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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 163 records · Page 9

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NASA NTRS1982

Flight service evaluation of composite components on the Bell Helicopter model 206L: Design, fabrication and testing

The design, fabrication, and testing phases of a program to obtain long term flight service experience on representative helicopter airframe structural components operating in typical commercial environments are described. The aircraft chosen is the Bell Helicopter Model 206L. The structural components are the forward fairing, litter door, baggage door, and vertical fin. The advanced composite components were designed to replace the production parts in the field and were certified by the FAA to be operable through the full flight envelope of the 206L. A description of the fabrication process that was used for each of the components is given. Static failing load tests on all components were done. In addition fatigue tests were run on four specimens that simulated the attachment of the vertical fin to the helicopter's tail boom.

Zinberg, H.↗

NASA NTRS1983

Flight service evaluation of composite components on Bell 206L and Sikorsky S-76 helicopters

Progress on two programs to evaluate composite structural components in flight service on commercial helicopters is described. Thirty-six ship sets of composite components that include the litter door, baggage door, forward fairing, and vertical fin were installed on Bell Model 206L helicopters that are operating in widely different climatic areas. Four horizontal stabilizers and ten tail rotor spars that are production components on the S-76 helicopter were tested after prescribed periods of service to determine the effects of the operating environment on their performance. Concurrent with the flight evaluation, specimens from materials used to fabricate the components were exposed in ground racks and tested at specified intervals to determine the effects of outdoor environments. Results achieved from 14,000 hours of accumulated service on the 206L components, tests on a S-76 horizontal stabilizer after 1600 hours of service, tests on a S-76 tail rotor spar after 2300 hours service, and two years of ground based exposure of material coupons are reported.

Baker, D. J.↗

NASA NTRS1982

Energy efficient engine: Turbine intermediate case and low-pressure turbine component test hardware detailed design report

A four stage, low pressure turbine component has been designed to power the fan and low pressure compressor system in the Energy Efficient Engine. Designs for a turbine intermediate case and an exit guide vane assembly also have been established. The components incorporate numerous technology features to enhance efficiency, durability, and performance retention. These designs reflect a positive step towards improving engine fuel efficiency on a component level. The aerodynamic and thermal/mechanical designs of the intermediate case and low pressure turbine components are presented and described. An overview of the predicted performance of the various component designs is given.

Leach, K.↗

NASA NTRS1983

Ceramic components for the AGT 100 engine

Historically, automotive gas turbines have not been able to meet requirements of the marketplace with respect to cost, performance, and reliability. However, the development of appropriate ceramic materials has overcome problems related to a need for expensive superalloy components and to limitations regarding the operating temperature. An automotive gas turbine utilizing ceramic components has been developed by a U.S. automobile manufacturer. A 100-horsepower, two-shaft, regenerative engine geometry was selected because it is compatible with manual, automatic, and continuously variable transmissions. Attention is given to the ceramic components, the ceramic gasifier turbine rotor development, the ceramic gasifier scroll, ceramic component testing, and the use of advanced nondestructive techniques for the evaluation of the engine components.

Helms, H. E.↗

NASA NTRS1985

Flight service evaluation of composite helicopter components

An assessment of composite helicopter structures, exposed to environmental effects, after four years of commercial service is presented. This assessment is supported by test results of helicopter components and test panels which have been exposed to environmental effects since late 1979. Full scale static and fatigue tests are being conducted on composite components obtained from S-76 helicopters in commercial operations in the Gulf Coast region of Louisiana. Small scale tests are being conducted on coupons obtained from panels being exposed to outdoor conditions in Stratford, Connecticut and West Palm Beach, Florida. The panel layups represent S-76 components. Moisture evaluations and strength tests are being conducted, on the S-76 components and panels, over a period of eight years. Results are discussed for components and panels with up to four years of exposure.

