A 4-DOF Virtual Flight Test in a Wind Tunnel

A conventional virtual flight test generally refers to a 3-DOF dynamic flight test in a wind tunnel. In the wind tunnel test, the model aircraft is connected to the strut through a 3-DOF rotation mechanism and installed in the wind tunnel test section so that the model displacement is constrained but has 3 degrees of angular motion freedom. Open-loop and closed-loop control of the aircraft model is achieved by directly driving the rudder surface or by using commands from the flight control system.4-DOF Virtual Flight Test not only has three axes of freedom of rotation around the center of mass but can also rise and sink in the vertical direction. The 4-DOF virtual flight test can simulate real flight in a wind tunnel more realistically than the 3-DOF virtual flight test [12]. It fills the gap between actual test flights and traditional wind tunnel tests, and can simulate flight conditions more realistically before actual test flights, which has outstanding advantages in shortening the development cycle of aircraft, reducing risks and costs.