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At least 109 records · Page 6

A summary of rotorcraft handling qualities research at NASA Ames Research Center

The objectives of the rotorcraft handling qualities research program at Ames Research Center are twofold: (1) to develop basic handling qualities design criteria to permit cost effective design decisions to be made for helicopters, and (2) to obtain basic handling qualities data for certification of new rotorcraft configurations. The research on the helicopter handling qualities criteria has focused primarily on military nap-of-the-earth (NOE) terrain flying missions, which are flown in day visual meteorological conditions (VMC) and instrument meteorological conditions (IMC), or at night. The Army has recently placed a great deal of emphasis on terrain flying tactics in order to survive and effectively complete the missions in modern and future combat environments. Unfortunately, the existing Military Specification MIL-H 8501A which is a 1961 update of a 1951 document, does not address the handling qualities requirements for terrain flying. The research effort is therefore aimed at filling the void and is being conducted jointly with the Army Aeromechanics Laboratory at Ames. The research on rotorcraft airworthiness standards with respect to flying qualities requirements was conducted to collaboration with the Federal Aviation Administration (FAA).

Chen, R. T.↗

Status of Regenerative Life Support Research and Technology Program at NASA Ames Research Center

Future long duration manned space missions will require life support systems that minimize resupply requirements and ultimately approach self-sufficiency in space. This presentation will provide an overview of the Advanced Life Support program unclassified fundamental research and technology development activities being conducted at NASA Ames Research Center. Top level program goals and technical objectives, and the role of NASA-Ames within the Advanced Life Support program, will be reviewed. The presentation will focus on FY97 and FY98 research tasks that were directed at physicochemical processes with emphasis on system closure and self-sufficiency. Research areas include solid waste processing and resource recovery, water recycling, air regeneration, and regenerative system dynamics. Proposed future work and potential applications of this research to both terrestrial and space closed ecology experimentation in space will be addressed.

Kliss, Mark↗

The 1979 Ames Research Center Publications: A continuing bibliography

This bibliography lists formal NASA publications, journal articles, books, chapters of books, patents, and contractor reports issued by Ames Research Center which were indexed by Scientific and Technical Aerospace Reports, Limited Scientific and Technical Aerospace Reports, and International Aerospace Abstracts in 1979. Citations are arranged by directorate, type of publication, and NASA accession numbers. Subject, Personal Author, Corporate Source, Contract Number, and Report/Accession Number Indexes are provided.

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Construction of a 2- by 2-foot transonic adaptive-wall test section at the NASA Ames Research Center

The development of a new production-size, two-dimensional, adaptive-wall test section with ventilated walls at the NASA Ames Research Center is described. The new facility incorporates rapid closed-loop operation, computer/sensor integration, and on-line interference assessment and wall corrections. Air flow through the test section is controlled by a series of plenum compartments and three-way slide vales. A fast-scan laser velocimeter was built to measure velocity boundary conditions for the interference assessment scheme. A 15.2-cm- (6.0-in.-) chord NACA 0012 airfoil model will be used in the first experiments during calibration of the facility.

Morgan, Daniel G.↗

A decade of aeroacoustic research at NASA Ames Research Center

The rotorcraft aeroacoustic research accomplishments of the past decade at Ames Research Center are reviewed. These include an extensive sequence of flight, ground, and wind tunnel tests that have utilized the facilities to guide and pioneer theoretical research. Many of these experiments were of benchmark quality. The experiments were used to isolate the inadequacies of linear theory in high-speed impulsive noise research, have led to the development of theoretical approaches, and have guided the emerging discipline of computational fluid dynamics to rotorcraft aeroacoustic problems.

Schmitz, Frederic H.↗

Ames Research Center publications: A continuing bibliography, 1978

This bibliography lists formal NASA publications, journal articles, books, chapters of books, patents and contractor reports issued by Ames Research Center which were indexed by Scientific and Technical Aerospace Abstracts, Limited Scientific and Technical Aerospace Abstracts, and International Aerospace Abstracts in 1978. Citations are arranged by directorate, type of publication and NASA accession numbers. Subject, personal author, corporate source, contract number, and report/accession number indexes are provided.

