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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

In situ ozone instrumentation for 10-Hz measurements - Development and evaluation

The development of the fast-response ozone detector for the Electra aircraft is described. The selection of a technique to meet the design goal of 10-Hz detection is examined in terms of detection principles, instrument sampling parameters, signal conditioning, and aircraft and sampling environment. An instrument which employs a NO technique for detection of ozone with a reaction chamber volume of 16 cu cm, a pressure of 60 torr, and a sample flow of 1000 standard cu cm/min was developed. Laboratory and flight testings of the detector were conducted in order to evaluate its performance. The data reveal that the fast-response ozone detector is highly reliable with a response of 0.1 sec to 90 percent of reading, has a lower detection limit of 1 ppbv, and an S/N of 20 at 20 ppbv ozone.

Gregory, G. L.↗
NASA NTRS1988

The Design and Use of a Temperature-Compensated Hot-Film Anemometer System for Boundary-Layer Flow Transition Detection on Supersonic Aircraft

An airborne temperature-compensated hot-film anemometer system has been designed, fabricated, and used to obtain in-flight airfoil boundary-layer flow transition data by the NASA Ames-Dryden Flight Research Facility. Salient features of the anemometer include near constant sensitivity over the full flight envelope, installation without coaxial wiring, low-noise outputs, and self-contained signal conditioning with dynamic and steady-state outputs. The small size, low-power dissipation, and modular design make the anemometer suitable for use in modern high-performance research aircraft. Design of the temperature-compensated hot-film anemometer and its use for flow transition detection on a laminar flow flight research project are described. Also presented are data gathered in flight which is representative of the temperature-compensated hot-film anemometer operation at subsonic, transonic, and supersonic flight conditions.

Chiles, Harry R.↗
NASA NTRS1986

Boundary layer measurements using hot-film sensors

Measurements in the aerodynamic boundary layer using heat transfer, hot-film sensors are receiving a significant amount of effort at the Langley Research Center. A description of the basic sensor, the signal conditioning employed, and several manifestations of the sensor are given. Results of a flow reversal sensor development are presented, and future work areas are outlined.

Holmes, Harlan K.↗
NASA NTRS1988

Flight testing a highly flexible aircraft - Case study on the MIT Light Eagle

This paper describes the techniques developed for a flight test program of a human powered aircraft, the application of these techniques in the winter of 1987/88 and the results of the flight testing. A system of sensors, signal conditioning and data recording equipment was developed and installed in the aircraft. Flight test maneuvers which do not exceed the aircraft's limited capability were developed and refined in an iterative sequence of test flights. The test procedures were adjusted to yield maximum data quality from the point of view of estimating lateral and longitudinal stability derivatives. Structural flexibility and unsteady aerodynamics are modeled in an ad hoc manner, capturing the effects observed during the test flights. A model with flexibility-extended equations of motion is presented. Results of maneuvers that were flown are compared with the predictions of that model and analyzed. Finally the results of the flight test program are examined critically, especially with respect to future applications, and suggestions are made in order to improve maneuvers for parameter estimation of very flexible aircraft.

Zerweckh, S. H.↗
NASA NTRS1988

A discussion of some proposed measurement techniques for hypersonic flight and instrumentation research experiments

Sensors, instrumentation, and test techniques proposed for the Hypersonic Flight Instrumentation and Research Experiment are discussed. The project is concerned with Mach 4 to 16 flight at pressure altitudes of 50,000 to 150,000 feet. The developmental instrumentation for the program includes angle-of-attack sensors, transition sensors, skin-friction sensors, particle sensors, species-concentration sensors, and temperature and heat flux sensors. Support instrumentation (required to monitor basic flight parameters and to supply data from which the performance of the developmental instruments may be evaluated) considered include surface pressure sensors, inertial instrumentation, magnetic attitude sensors, and signal conditioning and data transmission instrumentation.

