Riaz, AtifWhidborne, James F.Bragado Aldana, Estela2025-07-102025-07-102022-12https://dspace.lib.cranfield.ac.uk/handle/1826/24181In the pursuit of reducing the environmental impact of aviation, novel aircraft concepts and technologies are receiving increased attention from researchers and manufacturers. Amongst the solutions expected to improve aerodynamic efficiency, aircraft with high aspect ratio wings are being regarded as a promising solution, despite the numerous hindrances derived from such a configuration. Furthermore, the current socio-economic prospect has exacerbated the need to address the multi-disciplinary nature of the conceptual design process, in which traditional methods are becoming less reliable for the modelling of the envisioned novel configurations and technologies. To address some of these challenges, an elegant analytical approach promising improvements in the aero-structural efficiency and flight dynamic characteristics of wings has gained the interest of researchers around the world. This design approach proposes to remove the fixed-span constraint and instead prescribe structural requirements. This yields a set of non-elliptic lift distributions with theoretically improved aero-structural efficiency and lateral-directional flight dynamic characteristics. However, conclusions on the actual benefits and practical implications of the application of this theory remain unsettled. This thesis investigates some of the research questions posed by such an approach applied to the conceptual design of high aspect ratio wings. To do so, it provides a multidisciplinary physics-based design environment that integrates in-house developed and existing computational models within a setbased design approach. This allows for the analysis of feasible solutions with regard to overall performance improvement whilst shedding light on the relevant trade-offs. The proposed design and analysis approach yields span-extended configurations for which aerodynamic efficiency is improved through span extension and the consequent growth in wing structural weight is reduced as a result of the applied non-elliptic spanloads. The presentation of alternative figures of merit to comparatively assess the performance of the designs provides further insight than the use of other traditional metrics such as the lift-to-drag ratio. This yields several span-extended configurations without penalties in performance, following the methodology and metrics employed in the proposed design and analysis process. Furthermore, the semi-analytical approach to proverse yaw enables to identify the unconventional behaviour of induced drag during aileron deflection on wings with the selected non-elliptic spanloads. Additionally, it highlights that attainment of these solutions are highly dependent on flight condition, aileron sizing and location within a given spanload, and the magnitude of deflection. Overall, this thesis contributes to a further insight on the aero-structural trade-offs and proverse yaw characteristics derived from the use of such a design approach. This can facilitate the identification of the determining contributors and compromises to be made at early stages of the design, amplifying the designer’s control over the design and decision-making processes, while delaying critical decisions and enhancing the optimisation process with more informed drivers.en© Cranfield University, 2022. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder.Conceptual Wing DesignNon-Elliptic Lift DistributionsHigh Aspect Ratio WingsAero-Structural AnalysisMission PerformanceProverse YawThesis