116 research outputs found

    Experimental Results of Winglets on First, Second, and Third Generation Jet Transports

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    Results of wind tunnel investigations of four jet transport configurations representing both narrow and wide-body configurations and also a future advanced aerodynamic configuration are presented including performance and wing root bending moment data. The effects of winglets on the aerodynamic characteristics throughout the flight envelope were studied. The results indicate that winglets improved the cruise lift to drag ratio between 4 and 8 percent, depending on the transport configuration. The data also indicate that ratios of relative aerodynamic gain to relative structural weight penalty for winglets are 1.5 to 2.5 times those for wing-tip extensions. Over the complete range of flight conditions, winglets produce no adverse effects on buffet onset, lateral-directional stability, and aileron control effectiveness

    Effect of winglets on a first-generation jet transport wing. 1: Longitudinal aerodynamic characteristics of a semispan model at subsonic speeds

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    The effects of winglets and a simple wing-tip extension on the aerodynamic forces and moments and the flow-field cross flow velocity vectors behind the wing tip of a first generation jet transport wing were investigated in the Langley 8-foot transonic pressure tunnel using a semi-span model. The test was conducted at Mach numbers of 0.30, 0.70, 0.75, 0.78, and 0.80. At a Mach number of 0.30, the configurations were tested with combinations of leading- and trailing-edge flaps

    Effect of an alternate winglet on the pressure and spanwise load distributions of a first generation jet transport wing

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    Pressure and spanwise load distributions on a first-generation jet transport semispan model at subsonic speeds are presented. The wind tunnel data were measured for the wing with and without an alternate winglet. The results show that the winglet affected outboard wing pressure distributions and increased the spanwise loads near the tip

    Effect of Winglets on a First-Generation Jet Transport Wing. 2: Pressure and Spanwise Load Distributions for a Semispan Model at High Subsonic Speeds

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    Pressure and spanwise load distributions on a first-generation jet transport semispan model at high subsonic speeds are presented for the basic wing and for configurations with an upper winglet only, upper and lower winglets, and a simple wing-tip extension. Selected data are discussed to show the general trends and effects of the various configurations

    Experimental results of winglets on first, second, and third generation jet transports

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    The results of wind tunnel investigations of winglets on four jet transport configurations are presented. Performance and wing root bending moment data were given. Additionally, detailed aerodynamic characteristics are presented at the design condition and also at several off design conditions for one configuration. Results of the investigations indicate that the winglets improve the cruise lift to drag ratio between 4 and 8 percent. These data also show that the ratios of relative aerodynamic gain to relative structural weight penalty for winglets are 1.5 to 2.5 times the ratios for wing tip extensions. The comprehensive investigation of the effects of winglets indicated that winglets produce no adverse effects on buffet onset, lateral directional stability, and aileron control effectiveness

    The effect of winglets on the static aerodynamic stability characteristics of a representative second generation jet transport model

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    A baseline wing and a version of the same wing fitted with winglets were tested. The longitudinal aerodynamic characteristics were determined through an angle-of-attack range from -1 deg to 10 deg at an angle of sideslip of 0 deg for Mach numbers of 0.750, 0.800, and 0.825. The lateral aerodynamic characteristics were determined through the same angle-of-attack range at fixed sideslip angles of 2.5 deg and 5 deg. Both configurations were investigated at Reynolds numbers of 13,000,000, per meter (4,000,000 per foot) and approximately 20,000,000 per meter (6,000,000 per foot). The winglet configuration showed slight increases over the baseline wing in static longitudinal and lateral aerodynamic stability throughout the test Mach number range for a model design lift coefficient of 0.53. Reynolds number variation had very little effect on stability

    Effect of winglets on a first-generation jet transport wing. 3: Pressure and spanwise load distributions for a semispan model at Mach 0.30

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    Pressure and spanwise load distributions on a first-generation jet transport semispan model at a Mach number of 0.30 are given for the basic wing and for configurations with an upper winglet only, upper and lower winglets, and a simple wing-tip extension. To simulate second-segment-climb lift conditions, leading- and/or trailing-edge flaps were added to some configurations

    A high subsonic speed wind tunnel investigation of winglets on a representative second-generation jet transport wing

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    The effects of winglets on the aerodynamic forces and moments, loads, and crossflow velocities behind the wing tip are discussed. The results of the investigation indicate that winglets significantly reduce the drag coefficient at lifting conditions. The experiments were conducted in an 8-foot transonic pressure tunnel at Mach numbers from 0.70 to 0.83 and over a lift coefficient range up to 0.65. A semispan model was used

    Alternatives to immediate release tacrolimus in solid organ transplant recipients: When the gold standard is in short supply

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    Given the current climate of drug shortages in the United States, this review summarizes available comparative literature on the use of alternative immunosuppressive agents in adult solid organ transplant recipients including kidney, pancreas, liver, lung, and heart, when immediate‐release tacrolimus (IR‐TAC) is not available. Alternative options explored include extended‐release tacrolimus (ER‐TAC) formulations, cyclosporine, belatacept, mammalian target of rapamycin inhibitors, and novel uses of induction therapy for maintenance immunosuppression. Of available alternatives, only ER‐TAC formulations are of non‐inferior efficacy compared to IR‐TAC when used de novo or after conversion in stable kidney transplant recipients (KTRs). All other alternatives were associated with higher rates of biopsy‐proven rejection, but improved tolerance from classic adverse effects of IR‐TAC including nephrotoxicity and development of diabetes. While most alternative therapies are approved in KTRs, access via third‐party payors is an obstacle in non‐KTRs. In the setting of IR‐TAC shortage, alternate therapeutic options may be plausible depending on the organ population and individual patient situation to ensure appropriate, effective immunosuppression for each patient.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156148/2/ctr13903.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156148/1/ctr13903_am.pd
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