Rich, M. J.↗

NASA NTRS1984

Number and placement of control system components considering possible failures

One of the first questions facing the designer of the control system for a large space structure is how many components actuators and sensors - to specify and where to place them on the structure. This paper presents a methodology which is intended to assist the designer in making these choices. A measure of controllability is defined which is a quantitative indication of how well the system can be controlled with a given set of actuators. Similarly, a measure of observability is defined which is a quantitative indication of how well the system can be observed with a given set of sensors. Then the effect of component unreliability is introduced by computing the average expected degree of controllability (observability) over the operating lifetime of the system accounting for the likelihood of various combinations of component failures. The problem of component location is resolved by optimizing this performance measure over the admissible set of locations. The variation of this optimized performance measure with number of actuators (sensors) is helpful in deciding how many components to use.

Vander Velde, W. E.↗

NASA NTRS1986

Study of ice accretion on icing wind tunnel components

In a closed loop icing wind tunnel the icing cloud is simulated by introducing tiny water droplets through an array of nozzles upstream of the test section. This cloud will form ice on all tunnel components (e.g., turning vanes, inlet guide vanes, fan blades, and the heat exchanger) as the cloud flows around the tunnel. These components must have the capacity to handle their icing loads without causing significant tunnel performance degradation during the course of an evening's run. To aid in the design of these components for the proposed Altitude Wind Tunnel (AWT) at NASA Lewis Research Center the existing Icing Research Tunnel (IRT) is used to measure icing characteristics of the IRT's components. The results from the IRT are scaled to the AWT to account for the AWT's larger components and higher velocities. The results show that from 90 to 45 percent of the total spray cloud froze out on the heat exchanger. Furthermore, the first set of turning vanes downstream of the test section, the FOD screen and the fan blades show significant ice formation. The scaling shows that the same results would occur in the AWT.

Newton, J. E.↗

NASA NTRS1986

Flight service evaluation of composite components on the Bell helicopter model 206L

This is the second annual report on the flight service components for the Bell Model 206L JetRanger helicopter. The components have been placed in service in the Continental United States, Canada, and Alaska. The report covers the period from 1 August 1983 to 1 January 1986. The status of 34 sets of components is discussed in this report. Approximately 73,000 flight hours were accumulated on the components as of 1 January 1986. Three years of coupon tests on the components are presented with test results. A vertical fin had been struck by lightning and the results of its examination and tests are included.

Wilson, H. E., II↗

NASA NTRS1985

The super-hot thermal component in the decay phase of solar flares

Solar X-ray observations from balloons and from the SMM and Hinotori spacecraft have revealed evidence for a superhot thermal component with a temperature of more than about 3 x 10 to the 7th K in many solar flares, in addition to the usual 10-20 x 10 to the 6th K soft X-ray flare plasma. The decay phase of 35 solar flare X-ray events observed by ISEE-3 during 1980 was systematically studied. Based on fits to the continuum X-ray spectrum in the 4.8-14 keV range and to the intensity of the 1.9 A feature of iron lines, it was found that 15 (about 43) of the analyzed events have a superhot thermla component in the decay phase of the flare. In this paper, the important properties of the superhot thermal component in the decay phase are summarized. It is found that an additional input of energy is required to maintain the superhot thermal components. Finally, it is suggested that the superhot thermal component in the decay phase is created through the reconnection of the magnetic field during the decay phase of solar flares.

Lin, H.-A.↗

NASA NTRS1986

Study of ice accretion on icing wind tunnel components

Newton, J. E.↗

NASA NTRS1987

On the presolar origin of the 'normal planetary' noble gas component in meteorites

