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Results for “Weight reduction”

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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Supersonic stability and control characteristics of a 0.015 scale model 69-0 of the space shuttle orbiter with forebody RSI modifications in the NASA/LaRC 4-foot UPWT (legs 1 and 2) (LA71A/B)

Investigations are reported for the determination of aerodynamic effects of reducing the thickness of the reusable surface insulation located along the sides of the shuttle orbiter in order to allow weight reduction in the nose region. Six-component aerodynamic force and moment data were obtained at Mach numbers from 1.5 to 4.6 over an angle of attack range from about -1 deg to 28 deg. Additional tests were made over an angle of sideslip range from -6 deg to 6 deg at selected angles of attack. Test results are presented in graph and tables.

Source record↗
NASA NTRS1977

Thermal control of power supplies with electronic packaging techniques

The integration of low-cost commercial heat pipes in the design of a NASA candidate standard modular power supply with a 350 watt output resulted in a 44% weight reduction. Part temperatures were also appreciably reduced, increasing the environmental capability of the unit. A complete 350- watt modular power converter was built and tested to evaluate thermal performance of the redesigned supply.

Source record↗
NASA NTRS1977

Coordinated NASA nickel-cadmium battery technology program

This paper describes the NASA nickel-cadmium (Ni-Cd) battery technology program which is being coordinated by JPL to provide NASA and other users with lighter and/or longer-lived Ni-Cd cells for low-earth-orbit, geosynchronous-orbit, and planetary spacecraft missions in the 1980s. The goal is to double the energy density and/or life of the system. Failure modes and mechanisms are differentiated and discussed to point out the critical design variables which affect Ni-Cd cell life. Cell component weights are listed, approaches for reducing weight are discussed, and program tasks and schedules are presented. The nine major tasks being worked on by various organizations are described. Progress has been made in weight reduction, understanding of life reliability mechanisms, and development of a process for manufacturing more stable electrodes. An accelerated and predictive life test program is approximately 30% complete. It appears feasible to double the life and/or usable energy density of the Ni-Cd cell.

Bogner, R. S.↗
NASA NTRS1977

Advanced supersonic cruise aircraft technology

A multidiscipline approach is taken to the application of the latest technology to supersonic cruise aircraft concept definition, and current problem areas are identified. Particular attention is given to the performance of the AST-100 advanced supersonic cruise vehicle with emphasis on aerodynamic characteristics, noise and chemical emission, and mission analysis. A recently developed aircraft sizing and performance computer program was used to determine allowable wing loading and takeoff gross weight sensitivity to structural weight reduction.

Baber, H. T., Jr.↗
NASA NTRS1979

Plug and drill template

Device installs plugs and then drills them after sandwich face sheets are in place. Template guides drill bit into center of each concealed plug thereby saving considerable time and fostering weight reduction with usage of smaller plugs.

Orella, S.↗
NASA NTRS1978

Lightweight multiple output converter development

A high frequency, multiple output power conditioner was developed and breadboarded using an eight-stage capacitor diode voltage multiplier to provide +1200 Vdc, and a three-stage for -350 Vdc. In addition, two rectifier bridges were capacitively coupled to the eight-stage multiplier to obtain 0.5 and 0.65 a dc constant current outputs referenced to +1200 Vdc. Total power was 120 watts, with an overall efficiency of 85 percent at the 80 kHz operating frequency. All outputs were regulated to three percent or better, with complete short circuit protection. The power conditioner component weight and efficiency were compared to the equivalent four outputs of the 10 kHz conditioner for the 8 cm ion engine. Weight reduction for the four outputs was 557 grams; extrapolated in the same ratio to all nine outputs, it would be 1100 to 1400 grams.

Kisch, J. J.↗
NASA NTRS1977

Epoxy graphite cell cases

The graphite epoxy cell case and header developed as a means of weight reduction are discussed. Aspects considered include gas permeability, KOH compatibility, pressure and structural dynamic integrity, fiber orientation, fabrication process, cover-to-case sealing, terminal installation and sealing, reproducibility, exposure to the extractable materials that might influence the electrochemical portion of the cell, and electrical conductivity between the terminals.

