Larry&Sallie Flesner wrote: >> I forgot who said it but would like to run it by the Mark's and Larry's..... >> Someone was using a 1.0 degree of washout instead of the 3.5... is >> this ok? He >> mentioned that it would bring the nose up a bit in flight. Just wanted to >> find out if it would make things better or worse? >> David Swanson >> > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > If I'm one of the "Larry's" I can't be of much help. I'm flying the old RAF48 > with 3 1/2 at the root and 1/2 at the tip (3 degrees washout) as the plans > call for and the ailerons are effective through the stall. I would not change > my wing except to go to the new airfoil. I assume that you're going > with the new airfoil and in that case I'd build it to the same spec's that > Langford and Jones did. They both like the way their KR's fly. Langford > mentioned that he might make one small change in a post the last day > or so and I suspect you could find that on his web page. Go with what > has been flight tested. > > I'm not an engineer but I suspect that changing the washout to near zero > will effect more than the stall characteristics. I'm guessing that it would > also change the lift distribution on the wing, moving more lift outboard, > and placing additional lifting loads further out on the wing panels. As I > stated, this is only a guess on my part. > > Larry Flesner > Larry,
You are right on. Mark Lougheed did extensive CFD analysis of the wing to come up with the optimum angle of attack and washout. The goal was to be flying level at the higher cruise air speeds and to have as close to the optimum elliptical lift distribution as possible to minimize drag. Steve Eberhart
