Finishing Kit

January 7, 2014

Fixing the Right Side Skirt on the Tipup Canopy - 11.0 hours

If you look back at when I first put the side skirts on the tipup canopy, on this page, from December 31, 2011, over two years ago, you will see what a nice fit I originally had. It not only fit tightly down on top of the red canopy deck railing, but it lined up on the aft end perfectly in line with the aft top fuselage skin. Now, fast forward, I don't know what happened along the way. One of the most maddening aspects of building your canopy is that everything has a tendency to change along the way, no matter how careful you are.

My left side still looks great, as you can see here. Fits tightly down on the deck railing, and is perfectly in line with the aft top skin, making a nice smooth transition and pleasing lines and appearance. No problem here.

Now look at the right side. I ended up with an ugly gap between the side skirt and the railing underneath it. Not only that, but the aft end of the skirt sticks up above the skin behind it (see red arrow). You don't see a nice line or smooth transition. I could actually live with that part if I had to, but this gap really bugs me. This is the one thing about my canopy that really disappoints me.

Here's a closeup. The above picture doesn't really show it very well. But look at this. It's an 1/8" or more in some places. Unacceptable. I really don't want to see this, or think about it, every time I climb inside my airplane.

And here's what it looks like from inside the canopy, sitting in the pilots seat. I know there will be a gasket in there to seal up any air leaks, but this just really bugs me. You could almost drive a truck through there. It has been bugging me over over a year now and I can't stop wondering what I did wrong, and how I might be able to fix it. I know, a lot of guys would just move on and maybe I should too. I've tried to, actually. But I've come up with a plan. I think I can really improve this. And since I have fresh SikaFlex materials on hand, left over from installing the rear window, it's now or never. My plan involves drilling out a lot of rivets. 38 of them, actually. It involves removing this side skirt, if I can, and if I'm successful in getting it off, installing a new one. This is a test with unknowns for me, since the SikaFlex that is installed under this skirt will have to be sliced through somehow, so I can pull the skirt off. I've been bragging about how tough this material is when it's cured, now I get to find out just how hard it might be to take this part off. So I began carefully drilling out rivets, one at a time. I'll do a short span at first. If it's impossible to go on, I'm being very careful not to damage the skirt. A small number of rivets can be re-installed and I can forget it.

So I started drilling out rivets. Then I was able to get a very sharp blade underneath the skirt and I started slicing through the Sika that held it tenaciously in place. Little by little, I was able to slice and drill, and after a lot of work I had successfully removed the side skirt. Now I can get a new one from Vans and fix this!

This will need a little cleanup, but it's not bad at all. One thing this convinced me of... I will never worry about how good this Sika is, in holding this all together. Tough stuff!

Here's what the back side of the skirt looked like. I had sliced right along the aluminum.

So, I went to Vans and bought a new side skirt. This will be the third one on this side of my canopy. I'm glad it's not an expensive part. Here's a picture taken after the cleanup and masking. It's now ready for a new side skirt.

Here's a closeup of the prep work. The old Sika was scraped off and the frame scuffed down to fresh aluminum. Here's what you're seeing here. A new masking piece of black tape has been applied across the top, right along the top edge of where the new skirt will go. The bottom edge of the tape defines the top edge of where the Sika fillet will be, right across the top of the new skirt. It was easy to do this, simply cleco the new skirt on and tape over the top of it on the plexi, leaving about 1/32" for a fillet, then take the skirt off again. Under the tape is the scuffed plexi, ready for a fresh application of SikaFlex. It looks black because you're seeing through it, and the Sika on the other side, against the canopy frame, blackens it. Under the scuffed plexi is the scuffed and cleaned aluminum canopy frame. It angles upwards under the plexi to the other side of the plexi. This "channel" under the plexi will be completely filled with Sika. Underneath that is another piece of tape, for masking. This is only on until the gooey Sika is applied and smoothed out. Then it will be pulled off and the new skirt will then be clecoed on and riveted in place. I don't want any Sika (adding unwanted thickness) under the skirt where it is riveted to the frame, so this masking will keep that area clean. I hope that makes sense. The Sika was applied, smoothed out, bottom tape pulled, skirt clecoed in place, then riveted. Then the fillet was smoothed out along the top edge of the skirt and the top piece of tape pulled. It's simple really, and gives beautiful results.

So I went ahead and very carefully drilled the new skirt to the frame, after trimming it carefully to fit just right. I went ahead and applied the SikaFlex as described and riveted the new skirt in place. Here's the finished result! Note the smooth transition line now, at the aft end of the skirt where it meets the fuselage skin. Now it looks right, like the other side of the plane.

Best of all, there's no gap left under the skirt. MUCH nicer! Here's a closeup, showing that the ugly gap is no longer there. I can't even slip a fingernail under the canopy skirt now. This is how it's supposed to fit. In case you're wondering, if you have sharp eyes, all you see is some of the clear protective tape sticking out, that I still have covering the red railing inside. That will all be removed very soon.

I didn't get a picture of the view from inside, but it's very good now. It's such a relief to have this annoying problem fixed. It was worth the effort.

So after about 11 hours of work, a trip to Vans and a small amount of money spent, I finally feel very good about this canopy. Time to move on!

<< Previous | Home | Next >>

Contact me: swayze "at" (replace "at" with the @ sign... no spaces... you know the deal)