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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 973 records · Page 54
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Flight test and evaluation of Omega navigation in a general aviation aircraft. Volume 1: Technical

A low cost flight research program was conducted to evaluate the performance of differential Omega navigation in a general aviation aircraft. The flight program consisted of two distinct parts corresponding to the two major objectives of the study. The Wallops Flight Program was conducted to obtain Omega signal and phase data in the Wallops Flight Center vicinity to provide preliminary technical information and experience in preparation for a comprehensive NASA/FAA flight test program of an experimental differential Omega system. The Northeast Corridor Flight Program was conducted to examine Omega operational suitability and performance on low altitude area navigation (RNAV) routes for city-center to city-center VTOL commercial operations in the Boston-New York-Washington corridor. The development, execution and conclusions of the flight research program are discribed. The results of the study provide both quantitative and qualitative data on the Omega Navigation System under actual operating conditions.

Howell, J. D.↗
NASA NTRS1976

Flight test of a stall sensor and evaluation of its application to an aircraft stall deterrent system using the NASA LRC general aviation simulator

A series of flight maneuvers were developed to cover the range of flight conditions and to define the repeatability and hysteresis of the sensors. Initial flights were made with two sensors at the + or - 68 percent span and 60 percent and 70 percent chord stations. The primary effort in simulation program development was to modify the LRC General Aviation Simulator (GAS) Fortran programs to allow execution on the MSU UNIVAC 1106. A simple model of the sensor-servo stall deterrent system was developed. A one degree of freedom model of pitch dynamics of the airplane and stall deterrent system was developed to make initial estimates of the control system gains. A position error plus rate damping control algorithm was found to have acceptable characteristics.

Bennett, G.↗
NASA NTRS1976

A general geometric theory of attitude determination from directional sensing

A general geometric theory of spacecraft attitude determination from external reference direction sensors was presented. Outputs of different sensors are reduced to two kinds of basic directional measurements. Errors in these measurement equations are studied in detail. The partial derivatives of measurements with respect to the spacecraft orbit, the spacecraft attitude, and the error parameters form the basis for all orbit and attitude determination schemes and error analysis programs and are presented in a series of tables. The question of attitude observability is studied with the introduction of a graphical construction which provides a great deal of physical insight. The result is applied to the attitude observability of the IMP-8 spacecraft.

Fang, B. T.↗
NASA NTRS1976

Sources and characteristics of interior noise in general aviation aircraft

A field study was conducted to examine the interior noise characteristics of a general aviation aircraft. The goals were to identify the major noise sources and their relative contribution and to establish the noise transmission paths and their relative importance. Tests were performed on an aircraft operating under stationary conditions on the ground. Results show that the interior noise level of light aircraft is dominated by broadband, low frequencies (below 1,000 Hz). Both the propeller and the engine are dominant sources, however, the contribution from the propeller is significantly more than the engine at its fundamental blade passage frequency. The data suggest that the airborne path is more dominant than the structure-borne path in the transmission of broadband, low frequency noise which apparently results from the exhaust.

Catherines, J. J.↗
NASA NTRS1976

Review of drag cleanup tests in Langley full-scale tunnel (from 1935 to 1945) applicable to current general aviation airplanes

Results of drag cleanup tests conducted in the Langley full-scale tunnel during the period from 1935 to 1945 are summarized for potential application to current propeller-driven general aviation airplanes. Data from tests on 23 airplanes indicate that the drag increments produced by many individual configuration features - such as, power plant installation, air leakage, cockpit canopies, control surface gaps, and antenna installations - are not large; however, when the increments are summed, the resulting total drag increase is significant. On the basis of results of the investigation, it appears that considerable reduction in drag can be obtained by proper attention to details in aerodynamic design and by adherence to the guidelines discussed.

Coe, P. L., Jr.↗
NASA NTRS1975

SEASAT economic assessment. Volume 3: Offshore oil and natural gas industry case study and generalization

The economic benefits of improved ocean condition, weather and ice forecasts by SEASAT satellites to the exploration, development and production of oil and natural gas in the offshore regions are considered. The results of case studies which investigate the effects of forecast accuracy on offshore operations in the North Sea, the Celtic Sea, and the Gulf of Mexico are reported. A methodology for generalizing the results to other geographic regions of offshore oil and natural gas exploration and development is described.

Source record↗
NASA NTRS1975

SEASAT economic assessment. Volume 9: Ports and harbors case study and generalization

This case study and generalization quantify benefits made possible through improved weather forecasting resulting from the integration of SEASAT data into local weather forecasts. The major source of avoidable economic losses to shipping from inadequate weather forecasting data is shown to be dependent on local precipitation forecasting. The ports of Philadelphia and Boston were selected for study.

Source record↗
NASA NTRS1976

Flight simulation study to determine MLS lateral course width requirements on final approach for general aviation

An investigation of the effects of various lateral course widths and runway lengths for manual CAT I Microwave Landing System instrument approaches was carried out with instrument rated pilots in a General Aviation simulator. Data are presented on the lateral dispersion at the touchdown zone, and the middle and outer markers, for approaches to 3,000, 8,000 (and trial 12,000 foot) runway lengths with full scale angular lateral course widths of + or - 1.19 deg, + or - 2.35 deg, and + or - 3.63 deg. The distance from touchdown where the localizer deviation went to full scale was also recorded. Pilot acceptance was measured according to the Cooper-Harper rating system.

