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Canopy Frame Repair

Lt Dan

Well Known Member
Greetings!

In January I bought a wonderful fastback RV-4 from a guy in Kansas City. I'm very happy with it - in about four months I've put about 100 hours on it! :D It was finished in '08 and is built nicely. From what I hear the 4's did not have very good plans and building instructions making them more difficult to build than the rest. No offense to the builder at all, but the canopy was definitely not his strong point. It has always bugged me that (1) it takes a considerable slam to close it right, (2) it leaked like crazy until I put about 10 feet of weather stripping on it during this latest record-setting cold winter, and now, most importantly, (3) the bulkhead / cross-brace just aft of the roll bar and above the passenger's knees has separated from the longitudinal frame tube on the right side. After some time, I noticed recently that the only thing keeping the bulkhead attached is a single rivet (to the skirt) on the right side. Furthermore, there's now a crack in the paint on the outside where the rivet attaches. I have no building experience so I need some help deciding what to do with this problem. I believe I may have to remanufacture the bulkhead entirely since the present one appears too short by about a half an inch, causing this problem to begin with. Not sure if there are plans for this part, etc...

Or, considering the possibility of a complete canopy makeover, does anyone know who the canopy building expert in my area is? (Dallas/Ft Worth - Oklahoma City - moving to Tucson, AZ in August '16)

Here are some pics:


A closeup of the sole rivet holding the bulkhead to the skirt



The right side of the skirt from the outside:


Showing the crack:
 
If it's a fastback then the canopy frame was fabricated from scratch. It looks like the welds broke loose so you may have to find a good tig welder.
 
Apparently nobody really likes building the canopy...

Dan,
The primary issue is that being a fastback RV-4, it is a hybrid, probably one of a kind airplane (I am not aware of anyone that ever sold an after market kit for a fastback canopy on an RV-4), so there is nothing specific that anyone can really provide you in the way of specific tips on how to repair it.

It appears to be a failure at a weld that was possibly poorly done (seems to be little penetration).
It would probably be risky to re-weld that location without first removing the canopy which would of course be a huge job.
At this point a better option might be to rivet some type of gusset between the tubes.
 
Isn't Jay Pratt up around Ft Worth? I think he is sort of a for hire RV guru type.

Better figure that out before you get a crack in the bubble.
 
Apparently nobody really likes building the canopy...

I did, but you wouldn't like my time frame! (about 6 months) :p

I'd call Jay Pratt of RV Central like CATPart said. He can probably get you fixed up, or at least point you toward someone who can. He's based at Hicks. Super nice guy.
 
Looks like you could split some tube length wise then weld up an el to fit the broken tubes and you could rivet it in place. Probably should do other same to the other side too_Otherwise your going to have a huge job removing the existing canopy, welding the tubes and attaching a new canopy.The old weld looks like they never melted the long tube and just gobbled on some weld and it broke.
 
Thanks for the advice. I know that welding with the canopy 'in-situ' is going to be next to impossible. So is it a viable alternative method to fabricate a new bulkhead and rivet the whole thing onto the side tubes (no welding at all), or do you think rivets alone are not going to be strong enough for this application?
 
Removing canopy

If the builder left you a short piece of hinge pin in the front, you should be able to pull the pin with a needle nose visegrip, remove a few attachments and the canopy should come off within 10 minutes of work. I also have a fastback and installed it myself, starting with Van's canopy frame, removing what you don't need and improvise the rest. Really wasn't a big deal.
 
I built this fastback canopy frame from scratch, with the exception of the cross brace. I got it from Vans. It is probably cheaper than fabricating one from raw stock aluminum.
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... yeah, I built this.

Not my proudest build. Some of it went well, some went awful. That's one of the awful.

Dan, while I think you could rebuild it better... without experience, I think you'd actually build it worse. It's the hardest part to build on the airplane. It's a totally custom, complex and structurally-unusual piece where small subtle tweaks cause real problems. Rebuilding this canopy would probably take 2-3mo and $2k (just parts). The canopy is glued, not riveted or screwed. I used Sika, which is a marine product for sealing hatches.

Unless you just don't like the fit (it doesn't fit well around the aft, no pictures)
My suggestion is to get it repaired stronger than before. I will help any way you need. I'm sorry to see your having problems.
 
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I am doing the canopy on my 4 right now and I can tell you that it is a bear. I really want it to fit well and close tight and it is a very large open box shape that can rack and twist in more axes than I thought could exist 3 dimensional space. And that's the stock one.

I have been building stuff all my life, I weld, I have a lathe and mill and I'm a pretty handy guy. I thought this would be a cake walk. It isn't. It is hard. And it is a huge task even with all of the main structure complete. I have to try hard not to be overwhelmed.

So if somebody built a 4 and completed it and it flies well and just the canopy is a bit wonky they still have my total respect. I even realize now that the QB kits are still a helluva lot of work and there are a million decisions to make.

I agree that if you can rivet in some gussets and tie the tubes together that way it will be the best way to get back flying and done well it won't be unsightly.

I have no trouble believing a canopy took 6 months.
 
After some pondering and careful consideration, I think I have a a plan. I ran into a gentleman at the Denton Air Show this weekend who had a marvelously built RV-4 with a really nice canopy that fit like a glove. He had a gas strut attached to the canopy, which I also liked very much.

Here it is:


Looking at the plans that came with the plane, that bulkhead is C-402B. I emailed Van's and they got back to me immediately, stating that C-402B is in stock and is only $23.

The problem which I need to solve now is that the ends of that bulkhead are 6-3/16 inches high and my canopy skirt is only 5 inches high at that point. I could use some help in this department.

The guy at the airshow had some nice brackets attaching his bulkhead to the frame (no welds on the top).

I emailed Van's that picture and they did not recognize it as a Van's part. Has anyone ever seen this bracket before? I'm dying to know where I can get one.

More pictures:




In need of some ideas to get this bird flying again, as I have no building experience. Your help is greatly appreciated.
 
Dan, how far are you from Nacogdoches, Tx? I scratch built my canopy and it has a few extras you might be interested in. Hendricks flush latch, electric taxi lock, gas strut
 
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