Thanks for the link! I was aware of the KF airfoil when it was new and followed it superficially for a while, but I hadn't realized how much use was being made of it or of subsequent developents. I was able to read some of the initial posts and then started skimming, finally looking every 10 pp. into the final few of the 400 pp. There's a lot of interesting input there! 'wish I had the time to read the entire forum thread.