I have a model that was modified by another. The intenetion was to go fast and turn left. It's a Mustang with what was originally a symmetrical wing much like the Great Planes 40 Mustang, only this one is smaller. The wing has been thinnned down on the bottom side. I would say it has nearly no arc "NOW". It seems to me that this should work, but I have never went this route. I have always used the apropriate air foil.
Any ideas out there? How about some one with first hand experience with said modifications?