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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 811 records · Page 45
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Summary of Lift and Lift/Cruise Fan Powered Lift Concept Technology

A summary is presented of some of the lift and lift/cruise fan technology including fan performance, fan stall, ground effects, ingestion and thrust loss, design tradeoffs and integration, control effectiveness and several other areas related to vertical short takeoff and landing (V/STOL) aircraft conceptual design. The various subjects addressed, while not necessarily pertinent to specific short takeoff/vertical landing (STOVL) supersonic designs being considered, are of interest to the general field of lift and lift/cruise fan aircraft designs and may be of importance in the future. The various wind tunnel and static tests reviewed are: (1) the Doak VZ-4 ducted fan, (2) the 0.57 scale model of the Bell X-22 ducted fan aircraft, (3) the Avrocar, (4) the General Electric lift/cruise fan, (5) the vertical short takeoff and landing (V/STOL) lift engine configurations related to ingestion and consequent thrust loss, (6) the XV-5 and other fan-in-wing stall consideration, (7) hybrid configurations such as lift fan and lift/cruise fan or engines, and (8) the various conceptual design studies by air-frame contractors. Other design integration problems related to small and large V/STOL transport aircraft are summarized including lessons learned during more recent conceptual design studies related to a small executive V/STOL transport aircraft.

Cook, Woodrow L.↗
NASA NTRS1992

Design Feasibility Study of a Space Station Freedom Truss

Here, the focus is on the design and configuration feasibility of the short spacer for the Space Station Program in its launch configuration. The product of this study is being used by Rockwell International (Rocketdyne Division) as they continue their design concept of the current short spacer configuration. It is anticipated that the launch loads will dominate the on-orbit loads and dictate the design configuration of the short spacer. At the present time, the on-orbit loads have not been generated. The structural analysis discussed herein is based on the transient events derived from the Space Transportation System (STS) Interface Control Document (ICD). The transient loading events consist of liftoff loads, landing loads, and emergency landing loads. The quasi-static loading events have been neglected, since the magnitude of the acceleration factors are lower than the transient acceleration factors. The normal mode analyses presented herein are based on the most feasible configurations with acceptable stress ranges.

Armand, Sasan C.↗
NASA NTRS1987

Integrating nonlinear aerodynamic and structural analysis for a complete fighter configuration

The coupling of a nonlinear aerodynamics program with a structural analysis program to include the effects of static aeroelasticity in early preliminary design studies is described. A nonlinear, full potential aerodynamics method with capability to model geometric details of a complete aircraft in supersonic flow is used. The deflections of the lifting surfaces are calculated using an equivalent plate structural representation which can readily accommodate the changes in stiffness and geometric properties required during the preliminary design process. An iterative solution procedure is used to obtain consistent aerodynamic loads and structural deflections at the specified flight conditions. The volume of data transmitted between programs is minimized. The procedure is applied to a complete aircraft and the numerical results illustrate the aeroelastic effects on pressure distribution as well as total forces and moments. During this design study, the thickness distribution of the wing cover skins was initially sized based on rigid loads and subsequently resized under aeroelastic loads. Comparisons are made between these nonlinear aeroelastic results and results obtained from linear aerodynamic methods applied to a rigid shape during conceptual design studies.

Tatum, Kenneth E.↗
NASA NTRS1974

Earth Observatory Satellite system definition study. Report 3: Design cost trade-off studies and recommendations

An analysis of the design and cost tradeoff aspects of the Earth Observatory Satellite (EOS) development is presented. The design/cost factors that affect a series of mission/system level concepts are discussed. The subjects considered are as follows: (1) spacecraft subsystem cost tradeoffs, (2) ground system cost tradeoffs, and (3) program cost summary. Tables of data are provided to summarize the results of the analyses. Illustrations of the various spacecraft configurations are included.

Source record↗
NASA NTRS1989

A natural flow wing design employing 3-D nonlinear analysis applied at supersonic speeds

A wing-design study has been conducted on a 65-deg-swept leading-edge delta wing in which a near-conical geometry was employed to take advantage of the naturally occurring conical flow which arises over such a wing in a supersonic flow field. Three-dimensional nonlinear analysis methods were used in the study. In preliminary design, wing planform, design conditions, and near-conical concept were derived and a baseline standard wing (conventional airfoil distribution) and a baseline near-conical wing were chosen. During the initial analysis, a full-potential solver was employed to determine the aerodynamic characteristics of the baseline standard delta wing and the near-conical delta wing. Modifications due to airfoil thickness, leading-edge radius, and camber were then applied to the baseline near-conical wing. The final design employed a Euler solver to analyze the best wing configurations found in the initial design, and to extend this study to develop a more refined wing. Benefits due to each modification are discussed, and a final natural flow wing geometry is chosen and its aerodynamic characteristics are compared with the baseline wings.

