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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
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

A Comparison of Measurements from ATMOS and Instruments Aboard the ER-2 Aircraft: Halogenated Gases

We compare the mixing rations of N 2 O, CFC-11, CFC-12, CCI 4 , SF 6 , and HCI in the mid-latitude stratosphere measured by the ATMOS Fourier transform spectrometer with in situ measurements acquired aboard the NASA ER-2 aircraft during November 1994. Good agreement is found between ATMOS and in situ correlations of CFC-11, CFC-12, and SF 6 with N 2 O. ATMOS observations of CCI 4 are approx. 15 percent higher than the ER-2 data, but within the systematic uncertainties.

N2O↗
NASA NTRS2021

Simultaneous Ice Water Content Measurements at Multiple Locations on the NASA DC-8 Aircraft during the 2018 HIWC RADAR Flight Campaign

Ice water content measurements were made simultaneously at three locations on the NASA DC-8 in natural, glaciated conditions during the 2018 High Ice Water Content RADAR flight campaign. The purpose of these measurements was to further evaluate efficiency factors of hot-wire total water content probes in glaciated conditions and investigate the enhancement of ice crystal concentrations near fuselage surfaces due to flow field inertial effects, and ice crystals impacting the nose, breaking up, and flowing downstream. The total water content measurements were made using either Science Engineering Associates Ice Crystal Detectors or Robust Probes. Three common sensors were mounted on an underwing canister considered to be in near free-flow conditions, a standoff from a fuselage window, and the nose of the fuselage near the pitot probes. The Ice Crystal Detector concave total water content sensor and Robust Probe sensor collection and retention efficiencies were evaluated through comparisons with the underwing Ice Crystal Detector and Robust Probe measurements to the Isokinetic Probe version 2 (IKP2), which provided the reference ice water content measurement. Local ice water content at the nose position was evaluated by comparing ratios of the nose and underwing ice crystal detectors to the IKP2. Local ice water content at the window-standoff location was also evaluated by comparing total water content sensor measurements from the window probes to the measurements made with the underwing and nose probes. The key findings were: (1) the Ice Crystal Detector concave water content sensor efficiency factor to glaciated conditions was similar to previous estimates, but reduced with increased ice crystal median mass diameter; (2) the ice water content at the fuselage nose location near the DC-8 pitot probes was approximately 2.5 times the freestream values—although this estimate is affected by a higher probe efficiency factor due to smaller particles in the debris cloud from impacts upstream of the probe; and (3) the ice water content at the 17 in. standoff from the port window varied from about 50 percent to nearly three times freestream values in a complicated manner. Similar measurement locations are not uncommon on cloud research aircraft, where ice particle measurements may be subject to similar uncertainties.

Aircraft Icing↗
NASA NTRSDate not supplied

Summary of Additional In-situ Cloud Data in High Ice Water Content Conditions from Three Recent Flight Campaigns

In-situ measurements of cloud Total Water Content and ice particle Median Mass Diameter have been previously collected during the High Altitude Ice Crystal – High Ice Water Content (HAIC-HIWC) and HIWC RADAR I flight campaigns. These measurements have been provided to an Ice Crystal Icing Aviation Rulemaking Advisory Committee to assess Title 14 Code of Federal Regulations (14CFR) Part 33 Appendix D, and recommend possible changes to the envelopes contained therein. Since then, NASA and the FAA have completed three additional flight campaigns in similar clouds. This article examines these new measurements and any impact they might have on Appendix D assessment. The addition of the new flight campaign data had little effect on previous estimates of the properties of high total water content regions of clouds. Some new information on the occurrence of graupel particles may be important to some ice crystal icing applications.

