Simulating Dynamics of Flight: New Approach for Old Problem

A generic FORTRAN code is developed, according to AIAA R-004-1992 standard, to simulate the aircraft flight dynamics (SAFlight: Simulation of Aircraft Flight). SAFlight reads a user provided aircraft data file, then trims and flies the aircraft according to the user-specified flight-condition, weight-configuration, and control-inputs. The code then transfers the time-domain traces to the frequency domain using the well-known Fast Fourier Transform technique. The main contributions in this work is using a state of the art Ordinary-Differential-Equation (ODE) solver to integrate the equations of motion in the state-space form, and reducing the trimming iterations by finding a good starting point. As expected, SAFlight was able to simulate 800 seconds of flight MHz with excellent accuracy in less than 1 computing second on a Pentium III 600. The code is validated against original equipment manufacturer codes for steady (trimming) and unsteady cases. The matching was found to be excellent in most cases.