A design analysis of vertical stabilisers for Blended Wing Body aircraft

Blended Wing Body (BWB) aircraft are a relatively new concept offering advantages of aerodynamic performance and fuel economy. In BWB aircraft design, directional stability has been identified as one aspect that remains under-researched. This paper presents a design analysis of vertical stabilisers on a BWB aircraft to determine their suitability and effects on stability. Founded on an existing model [1], a baseline BWB aircraft model has been developed with vertical stabilisers designed using the volume coefficient method which, although not created for BWB aircraft, is used to aid the design. To ensure suitability for transonic flight, stabiliser dimensions were kept in proportion to that of the Airbus A380 due to having a similar payload and cruise condition. Two BWB aircraft CAD models were developed; one with twin-stabilisers mounted vertically and another with them inclined. CFD analyses were performed to assess stability with respect to rudder inputs and sideslip angle. Stability derivatives calculated were similar for both twin-stabiliser configurations; however, the inclined configuration gave a smoother response. Drag performance was also assessed with the inclined stabilisers generating greater drag than the vertical stabilisers. This research has shown that a twin-stabiliser design is suitable for BWB aircraft.