Canopy Skin Fit

[pilot28906]

I am working on fitting the canopy frame and skin on my RV7. I have the frame on the fuse. and the skin clecoed on the frame. I also have the top forward skin clecoed on. I have the canopy skin and forward skin butted up against each other at the ends but there is a huge gap on top at the center. Am I supposed to file down the forward edge of the canopy skin at the ends until the center touches?[IMG][/IMG]

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Thanks

[wjb]

Hey John,

I'm going though this phase right now, too. Misery loves company! ;-)

Be sure that the aft end of the 702 skin (near the tab) is flush with the top surface of F-721A canopy deck. I found that I had to put some shims between the frame and the deck to hold this alignment. This will move the center part of the 702 skin forward, closing the gap. If you let the frame rest on the deck, it will be too low, leading to a bit gap in the middle.

I did have to file down the edges of 702 near the deck for a bit of fit help. I'm holding off doing any more until I get the forward panel substructure in place and the forward top skin on. Everything is a bit squishy up there with clecos only.

Here's what my gap looks like with no more than 1/16" trimmed off the outer edges of 702:



Any more trimming will wait until the structure is stable.

[pilot28906]

Thanks Bill, I will give this a try. The more I read the more I see the canopy will probably not be perfect.

[wjb]

Go slow ... as other posters have said, it is a bit of a Zen thing. Everything else on the AC is designed to be structural .. once you button everything up, the structure makes a solid, self-reinforcing, locked-in structure.

The canopy does not get any of this geometry magic. It's a big bubble of soft plastic with a thin Al frame. You need to coddle this part of he build. Go slow, listen to the frame and adjust to your particular canopy plastic, frame, and phase of the moon.

I'm going slow; so far so good.

[BillL]

Originally Posted by pilot28906

Thanks Bill, I will give this a try. The more I read the more I see the canopy will probably not be perfect.

Maybe not perfect, but there are a series of points that have to be right or the cascade of errors compounds.

1. drilling holes in pivot - must have spacers under frame rail.
2. splice joint riveting to control the center contour
3. pivot flange rivet to frame correctly to have curved sides mat
4. Canopy attached to side rails before attempting to match fuse contour.
5. Splice joint on back hoop to match width and shape of roll bar.
6. Length to back hoop

Please use the search function. I have addressed each of these. (as have others)

Here is the failure mode typical in each of the above steps.

1. Pivot is too far forward. No clearance for skins to open canopy. Frame rails seem too short.
2. The frame is too low at the center forward splice joint: skin is deflected and catches on lift, it also forces the curved ends high causing scoops.
3. Width and curve matching is resulting in scoops
4. Pefect rails will be off by .050 after the canopy twists the rail for the contact area to become flat. It is a deflection balance between the canopy and rails (in twist)
5. The contour of the canopy will not fit the roll bar and width be off at the rear lower corners.

I can not say addressing these will result in perfection, but they can definitely result in the listed issues. VOE

[pilot28906]

Thanks Bill L. This is great info. I will be moving slow and watching the details and referring back often.

Thanks

[pilot28906]

I think I messed up on #3 above from Bill. The fit looks pretty good except there is a scoop on the right side about 3/16" or so, left side looks good. The hinge brackets are drilled but the holes for the hinge pins have not been drilled. Can this be made better when drilling the hinge pin holes or should I try to bend the right side frame from the hinge down to the rail?

Thanks for you guys help on this!