Original Posted By: "walter evans"
I'm continually amazed at what incredible resources we have in this group!Having a good local EAA chapter is important. But having this group reallymakes the process amazing! (In fact, the spar article from Sport Aviationand the NACA ReportNo. 344 were mailed to me yesterday......)Thanks for everyone's help/feedback. The numbers are in and I'm quitesatisfied that an I beam spar design will work just fine. A 1/4"(quiteadequate) or 3/8"(probably more than adequate) plywood web is what I'll use.So full height ply with 1" tall strips of Doug Fir, each side of the top andbottom, to build out the "I" design.I found that a number of British Piets are flying with an I beam spar designthat incorporates aircraft quality plywood webs in the 1/8" thickness range.So actually doing the calculations can result in a good safe structure(estimated 1200# MUAW) with a lot less than my "overbuilding" tendencieswould dictate!Thanks again.Jim in Plano, TX having just completed my second Tech Counselor inspectionand it looks like I'm on the right track! :-)My build log: http://www.mykitplane.com/Planes/buildL ... __________