Hi. Still lurking.
I have been following these threads and learning a lot. You have all gotten me really interested in building foamies so I started looking around for some design software. Here is some free stuff from NASA that might help a lot on aircraft design. I haven't tried them yet but some are supposed to have wind tunnel sims that you can use to see what changes in your plans make in real life. It would be nice if it wound up to be that good, but try them for yourself and see. At least they ought to be interesting.
http://www.lerc.nasa.gov/WWW/K-12/freesoftware_page.htm
Bill