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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 415 records · Page 23
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NASA NTRS1975

Feasibility study of modern airships, phase 1. Volume 1: Summary and mission analysis (tasks 2 and 4)

The histroy, potential mission application, and designs of lighter-than-air (LTA) vehicles are researched and evaluated. Missions are identified to which airship vehicles are potentially suited. Results of the mission analysis are combined with the findings of a parametric analysis to formulate the mission/vehicle combinations recommended for further study. Current transportation systems are surveyed and potential areas of competition are identified as well as potential missions resulting from limitations of these systems. Potential areas of military usage are included.

Bloetscher, F.↗
NASA NTRS1975

Feasibility study of modern airships, phase 1. Volume 2: Parametric analysis (task 3)

Various types of lighter-than-air vehicles from fully buoyant to semibuoyant hybrids were examined. Geometries were optimized for gross lifting capabilities for ellipsoidal airships, modified delta planform lifting bodies, and a short-haul, heavy-lift vehicle concept. It is indicated that: (1) neutrally buoyant airships employing a conservative update of materials and propulsion technology provide significant improvements in productivity; (2) propulsive lift for VTOL and aerodynamic lift for cruise significantly improve the productivity of low to medium gross weight ellipsoidal airships; and (3) the short-haul, heavy-lift vehicle, consisting of a simple combination of an ellipsoidal airship hull and existing helicopter componentry, provides significant potential for low-cost, near-term applications for ultra-heavy lift missions.

Lancaster, J. W.↗
NASA NTRS1975

Feasibility study of modern airships, phase 1. Volume 3: Historical overview (task 1)

The history of lighter-than-air vehicles is reviewed in terms of providing a background for the mission analysis and parametric analysis tasks. Data from past airships and airship operations are presented in the following areas: (1) parameterization of design characteristics; (2) markets, missions, costs, and operating procedures, (3) indices of efficiency for comparison; (4) identification of critical design and operational characteristics; and (5) definition of the 1930 state-of-the-art and the 1974 state-of-the-art from a technical and economic standpoint.

Faurote, G. L.↗
NASA NTRS1975

Feasibility study of modern airships, phase 1, volume 1

The history of the airship is examined from a technical and operational/mission point of view. The impact on a modern airship design by present technology is defined in some selected, representative areas through a comparison between 1930 and 1975 state-of-the-art. A survey of missions with a potential for the airship was made and some viable applications are established. Several concepts of modern airships were taken through a parametric design analysis in the missions previously established, evolving in a new configuration of a hybrid airship - the Helipsoid -, combining static lift and dynamic lift from tilting propeller/rotors and the planform. Cruise speeds in the 150-200 kt (77-103 m/s) will be possible with this configuration with reasonable engine power. The Helipsoid offers at the same time a realistic and practicable solution to the ballast problem, which is inherent in a vehicle generating its lift (fully or partially) from a medium lighter than air.

Joner, B.↗
NASA NTRS1975

Study to investigate design, fabrication and test of low cost concepts for large hybrid composite helicopter fuselage, phase 1

The development of a frame/stringer/skin fabrication technique for composite airframe construction was studied as a low cost approach to the manufacture of large helicopter airframe components. A center cabin aluminum airframe section of the Sikorsky CH-53D helicopter was selected for evaluation as a composite structure. The design, as developed, is composed of a woven KEVLAR-49/epoxy skin and graphite/epoxy frames and stringers. To support the selection of this specific design concept a materials study was conducted to develop and select a cure compatible graphite and KEVLAR-49/epoxy resin system, and a foam system capable of maintaining shape and integrity under the processing conditions established. The materials selected were, Narmco 5209/Thornel T-300 graphite, Narmco 5209/KEVLAR-49 woven fabric, and Stathane 8747 polyurethane foam. Eight specimens were fabricated, representative of the frame, stringer, and splice joint attachments. Evaluation of the results of analysis and test indicate that design predictions are good to excellent except for some conservatism of the complex frame splice.

Adams, K. M.↗
NASA NTRS1975

Program to design, fabricate, test, and deliver a thermal control-mixing control device, phase 1

The development of a sensor capable of detecting temperature changes as a function of viscosity changes, was completed. This type of sensor, consisting of an orifice bridge circuit, resulted in a device with a threshold above internally generated noise of 0.8C (1.5F). Data were obtained using a noise free Freon source provided by an air pressurized bladder. Tests conducted to operate the sensor from a typical Freon centrifugal pump system employing an air bubble accumulator for noise attentuation disclosed the sensor could be used only to sense temperature changes greater than 3.3C (6F) because of the excessively noisy output. This is attributed to the high frequency-pressure fluctuations in the Freon supply to the sensor.

Thurston, T. S.↗
NASA NTRS1975

Experimental clean combustor program, phase 1

A program of screening three low emission combustors for conventional takeoff and landing, by testing and analyzing thirty-two configurations is presented. Configurations were tested that met the emission goals at idle operating conditions for carbon monoxide and for unburned hydrocarbons (emission index values of 20 and 4, respectively). Configurations were also tested that met a smoke number goal of 15 at sea-level take-off conditions. None of the configurations met the goal for oxides of nitrogen emissions at sea-level take-off conditions. The best configurations demonstrated oxide of nitrogen emission levels that were approximately 61 percent lower than those produced by the JT9D-7 engine, but these levels were still approximately 24 percent above the goal of an emission index level of 10. Additional combustor performance characteristics, including lean blowout, exit temperature pattern factor and radial profile, pressure loss, altitude stability, and altitude relight characteristics were documented. The results indicate the need for significant improvement in the altitude stability and relight characteristics. In addition to the basic program for current aircraft engine combustors, seventeen combustor configurations were evaluated for advanced supersonic technology applications. The configurations were tested at cruise conditions, and a conceptual design was evolved.

