Pocket rib length

[Erik]

I have seen a couple conversations about the aileron pocket ribs but still have a quick question. On drawing 9, it looks like the rib stops flush with the 90 degree attach flange and is then riveted through 1/8" cap strips and what I assume are the 1/8" x 1/2" vertical strips on the spar. But as I study the assembly, the rear spar doesn't appear to have many of the vertical strips as far outboard as the aileron. Will some of the pocket ribs be 1/8 " longer and have the attach angle riveted directly to the spar, or should an 1/8" strip be at every location and I'm looking at these drawings wrong?

[nichzimmerman]

Erik, most that I have seen rivet the attach angle to the capstrip and accept a 1/8" gap in the middle (no 1/2" strip) of the spar facing flange. These pocket ribs aren't critical structure. I would be curious how the kits do it.

One might think Bob intended it this way as the rear spar plans do not show lightening hole spacing to accommodate additional 1/8" x 1/2" verticals.

[Erik]

That would only allow for two rivet points for the pocket rib to the rear spar it would seem. And that doesn't sound sufficient to me, unless there is a way to rivet across that 1/8" gap that I'm unfamiliar with.

[keefer66]

here is a picture from Dave "the desert bearhawks" page showing how he did this task .

[keefer66]

Desert Bearhawk has a facebook page plus a bunch of youtube vids to use as reference. Thanks Dave !!!!

[nichzimmerman]

here is a picture from Dave "the desert bearhawks" page showing how he did this task .

Dave's page is a wealth of goodness. This picture shows a pocket rib that is aft of a center rib where you would already expect to have a 1/2" x 1/8" spacer bar installed. Two 1/8" rivets have a combined shear strength of over 600 lbs and these ribs experience almost no flight loads. But when in doubt, call Bob.

[marcusofcotton]

At each center rib location there is the 1/8" spacer used as mentioned. Pocket ribs that don't fall in line with center ribs don't use a spacer, rather just leaving the gap and only the two rivets over the cap strips for the front angle mount to spar joint.