Elevator horn issue

[Thunderpig]

Morning all...started with Section 9 yesterday and am now mired in trying to mate up E-903, -904, -913. First one cleco'd together just fine, lays nice and flat. Second one, I am having significant issues with. Individually, the pieces are laying flat with very little wobble. I cleco'd in the center, longer piece in then have been trying to use the smaller rib to determine where the items are misaligned. When the center, longer rib is installed, it lays nice and flat with no wobble...then when I put the smaller rib in..this is what I see...

http://u.cubeupload.com/Thunderpig/IMG0186.jpg

http://u.cubeupload.com/Thunderpig/IMG0187.jpg

http://u.cubeupload.com/Thunderpig/IMG0188.jpg

One side has the rib flange well above the E-913 piece, the other side settles in more and from the bottom you can see that when the flange holes are cleco'd to the -913, there is a significant gap between the pieces. I'm pretty good at spatial orientation, but this is not making any sense. I measured the smaller flanges, there is about a 1/32" difference in height at the end pictured.

[rvdave]

Hard to tell from the photos but you might try putting all the clecos in and see if it pulls together..

[flion]

I would suspect the E-903. But first, if you have not match drilled things, assemble the two ribs together and then the counterbalance skin (not elevator horn) to the E-904 and see if the misalignment is too much to be able to match drill the E-903. It might still be possible to make it work if you have to drill out for 'oops' rivets to match the holes. But from the photos, it looks like your E-904 is right on or maybe a touch proud (it should be flush with the counterbalance skin). The key for me was making sure the two ribs were together and flat before fitting the counterbalance skin.

[Reflex]

I had the same issues on that assembly. One of mine fit perfectly, the other gave me some problems.

What I did to solve the problem was to cleco every other hole on -903 and -904 starting in the middle of the pieces. I then laid the assembly on a piece of glass keep on my workbench to check for a warp. Indeed, there was a small "wobble" or twist.

Section 5.13 (Page 05-14) in the manual talks about twist and fluting. It says "any twist in the part can be ignored". It also says, "...It is normal for light pressure to be required to hold a twisted part flat on a table. Fluting does not remove twist from a part."

With this in mind, and clecos in every other hole, I then twisted the assembly with my hands ever so slightly in the opposite direction. I laid the assembly back on the glass at it was perfectly flat. At that point, I installed the remainder of the clecos. The assembly stayed flat after the balance of clecos were installed.

The next challenge was getting -913 to fit properly around the assembly. Be sure to start by putting the clecos on the front portion of -913 as per the plans on page 09-17. I had to work with -913 a bit to be happy with the fit.

While I don't have the experience of many here, a couple of things I've learned with the -14 are:

1) If you're having trouble getting something to fit properly, put in all the clecos before deciding you have an issue.
2) If the holes don't line up, you've probably done something wrong

My guess is that you'll have to work a bit to get -913 to fit like it should.

Best of luck,

Fred