Implementation and Validation of a 6-Degree-of-Freedom Nonlinear Model for an Aircraft

Resumo

Aircraft dynamic modeling at SAE Brazil Aerodesign competition has become a fundamental part of
the project to compute the payload and performance characteristics of the aircraft. With each year, the airplanes
become more refined and the analysis for the project, more complex. The need to evaluate in more detail the
behavior of the aircraft arises to ensure flight handling quality and verify that the mission requirements have been
fulfilled, even before building a prototype, specially since the beginning of the COVID-19 pandemic. Thus, in
alternative of the 3 degrees of freedom linear models described in the literature, it is proposed the use of a more
complete model, with 6 degrees of freedom, to describe with more fidelity the flight dynamics of the aircraft. The
implementation, written in Python, computes the movement of the airplane with twelve state variables in each
instant of the analysis, which is done by numerical simulation with either Euler’s or Runge Kutta’s method. It was
observed that the developed software can be used to estimate handling quality parameters with the aeronautical
regulations and, as a result, refine the project towards a more competitive aircraft capable of ranking the team
higher at the national competition.