Aircraft Icing, Aircraft Instrumentation, Airspeed↗
NASA NTRSDate not supplied

Air Data Probe Anomalies in Flight through Measured High Ice Water Content Conditions

High concentrations of ice crystals in convective storms have caused anomalous air temperature and airspeed readings during commercial and research flight operations. These anomalies occur when ice crystals are ingested in the heated probe inlet, melt or partially melt to liquid water, and then refreeze or remain in a liquid state depending on the probe heat and cloud conditions. In pitot probes, the refreezing may cause complete blockage of the total pressure, which causes airspeed anomalies. In total air temperature probes, the melted ice water may flow near the temperature sensing element and cause the total air temperature reading to approach 0 degree Celsius. During the High Ice Water Content (HIWC) RADAR and HIWC-2022 flight campaigns and the Convective Process Experiment (CPEX-CV) flight campaign, a total of 71 anomalies were recorded on the NASA DC-8 pitot probes when subjected to specific flight and cloud conditions. Similarly, a research TAT probe mounted near the pitot probes had 19 anomalies. This paper presents analyses of the measured natural conditions that led to these TAT and pitot anomalies, identifies two types of pitot probe anomalies, applies a concentration factor to estimate local TWC conditions near the TAT and pitot probes, and identifies the static air temperature and pressure altitude where the anomalies occurred on the Part 33 Appendix D envelope.

Aircraft Icing↗
NASA NTRSDate not supplied

Air Data Probe Anomalies in Flight through Measured High Ice Water Content Conditions

High concentrations of ice crystals in convective storms have caused anomalous air temperature and airspeed readings during commercial and research flight operations. These anomalies occur when ice crystals are ingested in the heated probe inlet, melt or partially melt to liquid water, and then refreeze or remain in a liquid state depending on the probe heat and cloud conditions. In pitot probes, the refreezing may cause complete blockage of the total pressure, which causes airspeed anomalies. In total air temperature probes, the melted ice water may flow near the temperature sensing element and cause the total air temperature reading to approach 0 degree Celsius. During the High Ice Water Content (HIWC) RADAR and HIWC-2022 flight campaigns and the Convective Process Experiment (CPEX-CV) flight campaign, a total of 71 anomalies were recorded on the NASA DC-8 pitot probes when subjected to specific flight and cloud conditions. Similarly, a research TAT probe mounted near the pitot probes had 19 anomalies. This paper presents analyses of the measured natural conditions that led to these TAT and pitot anomalies, identifies two types of pitot probe anomalies, applies a concentration factor to estimate local TWC conditions near the TAT and pitot probes, and identifies the static air temperature and pressure altitude where the anomalies occurred on the Part 33 Appendix D envelope.

Aircraft Icing↗
NASA NTRS1989

Flutter Clearance of the F-18 High-angle-of-attack Research Vehicle with Experimental Wingtip Instrumentation Pods

An F-18 aircraft was modified with wingtip instrumentation pods for use in NASA's high-angle-of-attack research program. Ground vibration and flight flutter testing were performed to clear an acceptable flight envelope for the aircraft. Flight test utilized atmospheric turbulence for structural excitation; the aircraft displayed no adverse aeroelastic trends within the envelope tested. The data presented in this report include mode shapes from the ground vibration and estimates of frequency and damping as a function of Mach number.

Freudinger, Lawrence C.↗
NASA NTRS2015

NASA SMD Airborne Science Capabilities for Development and Testing of New Instruments

The SMD NASA Airborne Science Program operates and maintains a fleet of highly modified aircraft to support instrument development, satellite instrument calibration, data product validation and earth science process studies. This poster will provide an overview of aircraft available to NASA researchers including performance specifications and modifications for instrument support, processes for requesting aircraft time and developing cost estimates for proposals, and policies and procedures required to ensure safety of flight.

