Simple universal nonlinear longitudinal flight simulation with avoiding of static and dynamic stability derivatives

This paper shows simple method to simulate nonlinear longitudinal flight dynamic of an aircraft in the most direct way. The method is based on physical principles of an analytical-empiric flight dynamics. Non-linearity, as stall or thrust dependent on velocity, can be included. Static and dynamic stability derivatives are not required but can be computed as an output. The model is applicable for various aircraft conceptions. Higher level model, for example, based on flight tests data, can be modified by low-level analytical methods, e.g. for modification of horizontal tail area. No special simulation software is necessary. The model is compared to linear model and flight test experiment. This model, together with valuable analytical-empiric data, might be applied for fast flight dynamic computations. Model is easily accessible and understandable even with basic knowledge of flight dynamic and computer programming. The main application of the method is conceptual design when high precision is not expected, even if VLM, CFD or flight test data can improve the precision.