Some of it was vague, but that wasn't my point. My post wasn't to point out errors in your post. I intended to expand on it and to point out that you appear to have an agenda against "formulas", despite the fact that relatively few formulas are posted in this forum. It almost seems as though you try to discredit anyone for using math. I suppose it doesn't matter. Anyone with the drive to learn quantitative aerodynamics isn't going to be deterred. Perhaps even this controversy might encourage further investigation. I know I have learned some things since I started contributing here.