A Lateral Directional Flight Control System for the MOB Blended Wing Body Planform

Abstract: In this work, analysis and design of a lateral directional flight control system for a Blended Wing Body (BWB) aircraft is considered. The BWB configuration chosen for this purpose is the European MOB (Multidisciplinary Optimization Blended Wing Body) planform. The MOB configuration does not have vertical control surfaces for directional stability, instead small winglets with rudders are used. The lateral directional behavior of the baseline MOB configuration is analyzed and the inherent deficiencies both in terms of directional stability and control power are highlighted. A modification to this configuration is then proposed in which two vertical rudders are placed at the trailing edge of the center body. The improvement gained in the stability and directional stiffness is compared with the baseline configuration. The open loop analysis is followed by the design of a flight control system and verification of the results through non-linear simulations. It is concluded that the MOB configuration with winglet rudders does not have enough trim/control authority especially under asymmetric thrust conditions. Rudder control needs to be modified in order to make this a practical design.