For this type of problem, unless you are trying to set range or climb rate records, understanding lift and moment (and control derivatives) is more important th

For this type of problem, unless you are trying to set range or climb rate records, understanding lift and moment (and control derivatives) is more important than accurately modeling drag. Panel methods shine at this, and are both easier to use and much much faster than CFD — enough that wrapping them in optimizers is trivial. I personally prefer AVL, but there are other open source alternatives as well.