Earth Sciences↗
NASA NTRSDate not supplied

NASA’s WB-57F High Altitude Research Aircraft is Looking Up: A Flexible and Capable Heliophysics Platform for Coronal Observations During Total Solar Eclipses

NASA's WB-57F "Canberra" high altitude research aircraft is a unique airborne platform that serves a critical need in airborne science. Although the aircraft has been conventionally used for earth observation/remote sensing and in situ atmospheric sampling, research teams have begun to recognize the aircraft’s emerging role in heliophysics research. With the ability to operate at altitudes in excess of 60,000 feet and with a range of over 2,500 miles, the particular capabilities of the WB-57 are unparalleled by other aircraft in the government or commercial spaces. The Canberra has capacity to carry nearly 9,000 pounds of instrumentation across the aircraft, including modular payload areas in the belly, the nose, wing pods, and wing hatches. The WB-57 features a dedicated "person in the loop" sensor equipment operator, real-time high bandwidth data link between air and ground, and an on-board data network allowing interoperability between multiple systems and operator interfaces. The aircraft has a truly global reach, and has operated out of airfields all over the world with a minimal personnel footprint. The Program maintains a highly qualified engineering team that will work closely with customer requirements to optimize efficiency of payload installation and operation on the aircraft. NASA maintains its own airworthiness authority, allowing a bespoke "in house" approach to aircraft modifications and instrument integration. This often saves months of coordination and cost when compared with commercial options. On 8 April 2024, the WB-57 program executed a one-of-a-kind observation the corona over North America and provided a first-flight opportunity for several instruments that were historically strictly terrestrial. By integrating imagers, spectrometers, and ionosondes on the aircraft, research team partnerships with Southwest Research Institute, University of Hawai’i Institute for Astronomy, and Virginia Tech have demonstrated new and exciting applications for this venerable platform, were able to effectively eliminate the risk of adverse weather spoiling the data collection during totality, and reduce the amount of atmospheric interference in the collected spectral data.

Airborne Science↗
NASA NTRS2020

A Summary of Airframe Results from a Fokker F28 Full-Scale Crash Test

On June 20, 2019, a full-scale crash test was conducted on a Fokker F28 MK1000 aircraft as a part of a joint NASA / Federal Aviation Administration (FAA) research effort to investigate the crashworthiness characteristics of a Transport Category Aircraft (TCA), as defined by 14 Code of Federal Regulations, Part 25. The test was conducted at NASA Langley Research Center’s Landing and Impact Research Facility and was the third in a test series to further understand TCA crashworthiness characteristics. The test article featured 24 Anthropomorphic Test Devices (ATDs, a.k.a. crash test dummies), and over 700 channels of instrumentation covering major aircraft structures such as the wings, tail, nose, cockpit and cabin, along with recording seat, overhead bin and ATD accelerations. Five different U.S. Government agencies collaborated on the test including: NASA, the FAA, the U.S. Army Research Laboratory, the National Transportation Safety Board (NTSB) and the National Highway Traffic Safety Administration (NHTSA). This report will covertest article build up, which includes weight and balance measurements and pre-test laser scans. It will also cover the events of the test, which includes the test sequence of events and post-test damage inspections. Finally, it will show airframe level accelerations at all positions measured, with discussion on correlation to the airframe damage witnessed. The test build up consisted of outfitting the main cabin section of the aircraft with 24 ATDs seated in 12 rows of seats, overhead mass and the under floor cargo area with foam representing the luggage. The main cabin also included all of the onboard data system pallets, which recorded711 channels of data from the test. All major portions of the aircraft were instrumented, including locations at the floor / frame junction locations in the cabin where the ATDs were located along with other major exterior components such as the nose, the tail, each engine cowling, and at overhead hat rack ballast locations. The aircraft impacted a soil surface at65.3 ft/s horizontal and 31.8 ft/s vertical velocities. The aircraft plowed through the soil and slid a distance of 32.5 feet from the initial impact location. There was a secondary impact occurring 0.9 s due to the “slap down” of the nose during the post-impact response. The duration of the event from impact to rest was1.62 seconds. There was major structural damage in the lower fuselage areas around the Wingbox and Aft Fuselage sections. The Aft Fuselage section deformation caused some cabin intrusion from the keel beams pushing the aft cabin floor into the cabin. Other structural deformations occurred around the tail and at transition regions in the aircraft structure; mainly in locations of differing overall stiffness. The data obtained showed average vertical accelerations between 12 and 16 g with spikes reaching almost 40 g at certain floor locations. Average horizontal accelerations were approximately 10 g for all floor locations measured with spikes reaching approximately 25 g in some locations. The report includes a full set of results on aircraft deformation and accelerations along with discussions as to the effect on the aircraft structure.