Bauer, Steven X. S.↗
NASA NTRS1992

A NASA study of the impact of technology on future multimission aircraft

A conceptual aircraft design study was recently completed which compared three supersonic multimission tactical aircraft. The aircraft were evaluated in two technology timeframes and were sized with consistent methods and technology assumptions so that the aircraft could be compared in operational utility or cost analysis trends. The three aircraft are a carrier-based Fighter/Attack aircraft, a land-based Multirole Fighter, and a Short Takeoff/Vertical Landing (STOVL) aircraft. This paper describes the design study ground rules used and the aircraft designed. The aircraft descriptions include weights, dimensions and layout, design mission and maneuver performance, and fallout mission performance. The effect of changing technology and mission requirements on the STOVL aircraft and the impact of aircraft navalization are discussed. Also discussed are the effects on the STOVL aircraft of both Thrust/Weight required in hover and design mission radius.

Samuels, Jeffrey J.↗
NASA NTRS2022

The Mass Change Designated Observable Study: Overview and Results

The 2017–2027 United States National Academy of Sciences Decadal Survey (DS) for Earth Science and Applications from Space identified Mass Change (MC) as one of five Designated Observables (DOs) having the highest priority in terms of Earth observations required to advance Earth system science over the next decade. In response to this designation, NASA initiated several multi-center studies, with the goal of recommending observing system architectures for each DO for implementation within this decade. This paper provides an overview of the Mass Change Designated Observable (MCDO) Study along with key findings. The study process included: (a) generation of a Science and Applications Traceability Matrix (SATM) that maps required measurement parameters to the DS Science and Applications Objectives; (b) identification of three architecture classes relevant for measuring mass change: Precise Orbit Determination (POD), Satellite-Satellite-Tracking (SST) and Gravity Gradiometry (GG), along with variants within each architecture class; and (c) creation of a Value Framework process that considers science value, cost, risk, schedule, and partnership opportunities, to identify and recommend high value observing systems for further in-depth study. The study team recommended the implementation of an SST architecture, and identified variants that simultaneously (a) satisfy the baseline measurement parameters of the SATM; (b) maximize the probability of providing overlap with the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission currently in operation, accelerating science return from both missions; and (c) provide a pathway towards substantial improvements in resolution and accuracy of mass change data products relative to the program of record.

D N Wiese↗
NASA NTRS1991

Magnetic suspension and balance system advanced study, 1989 design

The objectives are to experimentally confirm several advanced design concepts on the Magnetic Suspension and Balance Systems (MSBS). The advanced design concepts were identified as potential improvements by Madison Magnetics, Inc. (MMI) during 1984 and 1985 studies of an MSBS utilizing 14 external superconductive coils and a superconductive solenoid in an airplane test model suspended in a wind tunnel. This study confirmed several advanced design concepts on magnetic suspension and balance systems. The 1989 MSBS redesign is based on the results of these experiments. Savings of up to 30 percent in supporting magnet ampere meters and 50 percent in energy stored over the 1985 design were achieved.

Boom, Roger W.↗
NASA NTRS1992

A NASA study of the impact of technology on future sea based attack aircraft

A conceptual aircraft design study was recently completed evaluating carrier-based, subsonic attack aircraft using contemporary and future technology assumptions. The study examined a configuration matrix that was made up of light and medium bomb loads, one and two man crews, internal and external weapons carriage, as well as conventional and flying wing planforms. Use of common technology assumptions, engine cycle simulation code, design mission, and consistent application of methods allow for direct comparison of the aircraft. This paper describes the design study ground rules and the aircraft designed. The aircraft descriptions include weights, dimensions, layout, design mission, design constraints, maneuver performance, and fallout mission performance. The strengths, and weaknesses of each aircraft are highlighted.

