A weekend of relaxation at the Kanab Fly-in gets derailed by a canard delamination.
We have been working on Brian’s Defiant really hard for the last several weeks. I am pretty proud of the amount we have gotten done. I am even behind a post and need to update on the lower aft cowl layup that was done. But this post is about taking the holiday weekend off for some rest and relaxation, or so I thought.
The Kanab Canard Fly-In has been hosted annually for the last 30 years just the other side of the Grand Canyon and AZ/UT state line. It is a very low key fly-in in a small town that is relaxing. For once I am off work for the event. Seemed like a great time to go get some down time, fly Betty, and enjoy time with like-minded builders. Plus they host a “timed event” there so I actually get to race in 2020.
Friday morning, Kevin and I packed Betty up, and launched for Kanab. It is just over 200 miles from Deer Valley to Kanab, so about an hour and ten minutes. We left in the morning to have lower temperatures and better rides. Our route of flight was probably one of the most scenic I have ever flown in a small airplane. We flew up the Dragon Corridor of the Grand Canyon. The sights were beautiful.
We arrived in Kanab about 11 am amongst about a dozen other canard airplanes already there. We found a nice parking spot and started tending to Betty’s needs to put her to bed and get her cleaned up. While I was unpacking our bags, a Cozy owner, Steve Franseen, owner came up to the airplane and asked, “is this a de-lam?” (De-lamination) To which I responded, no, thats been there for a while, tap tests ok, and is a contouring issue from the paint shop.
A little background: For quite some time, in fact since I repossessed the airplane from the paint shop, there has been a noticeable discontinuity in the left canard tip. I remember seeing pictures during the paint job of a significant amount of filler added to the tip of the canard. All along I thought this surface discontinuity was from that. A delamination will have a hollow sound when you tap test it, and every time I had tap tested this area, I was unable to detect any hollow sound or difference in tone from the surrounding areas.
When I got the last baggage out of the spar, I dismounted from the strake and was immediately shocked at how large the discontinuity had grown. It was at least 3 times its previous size, and significantly taller too. It was inflating like a balloon right in front of my eyes. It tapped hollow, big time. The skin was hot to the touch. I had never felt it so hot, even in AZ summer days.
With the temperature nearing 100 degrees and the sun high overhead for direct harsh solar heating, I wanted to get the airplane into the shade, so I found and coordinated a hangar quickly. With the airplane in the shade, it was out of danger and time to evaluate the damage and our options.
This bubble was so big and had progressed so much so quickly that it needed to be fixed before further flight. It wasn’t the kind of thing I was going to limp it home at a slow speed and moderate altitude to make a repair. Some delaminations can be easily fixed by injecting epoxy between the skin and foam and letting it cure. That is the easiest repair if appropriate.
With our damage and the delam bubbling around an inch above the contour of the canard, we would have to get the skin to sit back down into contour for this to be a viable repair option. I tried pushing on the skin bubble slowly increasing pressure until there was a slight cracking sound. The skin only moved 1/16″. I further tried drilling a hole into the bubble to relieve any air pressure in there. But that didn’t improve the ability to move the skin back into place.
At that point, my options are to either try to heat the skin to the point where the epoxy becomes soft and try to reform the skin to contour and then let cool. Or to replace the skin. Heating the skin can do further damage and I have less control over the new contours of the canard. It also has the potential to do further damage to the foam core. I chose to cut away the skin.
I was pretty disappointed at this point. It was our first time to Kanab, and there are a lot of fun, but low key events planned for the weekend. A guided tour flight of Zion National Park and Bryce Canyon were the Saturday morning plans, and the race on Sunday. It also was embarrassing to have such an avoidable problem and was painting an airplane that is my pride and joy in a light not very becoming. Looks like my weekend of R&R is going to be a weekend of unplanned work, and we will miss the flying events.
I travel with a fly away kit (FAK, click here to see what I tend to travel with). My FAK has the tools in it that I think I could possibly need to make likely minor repairs while on a trip. I never plan on doing layups and skin replacements, so I didn’t have any of the tools or materials I needed with me. Not to worry though, this is where the aviation community really shines. Pilots, especially builders, go out of their way to help each other out.
