One of the flight simulator programs is supposed to model real life performance quite closely. It may be X plane or it may be some other simulator. Sorry I can't be more certain than that but I have no direct experience with it. But it only accepts basic 3D solid forms with no internal structure. You can enter in the shape and test it to the ability of the program in flight but then you need to put the 3D solid form into CAD and trace over it to develop some plans. There is no one step flight simulator to plans for building options.

Well, actually there probably is but mere mortals not involved with the aerospace industry probably can't afford it without mortgaging the house.