Hellbaum, R. F.↗
NASA NTRS1988

Flight test results for the Daedalus and Light Eagle human powered aircraft

The results of the flight test program of the Daedalus and Light Eagle human powered aircraft in the winter of 1987/88 are given. The results from experiments exploring the Light Eagle's rigid body and structural dynamics are presented. The interactions of these dynamics with the autopilot design are investigated. Estimates of the power required to fly the Daedalus aircraft are detailed. The system of sensors, signal conditioning boards, and data acquisition equipment used to record the flight data is also described. In order to investigate the dynamics of the aircraft, flight test maneuvers were developed to yield maximum data quality from the point of view of estimating lateral and longitudinal stability derivatives. From this data, structural flexibility and unsteady aerodynamics have been modeled in an ad hoc manner and are used to augment the equations of motion with flexibility effects. Results of maneuvers that were flown are compared with the predictions from the flexibility model. To extend the ad hoc flexibility model, a fully flexible aeroelastic model has been developed. The model is unusual in the approximate equality of many structural natural frequencies and the importance of unsteady aerodynamic effects. the Gossamer Albatross. It is hypothesized that this inverse ground effect is caused by turbulence in the Earth's boundary layer. The diameters of the largest boundary layer eddies (which represent most of the turbulent kinetic energy) are proportional to altitude; thus, closer to the ground, the energy in the boundary layer becomes concentrated in eddies of smaller and smaller diameter. Eventually the eddies become sufficiently small (approximately 0.5 cm) that they trip the laminar boundary layer on the wing. As a result, a greater percentage of the wing area is covered with turbulent flow. Consequently the aircraft's drag and the pow er required both increase as the aircraft flies closer to the ground. The results of the flight test program are examined critically, especially with respect to future applications. Maneuvers that allow the observation of stability derivatives for flexible aircraft are detailed. Considerations for the design of autopilots for future human power aircraft and high-altitude RPV's are discussed. Techniques useful in estimating the power required to fly aircraft of very high lift to drag ratio are described.

Sullivan, R. Bryan↗
NASA NTRS1986

Constructing a working taxonomy of functional Ada software components for real-time embedded system applications

A major impediment to a systematic attack on Ada software reusability is the lack of an effective taxonomy for software component functions. The scope of all possible applications of Ada software is considered too great to allow the practical development of a working taxonomy. Instead, for the purposes herein, the scope of Ada software application is limited to device and subsystem control in real-time embedded systems. A functional approach is taken in constructing the taxonomy tree for identified Ada domain. The use of modular software functions as a starting point fits well with the object oriented programming philosophy of Ada. Examples of the types of functions represented within the working taxonomy are real time kernels, interrupt service routines, synchronization and message passing, data conversion, digital filtering and signal conditioning, and device control. The constructed taxonomy is proposed as a framework from which a need analysis can be performed to reveal voids in current Ada real-time embedded programming efforts for Space Station.

Wallace, Robert↗
NASA NTRS1989

Integrated control and health monitoring capacitive displacement sensor development task. Orbit transfer rocket engine technology program

The development of a miniature multifunction turbomachinery shaft displacement sensor using state-of-the-art non-contract capacitive sensing technology is described. Axial displacement, radial displacement, and speed are sensed using a single probe within the envelope normally required for a single function. A survey of displacement sensing technology is summarized including inductive, capacitive, optical and ultrasonic techniques. The design and operation of an experimental triple function sensor is described. Test results are included showing calibration tests and simultaneous dynamic testing of multiple functions. Recommendations for design changes are made to improve low temperature performance, reliability, and for design of a flight type signal conditioning unit.

Collamore, Frank N.↗
NASA NTRS1988

A miniature, infrared pressure telemetry system

A miniature, single-channel, infrared telemetry system designed for making base pressure measurements on a wind tunnel model has been developed for the 13-inch magnetic suspension and balance system (MSBS) at Langley Research Center. The system consists of a transmitter installed in the wind tunnel model and a receiver station located outside of the test section. The onboard transmitter package includes a miniature pressure transducer, a signal conditioning circuit, and IR LED and a hearing-aid battery package. The IR LED, which is mounted flush with the model's surface, serves as the transmitter. The system is automatically activated in a magnetic field and has low power requirements. The system has been successfully employed to make low speed base pressure measurements at the 13-inch MSBS. The battery powered telemetry transmitter has a demonstrated one-hour operating life and an overall precision of better than 1/2 percent full scale.

