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Steve Sampson

Well Known Member
I have just arrived at the dreaded canopy. Having reviewed the past threads I cant see anyone else saying the frame itself did not fit too well.

The problem I have is that if you set the RHS so the skins will be flush with the fuse, on the LHS the frame sits about 0.25" inside the fuse outer face. Its .225 too narrow. (The skin thickness will be .025 so I still have a .225 mismatch.) Has anyone else had this degee of discrepancy?

I can bend the fore and aft frame, however the only way to adjust the centre, presumably, is to cut it and rivet a plate over. I am not too happy to do that.

I would welcome input from those who have been here. I will measure the fuse width tomorrow, but I doubt that is the problem.

Thanks, Steve.
 
Hi Steve
You hit right on it. I have seen a few canopy frames with this modification.
Have you check the width of the fuselage? It could be flexed outward.
Outside of asking Van?s for a replacement canopy frame your choices are limited.You could center the frame and install .100 shims under the skins. I think cutting the frame and installing a plate is the better choice.
 
Canopy frame

Steve....I had to modify mine both at the front and at the back......cutting and adding a piece at the back (tail) and then rewelding. The center section did not need too much in the way of changes. (Sorry I don't have any pictures of the changes (no digital cameras or scanners when I was building ;) ). Some guys choose to rivet tubing back together (inserting a stub) but I am comfortable at welding AL so it was not a problem.....If you have to cut the center, add or remove a piece and re-rivet it should not be too difficult.....In order for the side skins to fit up nicely the frame should fit properly first......
 
Cut the bulkhead

Yes, I cut the center canopy frame bulkhead. I have seen very few RV4's that didn't have to cut the frame. My fuse is slightly too wide by about 1/8 inch. I can't falt the canopy frame because it measures precisely as drawn in the builder plans. The blame falls on me for the need to cut.


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Hi Steve

My canopy frame was off by the same dimension. I cut it as well and came up with a solution that looks so much like what brian did that it is not worth adding another picture. The main problem seemed to be the front-bow though. It was almost one inch to narrow to match the shape of the panel. I checked and reckecked my fuselage wich obviously seemed to be to wide. It was not and I ended up with another cut. This time I inserted a solid centerpiece and riveted it in place using AN5 rivets. I do not have a good picture of it but it can be seen in the following video.

http://www.rv-4.de/video/Trudeln.wmv

Happy landings

Thomas
 
Dayton/Marc/Brian/Thomas - thanks so much for your supportive messages. Once again it has boosted my confidence that its not just me. It is interesting you used AN5 rivets on the front bow Thomas. Did you set them with a squeezer? Why did you choose to use those?

For this part of the project ally welding skills might be very useful. I wish!

The canopy frame is now on the back burner, because this morning I had the offer of help to get the wings on. This now opens up a whole range of jobs that need to be done. I will return to the canopy when the wings are back off.

Thanks again.

PS Thomas, your videos and 'Tree Top Flyer' are by far the best RV4 stuff I have seen on the web. I have all of yours downloaded onto my computer and regularly check them out for an enthusiasm boost if I am struggling with building. I look forward to flying my -4 to Germany and meeting up with yourself and Dirk.
 
Hi Steve

When I had cut front-bow, I somehow needed to fix it. One option would have been welding it up again. I do have a tig-welder and I am quite comfortable with aluminum but I did not now what kind of alloy it was made of and had no material available to go in between.
A solid splice-block out of thick aluminum was fabricated. It was cut
out without bending and filed into shape. It went inside the squared-tube on both sides. I could have welded it at this point but I did not know what kind of material the splice was made of. The only way to be sure was riveting although I agree that fixing the bow by welding in the correct tube using the correct alloy would have made the best repair from the cosmetic and structual point of view.
Maybe AN4-rivets would have been sufficient but I simply had no rivets of that length lying around.
So I took four of those AN5-spar-rivets, cut them to fit and set them with the C-Frame tool. Tt is not a light-weight-solution but it works for me.

PS Let me know when you are flying your RV to germany. You have to stop by then and we will arrange a little european RV-4 meeting with Dirk who will be flying his RV pretty soon.

Thomas
 
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