In the continuous challenge in aircraft design to further improve aircraft efficiency, variable camber has been addressed in aviation research several times. Examples of applications of variable camber are the optimization of lift distribution during cruise for standard operations and, more recently, enabling better performance on more diverse flight altitudes to avoid contrail formation. These and other applications call for considering variable camber in conceptual aircraft design, already employing its potential.The main purpose of camber variation pursued by this thesis is to choose the best available camber for the specific flight condition and to assess the conceptual overall aircraft level. The vast majority of aviation transport is realised with aircraft operating at flight speeds that create flow conditions on the wing,necessitating the incorporation of compressibility effects. Assessing any technology focusing on changing airfoil characteristics in the transonic regime should employ compressible analysis methods. Therefore, the main challenge motivating this work is to develop a method that enables variable camber assessment, incorporating 2D airfoil analysis, considering compressibility effects, while offering stability and adequate computational effort to allow the typical studies necessary for conceptual aircraft design.An extensive literature review showed that variable camber has been in aviation research and application for over 100 years. The results for the application on the aircraft level vary between 1 and 10 % drag reduction. A systematic approach incorporating variable camber in conceptual aircraft design was found to be lacking in the current state of the art. Therefore, a methodology for assessing variable camber in conceptual aircraft design has been devised to evaluate an advanced dropped hinge flap high-lift system as variable camber architecture.A reference aircraft has been selected based on the Airbus A350-900 due to its advanced dropped hinge flap high-lift system application. Substantial efforts were made to prepare this reference aircraft to ensure its suitability for a solid assessment basis. This comprised the selection of baseline airfoils suitable for the occurring flow conditions and optimising the twist to achieve an appropriate lift distribution with the analysis methods employed. The former was a challenging task for the airfoils available in the public domain. This became especially clear when the 2.5D method was applied, incorporating compressibility effects.Subsequently, the methodology was applied to the reference aircraft. After deriving the deployed airfoilgeometries, the application of the 2.5D method showed that the selected baseline airfoils were not ideal in their pressure distribution for the VC application.The trends originating from the deployment of the 2D airfoils and their succeeding 2.5D integration into, first, the wing and, secondly, the overall aircraft polars showed to be consistent and in line with expectations and literature statements (0.35 % L/D improvement). The concluding assessment on the mission level continued this consistent propagation. It yielded trip fuel reductions (0.43 %), which was in line with the pure aerodynamic results, which also held for the study on system failure. These results demonstrated the desired behaviour and suitability of the proposed methodology.
Fabian Peter (Wed,) studied this question.