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Old 06-10-2017, 05:58 PM
Snoho3 Snoho3 is offline
Join Date: Dec 2012
Location: Snohomish, WA
Posts: 74
Default Trimming a -9A Tip Up Canopy

I have the canopy sitting for the first time on my fuse as a trial fit. I have already trimmed off the extreme edges of the canopy, back to the tooling markings. I have drawn a line down the centerline, so side to side I can be sure it is positioned properly. My question is this - how do I know how much to trim off in the front vs. the back? I realize I will be doing many on/off fittings, and smaller and smaller trims, but I see no guidance on this.

The plans says the forward edge of the trimmed canopy should reside 1.75in from the front edge of the C-702 skin. Fine - does that mean I trim off 2 inches from the forward edge of the canopy and 4 inches from the back end (for example) or 4 inches from the front and two inches from the back? At some point the canopy has to contact the bow frame, so it seems to me the forward vs aft trimmed amount is critical as it affects the final height of the canopy.

Even if I do this 1/2 inch at a time, I have no idea what I'm shooting for, other than a flush fit on the C-702 skin.

Would someone who has been through this please let me know your approach to this initial, larger trim cut? Many thanks in advance - all input greatly appreciated.

RV-9A - Tail, wings complete
QB Fuse complete
Finish Kit in work
2018 dues gladly paid
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Old 06-10-2017, 06:29 PM
BillL BillL is offline
Join Date: Sep 2007
Location: Central IL
Posts: 4,270

State where you are on the separation - this might not make sense yet.

I don't remember the instructions clearly, but If you have made the separation cut, then it will be somewhat interactive between trimming the front and rear. As a goal, You will want to have the back of the canopy to reach to the center of the roll bar. It is unlikely to be even from the cut. Don't do anything yet as trimming the front and sides will drop the canopy and change the rear. So the first, just pay attention to where it is. Then begin trimming the front and sides. Don't do the front too much, as when the sides fit, and it is brought to be tight against the rail, it will pucker the front upward.

The so, between fitting the front and sides, while keeping the back in mind, just monitor the Vans specified dimension. Once the sides and front fit well, then square up the back, leaving some extra for perfectly matching to the window once the canopy frame is final and the front skin is installed. It is the LAST thing to trim on the canopy

My 2 cents.

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Last edited by BillL : 06-10-2017 at 06:33 PM.
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Old 06-10-2017, 06:30 PM
sahrens's Avatar
sahrens sahrens is offline
Join Date: Jan 2007
Location: Northern CA
Posts: 365

Here is my build log covering my process to trimming my canopy. Although I am building a RV-7 the process is very similar.

If I can answer any specific questions please let me know.
Scott Ahrens
RV-7 N818BG
Test flight in progress
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Old 06-10-2017, 11:08 PM
Snoho3 Snoho3 is offline
Join Date: Dec 2012
Location: Snohomish, WA
Posts: 74

Bill- thanks for your reply. Appreciate your insight. No, I have not made the big lateral cut yet.

Scott - great build log. Really appreciate the time you took to document your process. Wish I'd found this earlier. Thanks very much also for your PM - if I get stuck l'll definitely be in touch. I've taped off where I think the first cut on the forward edge should be. Tomorrow I'll give it another reality check then start the trimming.

RV-9A - Tail, wings complete
QB Fuse complete
Finish Kit in work
2018 dues gladly paid
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Old 06-11-2017, 05:08 AM
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KRviator KRviator is offline
Join Date: Oct 2009
Location: Sydney, Aust.
Posts: 687

G'day Lars,

I had my canopy frame essentially complete and traced around that onto the plastic, then trimmed to those lines before removing a few small iterations around the front corners to get the fit as close as I could.

Here you can see the "inner" line that marked the actual edge of the aluminium, with another line an inch or two further out. This second line was the "Cut here" line, and while it is not perfectly parallel to the opening when installed, it is close enough for RV work!

The Big Cut, Cut. Lots of duct tape used to keep things together as it progressed and stop the cut getting away from itself.
Once you have tasted flight you will forever walk the earth with your eyes turned skywards, for there you have been and there you will long to return - Leonardo DaVinci

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RV-9A 19-8519 - Finished on 10th February 2016 after 4 years, 9 months and 19 days! The 1020th RV-9 flying.

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Old 06-11-2017, 06:48 AM
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agirard7a agirard7a is offline
Join Date: Aug 2009
Location: Newport, RI
Posts: 626
Default Big cut

I think you have this under control. Don't cut the sides
For the rear canopy before you do the big cut. I mistakingly did this
And almost came up short.
Al Girard, Newport, RI
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