Vehicle design study of a straight flying-wing with bell-shaped spanload

Straight flying-wing configurations, that is flying wings with zero quarter-chord sweep, are key to understanding bird flight, have potential performance improvements, and are suitable for "survivable" applications. Straight flying-wings are also well suited for morphing geometry, e.g. with variable twist, since changes in lift distribution do not impact longitudinal equilibrium. The straight-flying wing can adjust its lift distribution to optimize aerodynamic efficiency across a wide range of flight conditions. The study vehicle is called "Biom T1", which has a more efficient directional control scheme by employing the same bell-shaped lift-distribution used by birds; this creates a downwash distribution favorable to proverse yaw in the outer portion of the wing. Morphing geometry is used in the form of an all-moving outer portion of the wing which changes angle to provide the most favorable lift distribution for reduced drag and high control power over the flight envelope. In this paper, flying qualities and control system robustness are demonstrated through linear analysis. Straight flying-wings are viable in terms of stability and control and are suitable for imaging, communications, and other high-efficiency, low-payload-volume applications.