# Aerodynamic Optimization and Characterization of a Ducted Tail for a Box-Launched Aircraft
## 1 Introduction
The stability of the proposed nonlinear neural network controller is demonstrated by Lyapunov theory, and the effectiveness and robustness of the method are verified by numerical simulation and hardware-in-the-loop simulation. In the research field of folded wing and morphing aircraft structure design, refs [1; 2; 3; 13; 14; 15; 16; 17; 18] and others designed a new type of wing-folding scheme, investigated the influence of wing thickness, hinge structure and other factors on the aerodynamic load distribution and hinge moment of folded wing aircraft, and proposed a structural design correction strategy based on the results of computational fluid dynamics and the structural strength of the coupling, to provide a basis for the optimal design of the structure of folded wing and morphing aircraft. Ref. [19] proposed an approximate global modal method (AGMM) to deal with complex boundary conditions, and analyzed the nonlinear flutter vibration of a folded wing composed of independent rectangular plates. A high-precision low-dimensional dynamic model of the folded wing is established, and the modal results of the AGMM model are compared and analyzed with those of the equivalent finite element model, and verified by forced vibration response experiments. On this basis, an AGMM model of aerodynamic loads for supersonic flight of a folded wing aircraft is further established. The critical flutter velocity and the aeroelastic response at different folding angles are comprehensively investigated by model-based simulation. [PERSON]. [20; 21] designed a folding wing based on inflatable and bionic elements, and based on the analysis of mechanical and geometric properties of flexible structure, the structural dynamics and even aeroelastic performance of the folding wing were improved through optimized design. The tail of the box-launched aircraft must be folded, and this complex structural design can easily cause mechanical failure. Therefore, it is important to design a box-type launch aircraft without folding tail based on the size constraints of the launch box and the aerodynamic optimization method. There are few studies on the aerodynamic optimization of the tail of a box-launched aircraft. However, the academic community has done a lot of research in the field of aircraft aerodynamic optimization, which provides research ideas for this paper. Refs. [22; 23; 24; 25] took the flying wing layout aircraft as a research object, and based on the free-form deformation (FFD) method, computational fluid dynamics (CFD), sequential quadratic programming (SQP) algorithm, and multidisciplinary design optimization (MDO), they carried out a comprehensive optimization of the aerodynamic and stealth performance of a flying wing layout aircraft, and achieved remarkable results. Refs. [26; 27; 28] developed a fully automated framework specifically for high-fidelity multidisciplinary design sign optimization of aircraft wings. The framework employs an approximate-model-based optimization strategy, and the reliability of the optimization framework is investigated through a high-speed airliner wing design optimization case study. Ref. [29] parametrically modeled a horizontal tail and optimized its aerodynamic performance using a multi-objective genetic algorithm to improve the cruise performance while designing the optimal horizontal tail that can meet safety requirements such as civil aviation regulations. Refs. [30; 31] investigated the influence of the wing on the wake flow field in subsonic flow, and proposed an analytical subsonic flow model based on the response surface method to calculate the lift characteristics of the wake in the vicinity of a low aspect ratio swept-back wing. The experimental wind tunnel data are compared with the data predicted by the model to verify the accuracy of the analytical model of the main wing's effect on the tail flow field. Ref.