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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Low speed wind tunnel tests of a 1/9-scale model of a variable-sweep advanced supersonic transport

Tests have been conducted in the Langley full-scale tunnel to determine the aerodynamic characteristics of a 1/9-scale variable-sweep advanced supersonic transport configuration. The model configurations investigated were the basic unflapped arrangement, and a takeoff and landing flap arrangement with several strake leading edge flow control devices. The tests were conducted for an angle-of-attack range from about minus 5 deg to 36 deg and a sideslip range from minus 5 deg to 10 deg. The tests were conducted for a range of Reynolds number from 3.92 million to 5.95 million corresponding to test velocities of about 54.5 knots and 81.7 knots, respectively.

Mclemore, H. C.↗
NASA NTRS1974

Coupled rotor/airframe vibration prediction methods

The problems of airframe structural dynamic representation and effects of coupled rotor/airframe vibration are discussed. Several finite element computer programs (including NASTRAN) and methods for idealization and computation of airframe natural modes and frequencies and forced response are reviewed. Methods for obtaining a simultaneous rotor and fuselage vibratory response, determining effectiveness of vibration control devices, and energy methods for structural optimization are also discussed. Application of these methods is shown for the vibration prediction of the model 347 helicopter.

Staley, J. A.↗
NASA NTRS1973

The applications of the remote control of the manipulation in manned space exploration

The teleoperator system incorporates many of the advantages of manned systems on the one hand, and mechanical systems on the other. Since man is always in the control loop of a teleoperator system, the system is provided the decision making and adaptive intelligence capabilities which are uniquely human. Conversely, since the actual work is performed by the remotely controlled device, the system incorporates the durability, strength, and the expendable nature of a machine. Use of a teleoperator system is generally safer than placing the man at the worksite, and is generally more flexible and adaptable than an automated mechanical system. Potential earth orbital space missions for teleoperator systems, candidate aerospace teleoperator systems to perform these missions, and the current status of teleoperator technology development within NASA are discussed.

Deutsche, S.↗
NASA NTRS1975

Preliminary data processing system for telemetry data from Interkosmos-8 type satellites

The preliminary data processing system (PDPS), a set of algorithms, programs, equipment, data storage and memory devices, and all devices controlling the processing, is described using the Intercosmos-8 satellite as an example. Each stage of the system is considered along with its content and sequence. The essential elements of the data processing structure are described and the concepts underlying the selection of these elements are discussed.

Vilchinskaya, A. S.↗
NASA NTRS1975

Prediction of vortex flow characteristics of wings at subsonic and supersonic speeds

The leading-edge-suction analogy of Polhamus, which has been successful in the prediction of vortex lift characteristics on wings with pointed tips at subsonic and supersonic speeds, has recently been extended to account for the vortex flow characteristics for wings with side edges. Comparisons of experimental data and other currently used methods with the extended method are made for wings having side edges at subsonic and supersonic speeds. Recent data obtained for a low-aspect-ratio cropped-delta wing with various amounts of asymmetrical tip rake, simulating a roll control device, are also presented.

Lamar, J. E.↗
NASA NTRS1975

Design and testing of new center inlet and S-duct for B-727 airplane with refanned JT8D engines

The work described in this paper was part of the NASA refan program. The airflow requirement of the refanned JT8D (-100 series) engine increased about 50% above that of the basic JT8D. This required a redesign of the center inlet and S-duct of the Boeing 727 airplane. The paper describes the design constraints for the S-duct and the analytic method used to define the lines of the new duct. Model tests that were conducted at static, angle-of-attack, and crosswind conditions are described with a variety of flow control devices. Test results showed that the new inlet and S-duct have a pressure recovery comparable to that of the existing inlet. By employing corotating vortex generators, less flow distortion was obtained for the core region than the existing duct has with its counter rotating vortex generators.

Ting, C. T.↗
NASA NTRS1977

Low-onset-rate energy absorber

Device controls deceleration rates without amplifying system loads. It dissipates energy of motion through friction heat and is 22 times more efficient than automobile brakes.

Keathley, W. H.↗
NASA NTRS1975

The Annular Suspension and Pointing (ASP) system for space experiments and predicted pointing accuracies

An annular suspension and pointing system consisting of pointing assemblies for coarse and vernier pointing is described. The first assembly is attached to a carrier spacecraft (e.g., the space shuttle) and consists of an azimuth gimbal and an elevation gimbal which provide 'coarse' pointing. The second or vernier pointing assembly is made up of magnetic actuators of suspension and fine pointing, roll motor segments, and an instrument or experiment mounting plate around which is attached a continuous annular rim similar to that used in the annular momentum control device. The rim provides appropriate magnetic circuits for the actuators and the roll motor segments for any instrument roll position. The results of a study to determine the pointing accuracy of the system in the presence of crew motion disturbances are presented. Typical 3 sigma worst-case errors are found to be of the order of 0.001 arc-second.

Anderson, W. W.↗
NASA NTRS1976

A method for predicting the stability in roll of automatically controlled aircraft based on the experimental determination of the characteristics of an automatic pilot

A method is suggested for predicting the stability of automatically controlled aircraft by a comparison of calculated frequency-response curves for the aircraft and experimentally determined frequency-response curves for the automatic pilot. The method is applied only to stabilization in roll. The method is expected to be useful as a means of establishing the specifications of the performance required of the automatic control device for pilotless aircraft designed as missiles.