Crumrine, R. J.↗
NASA NTRS1976

General Purpose Computer (GPC) to GPC systems interface description

The General Purpose Computer (GPC) 'subsystem' of the Orbiter Data Processing System was described. Two interface areas are discussed. One is the area of GPC intraconnections and intracommunications involving the hardware/software interface between the Central Processing Unit (CPU) and the Input/Output Processor (IOP). The other is the area of GPC interconnections and intercommunications and involves the hardware/software interface between the five Orbiter GPC's. Based on the detailed GPC interface given, it is felt that the basic CPU to IOP interface and the GPC to GPC interface have the potential for trouble free operation. However, due to the complexity of the interface and the criticality of GPC synchronization to overall avionics performance, the GPC to GPC interface should be carefully evaluated when attempting to resolve test anomalies that may involve GPC timing and synchronization errors.

Breyer, B. C.↗
NASA NTRS1975

General-altitude transformations between geocentric and geodetic coordinates

Formulas for the general-altitude (height above the ellipsoid) transformation from geocentric to geodetic coordinates and vice versa are derived. The set of four formulas is expressed in each of two useful forms: series expansions in powers of the earth's flattening and series expansions in powers of the earth's eccentricity. The error incurred in these expansions is of the order of one part in 30 million.-

Long, S. A. T.↗
NASA NTRS1975

General aviation and community development; Summer Faculty Fellowship Program in Engineering Systems Design, Hampton, Va., June 2-August 15, 1975, Report

The document summarizes the results of a faculty program in engineering systems design whose primary aim was to provide a framework for communication and collaboration between academic personnel, research engineers, and scientists in government agencies and private industry. Other objectives were to provide a useful study of a broadly based societal problem, requiring the coordinated efforts of a multidisciplinary team, and to generate experience in the development of systems design and multidisciplinary activities. The success of the program is evidenced by the resulting study of general aviation and community development, characterized by thorough scrutiny of ideas, philosophies, and academic perspectives.

Sincoff, M. Z.↗
NASA NTRS1976

A generalization of the Boltzmann superposition principle to polymer networks undergoing scission

Methods reported by Moacanin et al. (1975) and Moacanin and Aklonis (1971) are generalized with the objective to include strains (or stress) applied in an arbitrary manner to linearly viscoelastic materials. An imposition of changes in both the strain and the density of elastically effective chains in discrete increments is considered. In accordance with the Boltzmann superposition principle, each strain increment may be treated as a new independent experiment which adds linearly to the total response of the system.

Moacanin, J.↗
NASA NTRS1975

A general non-parametric classifier applied to discriminating surface water from terrain shadows

A general non-parametric classifier is described in the context of discriminating surface water from terrain shadows. In addition to using non-parametric statistics, this classifier permits the use of a cost matrix to assign different penalties to various types of misclassifications. The approach also differs from conventional classifiers in that it applies the maximum-likelihood criterion to overall class probabilities as opposed to the standard practice of choosing the most likely individual subclass. The classifier performance is evaluated using two different effectiveness measures for a specific set of ERTS data.

Eppler, W. G.↗
NASA NTRS1975

Treating the insomniac patient - General measures and psychological and pharmacological treatment

The general preliminary measures for treating insomnia include moderate physical exercise several hours before bedtime, and the relaxation of complex mental activity before bedtime. A case history concerning a woman with marital troubles is offered as evidence that insomnia may be caused by deeply rooted psychological and situational problems. Another case history illustrates how prior pharmacological treatment may complicate the process of clinically evaluating an insomniac.

Kales, A.↗
NASA NTRS1975

On relative periodic solutions of the planar general three-body problem

We describe two relatively simple reductions to order 6 for the planar general three-body problem. We also show that this reduction leads to the distinction between two types of periodic solutions: absolute or relative periodic solutions. An algorithm for obtaining relative periodic solutions using heliocentric coordinates is then described. It is concluded from the periodicity conditions that relative periodic solutions must form families with a single parameter. Finally, two such families have been obtained numerically and are described in some detail.

Broucke, R.↗
NASA NTRS1976

Apollo 16 far ultraviolet imagery of the polar auroras, tropical airglow belts, and general airglow

Far-ultraviolet imagery of the earth in the wavelength ranges from 1050 to 1600 A and from 1250 to 1600 A was obtained from the lunar surface during the Apollo 16 mission on Apr. 21, 1972. The images have an angular resolution of about 2 arcmin (230-km linear resolution) and have been quantitatively analyzed to obtain absolute intensities and spatial distributions of the polar auroras (both wavelength ranges), the day and night airglow, and tropical airglow belts (1250-A to 1600-A wavelength range). The observations are consistent with previous results obtained from the OGO-4 spacecraft, but they have also provided details on the spatial distributions of the various emissions over an entire hemisphere at a single time. A general night airglow, at least in the Northern Hemisphere, is indicated.

Carruthers, G. R.↗