Virtual Flight Testing in a Ground Test Facility

Typically wind tunnels are used to obtain static aerodynamics for the prediction of aircraft and missile systems performance. Wind tunnel testing generally provides the basic data for autopilot design and performance predictions. Dynamic derivatives of the aerodynamic loading are generally estimated offline through semi-empirical or other computational analyses. Following this initial design, a series of flight tests are performed for design verification, optimization, and model validation. Flight-testing is time consuming and extremely expensive. To reduce cost and mitigate the risk of Development, Test, and Evaluation (DT&E) phase of weapon acquisition, it would be desirable for a ground test facility to mimic free flight. This facility could provide the additional benefit of testing actual flight hardware. The Wind Tunnel Based-Virtual Flight Test (WTBVFT) would provide this capability. The proposed WTBVFT facility would mount the actual flight hardware on a specialized mounting system which allows for "free" three-dimensional rotation of the test article. This arrangement would allow the test article to "virtually fly in the wind tunnel" under its own flight control. Augmenting the rotational motion of the test article with "simulated translational motion" may produce the desired similarity to free-flight trajectories. The WTBVFT is considered a risk-reduction tool useful as an intermediate step between simulations and flight test, providing a pseudo-free flight environment in a ground facility. This paper discusses the WTBVFT concept, its challenges, and potential use. Preliminary modeling results are presented showing the concept ability to mimic free flight