## 1 Introduction
The research holds significant practical application value and has garnered widespread attention. After establishing the dynamic model of the aircraft, it is necessary to select appropriate methods for calculating aerodynamic forces. Over the past decade, the development of computer technology has made it possible to solve unsteady flow fields and multi-disciplinary coupled simulations based on CFD methods. The CFD method offers high accuracy and good efficiency. [PERSON] [14] tried to obtain the static and dynamic aerodynamic characteristics of an aircraft under different flow parameters through the CFD method and established an aerodynamic model to simulate the flight mechanics problem. [PERSON] [15] studied the aero-elastic effect of the rotating missile by coupling CFD/CSD. The SikMa project team of DLR [16] simulated the X-31 free roll maneuver and angle of attack using the flow field solver FLOWer and TAU, coupled with flight dynamics software and structural finite element software. [PERSON] [17] established a CFD/CSD coupling method based on the high precision in-house solver, and the reliability of the CFD and the CFD/CSD coupling method was verified. [PERSON] [18] proposed an accurate flutter prediction method based on computational fluid dynamics/computational structural dynamics, and the flutter characteristics of the computational model are in good agreement with the experimental results. [PERSON] [19] studied the aeroelastic effect in the ballistic simulation of a large-slenderness-ratio rotating missile, and the results show that the aeroelastic effect will reduce the range of the missile and the landing accuracy. The preceding paragraphs discuss the necessity of establishing a multidisciplinary coupled analysis method for elastic aircraft, introduce the dynamic modeling methods and aerodynamic force calculation approaches, and ultimately form a multidisciplinary methodology that couples aerodynamics, structural dynamics, and flight mechanics. Through the systematic coupling of these disciplinary domains the flight dynamics of large and slender ratio missile aircraft can be studied to simulate and present the flight state of elastic aircraft as realistically as possible. The structure of this paper is as follows. Section 2 details the flight dynamics model of aircraft and introduces an unsteady CFD solver, a mesh deformation strategy, and a simulation flowchart based on a rigid-flexible coupling model. Section 3 presents the test results for validating the numerical method. Section 4 is aimed at typical air-to-air missile aircraft with a large slenderness ratio, studying the coupling phenomena of aerodynamics, flight dynamics, and structural dynamics under forced pitching motion and during different rudder deviation control maneuvers, revealing the differences in aerodynamic and dynamic characteristics between rigid and elastic aircraft, and verifying the effectiveness of the multidisciplinary coupling numerical simulation method of aerodynamics/structure/motion in the flight process of slender body and high maneuverability developed in this paper. Finally, Section 5 encapsulates the primary conclusions derived from this study.