Wing Spar on RV-9

[G Swartley]

I seem to have a problem with my wing Spars. I was starting to inspect my left wing spar prior to doing any work on it and I noticed the holes in the spar that line up with the holes in the read doubler don't line up. The holes in the spar are #30 and the larest drill bit I can fit through the offset holes is a 7/64 and that is at an angle. By my calculations that is a .019125 offset. This is huge!!

Ok so here is my question has anybody seen anything like this?

And do you think I'll be getting new spars?

Yes I will be calling vans about this. And yes the other spar has offsets in the hole allignment. not sure as to the severity on the right spar.

[mlw450802]

Originally Posted by G Swartley

I seem to have a problem with my wing Spars. I was starting to inspect my left wing spar prior to doing any work on it and I noticed the holes in the spar that line up with the holes in the read doubler don't line up. The holes in the spar are #30 and the larest drill bit I can fit through the offset holes is a 7/64 and that is at an angle. By my calculations that is a .019125 offset. This is huge!!

Ok so here is my question has anybody seen anything like this?

And do you think I'll be getting new spars?

Yes I will be calling vans about this. And yes the other spar has offsets in the hole allignment. not sure as to the severity on the right spar.

Gregg,
Can you provide a photo?
If you are talking about the rear spar and doubler, I think that the doubler lines up only one way. Try flipping it over and check again.
I can't remember for sure since it's been a while.
-mike

[G Swartley]

Mike
I can't get to a web site here at work to put pictures into a post, so I'll post some when I get home tonight.

Anyway the holes that don't allign are in the main spar. between the large channel and the doubler on the rear side of it. This is pre-made at van's.

[vmirv8bldr]

Mine were a little off as well, but just the nutplate holes in the web, not the actual attach holes that hold the wing on. The four main holes (in each side) were perfectly straight. For the nutplate holes, I just hit them with the #40 and riveted.

Keep us posted.

[G Swartley]

Here are the best of about 15 photos.




As you can see the spar web and doubler holes don't line up.

I called Vans today and they said that this is not a critical area, so if the holes in the spar web are oblong due to the two holes being offset don't worry about it the rivets will swell in the hole.

I was also told if I needed to I could use pop rivets to hold the ribs to the spar if bucking was an issue.

NOW This is not a "hey Gregg said it's ok so I'll do it too" thing if anybody has any issues or problems like this and want some structural assistance you need to call Vans.

Happy Building

[N941WR]

You might want to call them back when the gang returns from OSH and ask for Ken Kruger and see what he has to say.

[lucky333]

Some of those holes are off close to 1/2 diameter . Van punches this stuff out on a CNC punch press (I've seen theirs and lots of others, too). Something is not right about your part.

No way this is a rivet-fillizit deal, that's not what the plans OR the CNC program say. All of the punched holes on a CNC part absolutely must line up, within a few thousanths of an inch. If they don't, the part was not indexed right in the machine or it slipped during punching.

I've done a lot of CNC sheet metal design and supervised its fabrication. I would not let a mismatch like that go into the map box, let alone the spar. Consider this: whatever has moved has moved in relation to some reference point. What does that do to the rest of the dims? Are you going to be shaving metal edges flush because the holes don't line up?

I didn't build my spar but just assisted a buddy in rebuilding his entire starboard wing, spar included, and everything lined up perfectly.

You should of course, make sure you aren't missing something by looking for the easy stuff, like flipping it over or moving it to the other side, mirror images and all of that. And, is the part you are trying to match it to correct?

Personally, I was a bit put out when my 1" holes for the fuel lines through the fuze did not line up perfectly. I had to use a different grommet to take up the difference.

Me, grommets in the sidewall. You are asking about your freakin' SPAR. All of the loads on your airplane are taken up by the wings and transferred to the structure through the bolts that go through the holes that you are thinking about making into slots. Highly stressed holes transferring loads to specially hardened, BIG bolts.. in slots?? Cmon.

I suspect that Ken K. will send you some new parts. Insist on them. If Van's won't give them to you, buy them anyway. Something here is clearly not right.

Get it resolved.

John

[-goose]

I found the angle of the flanges on one of my main spar channels was almost 10-15 degrees out at the root end, and quite variable down the length - I'm now in the process of attempting to seam them with a couple of lumps of 1x4 clamped on.

It seems to me there might be some quality control issues with the manufacturers of the spars - worth checking them over carefully before starting any work - I'd already done all the countersinking and nutplates before I found the problem.

[Paul Eastham]

Although I don't feel as strongly about such a mismatch as John does (I might live with a quarter-hole off on my map box ) I agree it's pretty cheezy for such an important part to come with such a big built-in error.

Unfortunately, these are high-dollar parts and they may not be so quick to give you new ones. If it were anything cheaper, I'm sure they would make it right -- I got a couple of misdrilled pieces myself.

I agree that you should talk to someone in the engineering department about this, not just the builder support line. Send them your photos.

[frankh]

Could you not drill freah holes as the spars are already partially rivetted together?

Frank