This study considers the performance possibilities of a clean-sheet, conventionally configured Boeing 737/Airbus A320 class single-aisle transport aircraft. It demonstrates that significant efficiency improvements can be achieved without a radical reconceptualization of the basic wing-body configuration. This study applies ModelCenter to perform singleobjective and multi-objective optimization of an ultra-high bypass ratio powered wing-bodytail aircraft. The broad design goals are consistent with NASA's earlier N+1 study objectives: low emissions, transcontinental range, and unrestricted operations from airports such as LGA, BUR, or DCA. A collection of linked industry standard tools including NASA's NPSS propulsion system simulation along with NASA's EDET and VORLAX aerodynamic estimation codes substantiated the final design. The optimizer suggested design meets and/or exceeds NASA's range, efficiency, and airport compatibility requirements with a conventionally configured, but carefully tailored specification. It should be noted that this was achieved with thrust loading, cruise altitude, and cruise Mach number elevated above customary expectations. However, the aircraft successfully utilized its inherent aerodynamic capability, even on short flights, cruising efficiently in the neighborhood of 44,000-ft. NomenclatureAR w = wing aspect ratio b = wing span (ft) BPR = engine bypass ratio C D = dimensionless drag coefficient %C Di = drag fraction C Dp = dimensionless zero-lift drag coefficient (parasite drag) C L = dimensionless lift coefficient C lβ = rolling moment stability derivative (per degree) = design coefficient of lift with respect to the oncoming free-stream airflow C Mα = pitch stability derivative (per degree) C nβ = yaw (weathercock) stability derivative (per degree) = Oswald Efficiency Factor FPR = engine fan pressure ratio γ = dihedral angle (degree) = airfoil technology factor Λ = quarter chord sweep of the wing (degree) λ = wing taper ratio Λ le = leading edge sweep of the wing (degree) LCDP = Lateral Control Departure (Spin) Parameter L/D = aerodynamic efficiency LDR = landing distance required (ft) AIAA Aviation 2 M = Mach number = critical Mach number with respect to the oncoming free-stream airflow MDO = multidisciplinary design optimization M(L/D) = aerodynamic performance efficiency MLW = maximum landing weight (lbm) MTOW = maximum takeoff weight (lbm) n/α = longitudinal load to angle of attack ratio (g's per radian) NO X = mono-nitrogen oxides  nSP = short period frequency (Hz) S ref = reference planform area of the wing (ft 2 ) /= thickness ratio of the wing normal to the leading edge / = thickness ratio of the wing with respect to the oncoming free-stream airflow TIT = turbine inlet temperature ( º F) TOFL = takeoff field length (ft) TSFC = thrust specific fuel consumption (lbm/lbf-hr) T/W = thrust loading (thrust-to-weight ratio) V f = vertical tail volume coefficient V H = horizontal tail volume coefficient

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An Energy Maneuverability (E-M) point-performance approach is used to study the effects of changing engine parameters upon a baseline airframe. This work considers, as independent variables, the effects of overall engine scale factor (sea level static thrust), power extraction, bleed air extraction, bypass ratio, turbine inlet temperature, fan pressure ratio, and overall pressure ratio against a reference aerodynamic database. This design study integrates propulsion analyses developed using NASA's NPSS propulsion modelling language. The E-M "skymap" grids demonstrate relations between the independent variables and their resulting impact on overall aircraft performance across the flight envelope. The results show the negative impact of bleed air extraction and shaft power extraction and the positive effect of high bypass ratio engines on cruise performance and sustained turning fuel burn but the negative effects on the maximum thrust of the engine. Overall the methods and data capture the relationships between several engine designs and the resulting impact on aircraft performance using a grid contour display. Nomenclature AR= wing aspect ratio BPR = engine bypass ratio C D = dimensionless drag coefficient C L = dimensionless lift coefficient FPR = engine fan pressure ratio L/D = aerodynamic efficiency M = Mach number M(L/D) = aerodynamic performance efficiency OPR = overall pressure ratio PLA = power lever angle Ps = specific excess power ROC = rate-of-climb (ft/min) S ref = reference planform area of a wing surface (ft 2 ) SE = specific endurance (hr/lbm) SR = specific range (nM/lbm) T = thrust (lbf) TIT = turbine inlet temperature ( º R) TSFC = thrust specific fuel consumption (lbm/lbf-hr) T/W = thrust loading (thrust-to-weight ratio) W = aircraft flight weight (lbm)