full vs "stick" rib strength?

[jwzumwalt]

I am building the Hummel airplane and have the option of a using a full (one piece) rib or a rib built from stringers. Does anyone know of any tests comparing strength or wing buckling? Obviously the results would be determined on physical size, so perhaps there is some rule of thumb such as "stringer widths 10% of the max camber...", would equal a one piece rib; or something similar.

I have hundreds of Sport Aviation and other magazine articles categorized by topic and have never seen any data on this. Thanks for the input.

[Bill Berson]

Don't think there is a rule of thumb for rib design. Ribs should be load tested. The only source I can recommend for rib testing is FAA Basic Glider Criteria. Should be available online.

[Dana]

Check out this thread on the Homebuilt Airplanes forum (http://www.homebuiltairplanes.com/forums/showthread.php?t=5666), I posted a pdf from a builder who tested various rib construction techniques.

[BoKu]

Check out this thread on the Homebuilt Airplanes forum (http://www.homebuiltairplanes.com/forums/showthread.php?t=5666), I posted a pdf from a builder who tested various rib construction techniques.

Thanks for posting that, I missed it the first time around! The test loading is not necessarily representative of actual conditions (point loading instead of distributed), but is probably a perfectly valid indicator of the overall strength of the construction method.

[jwzumwalt]

Thanks Dana, that's what I was looking for and even better than I could have hoped for. :)