Tip: Installing the F6111 Stiffening rib

I just finished installing the F6111 stiffener ribs on the fuselage of my 7A. What I thought was going to be a PITA ended up being a relative non-issue. As those that have already gone past this point in the build will attest the plans were less than helpful in understanding how they are fitted. Reviewing the other posts that were available on the subject found that installation went from not installing them at all, to cutting them to fit, to trying to bend and flute them to fit. I found none of that was necessary. While the procedure I used is fresh in my mind, I thought I would share it with the builders that have not reached this point.

1) Draw a centerline along the outside flange.
2) Trim the lower tip of the outside flange to match the angle of the longeron.
3) Start with the bottom of the rib just above the longeron.
4) Move the outside flange until you can see the line you drew through the
two bottom rivet holes in the skin.
5) Drill the first hole and cleco.
6) Drill and cleco each of the holes as you go up the skin.
7) Once you have drilled a few holes you will notice that the upper outside
flange will hit the F706 bulkhead, this needs to be trimmed to match the
angle of the F706.
8) You may need to trim the upper inboard flange as well to keep it from
hitting the F706 bulkhead.
9) Finish the drilling following the centerline.
10) Mine needed some additional minor trimming to keep it from chafing the
longeron and F706. I also twisted the upper end of the F6111 and bent
the outboard flange a little to get the end of the rib to lay level with the
F706.


Jim Kinsey
7A Fuselage

If having trouble check out this web site

When you are ready to install the F6111's you might want to check out this web site that Mike Schipper has up - www.my9a.com. If you go to his Top Skins section you will see a picture of how to go about putting these in. I found Mike's site early on while working on my plane and often go out and read sections before I attempt to tackle them for real. This really helped me on these stiffener ribs because the information in the plans for this amount to zilch. Tim has the steps down in his earlier post but seeing a picture can be very helpful indeed. Not sure how long Mike will leave his site up but it helps me visualize how to go about doing things while its still available.

He is currently building a RV-10 and has a link to his progress on it as well.