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Old 07-10-2017, 10:55 PM
JPalese's Avatar
JPalese JPalese is offline
Join Date: Apr 2011
Location: KHXF
Posts: 143
Default RV-7 Tip-up Canopy Question

I finally did it and pulled the trigger on an RV-7; which passed it's pre-buy inspection with flying colors.

The aircraft has a tip-up canopy - after several flights - during the last 12" or so of travel when closing the canopy (or ~12" of initial travel when opening the canopy) the trailing edge of the canopy has a pronounced movement to port. The movement during this 12" or so of the canopy arc is enough to have the inside edge of the starboard side of the canopy contact the outside edge of the starboard seat.

Any thooghts?
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Old 07-11-2017, 06:19 AM
BillL BillL is offline
Join Date: Sep 2007
Location: Central IL
Posts: 5,745
Default Tip up canopy was my greatest challenge . . .

The finished canopy and frame is decidedly flexible and it is easy to twist the back if not lifted from the center. I am not flying but have completed the canopy fitting with about a 1000 openings. Have you tried lifting the corner then opening from the top center and then when closing only using the center latch handle, is it still twisted and scrape on one side?
Does it have plastic guides on the roll bar to guide the last 3" before closing?

Getting deeper. If it IS twisted, now we need to know how much, and if it is a combination of yaw and twist. Then, how is the front skin mating to the fuse? i.e. if simply rolled a bit, the mate with the fuse should also show it being off.

There are many indicators for what is really happening from operating technique to lets call it "assembly tolerance". I have gotten mine to fit pretty well around the perimeter and had to use a lot of off book tricks.

Pictures would be a big help.

Edit - you might remove the gas struts for a check to see if how the canopy acts unstressed.

Lord Kelvin:
I often say that when you can measure what you are speaking about,
and express it in numbers, you know something about it; but when you
cannot measure it, when you cannot express it in numbers, your knowledge
is of a meager and unsatisfactory kind.

Last edited by BillL : 07-11-2017 at 06:23 AM.
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Old 07-11-2017, 06:57 AM
dpansier's Avatar
dpansier dpansier is offline
Join Date: Jan 2006
Location: Green Bay, WI (GRB)
Posts: 504

Assuming the canopy is built straight, check the gas struts. A weak strut will cause the canopy to twist.
Don Pansier
Green Bay, WI (GRB)
RV-7 N450DP

Antennas for Experimental Aircraft
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Old 07-11-2017, 08:24 AM
DBone DBone is offline
Join Date: Dec 2006
Location: McKinney, TX (T31)
Posts: 208
Default takes a little practice

It takes a little practice to operate the tip-up without banging the opposite side on closing as you describe. When standing on the pilot side and you're closing the canopy... As you are lowering it down and you get to the last 12" or so, the whole thing is twisting so your side is out a little and the opposite side is in a little. As you're lowering it, you have to push just a little bit so that the canopy doesn't twist towards you. If you just hold the canopy 6" above full closed, you can feel how the canopy moves as you push it a little. Once you practice this a few times, you'll get a feel for how much of a push your canopy needs to close properly.
Dave B
McKinney, TX (T31)
N517AD - RV-7A - Sold
N963TP - RV-7A - Partner
N10HW - RV-10 - Partner
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