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Arrgghh: QB F-704 Center Section out of alignment

grayforge

grayforge

Well Known Member
Another couple roadblocks on the QuickBuild highway...

  1. The Forward and aft Center Section Sides (F-704C & F-704D) were riveted to the F-704E & F Center Section bars while out of alignment. The sheet metal slightly overhangs the bar hole opening on one edge, preventing the close tolerance bolts from slipping in. I ended up using a dremel tool and pneumatic angle drill (for the hard to reach holes) to grind away the sheet metal overhanging the bar holes, being careful not to touch the bar holes. What a pain!
  2. The bigger problem: After I was able to get the bolts in, I found the forward & aft bars to be out of alignment horizontally by 1/32 to 1/16. The aft side of the spar is offset to the left in relation to the forward side. Any suggestions on what to do here? Try using a big pry bar to shift the forward and aft sections into alignment? :-(

Close Tolerance Bolts Holes not aligned...
DSC01046_zoom.JPG


Further back for context...
DSC01046.JPG
 
Ouch

That looks like a real pain. I have a QB fuse on the way and have been dreading the potential of any similar issues. I'd be on the horn, with som photos to Vans first thing in the morning.
 
I received delivery of a quick build rv9a in August. Never thought to check that the bolts would go through the holes without the wing spar in place. So I just tried a few minutes ago. I'm having trouble just getting them through the aft center section piece, let along all the way through to the other side. I would try from the front but I have my landing gear weldments there right now for fitting.

I too will call on Monday to see what's going on here.
 
Hang on a minute ?

If you are using your CT bolts at this point, you are making a large mistake as they will NOT "SLIP" through. They are not designed to slip and will need to be driven in using a mallet, air gun, etc. but not now. You only want to use the CT bolts one time and that is the time you put the wings on for good. You stand a good chance of damaging something getting them in and back out if you do get them in.

At this point you should be using hardware store bolts which may but not necessarily slide through. Either way, they are substantially undersize compared to the CT bolts and you can get them in an out pretty easy.

It does look like you have a problem but it may not necessarily be so. I would trial fit the wings before I started prying anything around. I "think" don't recall for sure that the wing spars and center section are drilled as one piece. If that's true, it may be that they will align better with the wing spar in place. I would think it highly unusual for them to be mis-aligned but it does look that way in the pictures. I would think (not positive) that if you can get the standard bolts through without a lot of wacking, the CTs will go at final assembly. Call Vans before you do anything but dump the CT bolts for the moment.

My best advice is that anytime you think that Vans has messed something up, double and triple check the instructions. When it comes to the CnC machining, I had zero errors on my 7 QB but I did have some builder alignment issues :eek: trying to pull things into place.

Bill S
7a Flying
 
Thanks for the input Bill.

I used a close tolerance bolt to ensure the F-704C & D were aligned properly with the 3/4" bars. Alas, I couldn't even get the threaded portions of the bolt in. Once I made clearance in the C&D pieces, the close tolerance bolt actually went in with minimal effort... until it hit the bar on the other side of the gap, offset by 1/16 or so. :-(

I did buy some hardware store bolts for wing fitting. Slipping these bolts in shows the same issue.

I don't see an obvious solution. The forward and aft spar sections are solidly riveted to the bottom skin, so shifting them isn't gonna be very feasible. I'll have to check how far off the lower holes are. Maybe they're closer to fitting on the bottom portion and driving the upper bolts in will get them in. But I worry this will tear up the holes.

The center section spacer bolts go in, but they require tapping with a hammer to go in & out.

I'll report back with what I hear from Vans.

Thanks,
Russ
 
grayforge said:
Thanks for the input Bill.

I used a close tolerance bolt to ensure the F-704C & D were aligned properly with the 3/4" bars. Alas, I couldn't even get the threaded portions of the bolt in. Once I made clearance in the C&D pieces, the close tolerance bolt actually went in with minimal effort... until it hit the bar on the other side of the gap, offset by 1/16 or so. :-(

I did buy some hardware store bolts for wing fitting. Slipping these bolts in shows the same issue.

I don't see an obvious solution. The forward and aft spar sections are solidly riveted to the bottom skin, so shifting them isn't gonna be very feasible. I'll have to check how far off the lower holes are. Maybe they're closer to fitting on the bottom portion and driving the upper bolts in will get them in. But I worry this will tear up the holes.

The center section spacer bolts go in, but they require tapping with a hammer to go in & out.

I'll report back with what I hear from Vans.

Thanks,
Russ
Click to expand...

I have a feeling when the wing is installed and the holes are aligned with drift pins, before driving the close tolerance bolts, it will all work out. Those holes are off a bit, could be caused by the exterior plate on the entry side, but I think the drift pins will pull it together. The close tolerance bolts have to be turned in sometimes and/or driven with low pressure hits from a rivet gun. The plates also need to turned down with a handle reamer, that is in the plan instructions.

I have coated the bolts with Corrosion X oil (spray can available from ACS) and that makes them go in (and come out) a lot easier. It also prevents any corrosion in that area for some time but don't let it run through to the exterior surface or it will be a problem getting paint to stick. :)

I think you will be ok.
 
Taper the bolts

Russ, take the store bought bolts and taper them
on a bench grinder. Leave at least a 1/4" diam. At the end
so you have a surface to bang them out. My thoughts are A-
You should not have the threads messing up the holes. B, if you need
To align things a tapered pin will help. If you have to move
One of the spars for better alignment, the forward spar would
Be the one to move. Have some ideas on that if it comes to that.
 
OK, I think I was a bit paranoid.

I heard back from Gus at Vans. He said that the forward and aft center section sides often overhang the bar holes a bit when riveted in place. Dremeling them out is a reasonable option and placing a dowel in the hole to prevent the grinder from touching the bar hole is a good idea.

As for the bar holes being out of alignment, he said this is normal too and that the fuselage shifts a bit when riveted. Using drift pins made from hardware store bolts is the suggested method of getting them back in alignment for wing attachment.

The suggestions above that talked about installing the wings and using drift pins to pull things into alignment were right on.

Thanks!
Russ
 
if anyone has access to or is making some of these tapered bolts, i'd be interested in buying a set versus making my own
 
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