To quist:

I believe the foam ribs where changed out to balsa because of manufacturing difficulties. The foam (Divinycell) is much more expensive than balsa, it cannot be lazer cut (toxic gas), and by the time you get them properly prep'ed (micro ballon/epoxy on edges to fill the cells) for bonding they weight the same as contest balsa. I at the end of the day, nothing beats balsa for lightweight and simple.

I do composites for a living, (Scaled Composites) and it's tough to beat what balsa gives you for our models. You can lay-up (layers with a alternating orientation), of say a 1/8inch panel balsa, using 1/16th (or thinner preferably, you want a odd number of layers, 0/45/0 for longentual strength, 45/0/45 for torsional strength) of 4 to 6lb contest balsa with CA (go light) like a composite panel, and end up with a extremely light, extremely stiff piece. There really is no need for plywood and epoxy in a model.

Sorry, I seem to be on a soap box.

I have spoken with Gene for a couple of years, he truly has a passion for building the lightest weight, structurally sound airplanes available.

I envy him.