B-1 Technology Applications to Advanced Transport Design 730348

Several unique design approaches have been used to configure the B-1 strategic bomber. These innovations are applicable to future advanced supersonic transport (AST) design approaches.The combined aerodynamic/structural efficiency of the B-1 is enhanced by using the blended wing/body concept. Structural mode control has been incorporated to alleviate structural motion, because the B-1 will be involved in considerable low-altitude, high-turbulence flying. Application of this system should be considered for the AST to reduce the structural penalties inherent at the high-speed portion of the flight envelope. The B-1 is the first airplane to be designed to a specified fracture mechanics requirement. Future transport designs, including future ASTs, probably will have a similar requirement to augment the present fatigue criteria. Several B-1 subsystem advancements applicable to the AST program scope are discussed. In particular, the B-1's flight control systems incorporate many unique features to enhance its safety, mission success, and survivability/vulnerability characteristics. Command augmentation is used in all control axes, providing undegraded fail-operational, fail-safe capability. Mechanical component protection from jams and disconnects is provided, along with rotary surface actuators in certain advantageous locations. A combination of fly-by-wire control of certain surfaces to a dual fly-by-wire/mechanical control of other surfaces provides a high probability of mission completion in any environment. All primary control surfaces are designed to operate after any two hydraulic failures. Extensive use of diffusion bonding is being employed in constructing the major structural components of the B-1. Complicated shapes can be easily molded into homogeneous parts. Since the AST will have similar component requirements, the use of diffusion bonding should allow the designer much more latitude in obtaining efficient structural members.