Unsteady Weapon Bay Aerodynamics-Urban Legend or Flight Clearance Nightmare

摘要

All new attack aircraft in the US, such as the F-22, F-35, P-8A, and the Unmanned Combat Air System (UCAS), employ weapon delivery from bomb bays. The issue of whether the flowfield in weapon bays is unsteady or can be treated as quasi steady is of critical concern for flight clearance purposes. If the flowfield is truly unsteady, and the unsteady forces are of sufficiently high magnitude, then not only is the principal tool for flight clearance purposes (the wind tunnel and sting-mounted model) of limited use, but any flight clearance issued for such a case would have to be extremely conservative since the trajectories would not be repeatable. Available wind tunnel, flight test, and computational results are reviewed, and suggestions made for addressing this extremely challenging integration problem.