XB - 70 bombers, adopt the canard, not flat tail, general layout of triangle wing leading edge down, and will be about 47 square meters of wing tip and the main wing in hinge joint, flying at high speed, wing tips can be lowered 25 degrees to 65 degrees. In theory, there are three advantages to this folding of wings (at high speed) : (1) the wing tip plays a part of the vertical stabilizer, which is helpful for the direction of b-70 stability. There are fewer existing three views (2) when supersonic, the anti-angle effect can be offset. (3) destroy the partial lift generated at the rear of the airfoil, avoid the over-backward movement of the lift center and stabilize the aircraft. (4) manufacturing compression lift. And before the design B - 70, the committee (for NASA's forerunner) has found a compressed lift phenomenon, namely, in a high speed, an appropriate shape of the object can make the sound barrier formation of the shock wave hold up, like surf boat by waves of Mercedes, so XB - 70 - a inlet is located in the delta wing, just shock wave form up huge volume of compressed air, can be the wing capture, thus provides a free lift. The design part of the XB-70 front canard wing was designed to counteract the downward trend of the nose when the main wing lift center was removed. The front edge of the canard wing has a fine-tuned flange, the trailing edge is the flap of each independent action. But when Mach 3, front canard cannot offset the torque developed by the lift centre back, at this point it is necessary to make the main carefully pointed downward bending, in order to increase its pitch and direction stability, this kind of design, however, its structure, control system to increase the complexity of the danger. The main wing has six elevons (12 pieces in total) and two elevons on the tip of the outer wing, which cannot be used when the tip of the wing is broken. The double vertical tail fin has a fixed vertical fin surface except the small triangular area