Toward zero sonic boom and high efficiency supersonic flight, Part I: A novel concept of supersonic bi-directional flying wing

This paper introduces a novel concept for supersonic airplane: supersonic bi-directional (SBiDir) flying wing (FW) concept, which is to achieve low sonic boom, low supersonic wave drag, and high subsonic performance. The SBiDir-FW planform is symmetric about both longitudinal and span axes. For supersonic flight, the planform will have low aspect ratio and high sweep angle to minimize wave drag. For subsonic mode, the airplane will rotate 90° and the sweep angle will be reduced and the aspect ratio will be increased. To minimize sonic boom, the pressure surface of the flying wing will employ an isentropic compression surface. At zero angle of attack (AoA) as the example studied in this paper, a flat pressure surface achieves this purpose. The CFD simulation shows that it obtains low ground sonic boom overpressure of 0.3psf with L/D _p = 5.3. Furthermore, the ground pressure signature is not the N shape wave with two strong shock wave pulses, but is in a smooth sin wave shape. The results show that it is possible to remove or achieve very low sonic boom using a supersonic bi-directional flying wing or blended wing body configuration. Future work will optimize the SBiDir-FW concept to achieve high aerodynamic efficiency and maintain low sonic boom.