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Sikaflex slider canopy

tomcostanza

Well Known Member
I'm considering going over to the dark side, and gluing my canopy. To those who have gone before, how did you fasten the side of the canopy (section F-F on DWG 43) where the skirt attaches? There doesn't seem to be anything to glue it to. I would be grateful for any photos. I'm building a -7A, so any side-by-side pics would be appreciated. Haven't been able to find any close-ups of that section.

Thanks in advance,
 
The bottom of the side doesn't attach to the frame...it's cut about 1 or 2 inches above it so you'll have room to fit the metal side skirts to it (both inner skirt and outer skirt). I ended up sikaflexing the skirts to the plexi as well, but riveted the skirts to the frame. Came out nice...I have pictures, but I'm currently not home so I can't send them.
 
Here's how I did this.

Just finished this part of my slider and I have a bunch of pics on the camera but haven't had time to look at them on the computer yet. Hopefully will have something put together to share with the group next week.

I followed Van's instructions for cutting the plexi except that I didn't cut the sides up as far as what the plans show; I trimmed the sides so that they are just barely (1/32-1/16") above the top of the side bow. All plexi trimming was done with 1/8" spacers in place.

When I clamped the plexi to the frame I also clamped a 2" strip of scrap aluminum to the outside of the side bow such that this strip overlapped both the plexi and the side bow. Then, on glue day, along with all the other gluing, I ran a bead of Sika adhesive along the sidebow-to-plexi joint and smoothed it out with a gloved finger making a nice fillet between the side bow and the plexi. The strip of scrap keeps the glue from ooking out too much and since the strip is not primed it just peels off of the glue easily after the glue is cured. Any glue that leaks out is easily removed with an Ex-Acto knife.

I will leave off the C-759 Inside Canopy Skirt. Since I am not using any mechanical fasteners there is no real good way to secure the C-759 to the plexi other than a thin application of glue bewteen the shirt and the plexi and the tech folks at Sika USA said that a fillet joint like the one here will provide a bond that is "basically as good as a 1/8 inch thick joint".

Quality Control:

While I was doing all of this I threw together some scraps of plexi and .032 (2x2" - 1x4"), poorly prepped, cleaned and primed (half a--ed on purpose so that I would be seeing a worst case scenario) and glued them. Some I glued with a 1/8" spacer, some with a thin layer of glue and some had voids in the glue. I let them sit for a week. These babies are strong. I put one sample that was bonded with a very thin layer of glue in the freezer (20 degrees +/-) for a day and then plopped it in the oven at 175 to simulate some pretty severe thermal expansion/contraction. At 100 degrees (by the oven thermometer) the glue was rubbery but still strong; couldn't pull it apart with my fingers. I have yanked, pried and pulled on these samples and can't see any way that any inflight stresses will disrupt these glued joints. I'll agree, in advance of any criticism, that my "testing" is not especially scientific (or even remotely scientific for that matter). YMMV.

Jim McChesney
RV-7A QB slider
 
One more question

Can I assume correctly, that because of the extra 1/8" glue space, that you adjusted the frame 1/8" lower, but NOT 1/8" narrower than you would have if riveting?

Also, here is my non-scientific thought experiment. Many people have mentioned that it is impossible to open a sliding canopy in flight. This infers (to me at least) that the in-flight forces are down, and tend to hold the canopy in place, rather than tending to remove it from the plane. Before firing up the torches, remember I admitted it was non-scientific.

I'm still not sure what I'm going to do, but all options are open. Again, if you can post or privately send photos, I would be grateful.

Thanks again,
 
Can I assume correctly, that because of the extra 1/8" glue space, that you adjusted the frame 1/8" lower, but NOT 1/8" narrower than you would have if riveting?

Also, here is my non-scientific thought experiment. Many people have mentioned that it is impossible to open a sliding canopy in flight. This infers (to me at least) that the in-flight forces are down, and tend to hold the canopy in place, rather than tending to remove it from the plane. Before firing up the torches, remember I admitted it was non-scientific.

I didn't adjust the frame lower...I just built it as per plans and put in 1/8" spacers. The 1/8" spacers on the windscreen will keep it lined up (I already did a "dry run" to make sure of this). I made the aft canopy skirt out of fiberglass, so that takes care of any problems back there...the side skirts fit fine, too.

As for the "opening the canopy in flight" question...I don't know if this can be done or not, but since I want to get it open in an emergency, I replaced the bolts on the front of the frame/roller bracket with pip-pins from McMaster Carr. Do a search and you'll find a great thread about it. If I need to bail out, I'll yank the pins (drilled the hole at 45-degrees, angled toward the middle of the cargo area for easy pulling) and push straight up. Not sure if it works, but I'm guessing it will.
 
