# Model-Based Design of Aircraft Landing Gear System
## 5 Conclusions  
From the study on the landing gear and the dynamics involved during landing, some relevant conclusions may be drawn. First of all, it is very clear that the design of the landing gear of an aircraft, whatever class or category it belongs to, is a very complex process that inevitably involves a large number of experts in various fields, thereby making it a very multidisciplinary system. Additionally, it can be considered to be a highly granular system, since it comprises numerous subsystems, such as the brakes and the wheels, each with its own specific function. It is therefore imperative to strive towards finding more and more efficient methods and techniques to properly design the said system, while all the while ensuring a high level of accuracy and reliability of the results from each analysis performed. In this context, the current work presents a potential model-based design process, which makes it possible to quickly achieve a suitable configuration of the landing gear and verify its behavior during its expected operational scenario with a time-based dynamic model. In particular, the first section presented a complete mathematical workflow through which the characteristics of the individual subsystems may be estimated, starting with the main dimensions of the tires and wheels, based on data from real suppliers, which provided the data for the prediction of the wheel dynamic and kinematic behavior. Then, the braking system was sized to cope with the high mechanical and thermal stress deriving from the braking action during landing and to fit in the previously found wheel assembly solution. Finally, the shock absorber was considered, thus finding suitable dimensions to make it possible to support the airframe and manage the impacts generated during landing. As the last step of the process, a dynamic model of the landing phase was introduced, which, based on the data obtained from the sizing script, made it possible to immediately verify the correct behavior of the landing gear and the interaction between its subsystems. In particular, it showed the temporal evolution of the dynamic behavior of the overall aircraft--both in the longitudinal and vertical directions--the thermal characteristics of the brakes, and how well the braking action was delivered, thereby taking into account the possible control logic that is employed and the rotational dynamics of the wheels, as well as showcasing the interaction between tires and runway. All these aspects can be confirmed through the results of the three aircraft test cases, thereby demonstrating the high flexibility of the process to size a wide variety of aircraft. Additionally, since the sizing model and dynamic model have been implemented in an inherently integrated digital environment, the need for complex manual computations, models setup, and data exchange between such models is completely eliminated. As future developments, many improvements and additions may be performed on the models and the mathematical analysis. For instance, the sizing of all of the mechanical linkages composing the landing gear retraction mechanism may be added, alongside a multibody model, which makes it possible to quickly verify how the landing gear would retract and extend. Such a model could also be integrated with the prediction of the individual subsystems behavior to achieve a comprehensive dynamic analysis of the landing gear. Moreover, the subsystems that have been considered here could be further developed in order to obtain a more detailed analysis of their parameters, thereby even allowing for the automatic creation of a parametric CAD model, thus reducing the time required to set up complex simulations, such as through CFD or FEM analysis. Conceptualization, E.B., A.D. and C.D. ; methodology, A.D.; software, A.D.; simulation, A.D.; investigation, A.D., E.B. and C.D. ; formal analysis, A.D.; writing--original draft preparation, A.D.; writing--review and editing, E.B. and C.D. ; supervision, E.B. and C.D.