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Old 12-16-2012, 08:05 PM's Avatar is offline
Join Date: Aug 2006
Posts: 165
Default Tip up canopy buldge fwd ends


Seeking advice on how to eliminate my canopy outward bow where it transitions to the C-702 skin.

I have already aggressively trimmed the canopy and the C-702 with not much success.

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Old 12-16-2012, 08:26 PM
bruceh's Avatar
bruceh bruceh is offline
Join Date: Mar 2008
Location: Ramona, CA
Posts: 2,511

Looks like you cut off the ears that are on the forward skin that would normally hold that bulging plexiglass in place. Once you get the side skirts on, they should help hold this in place, along with the screws or whatever you use to fasten the bubble in place on the frame. Ultimately, you will be building up a fiberglass fairing around the front and that will cover this area.
Bruce Hill
RV-9A N5771H flown over 900 hours!
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Old 12-17-2012, 09:18 AM
Rupester Rupester is offline
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Location: Mahomet, Illinois
Posts: 2,195
Default I had the same issue ...

My canopy lay nicely there on the L side, but clearly bulged outward more on the R side. I was just very careful working that R side .... that's where many TU builders have ended up with a crack when screwing that down tight. I just "massaged" that area as best I could, and when I finally put in the screws and nuts on the R side, I did not fully cinch down the 3 most forward screws. Canopy now looks good with no cracks. The ensuing fiberglass work (i.e. the laid-up fairing) around the front will seal everything up and cover most sins in that area.
Terry Ruprecht
RV-9A Tip-up; IO-320 D2A
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Old 12-17-2012, 05:11 PM's Avatar is offline
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Posts: 165

Thanks guys for the tips and suggestions.
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Old 12-17-2012, 09:12 PM
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N130WN N130WN is offline
Join Date: Jan 2005
Location: 8A7 (NC)
Posts: 339

I had the same thing. I kept trimming and it finally laid down. I cut the ears off the skin too, like you.

Then I did sikaflex. No holes or fasteners.
Larry Bowen
RV-8 Built, sold, missed.
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Old 12-18-2012, 02:43 AM
instructor_bill instructor_bill is offline
Join Date: Jul 2009
Location: Petaluma, CA
Posts: 233
Default yes, but wait-- there's more

yes, lop the ears off

Yes, trim to get a good fit

Yes, no mechanical fasteners is great

But, the bottom-most edge can be softened by sanding and filing so the transition is less drastic. We're not talking a bunch of material here, just enough to ensure there is less required filler to make the fairing roll smoothly into the skirts. Say 3/32 inch at most in thickness right at the bottom corner edge tapering to nil over about a half inch. Throw a straight edge against the skirt vertically across the lap joint to see how much you need to do.

You can do this after the canopy is fixed in place. Did mine this way with a 3m roloc disk in a angle die grinder and smoothed it out. It makes for a good mechanical bond for glass and filler as well.

I'd look for pictures, but its late. Maybe tomorrow.
Bill Mason

RV7 SB in construction
Avionics, Wiring, FWF, interior, and paint to go.

Last edited by instructor_bill : 12-18-2012 at 02:45 AM. Reason: I can't spell well, and I often ignore spell checker
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Old 12-18-2012, 07:30 AM
BillL BillL is offline
Join Date: Sep 2007
Location: Central IL
Posts: 6,320
Default Beware . .

Mine did this too and I used small pieces of modeling clay to determine the pressure areas forward of the last "factory screws". Beware:mine puckered at the front when the sides pulled in and resulted in a 3-4 mm gap due to the lift over the front frame skin. I think I am ok, but wish i had taken more time to firmly pull in the sides before drilling.

Others (don't remember who, B Swayze maybe) made some small clamps with a 1/8" thickness under the side rails to pull that bulge in. I wish I had taken the time to make those.

Another thing, that bulge will pull out the frame and "modify" your good work on frame tweaking. I have made a hanging rig to take the full canopy on/off, solo, in order to lower it to a shrinker/spreader and do final alignments. I just pick it up, roll fuse away and slide in a table with the shrinker. That alignment thing is something I want to conquer.

Good luck!

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Old 12-18-2012, 04:56 PM
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Steve Melton Steve Melton is offline
Join Date: Apr 2011
Location: Cincinnati, OH
Posts: 3,520
Default you will never see if after fiberglass

glass over it and fill to contour. mine bulged more on the L than R. after glassing it is same on both sides.... or close enough.

Thocker loaned me this. I like it.
Steve Melton
Cincinnati, OH
RV-9A, Tip-up, Superior O-320, roller lifters, 160HP, WW 200RV, dual impulse slick mags, oil pressure = 65 psi, EGT = 1300F, flight hours = 900+ for all

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