Leading edge rib madness...

[aarvig]

Installing the leading edge ribs in the leading edge skins of my 9A. First, let me say...IT SUCKS! Am I the only one who thinks they are way to difficult to fit? Also, and my primary question...
As a result of trying to ram rod the ribs into the leading edge the inside of the skins have had the bejeezers scratched out of them. Is this normal? If so, can I just scotchbrite the snot out of them and call them good?
To date, this has to be my least favorite part of the build.

[Pmerems]

Aaron,

I can't speak to the fit of RV-9 LE ribs but the RV-7 had similar issues. Make sure the rib is as smooth as possible and take your time. Once match drilled, clean up the internal scratches to the skin and prime over the area.

Just another step in the process.

[SeanB]

Aaron,
These can be very difficult as you describe. A trick that usually makes this much easier: Cleco each rib starting at the leading edge (top side first) and install about 3-5 clecos. Do this for all ribs with nothing else fastened. Once you have those in, install several in the same manner from forward to aft on the bottom of each rib. I had more success starting with the middle ribs and working toward each edge. From there you can usually get the rest installed easily. Good luck.

[DaAV8R]

I notice from pictures posted that many people perform the first fit prior to edge preparation and deburring. Many parts, including the nose ribs, fit much better with all the prep work done prior to the initial fit. While this doesn't prevent all scratching, it does minimize it.

The nose ribs need aggressive work for a smooth fit.

[wjb]

You think the LE is bad .. wait for the tanks! (0.032 vs 0.025 skins).

Getting the ribs in the first time, especially with the tank with its thicker skin, is sure a challenge. At one point, I was really questioning if it could be done at all (even though lots of others have done it). I found that Jason Beaver's method worked well. Dump the cradle. Straddle the skin. Put something firm but pliable under the leading edge (I used some pretty dense packing foam), and then push hard on the trailing edge flange until the holes line up. It helps if you have a a cleco already inserted into the last two holes in the skin, so you can snap them into place once the rib is in position.

It's funny, after this maneuver, I thought "how the heck am I gonna do this with proseal gooped all over the place?" Happily, after the drilling to size and dimpling, things went together easily. I did use a bit of a pry bar (a sharp poker that I inserted thru the skin, thru the rib hole, and levered everything into place prior to the first cleco) to get the alignment right, but it was quite a bit easier than expected. Thank God!

The first time is really the hardest .. all other assemblies are 10x + easier.

Keep at it; once you get it, you're done!

[Vlad]

Originally Posted by aarvig

Also, and my primary question...
As a result of trying to ram rod the ribs into the leading edge the inside of the skins have had the bejeezers scratched out of them. Is this normal?

Scratched mine are inside. I did my best fitting them then riveted and forgot. There are couple spots on finished leading edge where you can see a slight rivet gun indentations if you look at a different angle. Painter will fix it the RV flies just fine

[s10sakota]

Aaron,

I don't usually answer too many posts because I consider myself a very beginner in RV building so I don't often want to add my two cents.

But being a beginner, I was just in your shoes not long ago at all! I can tell you that I was just as frustrated as you are now and thought many times that something was wrong with the ribs because they don't fit correctly. I got mad a few times and walked away into the house to get away from it all.

But let me just assure that they will go together. Yes they are a bear to do, but you will get them fitted. Start from the leading edge and work backwards one at a time. The first time you put them together it will be really tough. But after putting it together and taking it apart a few times, they start going together pretty easily.

Many times I felt very frustrated and wanted to give up. But once you conquer that leading edge, you're going to feel awesome!

And like someone else said-wait til you get to those tanks! Take it from me-I stopped working on my RV-7 for 10 months because I was so sick and tired of those tanks! I even listed my tail and wing kits for sale here on VAF because I was so frustrated with the whole thing!!

But today, I just riveted on the top wing skins! I just made a decision to ask questions and stay out in that garage until I got things done!

Rest easy friend, it does get better!

[bruceh]

Run the most forward part of each rib along the scotchbrite wheel and make sure they are smoothly rounded off. The little segments of the forward rib don't make a nice continuous curve like the leading edge skin. When you try to force the rib into the leading edge skin, you will see lots of little pressure points from the underlying rib. Just grind (lightly) those down on the scotchbrite wheel. Makes a big difference and that will reduce that tendency to scratch up the inner surface of the skin.

[Bruce9A]

Aaron,
In my case, working on the ribs was only part of the solution. I found that "unbending" the skins also helped a lot. It seems that the angle formed into the skins is a bit overdone--at least in the ones I got. It's hard to quantitate, but I think I ended up taking about 10% of the bend out.
-Bruce

[agirard7a]

Had the same problem with my 9a. When I clecoed the ribs in and looked at the skins, it looked like I was building a fabric wing. The ribs where creating bulges in the skins and actually created pressure point dimples. I removed the ribs, and smoothed the pressure point dents with a slight hammering with a bucking bar.
I analyzed the part of the ribs causing the dimples , bent them in slightly and smoothed them off with a file. The problem in the ribs was in the forward upper part of the flanges. That area of the ribs does not get any riveting and does nothing to support or form the shape of the skin, thus eliminating what was causing the the pressure dents and buldges.

The ribs need tweaking so you don't get a wing section looking like fabric wing from a Stinson.