W

walkergp

Member
I am getting ready to start installing front seat ramps and need to get the weldments installed. I can't seem get them to sit flush to the forward face of the of center section or the flange at the bottom. This results in wing attach holes and holes along lower longeron not lining up. I have tried to trim any skin interferences with the landing gear leg cutouts but it still will not seat right. It appears from the time I drilled the holes in the forward fuselage sub assembly and riveting the fuselage some alignment or angles have changed.

Very frustrating. Any ideas?

Thanks,
Greg Walker
81231
 
I had the same problem

You are right, it is frustrating. There is no silver bullet here. I just kept fiddling and trimming till it finally fit flush (and it will). Use a good light to see where your interference is and then trim to fit. You will have to put it in and take it out scores of times, but you can massage it in there.

May the force be with you.
 
Not your fault

FYI, while my 8A gear weldments were spot on, two other local builders had problems with theirs. Both had warped during the welding process. One builder had an issue with the left side weldment where the tube which runs forward/outboard to the lower longeron area. It was welded so that it was about 1/2" to high where it contacted the side of the fuselage.
His options were to send it back and get a replacement or repair the problem. To save time, he cut the tube, machined a plug to fit inside the tube then re-welded the tube [over the plug] so that it fit properly.
Second builder was not so lucky. His was so messed up, that he had to send it back. When you call Vans to report the problem, expect the following reply. "Gee, no one's ever had a problem with [insert part number or name of piece here]. You are the only one who has ever had a problem."
I've had to send a few parts back, due to errors in Pre-Punched parts. I ALWAYS was given that line. [even when I knew other builders who had the identical problem] All the other local builders have heard it as well! You need to determine if the issue is with the weldment or if something has changed with the fuselage. One way to determine that is to compare the left and right weldments to each other [place them side by side to compare]
Your choice as to how to handle this problem.
Charlie
 
Last edited:
Different Problem

Thanks for the insight. Looking at it closer the aft portion of the lower longeron is displaced vertically about 1/8" higher than the lower flange of the center section. Not sure how this could happen when everything was aligned during the initial drilling. I don't think replacing any parts will help since the canoe is completely riveted. I need to figure out a repair approach.
 
Tough Puzzle

My weld mounts where installed on my QB but on the advice of another builder I checked the clearance of the wing bolts and sure enough they would stop at the weld mount holes. I had to remove them to open up these holes so the wing bolts would slide through without interfering with the weld mount. There was a bit of tension on the bolts holding the weld mount extension to the lower longeron, so much so the AN3 bolts I took out where bent. This sure made getting the weld mounts in and out a pain but I am glad the builder told me to check this otherwise I would have discovered the interference when I went to fit the wings. When I read through the plans it is when you are working the center section that you are to check the fit of the weld mount and clearance with the wing bolt holes through the spar. When I called Van's with the problem they said the QB factory uses another gear weld mount during this part of the build not the ones that end up in your plane.

It was then I cursed doing the nose wheel model, then more cursing as I worked all the engine connections in and around the nose gear mount. In the end I think it was worth it, I now have 7 hours on my RV-8A and it sure is easy to land.

Good luck and keep at it.

Cheers
 
Lower longerons

I am working on a slow build -8.

Not sure if this helps but my lower longerons were under bent from the factory. A few good whacks with a big hammer did the trick.
 
walkergp said:
Thanks for the insight. Looking at it closer the aft portion of the lower longeron is displaced vertically about 1/8" higher than the lower flange of the center section. Not sure how this could happen when everything was aligned during the initial drilling. I don't think replacing any parts will help since the canoe is completely riveted. I need to figure out a repair approach.
Click to expand...

A photo or two would help greatly to visualize your issues.

Charlie
 
You must log in or register to reply here.