paint, except for the rudder bottom. I decided to paint them silver for now, as the metal won't get painted until after the flight test program, and silver is the best match. The paint looked great, until it dried. Then some areas were shiny, and some were flat. Another coat. A bit better, so one more coat. One of the six pieces looked good, but the rest needed a fourth coat. I riveted the horizontal stabilizer tips on today, and the rest will go on this week.

I put the first coat of primer on the rudder bottom and the empennage fairing. The rudder bottom isn't in too bad shape, but the empennage fairing has a good number of pin holes to fill.

Then I started on the lower cowl. I didn't think it had too many pin holes, but I just about had a heart attack after spraying the first coat of primer. Thousands of pin holes. Several tens per square inch, I think. :(

I was looking at the cowl of an RV-8A last year in Oshkosh, and saw quite a few pin holes. I couldn't understand how someone would bring their aircraft to the big show looking like that. Now I understand. I thought he had done a poor job filling pin holes, but he probably got 99.99% of them.

This is a close-up of part of the lower cowling, showing the horror of pin holes.

I had been using a UV-activated filler that another builder had recommended to me. He liked it because he could squeegee it on, then put the part outside for a few minutes and then sand it. I tried the stuff, but I found it was too thick, and it was hard to get a thin layer. Plus it was hard to sand, and it didn't cure as fast as I expected. So, I tried some automotive glazing putty. It was much thinner - I could squeegee it on and have it only go in the pin hoses, plus a very thin coat on top. It took over an hour to cure, but it was easy to sand and paint went over it well. It is my current pin hole weapon of choice.

The canopy skirt is slowly coming along. Still lots of pin holes to fill, etc. The red blotches are the glazing putty curing.

I have been supporting the canopy on saw horses, but that is a real PITA. If I need to move it inside or outside, I have to take it off, carefully set it on the grass. Move the saw horses, carefully pick the canopy up and get it set on the supports that are C-clamped to the saw horses. This is an accident waiting to happy. So, this evening I built a canopy stand on castors. It is 95% complete - it should be operational tomorrow.

Back to work tomorrow.

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Fibreglas, and more fibreglas

Finishing Kit

I was on the road for several days last week, so I didn't make much progress on the project. I took a week of vacation this week, so I'm trying to make progress on the fibreglas.

Yesterday I sanded the canopy skirt so much my arms were aching. I finally realized that I needed to get some better sanding blocks - something with a decent handle so it is not so hard to hang onto them. The new ones work much better.

Today I did some more sanding, put some filler over the rivet heads, and sanded some more. Late this afternoon I taped some garbage bags over the plexiglas, and sprayed the first coat of primer on the canopy skirt. I knew the surface wasn't smooth enough yet, but the primer helps you see where the uneven areas are. And there sure are a lot of spots that need filler. Wow. I still have a lot of work to do on this yet.

I've done several cycles of sand, prime, repeat on the tail surface tips. They are almost ready for a coat of silver paint, except for the one on the bottom of the rudder. Tomorrow I'll start on it, and the empennage fairing, and the cowlings. Plus more sanding on the canopy skirt. Ugh. :( I don't know how people actually build a composite aircraft. I've only got a few square feet of the stuff to deal with, and it is just about driving me nuts trying to get it smooth enough for paint.

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Canopy Tribulations

Finishing Kit

I made a depressing discovery on Monday when I took a close look at the canopy. I noticed that the edge of the plexiglas was touching a diagonal tube on the canopy frame. This would put a lot of stress on that spot, and a crack would likely start there. Any crack would probably propagate up the canopy. Very bad news.

The instructions recognize the potential for the edge of the plexiglas to touch the canopy frame vertical and diagonal tubes. The builder is instructed to relieve the edge of the plexiglas in half-moon shaped spots to keep it from touching those tubes. I had done that, but I hadn't removed quite enough plexiglas at that spot. I had noticed this a few months ago, and marked the plexiglas where it needed to be removed. But I couldn't do the work then as the plexiglas was temporarily riveted to the frame, so I planned to do it when I removed the plexiglas later. But I forgot, and I was in too much of a rush when I riveted the assembly together on Sunday, and I didn't give it as close an inspection as I should have before I started riveting.

I couldn't leave the plexiglas touching the frame, as it would almost certainly crack. I couldn't drill out the rivets and remove the plexiglas as I had used marine adhesive to seal the skirt. I would almost certainly damage the skirt and canopy when removing it. I had to devise a way to fix it in place.