Bogner, S.↗
NASA NTRS1978

Development of long life lightweight nickel-cadmium cells and batteries

The paper describes the development of a high-specific energy Ni-Cd cell for a lightweight battery. After preliminary cycling tests on laboratory and commercial cells, a cell was produced that features electrochemically impregnated positive and negative electrodes, a single terminal, and increased amount of electrolyte. This cell weighed an average of 948 g and had a measured specific energy of over 50 Wh/kg at a C/2 discharge to 1.0 V. The epoxy graphite case capable of withstanding internal pressures in excess of 300 psig represents a 35% weight reduction from a lightweight 0.30 mm Ni-Cd case. A pack of these cells was cycled at 70% maximum depth of discharge beyond 10 simulated geosynchronous orbit-eclipse seasons, and high end-of-charge voltages were obtained. A prototype battery consisting of 14 such cells was fabricated and has a measured specific energy of 46 Wh/kg.

Ritterman, P. F.↗
NASA NTRS1979

Configuration considerations in the design of earth-to-orbit transports

The various configuration options for earth-to-orbit transports are discussed with specific attention given to: ballistic vs. winged vehicles; horizontal takeoff vs. vertical takeoff; two stage vs. single stage; rocket propulsion system options; structure and thermal protection systems options; and weight growth vs. size. It is suggested that the single-stage system has many attractive features such as the elimination of booster-to-orbiter mating problems and the elimination of the need for the development of a cruise system. From the standpoint of weight reduction, it appears desirable to combine as many functions as possible in the outer shell of the transport system.

Macconochie, I. O.↗
NASA NTRS1980

ESA battery development

The improvement of nickel cadmium batteries and the development of a silver hydrogen cell for spacecraft power systems are discussed. The design of nickel cadmium batteries is examined with a particular emphasis on weight reduction concepts. Results from performance tests on silver hydrogen cells are given and comparisons are made with current nickel cadmium cells.

Young, H. J.↗
NASA NTRS1980

Titan probe technology assessment and technology development plan study

The need for technology advances to accomplish the Titan probe mission was determined by defining mission conditions and requirements and evaluating the technology impact on the baseline probe configuration. Mission characteristics found to be technology drivers include (1) ten years dormant life in space vacuum; (2) unknown surface conditions, various sample materials, and a surface temperature; and (3) mission constraints of the Saturn Orbiter Dual Probe mission regarding weight allocation. The following areas were identified for further development: surface sample acquisition system; battery powered system; nonmetallic materials; magnetic bubble memory devices, and the landing system. Preentry science, reliability, and weight reduction and redundancy must also be considered.

Castro, A. J.↗
NASA NTRS1980

Development of a Kevlar/PMR-15 reduced drag DC-9 nacelle fairing

The paper describes an advanced composite fairing designed to reduce drag on DC-9 nacelles as a part of the NASA Engine Component Improvement Program. This fairing is the aft enclosure for the thrust reverser actuator system on JT8D engine nacelles and is subjected to a 500 F exhaust flow during the reverse thrust. A reduced-drag configuration was developed by using in-flight tuft surveys for flow visualization in order to identify areas with low-quality flow, and then modifying the aerodynamic lines to improve the flow. A fabrication method for molding the part in an autoclave was developed; this material system is suitable for 500 F. The resultant composite fairing reduces the overall aircraft drag 1% with a weight reduction of 40% when compared with a metal component.

