The changes in structural and flight safety due to flap design of blended-wing-body civil aircraft

Based on the 250-passenger BWB configuration, the effect of the configuration of flap on BWB civil aircraft flight loading during takeoff and landing is studied by computational fluid dynamics. Flight loading varied with the flap deflection, area and the layout is discussed. It is shown the existence of flap makes the angle of attack smaller in takeoff and landing and aerodynamic forces and moment larger. In addition, it can change the loading distribution along span wise of the wing and affect the structural safety. Especially, increased pitch moment can make flight safety worse in takeoff and landing. In some cases, it is important that the function of flap is to improve the drag significantly and reduce the distance of taxiing to benefit to safety in landing. The airworthiness will have to be re-evaluated before the flaps are used in BWB on basis of the structural and flight safety considerations according to CCAR25.