I grabbed my collection of needle files and started filing the edge of the plexiglas. It took hours, and hours and hours, but I eventually was able to file away the offending plexiglas, and then smooth the new edge very carefully. It took all week, but it turned out OK. Lesson learned (again) - Don't be in too much of a rush. A few minutes of haste can require hours to recover from.

Several RV-8 builders have noted that the rivets along the top aft part of the canopy skirt eventually move a bit, and this cracks the paint. They said that if they did it again they would put a layer of fibreglas over those rivets so any movement wouldn't crack the paint. I decided I should take advantage of their experience.

Today I masked off the lower portion of the canopy using electrical tape, and cleaned and sanded the canopy skirt. Then I cut some 1" strips of 1.5 oz "deck" cloth and fibreglassed it over the row of rivet heads at the top of the canopy skirt. Tomorrow I'll pull the peel ply off and see how it turned out. If it looks good, I'll roll a couple of coats of thinned resin over the filler on the skirt and start sanding, filling pin holes, etc.

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Canopy, riveted

Finishing Kit

I was on the road for quite a bit of the last three weeks, so progress has been depressingly slow. I did some odds and ends of fibreglas work, and spent quite a bit of time preparing the canopy for assembly.

I also spent a lot of time trying to resurrect my ancient iBook laptop which finally died, but it looks like it had a major failure. So, I went out and bought a new 12" PowerBook G4. Very nice machine, but it take a fair bit of time to install all my software, and restore the backup from the old iBook.

Today I was finally finished prepping the canopy for assembly, so I screwed up my courage and got Terry to help me. I was quite afraid that it might crack as I pulled blind rivets that hold the plexiglas to the frame, but it all came out OK. I only did the rivets around the plexiglas - I'll do the ones at the bottom of the skirt tomorrow morning.

I wanted some sort of sealant to go between the plexiglas and the fibreglas canopy skirt to make the joint watertight. Some builders use Pro-seal, the same stuff that is used to seal the fuel tanks. But I had had enough of that messy Pro-Seal, so I looked for another solution. Some builders use Lexel, but I couldn't find a local distributor.

So, I ended up using a marine product that is designed for the installation of plexiglas windows on boats - Sikaflex 295 UV. The only downside of the Sikaflex is that it only comes in one colour - black. I laid a small bead of it between the frame and the plexiglas (except around the canopy bow at the front) to provide a bit of cushion for the plexiglas to ride on. I also put a bead between the plexiglas and the skirt. I'll buy another tube and cut the tip very small so I can run another very small bead along the edge of the canopy skirt.

Here is a close-up of the front of the canopy, showing the canopy bow and the canopy skirt

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Canopy Skirt Spacers

Finishing Kit

I pondered the gaps between the canopy skirt and the vertical tubes in the canopy framework for a few days, and finally decided how to proceed. I measured the gap at each hole, and then laid up a bunch of flat pieces using between one and seven layers of fibreglas cloth. This gave me a wide variety of different thicknesses to make spacers from. I needed spacers from 0.025" to 0.150" thick.

I first did a test with three spacers to be sure that the concept would work. They bonded well, and the fit was quite good.

I used some 1/8 inch bolts and washers to hold the spacers tight to the skirt while the resin cured. I was afraid that I might have trouble getting the hardware off, but the hardware for the three test spacers popped free fairly easily.

I fibreglassed all the spacers in place this afternoon. I'll remove the hardware tomorrow morning before the resin is completely cured. I'll test the fit later in the week. Tomorrow I'll work on tidying up the wire bundles, I think.

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Cockpit details

Finishing Kit

The 12 volt power supply I had been using to power up the aircraft's electrical system died last week. I was checking out some wiring and suddenly everything went dead. I opened up the power supply and checked the fuse - it was good. None of the components showed obvious signs of distress either. I checked the continuity of the input and output wiring - OK.

The power supply was one of several that another builder had assembled. He gave them to other builders, with the understanding that they would in turn pass them on to someone else. Ken Balch, an RV-8 builder, gave me his when he was done with it. I served at least three builders before it gave up the ghost.

So, I ordered an Odyssey PC-680 battery. Hopefully it'll arrive this week. I'll keep it trickle-charged, and use it to power the electrical system. I choose the PC-680 as it has gotten raving reviews from RV flyers. The best price I could find in Canada was $CDN 175, so I ordered it from the US, for $US 53.50 + $US 19 for shipping, which is a total of about $CDN 97. I'm prepared to pay a small premium to support local business, but not an extra 80%.

I spent a few days in Montreal last week, so I didn't make much progress. This weekend I made a bracket to hold the cockpit end of the cable for the alternate air door. And I punched the hole in the firewall for the cable to go through. I also started working on the cockpit heat control.