External stores grouping for aero database update

For any high performance fighter aircraft, validation and update of wind tunnel aero database from flight testing is a mandatory requirement for developing high fidelity simulators and for upgrading the control laws. System identification techniques are routinely applied by the aircraft industry for this purpose. The flight test effort increases manifold if all the store combinations are to be flight tested. The importance of grouping store combinations to reduce the flight test efforts towards aircraft system identification cannot, therefore, be undermined. This paper demonstrates the concept of store grouping using wind tunnel aero database of a high performance aircraft. Classification is performed using both longitudinal and lateral-directional aerodynamic characteristics. The store grouping tolerances are obtained heuristically by utilizing the standard deviation among the members of a particular store group. The success of the classification approach is demonstrated by presenting typical results of identified updates to the aerodynamic coefficients from flight test data and through time response validation plots. This concept of store grouping can be extended to provide clearance for any new store as the flight envelope is expanded.