RV-9A Leading Edge Ribs - Difficult to install

Hi everyone, working on 9A Left wing LE and I'm having a lot of trouble installing them with clecos.

The plans say place LE sking in jig, cleco ribs starting with top skin and beginning from the front, then put clecos in the bottom skin starting from the front.

Putting the clecos in the top skin was OK, but when it came time to put the clecos into the bottom part of the LE, the wholes are not even close to the rib holes. To get them even close I have to use a lot of force on the rib.

I thought I had the wrong ribs or something. I double checked the flanges for 90 degrees and made sure the ribs were straight.

I would appreciate any thoughts, I am so frustrated after spend hours trying to figure this out.

Thanks
james

All part of the learning curve. The ribs may take some "massaging" to get into place, and you may need to work your way from the nose back alternating top and bottom. It will take several attempts. I remember gently filing down the front flanges ever so slightly as well to improve the fit. Just wait til you get to the tanks!

Chris

Yes, you'll need to to massage them a bit to get the rib shape to match the LE, and the LE curve to meet the ribs. One cleco at a time. Once you've got it the first time, it gets easier the next time. Using an awl in the holes to line them up helps.

Please see my blog

I had a lot of trouble with this. Here is what I did, right wrong or indifferent:
1) i smooth the ribs per the chapter 5.
2) that wasn’t enough so i reshaped the very tipnof the leading edge slightly and bent the flanges a liitle tighter in ( a small change to the leading edge radius). I made a template so they were all the same. Remember 90% of the airfoils performance comes from the first 10% of chord. So I just increased the leading edge radius slightly, keeping the rest of the airfoil shape the same. Made all the difference.
3) I am not flying yet, so this is at your own risk; I will be flying this year thou.

The way I did it

After tidying up the ribs nose per the instructions, I put the skin on its end on the floor. (No cradle)

Then started with the nose of the top rib, I could get the first 1 or perhaps 2 clecos in the top and bottom of the nose rib.

I did the this to all the ribs and then went back an added 1 cleco at a time each rib.

Once everything was cleoed up I put the whole thing in the cradle. I found it impossible to put the skin in the cradle an then try adding the ribs.

YellowJacket RV9 said:

All part of the learning curve. The ribs may take some "massaging" to get into place, and you may need to work your way from the nose back alternating top and bottom. It will take several attempts. I remember gently filing down the front flanges ever so slightly as well to improve the fit. Just wait til you get to the tanks!

Chris

Click to expand...

This was my experience as well. I was very frustrated and found this to be more difficult than the "big cut" or bending the longerons. There is a lot of pressure on the first few clecos as you move back which I was troubled by but all of this results in a nice fit and look. It'll all work out.

Common problem

This happens to a lot of us including me. In my opinion Vans needs to redesign it's leading edge wing ribs. I had to bend/narrow my ribs by nearly 1/8". A SERIOUS PITA.