6.10.2 Canard Top Attachment Points

The first step in the process is to remove the canard and place it on some saw horses. I previously trimmed the cover for a good fit and marked its location on the canard surface to make sure it is properly aligned. Because these pads, or tabs, need to stick out, I have to make something to do that. The manual recommends using some small boards or Divinycell scraps. You can see those in the photo below. I hot glued the Divinycell scraps to the side of the dog house cover to hold them in place while doing the layups.

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Creating installation tabs for the dog house cover.

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View showing the lay up inside of the dog house cover.

The layups have cured and have been trimmed so I reinstalled the canard back in the fuselage to check for fit. Luckily it all fit perfectly!

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The canard with the finished tabs is back in the fuselage. These tabs not only hold the cover on but will also be used to prevent torsional movement once they are locked to the fuselage.

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Another view showing the completed canard tabs.

Once the tabs on the canard are cured, it’s time to make mating pads that eventually get attached to the fuselage walls. Because these pads stick out, the manual again recommended that I use boards, or whatever, as a backing for the Triax that’s used for this. In this case, I decided to use some cardboard covered in duct tape (which acts as a release agent) for making these pads.

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I'm using some cardboard covered in duct tape to create forms for the tabs that get attached to the fuselage.

After the layups cure, it’s time to separate the duct tape covered cardboard from the pads. I also need to remove the canard again so that I can trim and match the shape of the pads between the two surfaces. The photo below shows one of the pads as I prep it for attaching a 1/4” nut plate.

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Here's a closeup shot of one of the finished fuselage tabs.

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I needed to create four tabs altogether - two in the front and two in the back. This photo shows both tabs on the left side of the aircraft.

If you look close at the left side of the photo below you can see the 1/4” nut plate that’s installed on the fuselage pad. The locking bolt passes through the tab on the canard to the pad on the fuselage and locks the assembly together. All four corners are attached the same way.

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This view shows the completed left side tab with bolts in place locking the carnard to the fuselage.

Because I purchased the side stick controller option, I needed to create some openings in the tabs for the elevator torque tubes to pass through. You can see that in the photo below.

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After completing the tabs I had to cut access holes in them so that the elevator torque tube control can get through.

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Here's a wider view of the completed tabs showing the side stick controller in place.

The manual recommends drilling holes through the cover and into the tabs for holding the cover down to the canard. Most builders no longer do that. They try to keep the surface of the airplane as smooth as possible. Some people use hinges to attach the cover to the canard, but that seemed like somewhat of a pain. So, I purchased some Dzuz latches and will use those to latch the cover to the canard. The neat thing about these latches is that they can be safety wired shut eliminating the concern that the latch may pop open letting the cover go flying. When the cover needs to be removed it’s easy enough to cut the wire, pop the latch and open it up! (See followup to this below. It turns out that trying to get these latches aligned is more difficult than I thought it would be, so I’m switching over to the piano hinge concept.)

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I'm using some Dzuz clasps to hold the dog house cover to the canard. What you see in this photo are the mating hooks for the clasps.

Since many builders end up installing their panel electronics underneath the dog house cover, (which I also plan to do) I am a bit concerned about moisture getting in through the gaps between the cover and the fuselage. I decided to try to seal that area by making some flanges which will get covered with a rubber seal. To make those flanges, I decided (after a number of other attempts at doing this that didn’t work well at all) to use the cover as a mold. I also need a slight edge for the rubber seal so I used some 1/16” cardboard to create that edge along with more cardboard outside of the dog house cover to create a surface that I could use to epoxy it to the underside of the fuselage. This actually worked quite well, even though it was an involved process, as you can see in the photos below!

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Prepping the dog house cover to make short ledges to be used for water proofing the cover to canard intersection.

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Here's a photo of the completed layups using the dog house cover as a form.

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Here are the two water proofing flanges after removing them from the dog house cover and before installing them onto the fuselage.

I think I used just about every clamp I had to hold those flange pieces tightly against the fuselage while the epoxy cured. In the end, it worked well. And since I was using EZ-poxy + Microballoons for the mixture, I was also able to smooth the transition between the fuselage and the flanges in preparation for applying a layer of BID later to protect the edges.

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It takes a lot of clamps to make sure that the ledges adhere properly to the fuselage.

I’m finally getting around to protecting the edges of the dog house cover with a layer of BID. Eventually a light coating of Velocipoxy + Micro will seal the edges before getting painted.

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I need to protect the edges of the cover so here's a photo showing one layer of BID epoxied in place before trimming.

The photo above still shows the Dzus clasps that I had planned to use to hold the cover down. Well, basically, I wasn’t happy with the way in which they are working. It became too hard to get them aligned properly, especially with addition of the ledge seal. So, I’m switching to piano hinges which other builders have used successfully.

So, the clasps came out and the hinges are going in. I probably should have just done it this way to begin with but I thought I had a better idea. Shows you what I know! Ha ha! I just couldn’t get the clasps to align properly so I tore them out, bought some hinges from Aircraft Spruce and went to work. Installing them is pretty easy and it’s much easier to get everything aligned.

The Clecoes, shown below, are temporarily holding the hinge in place. They come out when I epoxy and rivet the hinges in permanently.

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One of the hinges used to hold the dog house cover in place is temporarily Clecoed into place before applying epoxy and rivets.

The photo below shows the other half of the hinge attached to the cover. These hinges are held down with rivets and structural epoxy. I probably will also add a layer of BID over the bottom of the hinges just for a tad more strength.

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Dog House cover hinges are now attached!

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Here's a close up shot of the installed hinge.

Since the hinges curve ever so slightly, I was having problems getting the hinge pins to re-insert. I used my belt sander to grind the ends down to a slight point and that did the trick. Adding a bit of grease on the pins makes them slide in fairly easily. 

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In order to help the hinge pin go through the slightly curved hinges, I tapered the end of the pin slightly on my belt sander.

Most builders just “butt-joint” the edge of the dog house cover to the canard, but I’ve seen a few that gently flange the ends to make a prettier transition which also, I’m guessing, helps to keep out moisture. So, I decided to do the same thing. I duct taped the areas that I don’t want the fiberglass and epoxy to stick to. (The duct tape acts as a release agent since epoxy does not stick well to it.) I reinstalled the dog house cover and locked it into place with the hinges. I mixed up some EZ-Poxy with some Micro to make a paste that I used to create a curved surface.

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EZ-poxy plus Micro to create a smooth edge before laying down the fiberglass.

Once the pasty epoxy is in place I laid up a couple of layers of BID to lock the Micro in place and to make the flange. It’s still curing in the photo below. I also covered the lay ups with peel ply to help smooth everything out.

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Two layers of BID applied to the dog house cover to create the flanges.

I also decided to add a layer of BID on the inside. That caused the cover to raise up ever-so-slightly which means that the hinges aren’t quite aligning now. I’m working on sanding down both the layer of BID that I added to help strengthen that joint as well as a bit of sanding on the canard itself where the cover with the flanges rest. That should easily solve the problem. I’ve also just started trimming the edges so no photos of the completed product yet. I should have that done by the next update though.

ui© John Trautschold 2018