34,963 research outputs found

    Angle-of-attack analysis of a spinning slender cone with slight aerodynamic and mass asymmetries /reentry F/

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    Angle of attack analysis of spinning slender reentry cone with slight aerodynamic and mass asymmetrie

    Flight testing the fixed-wing configuration of the Rotor Systems Research Aircraft (RSRA)

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    The Rotor Systems Research Aircraft (RSRA) is a unique research aircraft designed to flight test advanced helicopter rotor system. Its principal flight test configuration is as a compound helicopter. The fixed wing configuration of the RSRA was primarily considered an energy fly-home mode in the event it became necessary to sever an unstable rotor system in flight. While it had always been planned to flight test the fixed wing configuration, the selection of the RSRA as the flight test bed for the X-wing rotor accelerated this schedule. This paper discusses the build-up to, and the test of, the RSRA fixed wing configuration. It is written primarily from the test pilot's perspective

    Turbid water measurements of remote sensing penetration depth at visible and near-infrared wavelength

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    Remote sensing of water quality is dicussed. Remote sensing penetration depth is a function both of water type and wavelength. Results of three tests to help demonstrate the magnitude of this dependence are presented. The water depth to which the remote-sensor data was valid was always less than that of the Secchi disk depth, although not always the same fraction of that depth. The penetration depths were wavelength dependent and showed the greatest variation for the water type with largest Secchi depth. The presence of a reflective plate, simulating a reflective subsurface, increased the apparent depth of light penetration from that calculated for water of infinite depth

    Investigation of conventional and Super-X divertor configurations of MAST Upgrade using SOLPS

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    One of the first studies of MAST Upgrade divertor configurations with SOLPS5.0 are presented. We focus on understanding main prospects associated with the novel geometry of the Super-X divertor (SXD). This includes a discussion of the effect of magnetic flux expansion and volumetric power losses on the reduction of target power loads, the effect of divertor geometry on the divertor closure and distribution of neutral species and radiation in the divertor, the role of the connection length in broadening the target wetted area. A comparison in conditions typical for MAST inter-ELM H-mode plasmas confirms improved performance of the Super-X topology resulting in significantly better divertor closure with respect to neutrals (the atomic flux from the target increased by a factor of 6, but the atomic flux from the divertor to the upper SOL reduced by a factor of 2), increased radiation volume and increased total power loss (a factor of 2) and a reduction of target power loads through both magnetic flux expansion and larger volumetric power loss in the divertor (a factor of 5-10 in attached plasmas). The reduction of the target power load by SXD further increases with collisionality (high density or detached regimes) thanks to larger importance of volumetric power losses. It is found that a cold divertor plasma leads to stronger parallel temperature gradients in the SOL which drive more parallel heat flux, meaning that the effectiveness of perpendicular transport in spreading the power at the target can be reduced, and this needs to be taken into account in any optimisation.Comment: 32 pages, 23 figures. This is an author-created, un-copyedited version of an article accepted for publication in PPCF. IOP Publishing Ltd and IAEA are not responsible for any errors or omissions in this version of the manuscript or any version derived from i

    A review of the NASA V-G/VGH general aviation program

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    The V-G and VGH data collected from a wide variety of general aviation airplanes since the inception of the NASA V-G/VGH General Aviation Program in 1962 are presented. These data were analyzed to obtain information on the gust and maneuver loads, on the operating practices, and on the effects of different types of operations on these parameters

    Aerodynamic tests and analysis of a turbojet-boosted launch vehicle concept (spacejet) over a Mach number range of 1.50 to 2.86

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    Results from analytical and experimental studies of the aerodynamic characteristics of a turbojet-boosted launch vehicle concept through a Mach number range of 1.50 to 2.86 are presented. The vehicle consists of a winged orbiter utilizing an area-ruled axisymmetric body and two winged turbojet boosters mounted underneath the orbiter wing. Drag characteristics near zero lift were of prime interest. Force measurements and flow visualization techniques were employed. Estimates from wave drag theory, supersonic lifting surface theory, and impact theory are compared with data and indicate the ability of these theories to adequately predict the aerodynamic characteristics of the vehicle. Despite the existence of multiple wings and bodies in close proximity to each other, no large scale effects of boundary layer separation on drag or lift could be discerned. Total drag levels were, however, sensitive to booster locations

    Laboratory upwelled radiance and reflectance spectra of Kerr reservoir sediment waters

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    Reflectance, chromaticity, and several other physical and chemical properties were measured for various water mixtures of bottom sediments taken from two sites at Kerr Reservoir, Virginia. Mixture concentrations ranged from 5 to 1000 ppm by weight of total suspended solids (TSS) in filtered deionized tap water. The two sets of radiance and reflectance spectra obtained were similar in shape and magnitude for comparable values of TSS. Upwelled reflectance was observed to be a nonlinear function of TSS with the degree of curvature a function of wavelength. Sediment from the downstream site contained a greater amount of particulate organic carbon than from the upstream site. No strong conclusions can be made regarding the effects of this difference on the radiance and reflectance spectra. Near-infrared wavelengths appear useful for measuring highly turbid water with concentrations up to 1000 ppm or more. Chromaticity characteristics do not appear useful for monitoring sediment loads above 150 ppm

    Scenic Gems of Bath

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    A 40-page booklet of photographs of attractions around Bath, Maine, circa 1900. Cover title: Scenic gems of Bath, Boothbay Harbor, So. Bristol, Squirrel Island, Christmas Cove, Pemaquid, and other points of interest

    Laboratory measurements of physical, chemical, and optical characteristics of Lake Chicot sediment waters

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    Reflectance, chromaticity, diffuse attenuation, beam attenuation, and several other physical and chemical properties were measured for various water mixtures of lake bottom sediment. Mixture concentrations range from 5 ppm to 700 ppm by weight of total suspended solids in filtered deionized tap water. Upwelled reflectance is a nonlinear function of remote sensing wave lengths. Near-infrared wavelengths are useful for monitoring highly turbid waters with sediment concentrations above 100 ppm. It is found that both visible and near infrared wavelengths, beam attenuation correlates well with total suspended solids ranging over two orders of magnitude

    Operating experiences of retardant bombers during firefighting operations

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    Data are presented on operational practices and maneuver accelerations experienced by two Douglas DC-6B airplanes converted to retardant bombers and used in firefighting operations. The data cover two fire seasons in the mountainous regions of the northwestern United States
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