Justin D Littell↗
NASA NTRSDate not supplied

Isokinetic Probe Total Water Content Measurements in the NASA Icing Research Tunnel with Supercooled Large Drop Conditions

An Isokinetic Total Water Content Evaporator (IKP2) was used to measure liquid water content (LWC) in the NASA Icing Research Tunnel (IRT) with spray conditions that ranged in LWC and cloud drop size spectra as characterized by the median volumetric diameter (MVD). The IKP2 measurements were made as part of an international collaborative effort to investigate the measurement of supercooled large drop (SLD) conditions in several icing wind tunnels. This report focuses on the IKP2 and background water vapor (BWV) measurements made within the NASA IRT during the October 2017 test entry. The IKP2 TWC results are compared to the IRT LWC calibration values for a range of LWC and MVD values. The IRT LWC calibration is based on measurements from a multi-element hot-wire probe. In general, the IKP2 TWC values were approximately 9% greater than the IRT LWC calibration values over a range of LWC from 0.4 g/m3 to 3.0 g/m3. The ratio of IKP2 TWC to IRT LWC calibration ranged from approximately 0.9 to 1.27 over a range of MVD from 15m to 460 m. Comparisons of this data set to IKP2 data from a 2014 IRT test entry show similar results in the regions where overlaps occurred. The results support the theory and observations of water mass loss from hot-wire TWC sensors when subjected to large MVD conditions.

o Aircraft Icing↗
NASA NTRSDate not supplied

Simultaneous Ice Water Content Measurements at Multiple Locations on the NASA DC-8 Aircraft during the 2018 HIWC RADAR Flight Campaign

Ice water content measurements were made simultaneously at three locations on the NASA DC-8 in natural, glaciated conditions during the 2018 High Ice Water Content RADAR flight campaign. The purpose of these measurements was to further evaluate efficiency factors of hot-wire total water content probes in glaciated conditions and investigate the enhancement of ice crystal concentrations near fuselage surfaces due to flow field inertial effects, and ice crystals impacting the nose, breaking up, and flowing downstream. The total water content measurements were made using either Science Engineering Associates Ice Crystal Detectors or Robust Probes. Three common sensors were mounted on an underwing canister considered to be in near free-flow conditions, a standoff from a fuselage window, and the nose of the fuselage near the pitot probes. The Ice Crystal Detector total water content sensor and Robust Probe sensor collection and retention efficiencies were evaluated through comparisons with the underwing Ice Crystal Detector and Robust Probe measurements to the IKP2 isokinetic evaporator probe, which provided the reference ice water content measurement. Local ice water content at the nose position was evaluated by comparing ratios of the nose and underwing ice crystal detectors to the IKP2. Local ice water content at the window-standoff location was also evaluated by comparing total water content sensor measurements from the window ice crystal detector to the measurements made with the underwing and nose Ice Crystal Detectors The key findings were: 1) the Ice Crystal Detector total water content sensor ice water content efficiency factor was similar to previous estimates, but reduced with increased ice crystal median mass diameter; 2) the ice water content at the fuselage nose location near the DC-8 pitot probes was approximately 2.5 times the freestream values – although this estimate is affected by a higher probe efficiency factor due to smaller particles in the debris cloud from impacts upstream of the probe; and 3) the ice water content at the 17” standoff from the port window varied from about 50% to 3 times freestream values in a complicated manner. Similar measurement locations are not uncommon on cloud research aircraft, where ice particle measurements may be subject to similar uncertainties.

o Aircraft Icing↗
NASA NTRS2021

Isokinetic Probe Total Water Content Measurements in the NASA Icing Research Tunnel with Supercooled Large Drop Conditions

