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Tsabean 05-09-2021 08:30 AM

Fitting Plexiglass Bubble to Canopy Frame
Working on fitting the bubble to the frame. It sits too high at the aft end.
Searching the archives, some have mentioned cutting off the aft end of the support tube.
Any tips on how much to remove?

Cheer, Tom

HFS 05-09-2021 10:00 AM

Sitting Too High @ The Aft End
If you mean the canopy hits the tubular frame before contacting the turtleneck skin - hence the canopy won't go any lower for the install, that is a problem that is not unusual given the vagaries of the RV-4 canopy frame production.

Not unusual to cut the bow right at the trailing edge, draw it together the necessary amount, re-weld it and build on.

I'm not sure I've seen it before on -4's, but I do know of -3's that have completely removed the aft portion of the bow to solve your problem.

I have seen -4's with partial removal (without the re-weld at the back) of the tube, and the amount of removed material was kind of all over the board - some go almost to the tail, others more (some much more) forward. They all seem to work - kind of up to you as to what you feel comfortable with?

YMMV - And probably will!

RV4 S/N 1136 Built, Flying, Sold

fixnflyguy 05-10-2021 06:12 AM

What I did
2 Attachment(s)
I cut my bow at the centerline and removed a little bit at at a time until the canopy bubble fit down over it. I then got a piece of tubing (3" or so long) that fit inside of it, curved it to match and and installed it with a few pop rivets and epoxy. Welding is also a "normal" operation as its 6061 and very weldable. I simply didn't want to haul it off to weld it. The canopy is the hardest part of building a -4! Can't really see in these pics, but I can take some when I'm down at the hangar..The side skins are the next challenge once you get the frame/bubble fitted. Lots of dynamics here that need much pondering before drilling and riveting!

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