Influence of external store aerodynamics on flutter/LCO of a fighter aircraft

The effect of external store aerodynamic modeling on the flutter and limit cycle oscillation (LCO) of a F16 aircraft is investigated in the present paper. Three different aeroelastic instability associated with the F16A flight flutter test were considered, namely; classical flutter, typical LCO, and non-typical LCO. To rapidly compute the flutter prediction of the aircraft with multiple store configurations, a procedure is proposed to efficiently reuse the aerodynamic influence coefficient (AIC) matrices of aircraft with multiple stores by the ZAERO code that contains a unified aerodynamic module for all Mach numbers. To discern the difference between the flutter and LCO responses, and to correlate the numerical predictions with the flight altitude, the matching point option of the g-method is used. The influence of the aerodynamic stores on the aeroelastic instability is investigated using a number of aerodynamic model for the aircraft configurations, including the isolated wing-tip launcher model, and the whole aircraft with and without stores. The results, with a more refined aerodynamic model, show a good agreement between the present numerical predictions and flight flutter test data.