Don, I do not have any flight experience with them, but I had designed another set of wings (using the same concept)for my giant protege. However before I could complete the wings, my protege had an untimely contact with terra very firma...There is a build thread on RCSCALEBUILDER.COM where the concept was used in a UHU 219 (I believe). so you may want to check it out. I will try and provide a link later....