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SUMMARY 8 Flight Controls Active control systems to improve aircraft stability can provide reductions in drag and weight. Active controls to alleviate stress from wind gusts or maneuvering also offer opportunities to reduce weight or alternatively increase wing aspect ratio and thus reduce drag. U.S. manufacturers and Airbus appear to be approximately equal in both of these fields. Advanced Structures New high strength-to-weight alloys and new superplastically formed metals offer significant potential for saving weight. The United States and Europe are regarded as on a par in technology, but the U.S. leads in application experience with new alloys. This lead enables us to project longer ''economic life" at this stage of application. Composite materials offer the greatest opportunity in airframe materials. They offer high stiffness and extremely light weight. Long-term benefits could be a 15 to 20 percent reduction in total structural weight, a 7 to 15 percent improvement in fuel efficiency, and a resulting 4 to 8 percent reduction in direct operating costâthe latter is more uncertain because manufacturing costs for composites and future fuel costs are very uncertain. European R&D efforts are extensive and continue to accelerate. Aerospatiale has an aggressive program for progressive introduction of composite components on the A300 and the A310 as well as on helicopters and smaller aircraft. The A320 will incorporate still more extensive applications. The United States also is active, but the present NASA program calls for a six-year effort to develop design data for fuselages. Given the moderate pace of the current NASA program and the budget pressures it is encountering, the U.S. position in this very important technology could be threatened. Propulsion Integration This technology is regarded as relatively mature for conventional turbofans, and the United States and Great Britain are regarded as equal in nacelle design. Propulsion integration becomes crucial for the high-speed turboprops or propfans that are widely regarded as offering great promise for improved efficiency in smaller transport aircraft. The development of advanced propellers and their gearboxes is central to progress in this field. It is known that the European companies are active,
