(Fabrication) Order for some things on the canopy

[Draker]

Working on a rough plan for the canopy. I'm at the stage where my canopy frame is riveted together except for the aft section where the two U shaped flanges meet. Some of the steps are spelled out in the plans, some not so much. Any best practices or tips you'd like to share? I'm planning to go the Sikaflex route if that matters.

1. Centerline on the canopy, frame, and skins
2. Rough trim the canopy
3. Progressively trim until the fit is good across the canopy skin and roll bar
4. Mark big cut line on roll bar and canopy
5. Big cut
6. Final trim to correct fit and position
7. From inside, adjust F-631 ribs so they contact the canopy and then clamp to rollbar
8. Drill remaining holes through F-631 and splice plate
9. Attach canopy to frame
10. Final trim aft edge to the roll bar
11. Trim aft window
12. Attach aft window to roll bar and aft top skin
13. Drill and rivet side skirts
14. Install WD-622 canopy lug "fingers"
15. Install WD-621 aft canopy handle

A few things that are not spelled out in the plans. Not sure where they should go in the sequence:

• Rivet the C-702 skin to the frame - Obviously needs to happen before attaching the canopy but when?
• Optional canopy reinforcement braces - Also needs to be done before attaching the canopy but does it matter when?
• Rivet the F-631 and splice plate - Obviously after final drilling them, but should these get riveted before attaching the canopy?
• Gas struts - No mention at all in the plans as to when these go on. Probably can defer to much later
• Canopy lift handle - Ditto
• Rivet cabin frame channel to rollbar and F-706 bulkhead - These are still unriveted. Not sure if I should wait until after the rear window is fit to do them
• Rivet the curved skin that the window attaches to. My guess is this needs to be riveted in place before the window is attached.

Read a few build logs but where these steps fit in is still pretty hazy to me. Any best practices or pitfalls I should know about?

[Draker]

Changed the thread name to include other general canopy questions. This part of the build is a real head scratcher.

While fitting the canopy I happened to notice that the forward part of the frame now sits about 1/4" from the deck, instead of 1/8". Aft is still 1/8" as it should be. This must have changed some time between when I built the frame and now, probably when I drilled the pivot holes. Is this something I can fix? I'd hate to go build a new canopy frame but then again I don't want wind blowing in through this gap. I think I'm going to have to stop trimming/fitting the canopy until I figure out what to do about this gap.

[Blake]

I have a gap on my front of my canopy just like that if not more. You can buy thick foam to close that gap. Stuff that they use to seal canopy?s on truck beds. The gas struts on my canopy made my gap that big and I built forward canopy stops built into my sub- panel. Pm me and I can send pictures if need be. And I?m not flying yet.

[Draker]

I'm thinking at this point to try drilling out those rectangular C-613 splice plates that connect the forward and aft portions of the canopy deck and re-do them only. As far as I can tell, those are what "lock in" the forward/aft angle of the frame.

[Glen P]

I'll be following this thread. I'm doing the big cut (or is that The Big Cut) today. I've already spliced the F-631's together. It seemed reasonable to commit to a width more or less identical to that of the roll bar. I'll do the side skirts soon after attaching the canopy to the frame. My plan is to delay doing the aft window until I've finished a few more things in the aft fuselage.

[Draker]

Just to close on the canopy frame gap: Re-drilling new splice plates worked to correct the problem. I think the key was to rivet the thing together while securely clamped in place on the airplane, rather than riveting it together on the bench.

[Draker]

Originally Posted by Glen P

I'll be following this thread. I'm doing the big cut (or is that The Big Cut) today. I've already spliced the F-631's together. It seemed reasonable to commit to a width more or less identical to that of the roll bar. I'll do the side skirts soon after attaching the canopy to the frame. My plan is to delay doing the aft window until I've finished a few more things in the aft fuselage.

Good luck! If the weather heats up this weekend I'll be doing the same thing, now that my canopy frame is fixed. Of course after a scorching hot week, the weekend (when I planned to cut plexi) is forecast to be a little cooler.

[Davea320]

Take into account that the sika will need a space between the roll bar and canopy plus the forward skin and canopy. I used 1/8 solid tubing wrapped in electrical tape and pulled them out after the sika set up. I then filled the holes with extra sika.

I didnt realize how the 1/8? would affect my canopy side trimming. Trimmed a little more than I needed and ended up with less bonding surface than I would like. Fortunately that sika stuff is super strong, so after I bond on the side skin I think I?m still in good shape.

I?m not putting in the aft window and aft skin until all my wiring is done in the rear fuse. No forward aft skin made installing the static line and AHRS bracket easier too.

I installed the canopy frame brace kit which really stiffened up the frame and made canopy installation more secure. I also installed the gas struts as they seem to move things around too. Ie the gaps between the canopy frame and fuse seemed to change a little.

I fiddled and fretted about the canopy fit for a while and in the end it seemed to end up where it wanted. Had to make one new side skin and probably gonna need some thicker weather seal on on side.

Hope this helps.

[Draker]

Boy, this canopy changes shape every time you breathe on it. Even if you get it sitting on the frame exactly right after each step, you rivet it, then attach the canopy, then rivet the side skirts, then add the gas struts, then add the weatherstripping, by the time all that is done, the fit ends up completely different! Final verdict: mine nicely lines up with the fuselage skin along the sides, and rests evenly on the roll bar, but the front fit is pretty bad: The front frame+skin is 1/8" too wide on the left side and 1/16" too wide on the right side, and I'm back to having 3/32" 'air scoop' gaps between the canopy skin and the forward top skin, probably due to the weatherstripping on the sub-panel. Not sure if anything can be done at this point. I hesitate to squeeze/bend the frame since it's riveted together and the canopy is permanently attached. Maybe very gently work the skin with a sheet metal shrinker? I don't know. My instinct is to just leave it alone and accept that this is a tough subassembly to get perfect. Not a show plane.

[Draker]

....and as I lifted the canopy to make a few adjustments, I just managed to join the great and venerable "tip up canopy skin catching on the front skin" club. Have I mentioned how much I dislike this canopy assembly?