Zolko wrote: ↑
Mon Dec 16, 2019 12:43 pm
And I still don't understand how this fits with FreeCAD.
Think of it like this:
Normally tools working with airfoils are working with coordinates directly. But this can hide some information (how does the airfoil look in between discrete points?). Interfacing airfoils in spline format (parametrized form) is in my mind a better approach.
What are the advantages of the spline approach?
1. Wing-design in FreeCAD should be done with splines. A fixed number of poles will help too.
2. Discretizing splines is easy, so existing analysis tools can be interfaced easily
3. Iterative modifications like they are needed for optimization tasks can be done with the basic geometry definition.
Why not using the sketcher?
This should be possible, but accessing all the degrees of freedom from a sketch might be difficult (automatic calibration, optimization).
A different number of poles for each airfoil of a wing needs some recompution of the splines to generate spline-surfaces
But yes, using a sketch for this task might be the more generic approach in the long run.
montagdude wrote: ↑
Mon Dec 16, 2019 2:38 pm
There's still a lot of useful things you could do even without an automatic airfoil generation / optimization function. It would be cool to be able to slide control points around and see how the performance changes, or import an existing airfoil and re-fit it with a spline curve with a given number of control points.
There is not much difference between fitting an airfoil and optimizing an airfoil. I would like to use a local (nonlinear) optimizer which minimize a user-given target function .So the user selects a start configuration and the optimizer should find a better design.