Aeroelastic Stability of a Transport Aircraft With Wing Mounted Store Suspension: Part I — Analysis

The present study outlines the analysis work, backed by the relevant ground testing, performed for the verification of aeroelastic stability of a transport aircraft modified with the installation of an external store to the outer wing. The initial analysis work consisted of free vibration analysis and ground vibration testing of the modified aircraft for the identification of the natural frequencies and associated modes of vibration in still air. The beam-like half scale model of the aircraft was updated based on the results of the ground vibration test. External store wing connection stiffness was determined by means of vibration test performed for the identification of local store-wing structural interface modes. The dynamic model was updated again and flutter analyses were performed for different mass configurations of the aircraft. Mass configurations that are critical from flutter point of view were identified. Analysis results indicate that the flutter speeds of the aircraft with wing mounted store suspension, although lowered compared to the basic aircraft, stay above the values required by the flutter regulation MIL-A-8870C.