Creating radius arcs at leading edge & trailing edge using control points

Leading edge radius arc:
1. Calculate all AirFoil control points, as points only.
2. Using pt_ex1 as center, and pt_af1 as radius, form upper half of
semicircular arc_le.
3. Calculate pt_thales1, or locate it using midpoint of line segment from
pt_ex1 to pt_af2.
4. Using pt_thales1 as center, and pt_ex1 as radius, create upper
semicircular arc_thales1.
5. Find intersection of arc_le, and arc_thales1, which is point (pt_tan1).
6. Create new arc_le, using pt_ex1 as center, and pt_af1 as radius start, and
pt_tan1 as radius end.
7. Push arc_le into AirFoilfactories array.

8. Similarly, create arc_te at trailing edge, pt_thales2, and pt_tan2.

9. Starting at pt_tan1, create control points curve factory, using pt_af2...
pt_af24, and pt_tan2. and push into AirFoilfactories array.
10. Push arc_te int AirFoilfactories array.
11. Commit AirFoilfactories array.

12. Create Rails.
Done.