At 10:38 PM 4/12/2004, you wrote: >OK for a wing root but will be a poor choice for a control surface. > >Aileron control forces will be high.
>So is it tested and understood that the farther out on the wing, the less of >this "cusp or tuck" the better, as far as on the aileron goes? Has this >been proven on other airfoils? Would you fill in the tuck, keeping the cord >the same? Filling in the cusp is not at all unusual. The Glassaire original had an airfoil with similar characteristics and it was subsequently modified to remove the cusp. Their reason may have been due to excessive control forces, or a too large negative pitch moment, or too high a lift coefficient at cruise. All of those would be altered by making that change without making a significant change in their production molds. The reason that there are two suggested airfoils, the AS5048 and the AS5045, is that the 5045 is a much better choice for the wing tip. The other, a 5046 (I think) is a compromise between the two that will work with the original wing spar. People say that helicopters are a collection of vibrations that manage to fly in formation. I say that airfoils are a collection of compromises that cause lift. Don Reid - donreid "at" erols.com Bumpass, Va Visit my web sites at: AeroFoil, a 2-D Airfoil Design And Analysis Computer Program: http://www.eaa231.org/AeroFoil/index.htm KR2XL construction: http://users.erols.com/donreid/kr_page.htm Aviation Surplus: http://users.erols.com/donreid/Airparts.htm EAA Chapter 231: http://eaa231.org Ultralights: http://usua250.org VA EAA State Fly-in: http://vaeaa.org