Hahn, Andrew S.↗
NASA NTRS2018

Mars Ecopoiesis Testbed

Mars surface conditions where liquid water is absent were simulated for the purposes of laboratory research. A pressure-temperature (P-T) profile was maintained in which no combination of pressure or temperature corresponds to the liquid region of the water phase diagram. The triple point of pure water occurs at T = 0.1oC and P(H2O) = 6.01 mbar; therefore all temperatures and pressures must be kept below these values, respectively. A 35-day test was performed in a commercial planetary simulation system (Techshot, Inc., Greenville, IN) in which the minimum night-time temperature was -80oC, the maximum daytime temperature was +26oC, the simulated day-night light cycle in earth hours was 12-on and 12-off, and the total pressure of the pure CO2 atmosphere was maintained below 11 mbar. Any water present was allowed to equilibrate with the changing temperature and pressure. The gas phase was sampled into a CR1-A condensation-mirror low-pressure hygrometer, which uses liquid nitrogen (down to 77oK) to determine the dew point (Buck Technologies, Boulder, CO). Dew point was measured once every hour and recorded on a data logger, along with the varying temperature in the chamber, from which the partial pressure of water was calculated. The resulting calculated daily cycles were tracked on the water P-T diagram, and no points were found to fall within the liquid-phase region of the diagram. It is concluded that there was no liquid water present throughout the test except during the initial pump-down period when aqueous specimens were introduced on the first day (less than 1 hour). Mars regolith simulant was present during this test, and further investigation is needed to determine whether liquid water could have been present or absent in the regolith in the form of brine. Biological samples consisting of Cyanobacteria: Anabena sp., Chroococcidiopsis CCMEE171, Plectonema boryanum; Eubacteria: Bacillus subtilis, Pseudomonas aeruginosa, and Eukaryota: Chlorella ellipsoidia were maintained in the simulator under the above-described conditions. The exposed specimens were tested for intracellular esterase activity, chlorophyll content (where appropriate) and reproductive survival. All tests yielded low-level positive results in all cases. In parallel to these terrestrial studies a planned design study was undertaken for the proposed test bed. Design requirements include compact assembly for transport and installation on the planetary surface (multiple units per mission would be expected), protective internal package for the release of organisms, a means of atmosphere exchange, access to sunlight, a means of penetrating the planetary surface, and most importantly a means of acquiring regolith while meeting the requirements of planetary protection. In consultation with advisers a design was created, and a large-scale mock-up of this design was fabricated by additive manufacturing at Techshot, Inc. with moving parts that simulated the components of the design. The mock-up assembly has been demonstrated to interested parties. A means of detecting live metabolism will also be included in the test bed. Several options were reviewed, and it is concluded that, by the time the ecopoiesis test bed is ready for testing the optimum instrument will be the equivalent of a hand-held mass spectrometer for metabolic gas analysis. This will maximize versatility and reveal much more information than could a detector of a single product (such as molecular oxygen), and the

Ecopoiesis↗
NASA NTRS1975

A study of design trade (OFFS) using a computer model

The interaction between the efficiency of the structural design and the cost of the structure used was studied. It is shown that future effort is best directed at producing a low cost structure of medium efficiency, but with the ability to withstand normal service wear. The trade-off between aerodynamic drag and structure weight in selecting a length to diameter ratio for the hull is evaluated along with the implications of power plan type and fuel cost on the economics of the airship. The choice of lifting gas is considered.

Coughlin, S.↗
NASA NTRS1990

Conceptual design optimization study

The feasibility of applying multilevel functional decomposition and optimization techniques to conceptual design of advanced fighter aircraft was investigated. Applying the functional decomposition techniques to the conceptual design phase appears to be feasible. The initial implementation of the modified design process will optimize wing design variables. A hybrid approach, combining functional decomposition techniques for generation of aerodynamic and mass properties linear sensitivity derivatives with existing techniques for sizing mission performance and optimization, is proposed.

Hollowell, S. J.↗
NASA NTRS2007

A Parametric Geometry Computational Fluid Dynamics (CFD) Study Utilizing Design of Experiments (DOE)

Design of Experiments (DOE) was applied to the LAS geometric parameter study to efficiently identify and rank primary contributors to integrated drag over the vehicles ascent trajectory in an order of magnitude fewer CFD configurations thereby reducing computational resources and solution time. SME s were able to gain a better understanding on the underlying flowphysics of different geometric parameter configurations through the identification of interaction effects. An interaction effect, which describes how the effect of one factor changes with respect to the levels of other factors, is often the key to product optimization. A DOE approach emphasizes a sequential approach to learning through successive experimentation to continuously build on previous knowledge. These studies represent a starting point for expanded experimental activities that will eventually cover the entire design space of the vehicle and flight trajectory.