Several components of planetary noble gases, including CCFXe (Xe-X), s-process Kr and Xe, and Ne-E, are now thought to have had a presolar origin. It is proposed that the 'normal planetary' noble gas component, which contains most of the planetary Ar, Kr, and Xe, is also presolar. This component was trapped in carbonaceous mantles as the mantles formed on grain surfaces in the molecular cloud. The presolar dust grains and their carbonaceous mantles were then incorporated into primitive meteorites. This model naturally explains: (1) the affinity of 'normal planetary' noble gases for carbonaceous material in primitive chondrites; (2) the near absence of He and Ne in the 'normal planetary' component; (3) the elemental fractionation patterns of the 'exotic' and 'normal planetary' components; (4) the similarity of the isotopic compositions of 'normal planetary' and trapped solar Ar, Kr, and Xe; (5) the high noble gas content of the 'normal planetary' gas carrier; (6) several aspects of the chemistry of the 'normal planetary' gas carrier; (7) the correlation of planetary noble gases with the fine-grained material in primitive chondrites; and (8) the widespread occurrence of the planetary fractionation pattern throughout the solar system.

Huss, Gary R.↗

NASA NTRS1988

Component improvement of free-piston Stirling engine key technology for space power

The successful performance of the 25 kW Space Power Demonstrator (SPD) engine during an extensive testing period has provided a baseline of free piston Stirling engine technology from which future space Stirling engines may evolve. Much of the success of the engine was due to the initial careful selection of engine materials, fabrication and joining processes, and inspection procedures. Resolution of the few SPD engine problem areas that did occur has resulted in the technological advancement of certain key free piston Stirling engine components. Derivation of two half-SPD, single piston engines from the axially opposed piston SPD engine, designated as Space Power Research (SPR) engines, has made possible the continued improvement of these engine components. The two SPR engines serve as test bed engines for testing of engine components. Some important fabrication and joining processes are reviewed. Also, some component deficiencies that were discovered during SPD engine testing are described and approaches that were taken to correct these deficiencies are discussed. Potential component design modifications, based upon the SPD and SPR engine testing, are also reported.

Alger, Donald L.↗

NASA NTRS1988

Chondrules and matrix in the Ornans CO3 meteorite - Possible precursor components

Bulk compositions of 17 chondrules and one sample of matrix from CO3 Ornans were determined by instrumental neutron activation analysis. Chondrule precursor components deduced from chondrule compositions are characterized by: (1) common and slightly volatile siderophiles, Cr and chalcophiles, (2) refractory lithophiles and Na, (3) Mn, Si and modal pyroxene, and (4) FeO and olivine. Component 4 may be closely related to matrix material. Precursor components have now been inferred for OC, EH, CV, CM and CO chondrules. An MN- and Si-rich component occurs exclusively among carbonaceous chondrite chondrules. Although there are significant intergroup differences, common to chondrules in all chondrite groups are refractory-lithophile-rich, common-siderophile-rich, and (with the exception of EH) common-lithophile-rich components. This indicates that the siderophile/lithophile and refractory lithophile/common lithophile fractionations recorded in chondrite whole-rocks were established prior to chondrule formation at all nebular locations.

Rubin, Alan E.↗

NASA NTRS1989

Application of reusable software components at the SEI

Robert Holibaugh of the Software Engineering Institute described a project which is studying the application of reusable software components. The primary goals are to gain practical experience with state-of-the-art reusable components, methods, and tools and to capture the lessons learned in the application of reuse technology. In addition the project will assess the impact of reuse on the software development process and products and will identify and validate the information that facilities software reuse during system development. The project includes two tasks - a reuse experiment and a redevelopment effort. The reuse experiment will define a life cycle and a methodology for reuse-based development, and define and implement a data collection mechanism for measuring the development. The redevelopment effort will construct a reuse test bed and will redevelop and realistically test subsystems from an embedded mission-critical real-time application. The reuse experiment will produce several products including a tested real-time application, reuse-based components and tools evaluation, a reuse-based development method, a framework for data collection, a framework for measuring productivity, and lessons learned data. Successful development with reusable components will require a rich set of components and an integrating methodology. The Tomahawk Land Attack Missile system is the application for the redevelopment effort.

