Implementing VNAV support in FlightGear: Difference between revisions

{{cquote|What you need is a simplified performance model of the aircraft or, rather, a set of simplified performance models as function of your relevant variables which in your case may only be c.g. position. Once you have such a model, predicting flight paths is not difficult. The problem is getting such a model. The only way I've ever done it was totake a full-envelope aerodynamic model, a full-envelope thrust model, trim the aircraft at lots of Mach-altitude points, and derive a simple model at each point. Generally, what you want is lift-coefficient as a function of angle of attack, a drag polar model, and some simple moment coefficients so you can predict rotational effects (such as turning and turn rate). Building a program to beat the crap out of a standard model is the only sane way to approach the issue of generating performance models.