Roberts, R.↗
NASA NTRS1975

Noise addendum experimental clean combustor program, phase 1

The development of advanced CTOL aircraft engines with reduced exhaust emissions is discussed. Combustor noise information provided during the basic emissions program and used to advantage in securing reduced levels of combustion noise is included. Results are presented of internal pressure transducer measurements made during the scheduled emissions test program on ten configurations involving variations of three basic combustor designs.

Sofrin, T. G.↗
NASA NTRS1975

Multipurpose panel, phase 1, study report

The feasibility of a multipurpose panel which provides a programmable electronic display for changeable panel nomenclature, multiplexes similar indicator display signals to the signal display, and demultiplexes command signals is examined. Topics discussed include: electronic display technology, miniaturized electronic and memory devices, and data management systems which employ digital address and multiplexing.

Parkin, W.↗
NASA NTRS1975

Scintillation estimates for a Jupiter entry probe: Phase 1

A model of the electron density irregularities in the Jovian ionosphere is constructed based on a preliminary interpretation of the Pioneer 10 Jovian ionospheric scintillations. The ionospheric irregularities exist over an altitude range of 3000 km. The structure constant c sub n of refractive index fluctuations is constant throughout this altitude range. The spatial wavenumber spectrum of the electron density irregularities follows the Kolmogorov spectrum and the outer scale size is greater than 6 km. Estimates of scintillation for a Jovian entry probe based on this model indicate that it is small at S-band but could be substantial at 4000 MHz. The temporal frequency spectrum of the log-amplitude fluctuation is less than 1 Hz and is consequently rather narrow.

Woo, R.↗
NASA NTRS1975

Measuring snow cover using satellite imagery during 1973 and 1974 melt season: North Santiam, Boise, and Upper Snake Basins, phase 1

Measurements are examined of snow coverage during the snow-melt season in 1973 and 1974 from LANDSAT imagery for the three Columbia River Subbasins. Satellite derived snow cover inventories for the three test basins were obtained as an alternative to inventories performed with the current operational practice of using small aircraft flights over selected snow fields. The accuracy and precision versus cost for several different interactive image analysis procedures was investigated using a display device, the Electronic Satellite Image Analysis Console. Single-band radiance thresholding was the principal technique employed in the snow detection, although this technique was supplemented by an editing procedure involving reference to hand-generated elevation contours. For each data and view measured, a binary thematic map or "mask" depicting the snow cover was generated by a combination of objective and subjective procedures. Photographs of data analysis equipment (displays) are shown.

Wiegman, E. J.↗
NASA NTRS1975

Wind estimates from cloud motions: Preliminary results from phases 1, 2, and 3 of an in situ aircraft verification experiment

Low level aircraft equipped with Inertial Navigation Systems (INS) were used to define the vertical extent and horizontal motion of a cloud and to measure the ambient wind field. A high level aircraft, also equipped with an INS, took photographs to describe the horizontal extent of the cloud field and to measure cloud motion. The aerial photographs were also used to make a positive identification in a satellite picture of the cloud observed by the low level aircraft. The experiment was conducted over the tropical oceans in the vicinity of Florida, Puerto Rico, Panama and in the Western Gulf of Mexico. Results for tropical cumulus clouds indicate excellent agreement between the cloud motion and the wind at the cloud base. The magnitude of the vector difference between the cloud motion and the cloud base wind is less than 1.3 m/sec for 67% of the cases with track lengths of 1 hour or longer. The cirrus cloud motions agreed best with the mean wind in the cloud layer with a vector difference of about 1.6 m/sec.

Hasler, A. F.↗
NASA NTRS1975

Future space transportation systems analysis study. Phase 1 extension: Transportation systems reference data, volume 2

Transportation mass requirements are developed for various mission and transportation modes based on vehicle systems sized to fit the exact needs of each mission. The parametric data used to derive the mass requirements for each mission and transportation mode are presented to enable accommodation of possible changes in mode options or payload definitions. The vehicle sizing and functional requirements used to derive the parametric data are described.

Source record↗
NASA NTRS1975

Future space transportation systems analysis study. Phase 1 extension: Executive summary

Potential future space programs are analyzed beyond the scope of the current shuttle traffic model to determine their transportation needs and alternative ways of evolving future space transportation systems from the baseline space transportation system (space shuttle and upper stage). Objectives of the entire study are summarized along with results to date.

Source record↗
NASA NTRS1975

Development of a special purpose spacecraft interior coating, phase 1

Coating formulations were developed consisting of latex blends of fluorocarbon polymers, acrylic resins, stabilizers, modifiers, other additives, and a variety of inorganic pigments. Suitable latex primers were also developed from an acrylic latex base. The formulations dried to touch in about one hour and were fully dry in about twenty-four hours under normal room temperature and humidity conditions. The resulting coatings displayed good optical and mechanical properties, including excellent bonding to (pre-treated) substrates. In addition, the preferred compositions were found to be self-extinguishing when applied to nonflammable substrates and could meet the offgassing requirements specified by NASA for the intended application. Improvements are needed in abrasion resistance and hardness.

Bartoszek, E. J.↗