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  #1  
Old 03-20-2021, 08:29 PM
Skot7ac Skot7ac is offline
 
Join Date: Apr 2014
Location: Milan Mi
Posts: 32
Default Cracked Canopy

After reading several posts, I see Im not alone in the cold night at the hanger canopy crack club. It looks like the consensus is plastifix after stop drilling. Does anyone have any other thoughts or guidance on the repair? Crack is just behind the back seat, left side of the canopy, a little over 14 long.
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  #2  
Old 03-21-2021, 12:28 AM
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rv8ch rv8ch is offline
 
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Location: LSGY
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Quote:
Originally Posted by Skot7ac View Post
After reading several posts, I see Im not alone in the cold night at the hanger canopy crack club. It looks like the consensus is plastifix after stop drilling. Does anyone have any other thoughts or guidance on the repair? Crack is just behind the back seat, left side of the canopy, a little over 14 long.
That's a heck of a crack. I have no suggestions but will be following this thread in case it happens to mine.
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  #3  
Old 03-21-2021, 05:51 AM
ShortSnorter ShortSnorter is offline
 
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Location: NOLA
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How cold did it get & was there any movement that you are aware of that caused this? In other words, did you walk out to the plane in the morning and discover this happened overnight?
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  #4  
Old 03-21-2021, 06:05 AM
Skot7ac Skot7ac is offline
 
Join Date: Apr 2014
Location: Milan Mi
Posts: 32
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No movement, I had been in training for a little over a month and came back to find the crack waiting for me. I did have a friend working on an airplane in the hangar with bullet heaters running quite a bit, I think the heat cycles may have contributed. That being said, there were quite a few threads where people had the canopys crack in nearly the same spot.
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  #5  
Old 03-21-2021, 06:54 AM
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Skid Skid is offline
 
Join Date: Jun 2006
Location: KBUU
Posts: 229
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Quote:
Originally Posted by Skot7ac View Post
After reading several posts, I see Im not alone in the cold night at the hanger canopy crack club. It looks like the consensus is plastifix after stop drilling. Does anyone have any other thoughts or guidance on the repair? Crack is just behind the back seat, left side of the canopy, a little over 14 long.
Sorry to see you have joined the cracked canopy club.

If you are going to use plastifix be careful not to use too much which would require additional sanding. The additional sanding can create a lens effect.
You may see tiny cracks radiate from the ends of the crack after filling with platifix. Not sure what causes this other than the heat from the chemical reaction.

I am still flying with the canopy I repaired years ago, I may opt to finally replace it later this year, as I am planning on repainting the airplane.

Good luck!
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  #6  
Old 04-01-2021, 03:52 AM
Capt Capt is offline
 
Join Date: Feb 2017
Location: Australia
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OUCH! That's gotta hurt! -( I have a small crack about 3.5cm long from the same spot on my 8, near cried when I first saw it -)Stop drilled it and filled with clear silicon, not grown in over 2 years. My machine came from a warm climate all its lofe (18 years) I bought it back to a cold climate and the canopy wasn't happy! -(
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  #7  
Old 04-01-2021, 06:48 AM
BillL BillL is offline
 
Join Date: Sep 2007
Location: Central IL
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A cracked canopy would give me a headache.

I am surprised having seen posts for cracks in the same area for 10 yrs that no self-respecting analyst has done an FEA to determine precisely why it happens and generated an alternate design as a fix.

Paul Dye posted his floating sleeve fix, but have not seen "field test" results since then for a definitive confirmation.
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  #8  
Old 04-01-2021, 07:26 AM
Hwood Hwood is offline
 
Join Date: Feb 2005
Location: Central Alabama
Posts: 321
Default Crack Cause

Okay...Ill jump in here with my 1 1/2 cent thought...

It seems that everyone blames the canopy crack on the temps...or the drilling...or something else. I'm wondering if it's something that hasn't even been discussed yet.

When I was rigging the canopy latch to the frame/bow, I noticed that if the latch was pulling too much (a good tight fit!)...then the whole canopy frame would twist under the strain of the pulling latch. Could this be the cause of some of these cracking shells? Pulling and twisting the frame (and not very much) would certainly put a significant strain on the canopy when latched....then expose her to all the environmental stresses and that might be too much.

The latch doesn't have to be tight to the point of pulling the frame closed, it just has to be tight enough to latch.

Just my thoughts...
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  #9  
Old 04-01-2021, 07:34 AM
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rv8ch rv8ch is offline
 
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Quote:
Originally Posted by BillL View Post
A cracked canopy would give me a headache.

I am surprised having seen posts for cracks in the same area for 10 yrs that no self-respecting analyst has done an FEA to determine precisely why it happens and generated an alternate design as a fix.

Paul Dye posted his floating sleeve fix, but have not seen "field test" results since then for a definitive confirmation.
There used to be speculation that this was caused by drilling holes in the canopy, but not that long ago someone had a crack in a canopy glued on with sika, which was pretty surprising. Perhaps that was a very special case, but not a lot of data. I'm only aware of that one case of a cracked canopy which was glued on.
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  #10  
Old 04-01-2021, 07:37 AM
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MacCool MacCool is offline
 
Join Date: Aug 2020
Location: central Minnesota
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I feel a little lucky with the canopy on my 10 year old RV-9A slider. It was built in Atlanta and lived there for 5 years, then 5 years in St. Louis. This is by far the farthest north it's ever been (central Minnesota). My hangar is unheated and it was -30F more than a few days and nights here this winter, and the canopy tolerated my intermittent bullet-heater use for my little avionics project well, as well as the in-and-out of the heated hangar I borrowedfor part of it. This time of year is often even worse in terms of temp swings. This morning it was 12F outside...this weekend it will be 70F.
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