Design, Control Surface Optimization and Stability Analysis of a Blended Wing Body Aircraft (BWB) Unmanned Aerial Vehicle

Unmanned Aerial Vehicles (UAVs) are becoming an effective way to serve humanitarian relief efforts during environmental disasters. The process of designing such UAVs poses challenges in optimizing design variables such as maneuverability, payload capacity and maximizing endurance because the designing of a BWB takes into account the interdependency between the stability and aerodynamic performance. The Blended Wing Body is an unconventional aircraft configuration which offers enhanced performance over conventional UAVs. In this study the designing of a BWB is investigated with an aim to achieve structurally sound and aerodynamically stable configuration. The design has been done by taking into consideration the side and top view airfoil for fuselage, because fuselage is a major lift generating portion in the UAV. For designing the control surfaces, the two major requirements for a controlled and safe flight of a UAV are its stability and maneuverability. The purpose of this study is also to design and validate elevons for a UAV having Blended Wing Body configuration which requires knowledge of various domains applied in a complex combination. Elevons are the unconventional control surfaces for the flying wings which will cause a pitching moment when moved in the same direction and will cause a rolling moment when moved differentially and their preliminary design is affected by the function which is dominant. A MATLAB code was written to decide the position, shape and size of elevons and later on accurately evaluated them using high fidelity X-FOIL aerodynamic analysis. The MATLAB© code calculates the required roll time rate taking into consideration the longitudinal and lateral control requirements. Using this coupled approach of MATLAB© code and XFLR5 analysis significant optimization is achieved in designing the elevons. The Blended wing body has been iteratively optimized in XFLR-5 for its static and dynamic stability. The 3D CAD model was designed on Solidworks and analyzed in Pressure Based Solver. So, in this study a system engineering approach has been used wherein the first phase is to conceptualize the design followed by preliminary design wherein the airfoil selection and constraint analysis is being carried out and finally a detailed design phase was used to validate the design.