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Calibration of the 11x11-Foot Transonic Wind Tunnel at NASA Ames Research Center

A static pipe calibration characterizing the streamwise static pressure distribution was conducted at the 11-By 11-Foot Transonic Wind Tunnel at NASA Ames Research Center. This data is used to determine the local Mach number within the test section and evaluate buoyancy corrections to axial force measurements. The 60 foot long, 6 inch diameter pipe contained 444 static pressure taps spanning the test section and nozzle regions of the tunnel. The forward end of the pipe extends into the settling chamber and is held by four cables mounting to the tunnel shell, and the aft end is fixed on the institutional model support system. A hydraulic cylinder at the aft end of the pipe provides tension on the system to reduce vibration and to keep the pipe as level as possible throughout the test section. The previous calibration was improved upon by using pressure scanners with greater accuracy, ensuring a uniform pressure tube length for each tap to control pneumatic lag, optically tracking any streamwise movement of the pipe, and more tightly controlling the tunnel condition set points. Typically this calibration is conducted with the pipe on tunnel centerline and 33 inches below centerline for sting-mounted models and semi-span (i.e. floor-mounted) models respectively, however schedule demands permitted only the centerline calibration. The semi-span calibration is planned to be completed in the summer of 2020. Immediately following the static pipe calibration, a shorter, 9 foot static pipe used as the calibration check standard was installed to obtain its first post-calibration pressure dataset. This short static pipe consists of 148 static pressure taps distributed along the pipe section and one total pressure tap at the end of an ogive nose. Performing the calibration test and its check standard back-to-back allows this dataset to establish a reliable baseline for future calibration check standard testing. Over time the use of a calibration check standard offers the ability to assess the stability of the calibration through statistical process control in an efficient and costeffective manner, thereby potentially increasing the time required between full tunnel calibrations.

White, Bethany↗

Ames Research Center Shear Tests of SLA-561V Heat Shield Material for Mars-Pathfinder

This report describes the results of arc-jet testing at Ames Research Center on behalf of Jet Propulsion Laboratory (JPL) for the development of the Mars-Pathfinder heat shield. The current test series evaluated the performance of the ablating SLA-561V heat shield material under shear conditions. In addition, the effectiveness of several methods of repairing damage to the heat shield were evaluated. A total of 26 tests were performed in March 1994 in the 2 in. X 9 in. arc-heated turbulent Duct Facility, including runs to calibrate the facility to obtain the desired shear stress conditions. A total of eleven models were tested. Three different conditions of shear and heating were used. The non-ablating surface shear stresses and the corresponding, approximate, non-ablating surface heating rates were as follows: Condition 1, 170 N/m(exp 2) and 22 W/cm(exp 2); Condition 2, 240 N/m(exp 2) and 40 W/cm(exp 2); Condition 3, 390 N/m(exp 2) and 51 W/cm(exp 2). The peak shear stress encountered in flight is represented approximately by Condition 1; however, the heating rate was much less than the peak flight value. The peak heating rate that was available in the facility (at Condition 3) was about 30 percent less than the maximum value encountered during flight. Seven standard ablation models were tested, of which three models were instrumented with thermocouples to obtain in-depth temperature profiles and temperature contours. An additional four models contained a variety of repair plugs, gaps, and seams. These models were used to evaluated different repair materials and techniques, and the effect of gaps and construction seams. Mass loss and surface recession measurements were made on all models. The models were visually inspected and photographed before and after each test. The SLA-561 V performed well; even at test Condition 3, the char remained intact. Most of the resins used for repairs and gap fillers performed poorly. However, repair plugs made of SLA-561V performed well. Approximately 70 percent of the thermocouples yielded good data.

Tauber, Michael↗

A Summary of the Experimental Results for a Generic Tractor-Trailer in the Ames Research Center 7- by 10-Foot and 12-Foot Wind Tunnels

Experimental measurements of a generic tractor-trailer were obtained in two wind tunnels at Ames Research Center. After a preliminary study at atmospheric conditions in the 7- by 10-Foot Wind Tunnel, additional testing was conducted at Reynolds numbers corresponding to full-scale highway speeds in the 12-Foot Pressure Wind Tunnel. To facilitate computational modeling, the 1:8-scale geometry, designated the Generic Conventional Model, included a simplified underbody and omitted many small-scale details. The measurements included overall and component forces and moments, static and dynamic surface pressures, and three-component particle image velocimetry. This summary report highlights the effects of numerous drag reduction concepts and provides details of the model installation in both wind tunnels. To provide a basis for comparison, the wind-averaged drag coefficient was tabulated for all configurations tested. Relative to the baseline configuration representative of a modern class-8 tractor-trailer, the most effective concepts were the trailer base flaps and trailer belly box providing a drag-coefficient reduction of 0.0855 and 0.0494, respectively. Trailer side skirts were less effective yielding a drag reduction of 0.0260. The database of this experimental effort is publicly available for further analysis.