Tcheng, Ping↗
NASA NTRS1986

Independent Orbiter Assessment (IOA): Analysis of the instrumentation subsystem

The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The independent analysis results for the Instrumentation Subsystem are documented. The Instrumentation Subsystem (SS) consists of transducers, signal conditioning equipment, pulse code modulation (PCM) encoding equipment, tape recorders, frequency division multiplexers, and timing equipment. For this analysis, the SS is broken into two major groupings: Operational Instrumentation (OI) equipment and Modular Auxiliary Data System (MADS) equipment. The OI equipment is required to acquire, condition, scale, digitize, interleave/multiplex, format, and distribute operational Orbiter and payload data and voice for display, recording, telemetry, and checkout. It also must provide accurate timing for time critical functions for crew and payload specialist use. The MADS provides additional instrumentation to measure and record selected pressure, temperature, strain, vibration, and event data for post-flight playback and analysis. MADS data is used to assess vehicle responses to the flight environment and to permit correlation of such data from flight to flight. The IOA analysis utilized available SS hardware drawings and schematics for identifying hardware assemblies and components and their interfaces. Criticality for each item was assigned on the basis of the worst-case effect of the failure modes identified.

Howard, B. S.↗
NASA NTRS1989

Reusable rocket engine turbopump health monitoring system, part 3

Degradation mechanisms and sensor identification/selection resulted in a list of degradation modes and a list of sensors that are utilized in the diagnosis of these degradation modes. The sensor list is divided into primary and secondary indicators of the corresponding degradation modes. The signal conditioning requirements are discussed, describing the methods of producing the Space Shuttle Main Engine (SSME) post-hot-fire test data to be utilized by the Health Monitoring System. Development of the diagnostic logic and algorithms is also presented. The knowledge engineering approach, as utilized, includes the knowledge acquisition effort, characterization of the expert's problem solving strategy, conceptually defining the form of the applicable knowledge base, and rule base, and identifying an appropriate inferencing mechanism for the problem domain. The resulting logic flow graphs detail the diagnosis/prognosis procedure as followed by the experts. The nature and content of required support data and databases is also presented. The distinction between deep and shallow types of knowledge is identified. Computer coding of the Health Monitoring System is shown to follow the logical inferencing of the logic flow graphs/algorithms.

Perry, John G.↗
NASA NTRS1990

End-mass instrumentation for the first SEDS/Delta II mission

The dynamics instrumentation is described which will be flown in the end-mass of the first tethered satellite to be deployed from a Delta II launch vehicle with the SEDS (Small Expendable Deployer System) low-tension deployer. Transducers, signal conditioning, power supply design, data acquisition procedures and data recovery plans are discussed. The effects of temperature variations and other potential error sources are considered.

Deloach, R.↗
NASA NTRS1991

Digital Pitch-And-Roll Monitor

Highly accurate inclinometer developed. Monitors both pitch and roll simultaneously and provides printed output on demand. Includes three mutually perpendicular accelerometers and signal-conditioning circuitry converting outputs of sensors to digital values of pitch and roll. In addition to wind-tunnel applications, system useful in any application involving steady-state, precise sensing of angles, such as calibration of robotic devices and positioners.

Finley, Tom D.↗
NASA NTRS1990

Design and evaluation of thrust vectored nozzles using a multicomponent thrust stand

Future aircraft with the capability of short takeoff and landing, and improved maneuverability especially in the post-stall flight regime will incorporate exhaust nozzles which can be thrust vectored. In order to conduct thrust vector research in the Mechanical Engineering Department at Cal Poly, a program was planned with two objectives; design and construct a multicomponent thrust stand for the specific purpose of measuring nozzle thrust vectors; and to provide quality low moisture air to the thrust stand for cold flow nozzle tests. The design and fabrication of the six-component thrust stand was completed. Detailed evaluation tests of the thrust stand will continue upon the receipt of one signal conditioning option (-702) for the Fluke Data Acquisition System. Preliminary design of thrust nozzles with air supply plenums were completed. The air supply was analyzed with regard to head loss. Initial flow visualization tests were conducted using dual water jets.

