Investigation of adding fins to external stores for improving the flutter characteristics of a wing/store configuration

In this paper, the effect of aerodynamic damping produced by store rear horizontal fins on the aeroelastic instability of a wing with a large underwing store is investigated in an incompressible flow. The wing is modeled by using the classical Euler-Bernoulli beam theory while the unsteady strip aerodynamic theory based on the Wagner function is used to simulate the aerodynamic field. The underwing store is modeled as a concentrated mass attached to the wing by a rigid pylon and has rear horizontal fins. The numerical results of the developed generic and simple model are compared with available results, and an excellent agreement is observed. It is found that the aerodynamic damping of the store produced by its rear fin can compensate the flutter boundary of the wing-store configuration and therefore for more accurate analysis, in addition to the store weight and location, the effect of store fin must also be considered.