Hi Brian,

Are you seeing something wrong with them? I ran two examples with them and they work out pretty could. I still think my original method is better, because there is no round-off error when you do it inside MoI. The points I added were determined using my original method. However, there is some round-off error. Visually, when I made the models to check the new points, I could not see anything horrible. As far as ripples or lumps.

The last four points are for the circles. The two points preceding the last for are the new tangent points. You can place them in any order you need.

DATA AFXTAB
& /0.50D0, 1.250D0, 2.50D0, 5.0D0, 7.50D0, 10.0D0, 15.0D0, 20.0D0,
& 25.0D0, 30.0D0, 35.0D0, 40.0D0, 45.0D0, 50.0D0, 55.0D0, 60.0D0,
& 65.0D0, 70.0D0, 75.0D0, 80.0D0, 85.0D0, 90.0D0, 95.0D0, 0.20D0,
& 99.9810D0, 0.0D0, 0.5750D0, 100.0D0, 99.9790D0/

DATA AFYTAB
& /0.6880D0, 1.0650D0, 1.460D0, 1.9640D0, 2.3850D0, 2.7360D0,
& 3.2920D0, 3.7140D0, 4.0360D0, 4.2680D0, 4.4210D0, 4.4950D0,
& 4.4850D0, 4.3770D0, 4.1690D0, 3.8740D0, 3.5090D0, 3.0890D0,
& 2.620D0, 2.1170D0, 1.5940D0, 1.0690D0, 0.5440D0, 0.440D0,
& 0.0210D0, 0.0D0, 0.0D0, 0.0D0, 0.0D0/

Points X = 0.0D0, Y = 0.0D0 and X = 100.0D0, Y = 0.0D0 aren't really needed anymore. I left them there, they could be helpful. But you can make the arcs now without them. If you wanted it may be simplest to just make the airfoil arc from everything but the last six points. Then mirror that curve. The only thing left is the arcs and MoI may be able to do it without a center point. I haven't tried it that way, but want to next. If you wanted to leave the center points in, then I know you can definitely do it that way.