Page 15-05 - Help!

I am nearing the end of riveting the nose ribs to the left spar.

I have a problem at Step 3. Three of the four trimmed W-1208-R Nose ribs are clecoed in place ready to be riveted. The problem rib is the third after the rib with the nutplates clecoed to it. Here is a picture.



The aft flange of this rib is clecoed securely to the spar assembly. Problem: the holes in the rib do not align with the holes in the attach angle. I have this sinking feeling that when Vans assembled the spar they affixed the wrong attach angle. Note the difference in the two attach angles visible in the photo. The holes in the problem angle are approximately one hole closer to the spar.

Perhaps others have encountered this and there is a simple explanation. Of course it is entirely possible this is another piece of monumental stupidity on my part...........

Help!

Erik

Ausmo said:

I am nearing the end of riveting the nose ribs to the left spar.

Perhaps others have encountered this and there is a simple explanation. Of course it is entirely possible this is another piece of monumental stupidity on my part...........

Help!

Erik

Click to expand...

Hi Erik,

The rib clips on the spar are built in several sizes so that they get a longer flange and rivet holes a greater distance from the face of the spar as the spar layers end so that all of the rib rivet holes would line up in one plane. There are normally two rib clips with a given distance from the spar front then the spar front steps down 1/8 inch and the next two rib clips have a 1/8 inch longer flange and the rivet hole is an additional 1/8 inch from the spar front this continues until you get to the outer half of the spar where you start to attach the spar clips where they are all the same.

On my first RV-12 I had the same problem and Van's approved a doubler as a fix and sent me a part to make the doubler from. Please give them a call on Monday morning and they will be pleased to explain how to do the doubler and they will send you the part you will need to make it from.

If it is of any comfort this is only the second one I have heard of out of over 1,000 spars. But it is a simple fix once you have the proper instructions and the part from Van's.

Best regards,
Vern

Erik,

It is extremely easy to get confused about ribs, Left go on the right wing, right go on the left wing, some get trimmed, others don't etc. etc. Ask me how I know

My advice - go back to the very beginning of the section where you sort out the ribs, modify them, etc. and triple check everything you have done up to the point of the problem. Odds are, it's an Erik problem, not a Van's problem. Not that they are perfect, but mistakes are rare.

Happy hunting!

John

Hi Erik, this is truly an amazing forum isn't it? If memory serves, I had the same problem but found it while dry fitting the skin to cleco'd ribs. I think I got a little discombobulated with all the left/right ribs and became suspect. As John advised, retrace your steps first.

Indeed the forum is amazing and the support is wonderful, thank you for your prompt responses.

While I think I have taken great care with rib preparation and getting them in the correct places, I will surely go over this again before contacting Vans.

Cheers

Erik

I found the same problem during my wing assembly. Two of the angles were
in the wrong position. As I already had some ribs that Vans had replaced due to splits in the lightening holes, I was able to manufacture my own stub
ends/doublers with Kens blessing.

An update

For those generous souls who provided advice. It seems the spar builders did affix the wrong attach angle at the attach point for that rib.

Ken tells me they have manufactured some adapter plates and is sending me one.

Install and build on!



Erik