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  #1  
Old 06-16-2007, 09:45 AM
ratc's Avatar
ratc ratc is offline
 
Join Date: Jan 2006
Location: North Yorkshire UK
Posts: 152
Default Canopy drilling and riveting?

Clearly lot's of builders have completed this daunting and tricky task without incident! Let me say I've just about got the frame to fit the fuselage and the canopy is still safely tucked away in the finish kit box untouched

My thoughts on the sequence of drilling and riveting the canopy are this.
1.Drill the canopy to the frame.
2.Fit the sideskins
3. Using a hole finder drill the sideskins to the previously drilled canopy/frame.
4. Apply a thin coat of sealant [proseal] to the frame/canopy and the canopy/sideskin and rivet.
Sounds easy when I say it fast

What other methods have those who have been successful used?
Anything else I should consider before I start?
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  #2  
Old 06-16-2007, 11:02 AM
Brian Vickers Brian Vickers is offline
 
Join Date: Mar 2005
Location: Bainbridge Island, WA
Posts: 328
Default

Andy,
I just completed the canopy. I pretty much did what the builder manual suggested and it all worked out fine. My plexi bubble was wide in the tail and therefore required significant pressure to pinch it against the frame. I ended up using several rounds of heat lamp softening and pinching the bubble sides together to reform it. I then pop riveted it to the frame just in the tail area. I think only three rivets per side to tack it on and hold the tail section against the frame tube. The rest was held to the frame with fiberglass reinforced packing tape. I then fit the side skins. No other holes yet. Once the side skins fit I drilled through the entire assembly into the frame tube as per the plans. Others have done differently with good success also. I believe Steve in the UK is gluing his on, no fasteners; another worthy system to consider.

There have been pervious threads on the RV4 canopy phase so you might want to search and take advantage of the many posts explaining other ideas. Good luck

Sincerely,
Brian Vickers, RV4 finishing
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  #3  
Old 06-17-2007, 12:12 AM
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ratc ratc is offline
 
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Location: North Yorkshire UK
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Brian,
Thanks for your comments, I did check through previous threads but it's always nice to see if any of the "current" builders have found new methods based on updated techniques.
Steve and I have discussed gluing at length. Whilst the results are very good it does raise other issues which only he has addressed on the -4. Of course the two methods have unrelated problems of their own.
The secret seems to be just keep chipping away at it and solve the odd problem as they appear.
Back to the canopy.
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  #4  
Old 08-14-2019, 06:31 PM
FinnFlyer FinnFlyer is offline
 
Join Date: Aug 2018
Location: Bell, FL
Posts: 174
Default Pop rivets to hold canopy while fitting skins

(Hoping Brian is still monitoring posts here.)

After drilling the rest if the holes through side skins, canopy and frame tube, did you then drill out the three pop rivets on each side? Manual doesn't mention that, but I'd like to expand (elongate fore-aft) the canopy holes as well as polish the holes to avoid any cracks.

Maybe also countersink the canopy holes and dimple the side skins? Does countersunk (flush) 1/8" rivets come with soft alum mandrel?

I do have a tube of 3M5200. But says "not recommended for bonding windows", so I think I'll go with the pop rivets.

Finn

Quote:
Originally Posted by Brian Vickers View Post
Andy,
I just completed the canopy. I pretty much did what the builder manual suggested and it all worked out fine. My plexi bubble was wide in the tail and therefore required significant pressure to pinch it against the frame. I ended up using several rounds of heat lamp softening and pinching the bubble sides together to reform it. I then pop riveted it to the frame just in the tail area. I think only three rivets per side to tack it on and hold the tail section against the frame tube. The rest was held to the frame with fiberglass reinforced packing tape. I then fit the side skins. No other holes yet. ...
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  #5  
Old 08-14-2019, 09:30 PM
Brian Vickers Brian Vickers is offline
 
Join Date: Mar 2005
Location: Bainbridge Island, WA
Posts: 328
Default Canopy

Hi Finn,
No, I didn't drill them out, but seems like it wouldn't be too risky. I countersunk the plex and dimpled the skirt. I don't have any sealant or adhesive in between the frame, plexi or side skin. I do have "proseal" holding the fiberglass fairing around the front. When the canopy gets wet there is a little water in between the skirt and plexi, but I've never seen a drip while flying in rain (rarely fly in rain). Mostly I notice it when washing.

I don't know the mandrel material. I have several plastic bags of left over flush pulled rivets but the writing on the bags has faded and I can't read it to determine the part number.

The canopy is the most nerve wracking component of my airplane so I'm always super gentle with it opening and closing, cleaning, etc. I still haven't fabricated some type of hold open for taxi in hot temps, and I'm still using a rope lanyard to retain it when fully open.
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  #6  
Old 08-15-2019, 04:46 AM
fixnflyguy fixnflyguy is offline
 
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Location: Winston-Salem, N.C.
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Default What I did..

I finished mine 10 years ago, and did use Proseal between the skirt and Plexi, as well as the Plexi and frame. Essentially, I drilled everything up, countersunk the Plexi and dimpled the skin using 1/8th Clecos in every hole then when I was happy with the fit, I oversized the holes in the Plexi only slightly larger. Next I applied Proseal to all the members, Clecoed in every hole and let cure with no rivets.After that, I installed the pop rivets wet with Proseal in all the holes and edge sealed the entire perimeter. Proseal paints well, and the finished edge looks good inside and out. Using this technique, the Plexi has no hard point stress, and the canopy is completely sealed from water intrusion.
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  #7  
Old 08-15-2019, 06:58 AM
FinnFlyer FinnFlyer is offline
 
Join Date: Aug 2018
Location: Bell, FL
Posts: 174
Default

Thank you Brian and Bill.

There are reports of cracked canopies installed with no fasteners and only Sikaflex or 3M5200, leading me to think that those adhesives (even with a bit of spacing between frame and canopy) do not allow enough movement of the canopy relative to the frame.

After reading multiple threads on canopy cracking I'm convinced that the solution to cracking caused by thermal expansion/contraction is to let the canopy ride on rivets with oblong holes (horizontal slots) in the canopy.

On the RV-4 I think that the fixed area should be around the front bow, then progressively longer slots with the longest slots at the most rearward rivets. I'll obviously have to calculate the lengths of the slots based on alum and plexi expansion rates and temp when I drill the holes. (If drilling holes on a 90F day the slots mostly have to be elongated to the rear.)

I'm worried about the stress caused when pulling countersunk rivets with steel mandrels. I guess I could pull them to the tightness I want and then cut off the mandrel.

I realize that slotting and polishing the holes (especially if countersunk) sounds like a lot of work, but in the big picture of cutting and trimming the canopy and the cost of the canopy I think it will be worth it for peace of mind.

Finn
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