Hi Oz:
I did a quick search on Google Images and came up with the following listings. You should be able to poke around in the many pictures and find something suitable for your discussions. There is a series descibing a homebuilt Zenair which gives some very clear views of the spar and ribs. That is located here ...
http://images.google.ca/images?svnum...nair+wing+spar
The general search info is here ...
http://images.google.ca/images?sourc...ar&sa=N&tab=wi
Regards,
Fog