I texted three buddies at my home airport to see if one of them could pack up the materials I would need from my hangar and fly them up to me. Without hesitation, they agreed. Brian, Travis, and George were going to pack up materials, and George would fly it up to me Saturday morning early.
While they were heading to the airport, I borrowed a dremel and cutoff wheels from the Kanab Airport Manager, Jeff. Of course that was an exercise in frustration because the exploding dremel cutoff wheels only last for a couple inches of cut. So I eventually went to a hand held hack saw blade. I cut away skin until we got into good glass and foam that was free from de-lam. Doing this skin-ectomy only took an hour. I wanted to do it before the boys packed up my materials to make sure I didn’t have any unexpected material/tool needs.
While I was doing surgery on Betty in Kanab, Brian fortuitously ran into another Long Ez friend of mine, Gary, at Deer Valley. Gary was washing his Long Ez, in preparation for a trip to the Kanab fly-in early Saturday morning. Brian was able to coordinate with him to bring my materials up to me, saving George the early morning flight. Talk about good fortune.
When the boys got to the hangar, we did a 45 minute long FaceTime session of me guiding them though my workshop to find the items I needed. Of course, all the while they were ribbing me for my less than clean, somewhat disorganized workshop. I guess I have some work to do there. But they successfully packed up a care package that was compact enough to fit in an airplane. Care package contents:
- Pour foam
- Pro Set Resin/Hardener
- Mixing Cups
- Mixing Sticks
- Peel Ply
- Sanding Blocks
- DA Sander
- Sand Paper, (40/80/120/180)
- 5606 Hydraulic fluid (for someone else with gear/brake problem)
Saturday morning, I went out to the airport early to do whatever preparation I could on the canard tip until my materials arrived. I started with what ever tools I could get my hands on in the airport managers tool box. The preparation included digging a trough for a flox corner around the edges. By the time that was done, Gary arrived with my care package.
From there it was sanding to create my scarf joint. Sanding back 1″ per ply in the directions I could. Toward the trailing edge and the tip, I didn’t have the distance to do that kind of a scarf, but those areas are almost a fairing with only a 2 ply skin. So I wasn’t concerned with just lapping the repair onto the remaining skin “flange.” The DA sander and a variety of grits and interface pads made quick work of this.
We were working outside per the airport managers request, and rightfully so. The hangar was where multiple meals/banquet would be taking place and we didn’t want to create all the fiberglass dust in the meal location. But that also put the airplane back into the sun. Despite our best efforts to cover the airplane with borrowed canopy covers and tarps, the blue areas still were getting hot. So I sent Kevin and Greg to NAPA to get white paint. I scuffed up the dark stripes on the wings and we painted them white. No more heat worries for the rest the day for the wings. We also did locate a small delam on the right canard tip. This one was small enough to repair with injecting epoxy under the skin.
With the repair area on the left canard tip prepared, it was time to start rebuilding. I did a couple small pour foam areas into the larger gouges. By larger gouges, I mean the pour foam ended up being less than 1/2″ thick and in very localized areas. Since pour foam can continue to grow over time, I wouldn’t have used it in a big area as it is strong enough to change the canard shape. But with thin localized areas, it was fine.
It was time to mix up some epoxy and flox structural filler. The troughs around the perimeter were filled with this. Then the rest of the epoxy was mixed into a micro slurry the consistency of peanut butter. The foam was all slurried filling in the remaining dings and trying to keep the surface as close to proper contour as possible. I also had to do a small repair to the elevator counter weight cavity. There was about a 1 square inch area that needed to be replaced. So two tiny plies of Bid were put in place. I left this to gel for a while to make the next steps easier.
After a bit of time that allowed the flox and micro to get to a stiffer, but still manipulatable consistency, we started laying up our plies of glass. We replaced each ply per the plans schedule. This was uni, bid, uni, uni from elevator tip inboard, 2 plies bid or uni outboard of elevator end. Then per normal repair technique we added a ply of bid over the whole thing. Lastly, to save a cure cycle, and give me a shot of being able to fly Sunday, I mixed up micro and slathered it on the repair area. We had just exactly enough micro. To help the quality of the micro spread, I put peel ply over the fill to help prevent tearing and ridges. When I was satisfied we had the micro spread consistently, we called it done. The layup went really, really well. It was a really long day of work from 8 am to 5:30 pm for Greg, Kevin, and I.
