Modern aircraft has various combinations of external stores for the accomplishment of their tactical missions. Due to the externally mounted stores the flight characteristics will change and the dynamic stability will degrade which will result in degradation of flight quality. Especially in tactical aircraft with external stores, the correct prediction of the flight characteristics and the dynamic stability are mandatory factors that must be considered during the primary design phase.
In this study, finite element modeling of 3-dimensional multi-spar wing box of tactical aircraft was verified by comparing with previous numerical results. Using the verified model, flutter characteristics was performed for both clean aircraft wing configuration and wing with external stores. Flutter characteristics was also studied with respect for various aircraft speeds, mounting location of external stores and multi-stores.
For the wing with external stores mounted configuration, generally, low order frequency mode due to external stores was added to the natural frequency of the clean wing, which causes degradation of flutter stability. The flutter stability change with the pylon stiffness. Modeling the pylon as a rigid body gives more conservative result. The aerodynamic effect of store did not much influence the flutter characteristics of the under-wing store configuration but for the wing tip store the aerodynamic effects must be considered.
