Step 5.3 Ribs, ribs, ribs!

There are 28 ribs in the RV-7 wing.  That doesn't sound like such a large number, but at this point I'm tempted to leave a few out.  Each one requires a considerable amount of work to prepare.  First off, the rib flanges are not 90 degrees to the rib web as delivered from Van's.  The manual suggests that a hand seamer pliers may be employed to bend the flanges square.  This is the method I used on the horizontal stabilizer ribs, but just by chance I happened across a thread in the Vansairforce forum where a flange straightening tool was pictured.  I'm all about building time saving tools no matter how long it takes!  It turns out that Chuck is too and he wanted to build the labor saving machine.  So off he went and here is the result:

The problem was that none of the pictures I saw on the web showed the tool actually being used, unlike the picture above.  So initially, I was really unsure what the dang thing was for.  All I knew is that if it would save time, I wanted it.  Well once we got it in front of us and had the ribs as well, its utility was clear.  Chuck and I both found it easy to use and a real time saver to boot!  Now that the rib flanges are straight perhaps I can  use it as a high powered nut cracker.

After bending the flanges I still had to flute the ribs.  Unfortunately, there isn't any miracle contrivance that I know of for fluting the ribs, which is a further straightening process which corrects for warping of the ribs during  the manufacturing process (stamping).  So I sorted the ribs between the left wing and right wing and went to work with the fluting pliers.

Here is Carol helping me to flute the time away.  To review: fluting refers to the process of making small bends in the rib flange to affect a curvature along the length of the rib.  In this way, a curved rib can be straightened by the application of an opposite curve with the fluting process.

By-and-by, in the fullness of time, and after many moons had passed, I finally had 28 mostly straight ribs.

The next step is to lay them out in order to prepare for match drilling.  One must really resist the temptation to become hopelessly confused by the plans which only show the left wing.  My big mistake here was starting on the right wing.  Had I started on the left, there would only be half as many parts remaining when it was done.  Hence, there would be less chance of getting a left wing rib into the right wing.

Much of my minor difficulty surrounds the fact that the ribs all come in two types, left and right.  But the leftness or rightness of the rib has nothing whatsoever to do with whether or not that rib goes in the left or right wing.  Let's just say that after much counting and recounting of the seven rib types, and consulting of the plans, and just the right amount of hand wringing, the correct set and order was finally discovered and the right wing frame was nearly ready for the first test assembly.

Once the holes are match drilled at both ends of the rib, the frame is disassembled and the ribs are ready for deburring, scuffing, and priming.  Here Carol is helping me to scuff the ribs while I am off trying to drill holes for the wing conduits and touch up ribs that didn't pass her deburr inspection.

The conduit will be used to carry the wiring for the strobe, position, and landing lights out to the end of the wing,  The conduit holes have to be drilled before the final assembly as it would be difficult to get a drill in between some of the closer ribs. I'll be using a lightweight plastic tube for the conduit, but I'm also installing some plastic snap bushings to protect the conduit from the rib.   Van doesn't give any particular size or location for these holes so we're on our own.

A conduit hole cleaned up and ready for the snap bushing.

As a special favor to you, I'll spare you the obligatory picture of the ribs hanging in the paint booth -- just this one time.  So we'll finish this post with an picture of something actually happening.  

The right rear spar is riveted to the wing frame.