This paper provides an overview of the current technical issues and challenges associated with the design of hypersonic vehicles. Two distinct classes of vehicles are reviewed; Hypersonic Transports and Space Launchers, their common features and differences are examined. After a brief historical overview, the paper takes a multidisciplinary approach to these vehicles, discusses various design aspects, and technical challenges. Operational issues are explored, including mission profiles, current and predicted markets, in addition to environmental effects and human factors. Technological issues are also reviewed, focusing on the three major challenge areas associated with these vehicles: aerothermodynamics, propulsion, and structures. In addition, matters of reliability and maintainability are also presented. The paper also reviews the certification and flight testing of these vehicles from a global perspective. Finally the current stakeholders in the field of hypersonic flight are presented, summarizing the active programs and promising concepts.
The design of aircraft has evolved over time from the classical design approach to the more modern computer based design method utilising multivariate design optimisation. In recent years aircraft concepts and configurations have become more diverse and complex thus pushing many synthesis packages beyond their capability. Furthermore, many examples of aircraft design software focus on the analysis of one particular concept thus requiring separate packages for each concept. This can lead to complications in comparing concepts and configurations as differences in performance may originate from different prediction toolsets being used. This paper presents the GENUS Aircraft Design Framework developed by Cranfield University's Aircraft Design Group to address these issues. The paper reviews available aircraft design methodologies and describes the challenges faced in their development and application. Following this, the GENUS aircraft design environment is introduced, along with the theoretical background and practical reasoning behind the program architecture. Particular attention is given to the programming, choice of methodology and optimization techniques involved. Subsequently, some applications of the developed methodology, implemented in the framework are presented to illustrate the diversity of the approach. Three special classes of aircraft design concept are presented briefly.
In this paper, the GENUS multidisciplinary aircraft design and analysis environment is presented in its application to the conceptual design of tailless, low-observable unmanned combat aerial vehicles (UCAVs). Analysis disciplines comprise a variety of low to medium fidelity, physics-based and empirical methodologies, as well as higher order panel method aerodynamic analysis. Stealth considerations have been included in terms of a radar cross section analysis through a physical optics approximation method, with results verified against a well-known radar cross section prediction code. Preliminary results show good agreement for gross and empty masses when compared to several existing UCAV demonstrators and conceptual designs. A further validation of the presented methodologies is evaluated through the design, analysis, and optimisation of an unmanned strike fighter concept.
The number of aerial- and ground-based unmanned vehicles and operations is expected to significantly expand in the near future. While aviation traditionally has an excellent safety record in managing conflicts, the current approaches will not be able to provide safe and efficient operations in the future. This paper presents the development of a novel framework integrating autonomous aerial and ground vehicles to facilitate short- and mid-term tactical conflict management. The methodology presents the development of a modular web service framework to develop new conflict management algorithms. This new framework is aimed at managing urban and peri-urban traffic of unmanned ground vehicles and assisting the introduction of urban air mobility into the same framework. A set of high-level system requirements is defined. The incremental development of two versions of the system prototype is presented. The discussions highlight the lessons learnt while implementing and testing the conflict management system and the introduced version of the stop-and-go resolution algorithm and defines the identified future development directions. Operation of the system was successfully demonstrated using real hardware. The developed framework implements short- and mid-term conflict management methodologies in a safe, resource efficient and scalable manner and can be used for the further development and the evaluation of various methods integrating aerial- and ground-based autonomous vehicles.
Hybrid-electric, unconventional aircraft solutions can possibly be the solutions for the ambitious emission reduction targets set by regulators, based on society's demands. One such disruptive solution is a morphing wing cargo UAV, with distributed propulsion. This paper investigates the aerodynamics, flight dynamics and control of a scaled down technology demonstrator UAV, built to validate the feasibility of the morphing wing concept. Several types of analyses are run to gain knowledge on the performance, stability and control properties of the aircraft. The flight mechanical effects of the distributed propulsion system are taken into account based on the integral momentum theorem. The increased flow speed behind propellers increases the local lift forces. Therefore, the distributed propulsion can be used to control the roll, pitch and yaw motion of the morphing wing aircraft. The nonlinear 6 degrees of freedom, distributed propulsion aircraft model is constructed utilizing the stability and control derivatives obtained from the aerodynamic analysis. Grid and Tensor Product (TP) type linear parameter-varying (LPV) models of the morphing wing aircraft are generated via Jacobian linearization and TP model transformation. The LPV models capture the parameter varying dynamics arising from the airspeed, morphing wing and payload weight variations. Gain scheduled lateral and longitudinal baseline controllers are synthesized using the grid-based LPV model of the aircraft.
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