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A design study was performed for an advanced subsonic transport having a payload of 150 passengers and a 2500 NMi range with maximum payload. The development of the baseline aircraft is explained with attention to geometric constraints, design for growth, operational requirements, and interior layout. Computer modeling was performed using a new version of AirCraft SYNThesis (ACSYNT) which includes: an integrated beam structural analysis method for the wing and fuselage; NASA Engine Performance Program (NEPP) for propulsion cycle and weights analysis; and Aircraft Life Cycle Cost Analysis (ALCCA) for manufacturing and operations cost and cash flow analyses. All programs are incorporated within ACSYNT to permit optimization of the input parameters, with either aircraft gross weight or design mission direct operating cost as a figure of merit. In addition, sensitivity studies of the best design are presented for wing aspect ratio and engine design point bypass ratio.

The focus of the 5 year long ACSYNT Institute has been to greatly increase the capability of the aircraft synthesis computer program, ACSYNT. The key improvements have followed from the advanced geometric modeling and display technology of current workstations. The higher fidelity model enables more accurate and general aerodynamic propulsion and weight computations with less reliance on regression methods and estimations. This paper focuses on the improvements that can enhance the state of the art in general aviation aircraft synthesis.

Integration of propulsion and flight-control systems will provide significant performance improvements for supersonic transport airplanes. Increased engine thrust and reduced fuel consumption can be obtained by controlling engine stall margin as a function of flight and engine operating conditions. Improved inlet pressure recovery and decreased inlet drag can result from inlet control system integration. Using propulsion system forces and moments to augment the flight-control system and airplane stability can reduce the flight-control surface and tail size, weight, and drag. Special control modes may also be desirable for minimizing community noise and for emergency procedures. The overall impact of integrated controls on the takeoff gross weight for a generic high speed civil transport is presented.