Storms, Bruce L.↗

Space technology test facilities at the NASA Ames Research Center

The major space research and technology test facilities at the NASA Ames Research Center are divided into five categories: General Purpose, Life Support, Computer-Based Simulation, High Energy, and the Space Exploraton Test Facilities. The paper discusses selected facilities within each of the five categories and discusses some of the major programs in which these facilities have been involved. Special attention is given to the 20-G Man-Rated Centrifuge, the Human Research Facility, the Plant Crop Growth Facility, the Numerical Aerodynamic Simulation Facility, the Arc-Jet Complex and Hypersonic Test Facility, the Infrared Detector and Cryogenic Test Facility, and the Mars Wind Tunnel. Each facility is described along with its objectives, test parameter ranges, and major current programs and applications.

Gross, Anthony R.↗

Hypersonic Research Program at NASA Ames Research Center

This paper will describe the Airbreathing Hypersonic Research Program at NASA Ames Research Center. A main theme will be the "From Computation Through Flight" research effort. General research areas covered will include systems analysis, aerodynamics and aerothermodynamics, propulsion, materials, and flight research. Illustrative results from each discipline will be presented. The synergism between computational and experimental research will be demonstrated by examples. All examples given will have been published in the open literature.

Green, Michael J.↗

NASA Ames Research Center - An Overview

The center overview is intended to provide a general understanding of the mission, core competencies, and partnership opportunities at the NASA Ames Research Center.

Innovation↗

Investigations on an 0.030-scale space shuttle vehicle configuration 140A/B orbiter model in the Ames Research Center 9 by 7-foot supersonic wind tunnel (OA53B)

A wind tunnel test of an 0.030-scale space shuttle vehicle orbiter configuration 140A/B model was conducted in the Ames Research Center 9- by 7-foot supersonic wind tunnel. This part of test series OA53 was conducted at Mach numbers of 1.60 and 2.00 and at Reynolds numbers ranging from 1.0 million per foot to 4.0 million per foot. The objective was to establish and verify longitudinal and lateral-directional aerodynamic performance, stability, and control characteristics for the configuration 140A/B SSV orbiter. Reynolds number studies were performed on certain nominal control-setting configurations, and examinations were made of the incremental effects of an alternate wing leading-edge configuration and of a sealed elevon-split construction. Six-component force and moment data, base and cavity pressures, bodyflap, elevon, speedbrake, and rudder hinge moments, and vertical tail forces and moments were measured for the orbiter.

Nichols, M. E.↗

Overview of two-dimensional airfoil research at Ames Research Center

The five basic elements of the two dimensional airfoil research program at Ames Research Center are illustrated. These elements are experimental, theoretical (including computational), validation, design optimization, and industry interaction. Each area is briefly discussed.

Chapman, G. T.↗

Ames Research Center publications: A continuing bibliography, 1980

This bibliography lists formal NASA publications, journal articles, books, chapters of books, patents, contractor reports, and computer programs that were issued by Ames Research Center and indexed by Scientific and Technical Aerospace Reports, Limited Scientific and Technical Aerospace Reports, International Aerospace Abstracts, and Computer Program Abstracts in 1980. Citations are arranged by directorate, type of publication, and NASA accession numbers. Subject, personal author, corporate source, contract number, and report/accession number indexes are provided.

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NASA Ames Research Center's parabolized Navier-Stokes code - A critical evaluation of heat-transfer predictions

The viscous supersonic/hypersonic flow over a biconic configuration was numerically simulated using the NASA Ames Research Center's Parabolized Navier-Stokes (PNS) code, and results obtained for the effects of various computational parameters on the heat transfer are compared with experimental results. The PNS code is found to provide accurate results for heat transfer parameters using low smoothing coefficient values, assuming that the radial spacing is at some small value and that the body is simple in cross section. For the cases considered, the nominal value of the spatial step size was 0.05, and the grid density was 45 points in the meridional direction and 30 points in the radial direction.

Chaussee, Denny S.↗