Holibaugh, Robert↗

NASA NTRS1989

Component model reduction via the projection and assembly method

The problem of acquiring a simple but sufficiently accurate model of a dynamic system is made more difficult when the dynamic system of interest is a multibody system comprised of several components. A low order system model may be created by reducing the order of the component models and making use of various available multibody dynamics programs to assemble them into a system model. The difficulty is in choosing the reduced order component models to meet system level requirements. The projection and assembly method, proposed originally by Eke, solves this difficulty by forming the full order system model, performing model reduction at the the system level using system level requirements, and then projecting the desired modes onto the components for component level model reduction. The projection and assembly method is analyzed to show the conditions under which the desired modes are captured exactly; to the numerical precision of the algorithm.

Bernard, Douglas E.↗

NASA NTRS1990

The chemical effects of the Martian environment on power system component materials: A theoretical approach

In the foreseeable future, an expedition may be undertaken to explore the planet Mars. Some of the power source options being considered for such a mission are photovoltaics, regenerative fuel cells and nuclear reactors. In addition to electrical power requirements, environmental conditions en route to Mars, in the planetary orbit and on the Martian surface must be simulated and studied in order to anticipate and solve potential problems. Space power systems components such as photovoltaic arrays, radiators, and solar concentrators may be vulnerable to degradation in the Martian environment. Natural characteristics of Mars which may pose a threat to surface power systems include high velocity winds, dust, ultraviolet radiation, large daily variation in temperature, reaction to components of the soil, atmosphere and atmospheric condensates as well as synergistic combinations. Most of the current knowledge of the characteristics of the Martian atmosphere and soil composition was obtained from the Viking 1 and 2 missions in 1976. A theoretical study is presented which was used to assess the effects of the Martian atmospheric conditions on the power systems components. A computer program written at NASA-Lewis for combustion research that uses a free energy minimization technique was used to calculate chemical equilibrium for assigned thermodynamic states of temperature and pressure. The power system component materials selected for this study include: silicon dioxide, silicon, carbon, copper, and titanium. Combinations of environments and materials considered include: (1) Mars atmosphere with power surface material, (2) Mars atmosphere and dust component with power surface material, and (3) Mars atmosphere and hydrogen peroxide or superoxide or superoxide with power system material. The chemical equilibrium calculations were performed at a composition ratio (oxidant to reactant) of 100. The temperature for the silicon dioxide material and silicon, which simulate photovoltaic cells, were 300 and 400 K; for carbon, copper and titanium, which simulate radiator surfaces, 300, 500, and 1000 K. All of the systems were evaluated at pressures of 700, 800, and 900 Pa, which stimulate the Martian atmosphere.

Perez-Davis, Marla E.↗

NASA NTRS1990

Selection of component modes

Structural dynamic models of complex spacecraft are often assembled from a number of component models. In this paper, three methods for reducing the order of these component models are presented by selecting 'important' fixed interface component modes. These methods are applied to two component structures of the Space Station Freedom: a photovoltaic (PV) array and a solar dynamic collector. The reduced order models of these components retain a small fraction of the number of modes in the original models while accurately representing a set of outputs chosen by the user.

Blelloch, Paul A.↗

NASA NTRS1990

Flight service evaluation of composite helicopter components

An assessment is presented of ten composite tail rotor spars and four horizontal stabilizers exposed to the effects of in-flight commercial service for up to nine years to establish realistic environmental factors for use in future designs. This evaluation is supported by test results of helicopter components and panels which have been exposed to outdoor environmental effects since 1979. Full scale static and fatigue tests were conducted on graphite/epoxy and Kevlar/epoxy composite components removed from Sikorsky Model S-76 helicopters in commercial operations off the Gulf Coast of Louisiana. Small scale static and fatigue tests were conducted on coupons obtained from panels exposed to outdoor conditions in Stratford, CT and West Palm Beach, Florida. The panel materials and ply configurations were representative of the S-76 components. The results are discussed of moisture analyses and strength tests on both the S-76 components and composite panels after up to nine years of outdoor exposure. Full scale tests performed on the helicopter components did not disclose any significant reductions from the baseline strengths. The results increased confidence in the long term durability of advanced composite materials in helicopter structural applications.

Mardoian, George H.↗