Identification of Aerodynamic Parameter and Its Influence on Attitude Change of Rocket Assisted Torpedo in Parachute-Free Section

The motion characteristics of a rocket assisted torpedo in parachute-free section after separation of carrier and payload relate to its safety, so become an important factor affecting success of the flight test. And the aerodynamic characteristics associated with the motion characteristics are the main factors determining the flight stability. Due to the limitation of the wind tunnel test, it is difficult to obtain the aerodynamic characteristics of the torpedo in various flight attitudes, which leads to difficulty in the phenomenon analysis of torpedo navigation. In this paper, the aerodynamic layout and motion characteristics of the rocket assisted torpedo in parachute-free section are analyzed, and an aerodynamic parameters identification method based on real flight test data is proposed. Then the identification results are used in simulation of large attitude change of the torpedo in parachute-free section in real navigation test, and the change law of attitude angle consistent with that from real flight is reproduced, verifying the correctness of the proposed method. This method can also be applied to the study of motion characteristics of other air-dropped torpedoes in parachute-free section.