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I joined the cracked canopy club! Crap!
Posted: Sat Apr 21, 2012 7:45 pm
by lancef53
I joined the cracked canopy club
Had the plane in the shop to wash it up on Wednesday. Happened to notice a small crack near the rear of the canopy today. I tried to stop drill it, so I will see if it goes anywhere.
I did the sika flex method, and it doesn't have any riviets.
Time for a smoked canopy from Todds?
Posted: Sun Apr 22, 2012 5:39 am
by captain_john
Wow, that is a bummer!
Lance, I guess it is too large to live with or are you just wanting a tinted canopy and have an excuse to build one now?

CJ
Attachment method
Posted: Sun Apr 22, 2012 10:38 am
by DaAV8R
I keep reading about Sika attached canopies that have cracked. I'm just starting the fuse but I'm thinking I might just pop rivet or screw the canopy on so it will be easier to replace if it cracks.
What are your thoughts on this?
Robert
Posted: Sun Apr 22, 2012 11:09 am
by captain_john
I sika'ed only the leading edge of mine. All other areas I went "per plans".
For the -7 tipper, I just thought this was best.
My reasoning was that the Sika was better at bonding than the fiberglass that the plans prescribe.
Dunno... just my take on it.
As far as the -8... I probably might have done a similar thing too. A belt and suspenders approach there as well.
Either way, a sika'ed canopy will not move. That, in contrast to threaded fasteners that will allow some movement.

CJ
Posted: Sun Apr 22, 2012 11:24 am
by Spike
Yipes. I would say drill it and forget about it for another 20 hours. Then remeasure. You are probably going to be ok. Well, unless you want a new one of course.
Spike
Posted: Sun Apr 22, 2012 8:27 pm
by lancef53
Ya, I drilled it already. Hopefully it will stay where it is, at least for the summer. It is a small crack, at the back of the canopy. It will never bother me, if it stays where it is.
The actual attaching the canopy, with sika or rivets, is nothing compared to the trimming and matching up the skirts. I think the problem is the shape of the frame and the canopy trying to come together at the rear. I have seen others crack in the same spot.
Drill large holes if using screws and/or rivets!
Posted: Mon Apr 23, 2012 5:45 pm
by Bob Barrett
I followed the plans for a slider on my RV-6A and over sized the holes to allow for expansion and contraction. Some people oversize the holes and use a soft plastic tubing as cushion for the screws or rivets. I am convinced that you need to oversize the holes to allow for expansion and contraction. The guy I purchased my tools from didn't allow enough for expansion and his canopy cracked one winter while he was in Texas. One of the other guys was doing some work in EAA Chapter Hanger, and my friends RV-6A slider was there with the canopy clecoed on. It was a warm winter day and all of the sudden a cleco flew across the hanger but fortunately he wasn't hit by the flying cleco.

Posted: Mon Apr 23, 2012 7:01 pm
by captain_john
I have fallen victim to the flying cleco phenomenon!!!

CJ