Kawai, R. T.↗
NASA NTRS1980

Analysis of solid propellant combustion in a closed vessel including secondary reaction

A theory for combustion of solid propellants in a closed vessel is presented allowing for residual exothermic chemical reaction in the bulk of the gas in the vessel. Particular attention is given to propellants exhibiting thick gaseous flame zones such as nitrocellulose, double-base and nitramine propellants. For these, the reaction at high pressures is assumed to involve mainly the oxidation of residual hydrocarbons by NO. It is shown that the direct dynamic coupling between the exothermicity, the molecular weight reduction and the changing pressure can influence the dp/dt-p traces obtained, in a manner not directly related to mass burning rate of the solid. Energy and species conservation equations are derived for the bulk of the vessel in differential form; the system is solved numerically. The results show the effect of extended chemical reaction upon measurable combustion characteristics such as dp/dt-p and burn rate pressure exponent, demonstrating its potential importance in interpretation of closed vessel firing data, depending on the pace of the residual gas phase reactions.

Benreuven, M.↗
NASA NTRS1981

Super miniaturization of film capacitor dielectrics

The alignment of the stable electrical characteristics of film capacitors in the physical dimensions of ceramic and tantalum capacitors are discussed. The reliability of polycarbonate and mylar capacitors are described with respect to their compatibility with military specifications. Graphic illustrations are presented which show electrical and physical comparisons of film, ceramic, and tantalum capacitors. The major focus is on volumetric efficiency, weight reduction, and electrical stability.

Lavene, B.↗
NASA NTRS1981

Aircraft energy efficiency. Overview

Six advanced technology development projects that could cut fuel consumption of future civil air transports by as much as 50 percent are highlighted. These include improved engine components; better engine design; thin short blades for turboprop aircaft; using composite primary structures for weight reduction; the use of supercritical wings, higher aspect ratio, and winglets for improved aerodynamics; active controls; and laminar flow control. The time span of each of the six efforts and NASA's expected expenditures are also discussed.

Source record↗
NASA NTRS1980

Design, fabrication and test of a complex helicopter airframe section

A design solution is developed for the fabrication of an all-composite helicopter airframe cabin roof structure. Although this is inherently a complex structure, the parts count has been minimized by the avoidance of many mechanical fasteners, and a weight reduction of 26% has been obtained. The reduction of parts and elimination of mechanical fasteners will also result in a lowering of labor costs. The bonded graphite/epoxy elements of the structure employed aluminum tooling with control on all mating surfaces to yield accurate bond lines. A summary of static test results is presented for the basic structure and for the structure with mechanically fastened skin stiffeners. It is shown that the shear buckles caused the skin to peel from the stiffeners at about 960 lb/in. shear flow, calling for the addition of stiffeners with more bond area.

Rich, M. J.↗
NASA NTRS1981

Thermal design of the Space Shuttle External Tank

The history of the engineering and manufacturing requirements leading to the final Thermal Protection System (TPS) for the External Tank (ET) is presented. The thermal design for the ET must be optimized, based on considerations of cost, weight, and application of the TPS. The significant thermal requirements include the structural and component temperature limits, the propellant quality, the minimization of ice and frost, no air liquefaction, and no film boiling. The TPS materials selected to meet the requirements are a low density closed cell foam (CPR-488) and two light-weight ablators (SLA-56 and MA-25s). The first four flights of the Space Shuttle (1981) will measure and evaluate external environmental, structural, propulsion, electrical, and engine performance data. The ET will be instrumented to measure acoustics, pressures, heat transfer, vibration, temperatures, and structural strains. TPS weight reductions are planned for future ETs through the use of a comprehensive thermal instrumentation system.

Warmbrod, J. D.↗
NASA NTRS1981

Development status of a regenerative fuel cell system for orbital operation

Mission studies conducted by NASA for future long-term orbital operations have indicated the need for substantial increases in the power level of low-earth orbital energy storage facilities by the mid-to-late 1980's. A description is presented of the results of a comprehensive study for a state-of-the-art assessment of solid polymer electrolyte electrochemical cell technology. Questions related to the weight optimization of the dedicated system are investigated, and attention is given to the analysis of a system having reversible modules capable of operating in either the electrolysis or fuel cell mode. It was found that performance improvements and weight reduction can be realized by advancing the state of the art of solid polymer electrolyte cell technology.

Erickson, A. C.↗