If I need to bail out, I'll yank the pins (drilled the hole at 45-degrees, angled toward the middle of the cargo area for easy pulling) and push straight up. Not sure if it works, but I'm guessing it will.

I'll probably do the same, but I'll skip that part of the flight test.:eek:
 
Some pics finally...

I finally got some photos posted. The pics are not completely self explanatory but there are captions. Go to http://picasaweb.google.com/rvtach and click on "Gluing My Slider Canopy" and then click on the "slideshow" icon.

Why did I want to glue my canopy?

I decided some time ago (during the wing phase of my RV-7A project) that I was going to glue my plexiglass canopy and wind screen (with Sikaflex products) versus drilling multiple holes in the plexi and attaching with screws and rivets. I like the look and I like the reduced risk of cracks. I think it will be plenty strong enough for this application.

Materials I used were purchased from Jamestown Distributors:
1. 2 tubes of Sikaflex 295UV adhesive (black)
2. 1 bottle of Sika Cleaner 226
3. 1 bottle of Sika Primer 209N

I will need a 3rd tube of adhesive because I plan to form the windscreen fairing with Sikaflex adhesive and sand to shape as documented by Jim Ellis on the RV Wiki. Otherwise this could have been done with 2 tubes of the adhesive.

That said, one should remember that the safest, surest, simplest, quickest, least expensive way to build one of Van?s kits is to do it just the way Van says to. This is the only part of my project that I might say is actually ?experimental?. The rest is being built ?according to plans?.

Remember, don't follow me, I do not know where I'm going.

Jim McChesney
-7A QB Fuselage
 
I'm considering going over to the dark side, and gluing my canopy. To those who have gone before, how did you fasten the side of the canopy (section F-F on DWG 43) where the skirt attaches? There doesn't seem to be anything to glue it to. I would be grateful for any photos. I'm building a -7A, so any side-by-side pics would be appreciated. Haven't been able to find any close-ups of that section.

Thanks in advance,

I riveted an aluminum angle to the top of the side canopy support. You need to match the bend of the canopy frame of course. I did this with the shrinker/stretcher. Attach the alum angle inboard about 3/8 inch to allow room for the canopy side and the sikaflex.

I learned a lot while attaching my canopy with sikaflex. The best way to do it is the clean the canopy frame, prime it with the sika primer, then put the canopy in place using spacers. I used rubber gromets that squished down to about 1/8" (use a ton of small C clamps). Then squirt the sikaflex between the frame and the canopy. It actually "rubberizes" quite fast so only do about 10 inches and then smooth the edge for a nice look. Be sure to tape off around the canopy frame.

My canopy skirt is all fiberglass.

Steve
RV7A
 
how much space is it good to leave between the side of the fuselage and the side of the canopy frame ,1/16 like in the manual or little bit more?
 
I tried for 1/16 as suggested and was flush in a couple spots but worked out well for me. You can also very gently "roll" the skirt width-wise a bit, mine is done and just clears the side skin. Aft skirts are much trickier... I also bonded the dog house to the aft skits.

Canopy is just about done... little tweaking and I can move on by Dave Hock, on Flickr

Having done this on my -7...that is undoubtedly the best work I have ever seen! Bar set, not a scratch!

Really not fair...I was kind-of feeling good about my work too...haha

Excellent
 
Appreciate the reply's , the canopy is a TON-O-WORK as you all know....

I really would have liked to finish the windshield but want to get the wiring and instruments done first. By the time I get that done my Sika stuff will expire so will have to buy more... oh well.
 
I really would have liked to finish the windshield but want to get the wiring and instruments done first. By the time I get that done my Sika stuff will expire so will have to buy more... oh well.

Yep, been there done that...

I'm sure the old stuff is fine but I just couldn't bring myself to use it.
 
I tried for 1/16 as suggested and was flush in a couple spots but worked out well for me. You can also very gently "roll" the skirt width-wise a bit, mine is done and just clears the side skin. Aft skirts are much trickier... I also bonded the dog house to the aft skits.

Canopy is just about done... little tweaking and I can move on by Dave Hock, on Flickr

it s a really nice job
why did you use also the screws in the canopy and didn t you use only the sikaflex?
 
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That looks beyond amazing. I gave up on my metal skirts quickly and just went with a fiberglass layup. Makes glueing everything together really easy.
 
thank you for you pictures , the space between the rear skin and the canopy frame is it only the thick of the plexiglass or little bit more? because you used the sikaflex

You want to make sure that the canopy is level or a little bit taller that the rear skin. Cannot be below. 99% of my canopy is separated from the frame by 1/8” for expansion. On one of the back rear corners I had to omit a spacer because the canopy was a little too wide for my tastes. Using the fiberglass/carbon fiber layup allows for a lot of variations to be covered up. My rear skirt is about an inch longer than standard to make the smooth transition. The fit up to the rear skin and down the sides is flawless.
 
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