I don't know if I have a solution for you, but maybe there is something for you nevertheless.
There is a fabulous CAD program called MoI. With some extremely helpful people on the user-forum of said program. Drawing propellers is a regular subject, do you own searches, but a migration from a fortran program to nurbs curves has actually been treated, and solved, some years ago.
Here it is : http://moi3d.com/forum/messages.php?webtag=MOI&msg=4801.1
Hope this helps, let us know !