ABSTRACT
This work simulates and analyzes the behavior and performance of a light aircraft in
steady level flight subjected to gust wind. A home-made code is developed using
MATLAB to simulate the aircraft behavior using the nonlinear 6-DOF and the
aerodynamics and engine model were utilized in this code. The gust model used in
this analysis is sine-wave shaped gust.
The aerodynamic behavior of this aircraft was investigated using CFD at different
angles of attack and side slip angles. The x, y and z forces and moments were
calculated at a flight speed of 50m/s and at sea level conditions. Lift and drag curves
for different angles of attack were determined. The maximum lift coefficient for this
aircraft was 1.67 at angle of attack of 17º ; the maximum lift to drag ratio (L/D) was
found to be 13 at
=2º, and the zero lift drag coefficient was 0.0342. Also, the yawing
moment coefficient was determined for different side slip angles as well as rolling
moment. The static stability of the aircraft was analyzed based on these results.
Also, USAF digital DATCOM was used to estimate the dynamic derivatives of the
vehicle. The engine was modeled by a simple model such that engine power and
thrust vary with altitude and speed.
The simulation results indicate that the aircraft is stable, controllable and the gust
wind effect is eliminated and damped in a few seconds. In addition, the load factor
increment due to gust effect is not critical.