Mark, I did mean same airfoil, just thinner profile out to the tip. Like say 18% at the root and 14% or thinner at the tip. All the same chord. The drag at the root would be slightly higher but would the lift be slightly greater also because of the thickness?
You are correct, the AS is as good an airfoil as you could design based on the flight parameters of the KR. Fred Johnson Reno, NV Mark L Wrote: Well apparently you're talking about a different airfoil root to tip so the answer would be "that depends". Obviously the thickness ratio will have to get smaller if it's tapered going out, while retaining the same chord length. If the two airfoils are from the same family and the lift coefficients are anywhere near each other, the answer is almost certainly "no washout required". I suppose it's possible you could have two completely different airfoils and the one out on the tip is creating lots more lift than the inboard, but you'd have to try pretty hard to find that combination and screw it up that bad. As you mentioned before though, you'd be hard pressed to improve on an airfoil designed by one of the leading airfoil experts specifically for the KR2S. See http://www.krnet.org/as504x/ for details on that.