A study of the effects of store aerodynamics on wing/store flutter

Abstract

This study represents the first systematic analytical study of the effect of store aerodynamics on wing/store flutter. A large number of wing/store single carriage configurations and parameters were included in the study; multivariate analysis techniques were used for the first time to analyze wing/store configurations, modal data, and flutter results. This study has led to the following conclusions concerning the effect of store aerodynamics on wing/store flutter:

The inclusion of both tip store and underwing store aerodynamics can cause large variations in the computed flutter speed, when compared to results obtained when these effects are ignored. In the majority of the configurations analyzed the flutter mechanism remained unchanged with the addition of the store aerodynamics which allowed for the use of multivariate analysis techniques. The results of the factor analysis indicate that: a) It may not be possible to develop general guidelines or to predict store aerodynamic effects that will apply to all aircraft. b) It is possible to develop specific guidelines or to predict store aerodynamic effects that will apply to a given aircraft.

Due to the high cost of doing flutter analysis for aircraft carrying large numbers and types of stores, it is not economically feasible to include store aerodynamics when there will be little change in the flutter results. But store aerodynamics should be included if it will change the results of the flutter analysis. Using the methods demonstrated in this study, it would be possible to develop guidelines for a specific aircraft to indicate when store aerodynamics should be included in the flutter analysis of a particular configuration to obtain valid results.