Conceptual Design and Aerodynamic Shape Optimization for the Assembled Air Lunched Vehicles Based on the BWB Carrier Aircraft

The conceptual design and the aerodynamic shape optimization of the carrier for the assembled air launched vehicles via the blended wing body(BWB) carrier aircraft and the aerospace plane with rocket engines were presented in this paper. The first stage of the vehicles is a large BWB carrier aircraft with the subsonic/transonic configuration. The second stage is two external tanks of the propellant for the rockets. The third stage is a winged rocket aircraft. The air launching method, compared with the land or sea launching methods, can be used to decrease the initial weight of the launching system with the same orbital weight. The propellant for the rocket engines can be decreased obviously, so the launching can be more convenient and the cost can be decreased significantly. The weight of a space shuttle can be launched into the orbit with the initial weight of about 1×10⁶ kg, while the weight of the space shuttle system is over 2×10⁶ kg tons before launching via rockets, and the system can be reusable. For the third stage vehicle, the gravitational potential energy and the kinetic energy of the aerospace plane due to the altitude and speed can be used to glide around the earth with a hypersonic speed, so the method to slowly release the energy for the air launched boost gliding system is researched. Considering the limited aerodynamic optimization potential of hypersonic vehicles, the carrier aircraft is redesigned to get an optimized ratio of lift to drag at the launching state and an obviously higher lift coefficient for the take-off state with the multi-point multi-constraint aerodynamic optimization method. The increase of load capacity can be used to increase the orbital weight or gliding range, so as to optimize the overall system.