Thomas W. Carpenter↗
NASA NTRS1991

Urodynamic pressure sensor

A transducer system was developed for measuring the closing pressure profile along the female urethra, which provides up to five sensors within the functional length of the urethra. This new development is an improvement over an earlier measurement method that has a smaller sensor area and was unable to respond to transient events. Three sensors were constructed; one of them was subjected to approximately eight hours of use in a clinical setting during which 576 data points were obtained. The complete instrument system, including the signal conditioning electronics, data acquisition unit, and the computer with its display and printer is described and illustrated.

Moore, Thomas↗
NASA NTRS1991

An ultrasonic technique to measure the depth of burn wounds in humans

Whenever ultrasound encounters discontinuity in its medium of propagation, some energy is reflected from the interface. Such reflections or echoes occur when incident energy encounters the front skin, viable/necrotic, and dermis/fat skin tissue interfaces. It was shown that the most probable cause of the viable/necrotic interface is the uncoiling of collagen in the necrotic tissue, which can cause a reflection at the viable/necrotic interface of approximately 10 percent of the wave amplitude, and is approximately the same as that from the other two interfaces noted. The instrument, still in the prototype stage, was designed to detect the various reflections from within the skin layer. It is shown that, by studying the timing between the various echoes, one can use ultrasound as an aid in diagnosing the depth of burned skin tissue in humans. The instrument is a 60-MHz A-scan unit, modified to more easily identify the echoes occurring within the short time interval during which the reflections are received from the skin layers. A high frequency unit was selected so that various transducers could be utilized to optimize the system. Signal conditioning circuits were modified and added to provide an adequate display of the principle reflections expected. The unit was successful in studying burned tissue in pigs and was recently used to study burn wounds in humans. Measurement techniques and preliminary results are presented.

Yost, William T.↗
NASA NTRS1989

A digital pitch and roll monitor

A digital pitch and roll monitor was developed that will provide an easy measurement of angle in two axes simultaneously to an accuracy of approximately 0.005 degree. This system provides advantages over any other commercially available angle-measuring device in that an inexperienced operator can obtain quick reliable measurements. The system utilizes three mutually perpendicular accelerometers, mounted on an inclinometer base, and the intelligent signal conditioning equipment needed to convert the output of these sensors to pitch and roll. The two-axis inclinometer consists of three mutually perpendicular accelerometers mounted on an inclinometer base, three digital multimeters to provide power to the accelerometers and digitize their output, a computer to calculate the angles, and a printer to provide hardcopy output.

Finley, Tom↗
NASA NTRS1992

LDEF experiment M0003 meteoroid and debris survey

A survey of the meteoroid and space debris impacts on LDEF experiment M0003 was performed. The purpose was to document impact phenomenology and to obtain impact crater data for comparison to current debris and micrometeoroid models. The survey consists of photomicrographs of significant impacts in a variety of material types, accurate measurements of impact crater coordinates and dimensions for selected experiment surfaces and data basing of the crater data for reduction, manipulation, and comparison models. Large area surfaces which were studied include the experiment power and data system sunshields, environment exposure control canister sunshields, and the M0003 signal conditioning unit covers. Crater diameters down to 25 microns were measured and catalogued. Both leading and trailing edge surfaces were studied and compared. The results shows the different response of materials to hypervelocity impacts. Comparison of the data to curves derived from the Kessler debris model and the Cour-Palais micrometeoroid model indicates a marked tendency for overprediction of small impacts and underprediction of large impacts with there being better agreement for the medium sized impacts. Representative impact data is presented.

Meshishnek, M. J.↗