299 research outputs found

    Comparison of theoretical and flight-measured local flow aerodynamics for a low-aspect-ratio fin

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    Flight test and theoretical aerodynamic data were obtained for a flight test fixture mounted on the underside of an F-104G aircraft. The theoretical data were generated using two codes: a two-dimensional transonic code called code H, and a three-dimensional subsonic and supersonic code called wing-body. Pressure distributions generated by the codes for the flight test fixture, as well as compared with the flight-measured data. The two-dimensional code pressure distributions compared well except at the minimum pressure point and the trailing edge. Shock locations compared well except at high transonic speeds. However, the two-dimensional code did not adequately predict the displacement thickness of the flight test fixture. The three-dimensional code pressure distributions compared well except at the trailing edge of the flight test fixture

    Comparison of theoretical and flight-measured local flow aerodynamics for a low-aspect-ratio fin

    Get PDF
    Flight test and theoretical aerodynamic data were obtained for a flight test fixture mounted on the underside of an F-104G aircraft. The theoretical data were generated using two codes, a two dimensional transonic code called Code H, and a three dimensional subsonic and supersonic code call wing-body. Pressure distributions generated by the codes for the flight test fixture as well as boundary layer displacement thickness generated by the two dimensional code were compared to the flight test data. The two dimensional code pressure distributions compared well except at the minimum pressure point and trailing edge. Shock locations compared well except at high transonic speeds. The three dimensional code pressure distributions compared well except at the trailing edge of the flight test fixture. The two dimensional code does not predict displacement thickness of the flight test fixture well

    The use of a panel code on high lift configurations of a swept forward wing

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    A study was done on high lift configurations of a generic swept forward wing using a panel code prediction method. A survey was done of existing codes available at Ames, frow which the program VSAERO was chosen. The results of VSAERO were compared with data obtained from the Ames 7- by 10-foot wind tunnel. The results of the comparison in lift were good (within 3.5%). The comparison of the pressure coefficients was also good. The pitching moment coefficients obtained by VSAERO were not in good agreement with experiment. VSAERO's ability to predict drag is questionable and cannot be counted on for accurate trends. Further studies were done on the effects of a leading edge glove, canards, leading edge sweeps and various wing twists on spanwise loading and trim lift with encouraging results. An unsuccessful attempt was made to model spanwise blowing and boundary layer control on the trailing edge flap. The potential results of VSAERO were compared with experimental data of flap deflections with boundary layer control to check the first order effects

    A water tunnel flow visualization study of the vortex flow structures on the F/A-18 aircraft

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    The vortex flow structures occurring on the F/A-18 aircraft at high angles of attack were studied. A water tunnel was used to gather flow visualization data on the forebody vortex and the wing leading edge extension vortex. The longitudinal location of breakdown of the leading edge vortex was found to be consistently dependent on the angle of attack. Other parameters such as Reynolds number, model scale, and model fidelity had little influence on the overall behavior of the flow structures studied. The lateral location of the forebody vortex system was greatly influenced by changes in the angle of sideslip. Strong interactions can occur between the leading edge extension vortex and the forebody vortex. Close attention was paid to vortex induced flows on various airframe components of the F/A-18. Reynolds number and angle of attack greatly affected the swirling intensity, and therefore the strength of the studied vortices. Water tunnel results on the F/A-18 correlated well with those obtained in similar studies at both full and sub scale levels. The water tunnel can provide, under certain conditions, good simulations of realistic flows in full scale configurations

    In-flight thrust determination on a real-time basis

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    A real time computer program was implemented on a F-15 jet fighter to monitor in-flight engine performance of a Digital Electronic Engine Controlled (DEES) F-100 engine. The application of two gas generator methods to calculate in-flight thrust real time is described. A comparison was made between the actual results and those predicted by an engine model simulation. The percent difference between the two methods was compared to the predicted uncertainty based on instrumentation and model uncertainty and agreed closely with the results found during altitude facility testing. Data was obtained from acceleration runs of various altitudes at maximum power settings with and without afterburner. Real time in-flight thrust measurement was a major advancement to flight test productivity and was accomplished with no loss in accuracy over previous post flight methods

    Photographs of coronal streamers from a rocket on 9 May 1967

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    Analysis of coronal streamers photographed by white light coronagraphs flown on Aerobee 150 vehicl

    Flow direction measurement criteria and techniques planned for the 40- by 80-/80- x 120-foot wind tunnel integrated systems tests

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    A study was performed in order to develop the criteria for the selection of flow direction indicators for use in the Integrated Systems Tests (ISTs) of the 40 by 80/80 by 120 Foot Wind Tunnel System. The problems, requirements, and limitations of flow direction measurement in the wind tunnel were investigated. The locations and types of flow direction measurements planned in the facility were discussed. A review of current methods of flow direction measurement was made and the most suitable technique for each location was chosen. A flow direction vane for each location was chosen. A flow direction vane that employs a Hall Effect Transducer was then developed and evaluated for application during the ISTs

    Agricultural Innovation Systems: An Investment Sourcebook

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    The World Bank assembled this reference guide to explain the contributing aspects and limitations of the Agricultural Innovation System (AIS). The guide is divided into seven modules to better address topics through detailed overviews, recommended approaches and programs, and successful activities for each. The first module stresses the importance of a collaborative effort in a successful AIS structure, specifically, national coordination and governance, building innovation networks, increasing access to marketing chains, and building innovation capabilities in farmer organizations. Module 2 delves into the role of agricultural education and training as “a creator of capacity and supplier of the human resources that populate key segments of the AIS and enable that system to function more effectively” (Maguire, 2012, p. 107)

    Trowels, Trenches, and Transformation: A Case Study of Archaeologists Learning, Teaching, and Enacting Environmentally-Friendly, Community-Inclusive Practices

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    Guided by the framework of “critical transformative learning,” this study explores archaeologists as adult learners and seeks to understand how they are learning to practice a new vision of archaeology in Mexico. In this project, personal transformation is linked to disciplinary and social transformation

    Guerrilla Girls and Raging Grannies: Critical, Informal, and Performative Pedagogy

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    This paper offers two important historical examples, The Guerrilla Girls and The Raging Grannies, as ways to explore, experience, and better understand the value of embodied learning through culture jamming and critical performative pedagogy
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