Wing Twist Design Considerations for Transport Category Aircraft

Donovan, Shane; Takahashi, Timothy

doi:10.2514/6.2011-1251

Cited by 5 publications

(6 citation statements)

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“…29 As such, this method allocates the spanwise distribution of thickness using the Korn equation. 30 The Korn equation correlates the allowable wing thickness-to-chord-ratio with respect to the oncoming free-stream airflow / as a function of the critical Mach number with respect to the oncoming free-stream airflow , an airfoil "technology factor" ( ), and the non-dimensional design coefficient of lift with respect to the oncoming free-stream airflow .…”

Section: B Wing Design and Aerodynamicsmentioning

confidence: 99%

“…11 German, Patterson, and Takahashi derived closed-form approximate solutions defining the minimum thrust loading necessary to utilize maximum aerodynamic performance efficiency, M(L/D); they noted that these solutions typically required flight at altitudes approaching 45,000-ft. 12 Finally, Takahashi and Donovan as well as Takahashi alone used medium fidelity structural synthesis techniques coupled with linear aerodynamic models and a full time-step integrating performance code, to demonstrate how elusive the supposed system performance benefits of reduced root bending-moment wings (with triangular span-load) are, under the heightened scrutiny of a true MDO model. 13,14 The ASU N+1 Narrow-Body Reference Design utilizes an elliptical transverse span load to determine the necessary wing section and wing planform characteristics. In addition, the choice of wing design speed (Mach…”

Section: Design For Alternative Cruise Conditionsmentioning

confidence: 99%

“…13 The aircraft planform (plotted in Figure 16a) was chosen in conjunction with an assumed, elliptical span-load to 1) have a minimal variation in section design lift coefficient over the majority of the wingspan (plotted in Figure 16b) and 2) to provide both area and thickness in the inboard region suitable to affix the main landing gear.…”

Section: Detail Wing Geometry -Section Thickness Allocation Cambementioning

confidence: 99%

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Multi-Disciplinary Design of an Advanced Narrow-Body Transport Aircraft

Gedeon

Huffer

Takahashi

2013

2013 Aviation Technology, Integration, and Operations Conference

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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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Section: B Wing Design and Aerodynamicsmentioning

confidence: 99%

Section: Design For Alternative Cruise Conditionsmentioning

confidence: 99%

Section: Detail Wing Geometry -Section Thickness Allocation Cambementioning

confidence: 99%

See 1 more Smart Citation

Multi-Disciplinary Design of an Advanced Narrow-Body Transport Aircraft

Gedeon

Huffer

Takahashi

2013

2013 Aviation Technology, Integration, and Operations Conference

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“…Additionally, the bending ratios depend only on the shape of a distribution and not its amplitude, which is defined by C L . The root bending moment ratio is similar to the concept of root bending moment relief (RBMR) used by Donovan and Takahashi in [18] and to the concept of root bending moment reduction used by Iglesias and Mason in [16].…”

Section: Overview Of Previous Formulationsmentioning

confidence: 99%

“…Donovan and Takahashi [18] considered the optimization of the lift distribution and subsequent twist distribution to minimize mission fuel burn for a fixed planform. Wing weight was held constant and the changes in induced drag were computed as wing twist was varied.…”

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confidence: 99%

Lift Distributions for Minimum Induced Drag with Generalized Bending Moment Constraints

Pate

German

2013

Journal of Aircraft

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The previous works of Prandtl, Jones, and Klein and Viswanathan addressed the problem of determining the lift distribution that minimizes induced drag for a given lift and specified bending moment. In these formulations, bending moment is considered to be a surrogate for wing weight. These classical methods require the bending constraints to be imposed at the same lift coefficient at which drag is minimized. In practice, however, it is commonly desired to minimize drag at a representative cruise lift coefficient while imposing the bending constraints at a limiting structural load condition, such as a maneuver lift coefficient. This paper presents an approach to extend the classical methods by allowing the bending constraints to be imposed at different lift coefficients than that at which induced drag is minimized. An example for a wing planform similar to that of a Boeing 737 shows that the penalty for optimizing induced drag at the maneuver lift coefficient as implied in the classical methods results in between a 1-10% increase in drag at cruise compared to the results from this new approach. It is expected that the new approach will enable the classical methods to be extended to practical applications in multidisciplinary wing design.

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