Nonlinear Six-Degree-of-Freedom Flight Modelling and Trimming of a Single-Propeller Airplane

Abstract

A mathematical model based on the solution of nonlinear aircraft equation of motion for six-degree-of-freedom flight was developed by using MATLAB programming. This mathematical model was adopted for evaluating the flight motion of single-propeller airplane. The aerodynamic data for the flight model was obtained from wind tunnel tests of power-off and stick-fixed 1/12 scale model of the airplane. The propulsion data, on the other hand, was obtained from two engines used within a flight envelope defined by altitude and airspeed. Linear interpolations were performed to evaluate the input data available in look-up tables. The damping derivatives needed for the flight model were obtained from empirical USAF DATCOM methods. Airplane equation of motion was solved numerically at equilibrium condition for cruising velocity and altitude. Time history variations of all 12 state variables for trimmed flight show instantaneous motion of airplane. The procedure described in this chapter should be useful for the mission evaluation of such a propeller airplane during its preliminary design. © 2025 Elsevier B.V., All rights reserved.