Jones, R. T.↗
NASA NTRS1977

Optical integrated-circuit tester

Computer controlled device can check typical medium scale unit in less than one minute. System scans integrated circuit chip with narrow beam of light while simultaneously scanning reference chip.

Micka, E. A.↗
NASA NTRS1977

Modular test system for solar collectors

Portable, recirculating-water-flow, and temperature-control device is used with solar simulator and actual sunlight to test and evaluate several solar-collector panel coatings, panel designs, and scaled-down collector subsystems. System can be pressurized to prevent boiling and allows operation above 100 degrees Centigrade.

Dolan, F. J.↗
NASA NTRS1976

Potential biomedical applications of ion beam technology

Electron bombardment ion thrusters used as ion sources have demonstrated a unique capability to vary the surface morphology of surgical implant materials. The microscopically rough surface texture produced by ion beam sputtering of these materials may result in improvements in the biological response and/or performance of implanted devices. Control of surface roughness may result in improved attachment of the implant to soft tissue, hard tissue, bone cement, or components deposited from blood. Potential biomedical applications of ion beam texturing discussed include: vascular prostheses, artificial heart pump diaphragms, pacemaker fixation, percutaneous connectors, orthopedic pros-thesis fixtion, and dental implants.

Banks, B. A.↗
NASA NTRS1977

Wind tunnel investigation of an unpowered helicopter fuselage model with a V-type empennage

The applicability of a V-type empennage on an unpowered semiscale helicopter fuselage is considered as design criteria for improved directional control devices. Configuration changes included variations of V-tail dihedral angle, planform area, and incidence angle. Of the configurations tested, a V-tail with a dihedral angle of 55 deg, a total planform area of 0.244 sq cm, and an incidence angle of 5 deg most nearly match the trim and static stability of the baseline conventional empennage.

Freeman, C. E.↗
NASA NTRS1976

Energy conservation and analysis and evaluation

The survey assembled and made recommendations directed at conserving utilities and reducing the use of energy at the Slidell Computer Complex. Specific items included were: (1) scheduling and controlling the use of gas and electricity, (2) building modifications to reduce energy, (3) replacement of old, inefficient equipment, (4) modifications to control systems, (5) evaluations of economizer cycles in HVAC systems, and (6) corrective settings for thermostats, ductstats, and other temperature and pressure control devices.

Source record↗
NASA NTRS1977

Low-speed wind tunnel tests of 1/9-scale model of a variable-sweep supersonic cruise aircraft

Tests were conducted in the Langley full-scale tunnel to determine the aerodynamic characteristics at low subsonic speeds of a 1/9-scale model of a variable-sweep supersonic cruise aircraft. The model configurations investigated were the basic unflapped arrangement, a take-off flap arrangement, and a landing flap arrangement with several strake leading-edge flow control devices. The tests were conducted at angles of attack from about -5 to 36 deg, sideslip angles from -5 to 10 deg.

Mclemore, H. C.↗
NASA NTRS1976

Current status of longitudinal stability, 24 May 1948

The problems of static and dynamic longitudinal stability both at high speeds and at low speeds are discussed and data are presented which indicate progress made in the solution of these problems. It is shown that the incorporation of large amounts of sweepback on both the wing and the horizontal tail can significantly increase the Mach number at which critical trim changes and stability changes occur and can greatly reduce the trim changes and stability changes encountered at supercritical speeds. Data are also presented which demonstrate the possibility of obtaining satisfactory longitudinal stability in the landing configuration for wings with sweepback of the order of 45 deg utilizing various stall control devices. Optimum arrangements for such devices, however, should be determined experimentally.

Donlan, C. J.↗
NASA NTRS1976

Low-speed wind-tunnel investigation of the longitudinal stability characteristics of a model equipped with a variable-speed wing, 23 May 1949

The longitudinal stability characteristics of a complete model equipped with a variable sweep wings at angles of sweepback of 45 deg, 30 deg, 15 deg, and 0 deg investigated. Various wing modifications and an extern 1 flap arrangement designed to minimize the shift in neutral point accompanying the change in sweep angle were studied. The results indicate that stability at the stall was obtained at a sweep angle of 15 deg without recourse to stall control devices. The basic neutral point movement accompanying the change in sweep angle from 45 deg to 15 deg amounted to 56 percent of the mean aerodynamic chord (at zero sweep angle) and the most effective modification investigated only reduced this change to 47 percent of the chord. It appears, therefore, that for designs in which the fuselage is the major load carrying element some relative movement between the wing and center of gravity will be required to assure satisfactory stability at all sweep angles.

Donlan, C. J.↗
NASA NTRS1977

An aerodynamic investigation of two 1.83-meter-diameter fan systems designed to drive a subsonic wind tunnel

An experimental, aerodynamic investigation was made of two 1.83 m diameter fan systems which are being considered for the repowered drive section of the 40- by 80-foot wind tunnel at NASA Ames Research Center. One system was low speed, the other was high speed. The low speed fan was tested at various stagger angles from 32.9 deg to 62.9 deg. At a fan blade stagger angle of 40.8 deg and operating at a tip speed of 1155 m/sec, the low speed fan developed 207.3 m of head. The high speed fan had a design blade stagger angle of 56.2 deg and was tested at this stagger angle only. The high speed fan operating at 191.5 m/sec developed 207.3 m of head. Radial distributions of static pressure coefficients, total pressure coefficients, and angles of swirl are presented. Radial surveys were conducted at four azimuth locations in front of the fan, and repeated downstream of the fan. Data were taken for various flow control devices and for two inlet contraction lengths.

Page, V. R.↗