I don't know what type or number of airfoil it is. As I said. Very similar to a 4*60 shape. Semi-symetrical.

Currently--the thickest part of the rib--at the spars is 1-9/16" thick from the top of the rib to the bottom.

There is 1-1/16" between the spars. My wing tube is only .806" in diam.--so that leaves me with about .240" to fill in--if I install the tube in between the spars; as they are spaced right now.

Cord is 10.5"

I want to decrease the thickness to 1-5/16" and increase cord to 12.25"

That would space my spars so that my phenolic tube will fight tightly between them and not have to do a bunch of filling with balsa and epoxy.

I would be adding approx. 147sq.in. to the wing, via the lengthened cord. Total area would be approx. 1029sq.in.

Decreasing the thickness by approx. 36%--if my calculations are correct.

I don't know much technical stuff about airfoils; but, I would think that a thinner wing would need to fly faster to achieve the same lift. Maybe not--because of the added sq.in.??

At 1029sq.in--and weighing between 8--10 pounds-I don't think I'll have a problem with wing loading. I calculate it at 22.4oz/sq.ft--if the plane weighs 10 pounds.

If it weighs 8 pounds--then wing loading would be 17.9 oz/sq.ft.

Thanks