Craig-RCU

Not that a Clark Y wouldn't offer even better performance than my airfoil but, I'll have to disagree with you Bruce about the performance of my airfoil as compared to the stock, flat bottomed airfoil of the Eagle 2. The inverted as well as speed performance was greatly improved. With the flat-bottom airfoil, inverted performance could be described as more like the wing was "plowing" through the air instead of "planing" through it. At high speed the monokote on the original flat bottom would rattle a lot indicating much turbulence. I had hoped that the modified airfoil was going to improve inverted performance but, I was really surprised to find that making the airfoil thicker with the added bit on the bottom made it faster too.

In fact the camber of my airfoil actually is less than the original up to the point of the spar while the camber of my airfoil is greater than the original aft of that point. So, I gather from that fact and my testing that the camber of the forward part of the airfoil has more influence over the inverted performance than does the camber of the aft part of the wing in my situation of modifying the original Eagle 2 airfoil. I should also point out that airfoils designed for flying wings have reflexed aft cambers too, so the good inverted performance of my airfoil shouldn't be too shocking from that perspective.