The potential advantages of Blended Wing Body (BWB) aircraft in terms of fuel e©ciency are opposed by technical challenges such as the alleviation of gust loads. Due to the low wing, loading gusts, generally, have a more severe impact on BWB aircraft than on conventional aircraft. This paper presents the design and optimization of a Gust Load Alleviation System (GLAS) for a large BWB airliner. Numerical simulations are performed with an aeroelastic model of the aircraft including GLAS in order to compute time series of modal displacements for deriving equivalent static load cases which are used for the resizing of the aircraft structure.

Blended Wing Body (BWB) aircraft con¦gurations have been proposed for signi¦cant fuel e©ciency improvement on commercial transport. In order to §y with the optimum lift-to-drag ratio throughout most of the mission, an adaptation of the center of gravity (CG) by fuel redistribution is proposed. The most aft location of the CG which still is controllable is mainly limited by actuator bandwidth whereas the front CG location is limited by control authority of the trailing edge control surfaces. This paper provides an optimization of the CG position with regards to minimization of fuel consumption. Layout of the fuel tank system is illustrated. Moreover, active stabilization of faulty CG positions is discussed.

This paper describes the con¦guration selection process in the FP7 project ACFA (Active Control for Flexible Aircraft) 2020 in view of the Advisory Council for Aeronautics Research in Europe (ACARE) aims. The design process challenges and the comparison of a blended wing body (BWB) aircraft with a wide body carry-through wing box (CWB) con¦guration are described in detail. Furthermore, the interactions between the conceptual design and structural design using multidisciplinary design optimization (MDO) to rapidly generate and adapt structural models to design changes and provide early feedback of mass and center of gravity values for these nontraditional con¦gurations are discussed. Comparison of the two concepts determined that the developed all-lifting BWB airframe has the potential for a signi¦cant reduced fuel consumption compared to the CWB.

This paper describes a framework for the modeling and sizing of flexible aircraft subject to static and transient maneuver loads, control inputs and external disturbances due to atmospheric turbulence. An integrated coupled model of the flexible aircraft comprising a nonlinear rigid body flight dynamics model and a linear aeroelastic model is used to obtain the equivalent static loads on the structure for a given set of flight cases. These are used in a subsequent structural optimization step to update the structure to obtain a minimum mass design while fulfilling requirements on strength and stability. The updated structural model is fed back to the maneuver simulation in an automated process enabling a rapid search for a consistent design. In the paper, this process is applied to a blended wing body configuration developed within the ACFA 2020 research project. The structural loads resulting from a given set of flight inputs are examined and used to obtain a mass optimized structure.

This paper describes the full development process of a numerical simulation model for the ACFA2020 (Active Control for Flexible 2020 Aircraft) blended wing body (BWB) con¦guration. Its requirements are the prediction of aeroelastic and §ight dynamic response in time domain, with relatively small model order. Further, the model had to be parameterized with regard to multiple fuel ¦lling conditions, as well as §ight conditions. High e¨orts have been conducted in high-order aerodynamic analysis, for subsonic and transonic regime, by several project partners. The integration of the unsteady aerodynamic databases was one of the key issues in aeroelastic modeling.