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Bill Phillips

Well Known Member
I am triming my RV-8 canopy in prep for gluing with Sikaflex. I helped Tony Patti glue his canopy last month. I saw with his canopy that at the rear sides about where the rear pax shoulder would be that the canopy pulls out on both sides about an inch or more. The question is should I clamp that down to the 1/8 distance before applying the Sikaflex? Tony did not and he's having a fit with his skirts. Seems to me that if I was rivetting the sides to the frame I would be pulling the rear sides in so it seems I should with the Sikaflex, but will it hold with the canopy always wanting to bulge out on both sides? I can always put in a few rivets there, but I would prefer not to. Thanks for your help, Bill of Georgia
 
canopy to frame gap

Hi Bill,

I would make sure you have the same distance between the canopy and the frame. If you think the canopy frame is not the right shape, then pull it apart a bit. I had to do some "reshaping" of the canopy frame, as do most builders. If the frame looks like it is about the right shape, then I'd clamp the canopy to it, and glue it. Don't worry about the sikaflex holding - as long as you treat the frame and plexi correctly as described on the wiki, it will hold.

I recommend taking some time here, because the shape you set will affect the shape of the skirts as well, and you want it to look good when you look down the side of the aircraft. Of course, good fiberglass work can cover up just about any mistake - at least I hope so!

Regards,
Mickey
 
gap normal

I had the same concerns- - it seemed like forcing things into shape was not good. but after consulting with those who have gone before and the mfgr. of the canopy, I went ahead and boldly clamped things down (with the appropriate gap) and glued it in. so far so good. good luck with the skirts. exercise in futility. I'd go ahead and stock up on some liquid ameliorant (bushmills) beforehand.
 
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Canopy/frame gap

I would suggest that you be cautious on how much you clamp the canopy to close the gap. I had a gap at that spot and I clamped it down but I don't remember how much. Anyway, it does set up a stress in the canopy. I know this because mine cracked right behind the passenger's left shoulder. Started at the bottom and went up vertically about a foot. We were traveling from Tenn to PA on 6/30 and had cycled from 90 or so on the ground to 32 at altitude. It cracked on long final on an instrument approach into an airport in PA. It startled my wife who in turn startled me.

I believe that it cracked to relieve the stress I set up by clamping it. At the bottom half, the material forward of the crack was about 1/32" high and the at top half the material aft of the crack was high by the same amount. Stop drilled it and flew back to AZ a few days later.

I really, really don't want to have to replace the canopy though I will probably have to eventually. I dread having to remove all that Sikaflex. In the meantime, rewelded it using Weldon #4 and I'm resurfacing it using the Micromesh kit. I'm sure it will still show though.

The point is to be very cautious on how much stress you put on the plexi.
 
reshaping canopy frame

Hi Bill,

I didn't reshape the canopy, but I did reshape the canopy frame. I just did this by pulling, etc. with some leverage.

Regards,
Mickey
 
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