Sunday morning, it was back at the airport at 6 AM. With the 100 degree temperatures during the previous day, the repair layup was cured. Pulling the peel ply revealed a nice repair that needed only minimal contour sanding. A combination of DA sanding to knock off obvious high points and my contour sanding durablocks to refine the shape, were the tools of the morning. Within the hour, I had an airworthy repair that was blended well into the rest of the canard. Maybe I can make the race…
Doing a repair like this, in my opinion, requires a test flight. While I was confident in the repair, in my mind it was only prudent to confirm unchanged flying qualities before leaving the airport area or having another person onboard.
When transitioning roles from mechanic to pilot, I try to make sure I take the time to reset my mentality and to slow things down to an appropriate pace. No one is served by rushing things like this. I preflighted the airplane and also had Greg go over what we had done to make sure we didn’t miss anything. With flight control throws verified, and all areas where we worked given multiple looks it was time to fly.
It was a beautiful morning to fly, and the takeoff was conspicuously normal. I then orbited over the field, slowly increasing speed until a high speed cruise. Handling characteristics were normal. I then dove the airplane slowly increasing speed to Vne. Everything was normal. Last I did a power off stall/pitch buck test. Everything was normal. All handling was unchanged, even the pitch buck speed was the same as usual. I proclaimed the test flight a success and came in for a landing. I shut the airplane down about 7:50. With plenty of time to walk over for the pilot briefing for the race at 8 am.
The race was a ton of fun. In other years, I would have gotten at least one race in by now, and be preparing for Reno. In 2020, this is the first, and likely the last race I will do for the year. Of note, it is the very first time I have gotten to race Betty. Which was a goal of mine since well before Betty first flew. We launched second in the race behind Dick Rutan and ahead of Allen Floyd. It was a beautiful morning to fly and Kevin and I enjoyed the sights, probably even more so after all the work we did over the last two days. Allen ended up passing us during the race in the last 20 miles. We averaged 217 MPH. The official results has Allen faster than us by 6 mph. But he also has at least 30 more horsepower than Betty has. 🙂
There are a lot of things to take away from my experience. First off, Burt said that you can paint your Long Ez whatever color you want, as long as it’s white. I can attest to the fact that the implications of heat build up in the composite structure of a non-white Long Ez is no joke.
I don’t want to give the impression that I painted Betty silver and blue without thought. I did in fact have samples of the paint colors and temperature tested them in Phoenix, in June, on a 110 degree day, at noon. These tests resulted in changing the colors to lighter colors than initially planed. But, as I’m learning now, there are many more factors to look at than just the temperature of a paint chip. The heat transmissivity of a paint sample vs paint on the exact same substrate (glass/foam), in a no wind situation, oriented at harsh sun angles (pointing south), etc are not trivial factors. It requires a much more in depth study than I did.
In the end, analysis of the removed skin shows that my paint certainly transmitted enough heat to melt the polystyrene foam. This created a delamination between the skin/micro slury and the foam core compromising the structure. Therefore I will have to accelerate my plan to repaint the airplane, and when I do it must be lighter colors or using solar heat reflective paint.
It has been a whirlwind weekend. It was supposed to be a weekend of rest and relaxation, but it turned into a weekend of repair and repaint. We are very proud of the repair we did in Kanab. I don’t think it would have been any better had I done it in my own workshop. I now have a little more work to do to finish the body work on the canard. I knew I would have to repaint the whole airplane eventually, but looks like Betty has moved herself up the priority list.
Special thanks to those folks who helped make this repair happen. Kevin Vernon-Harris, Greg Struve, Gary Mowad, George Catalano, Travis Foss, and Brian Mitchell. I don’t know how I have been granted so many wonderful friends but I will keep you around for a while.