Rhew, Ray D.↗
NASA NTRS2018

A Proposed Approach to Studying Urban Air Mobility Missions Including an Initial Exploration of Mission Requirements

Urban air mobility (UAM) is an emerging aviation market that seeks to revolutionize mobility around metropolitan areas via a safe, efficient, and accessible on-demand air transportation system for passengers and cargo. In this paper we describe our three-pronged approach to studying passenger-carrying UAM missions, and we detail the first phase of this approach, which consists of defining an initial set of requirements for multiple exemplar UAM missions. The development of these mission requirements provides justifiable assumptions that feed the second phase of the approach, which is performing aircraft conceptual design studies. Vehicle design is not included in this paper, but the work described here will define sizing missions for follow-on design and sizing studies. The aircraft that emerge from the design studies can then feed the third phase of our UAM analysis approach, which involves simulating an entire UAM network over a metropolitan area to study transportation-system level characteristics. Iteration between each of the three phases of the UAM analysis approach will be necessary to propagate lessons learned as our research progresses and as the UAM community coalesces on a more unified vision for UAM. Therefore, we anticipate that the mission requirements set forth in this paper will be modified over time as the urban air mobility concept matures.

Patterson, Michael D.↗
NASA NTRS1977

Optimization of MLS receivers for multipath environments

Optimal design studies of MLS angle-receivers and a theoretical design-study of MLS DME-receivers are reported. The angle-receiver results include an integration of the scan data processor and tracking filter components of the optimal receiver into a unified structure. An extensive simulation study comparing the performance of the optimal and threshold receivers in a wide variety of representative dynamical interference environments was made. The optimal receiver was generally superior. A simulation of the performance of the threshold and delay-and-compare receivers in various signal environments was performed. An analysis of combined errors due to lateral reflections from vertical structures with small differential path delays, specular ground reflections with neglible differential path delays, and thermal noise in the receivers is provided.

Mcalpine, G. A.↗
NASA NTRSDate not supplied

Combined Electromagnetic and Thermal Design Optimization Studies of in-Slot Cooling for UAM Electric Motors

Abstract- Urban Air Mobility vehicles will require high specific power and high reliability electric motors. Motor specific power is limited by the temperature limits of stator windings insulation and the motor cooling system’s ability to extract heat from the motor windings. The temperature limits of the stator winding are set by both thermal-chemical aging and thermo-mechanical stresses. In-slot cooling is known to be able to both more effectively reduce the max hotspot temperature in a winding and the thermo-mechanical stress in a winding at a given hotspot temperature relative to external cooling jackets. In this paper, a combined electromagnetic, thermal, and mechanical optimization of in-slot cooled motors for UAM applications is completed. Initial thermal and mechanical studies of in-slot cooling topologies with a reference design were used to down select an in-slot cooled topology for optimization. Optimizations were carried out for a representative UAM mission profile on both the in-slot cooled topology and a traditional externally cooled motor. Results show that the in-slot cooling topology can achieve a smaller mass than a traditional water jacket cooled design, but at the cost of lower efficiency due larger required stator thicknesses and correspondingly larger stator iron loss.

Thomas Tallerico↗
NASA NTRSDate not supplied

Combined Electromagnetic and Thermal Design Optimization Studies of In-Slot Cooling for UAM Electric Motors

Urban Air Mobility vehicles will require high specific power and high reliability electric motors. Motor specific power is limited by the temperature limits of stator winding insulation and the motor cooling system’s ability to extract heat from the motor windings. The temperature limits of the stator winding are set by both thermal-chemical aging and thermo-mechanical stresses. In-slot cooling is known to be able to both more effectively reduce the max hotspot temperature in a winding and the thermo-mechanical stress in a winding at a given hotspot temperature relative to external cooling jackets. In this paper, a combined electromagnetic, thermal, and mechanical optimization of in-slot cooled motors for UAM applications is completed. Initial thermal and mechanical studies of in-slot cooling topologies with a reference design were used to down select an in-slot cooled topology for optimization. Optimizations were carried out for both the in-slot cooled topology and a traditional externally cooled motor. Results show that the in-slot cooling topology can achieve a smaller mass than a traditional water jacket cooled design, but at the cost of lower efficiency due to larger required stator thicknesses and correspondingly larger stator iron loss.

Thomas Tallerico↗