Sizing of control surfaces on a Flying V aircraft
V. TIWARI (TU Delft - Aerospace Engineering)
R. Vos – Mentor (TU Delft - Flight Performance and Propulsion)
C. Varriale – Graduation committee member (TU Delft - Flight Performance and Propulsion)
E Van Kampen – Graduation committee member (TU Delft - Control & Simulation)
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Abstract
The goals of governments and agencies around the world is to minimize fuel emissions for the upcoming decades. The Flying V offers a new concept, which is an aircraft of flying wing configuration, offering higher aerodynamic efficiency than conventional tube and wing configuration. However, such an configuration offers challenges with its stabilty and control characteristics, with difficulties arising in control authority, like for instance, longitudinal trim. This study aims to find the optimal control surface layout for the FV-1000 aircraft.First, the certification requirements relevant to each control surface to be sized in this study (aileron, elevator and rudder) are gathered, primarily based on CS-25 regulations, and they are expressed mathematically. AVL is chosen as the tool to conduct aerodynamic analysis, for sizing purposes. Two coefficients are compared for their viability as objective function for optimizing a control surface,hinge moment coefficient and drag coefficient, hinge moment coefficient turns out to be the better option, it also provides control surface for a given span as small as possible. A consistent optimization framework is applied to both the aileron and elevator, wherein the spanwise domain is discretized and various combinations of span length and hinge line chord percentage are evaluated. The resulting optimal configurations are spatially adjacent, with the sizing of each control surface constrained by the span available due to presence of the other. During validation procedure, the comparisons made between VLM and wind-tunnel when extrapolated to comparison between VLM analysis and full scale flight case, it is observed that aileron is oversized, (for time to bank) while control elevators are undersized (to be precise, for pull-up maneuver). Certain solutions like high-lift devices or other methods of reducing AoA are suggested to make control surface like elevator comply with requirements. Rudders are the final surface to be sized which satisfy requirements of OEI trim at VLM analysis and even for full scale case, but is not able to satisfy the Steady sideslip requirement by significant margin for both cases. However, these results signify need of research on other options to assist these control surfaces, like drag rudders to assist with directional control authority, high lift devices to decrease AoA, assist surfaces like elevator in meeting the certification requirement, which are discussed.