An Isokinetic Total Water Content Evaporator (IKP2) was used to measure liquid water content (LWC) in the NASA Icing Research Tunnel (IRT) with spray conditions that ranged in LWC and cloud drop size spectra as characterized by the median volumetric diameter (MVD). The IKP2 measurements were made as part of an international collaborative effort to investigate the measurement of supercooled large drop (SLD) conditions in several icing wind tunnels. This report focuses on the IKP2 and background water vapor (BWV) measurements made within the NASA IRT during the October 2017 test entry. The IKP2 TWC results are compared to the IRT LWC calibration values for a range of LWC and MVD values. The IRT LWC calibration is based on measurements from a multi-element hot-wire probe. In general, the IKP2 TWC values were approximately 9% greater than the IRT LWC calibration values over a range of LWC from 0.4 g/m3 to 3.0 g/m3. The ratio of IKP2 TWC to IRT LWC calibration ranged from approximately 0.9 to 1.27 over a range of MVD from 15um to 460 um. Comparisons of this data set to IKP2 data from a 2014 IRT test entry show similar results in the regions where overlaps occurred. The results support the theory and observations of water mass loss from hot-wire TWC sensors when subjected to large MVD conditions.

o Aircraft Icing↗
NASA NTRS2021

Test Results for the SEA Ice Crystal Detector (ICD) under SLD Conditions at the NASA IRT

The Science Engineering Associates hot-wire Ice Crystal Detector was tested under Appendix C and Supercooled Large Drop Conditions at the NASA Icing Research Tunnel, with the purpose of comparing the measurements to the tunnel LWC calibration, and to test the performance of the mixed-phase retrievals of the probe. The liquid water content measured by the total water content sensor of the probe agreed well with the tunnel calibration over a wide range of MVDs, not unexpectedly since the tunnel was calibrated with a similar Multiwire hot-wire probe. A scale factor difference of about 7% was attributed to the lack of an efficiency correction for the Ice Crystal Detector at smaller median volume diameters, and typical sample area uncertainties of liquid water content devices. In addition, the simultaneous equations that are used to retrieve liquid and ice water contents were tested under liquid and glaciated conditions. Using constant ice and water efficiencies for each wire, the equations were found to produce a large and false ice water content retrieval in large median volume diameter liquid cases. By applying a liquid efficiency to the liquid water content sensor that varied with median volume diameter, retrievals were improved such that false ice water content was less than ±10% of the total water content out to the 460 μm median volume diameter limit of the testing. The probe was also tested in glaciated conditions by freezing out a small median volume diameter spray. Using constant ice efficiencies for the two sensors provided from aircraft measurements, the retrieved ice water content was about 40% higher than expected for the case presented, likely due to the ice efficiencies that were used from aircraft measurements of natural clouds being too low for the tunnel’s glaciated sprays. Application of ice efficiencies that vary with particle size and potentially other parameters will be explored for future improvement of retrievals.

o Aircraft Icing↗
NASA NTRS1972

A solid state converter for measurement of aircraft noise and sonic boom

The problems inherent in present systems of instrumentation for measuring aircraft noise and sonic boom include limited frequency response, expensive connecting cables, sensitivity to cable length and type, high sensitivity to environmental conditions, and additional limitations of individual system components. Furthermore, differing requirements have resulted in the use of two different systems for aircraft noise and sonic boom measurements respectively. To alleviate these difficulties a unified system of instrumentation suitable for both types of measurements was developed. The system features a new solid state converter connected to a zero drive amplifier. The system was found insensitive to cable length and type up to at least 1000 ft and requires no impedance matching networks. The converter itself has flat frequency response from dc to 28 kHz (- 3 db), dynamic range of 72 db, and noise floor of 50 db in the band 22.4 Hz to 22.4 kHz.

Zuckerwar, A. J.↗
NASA NTRS1988

The meteorological measurement system on the NASA ER-2 aircraft

A Meteorological Measurement System (MMS) was designed for the high-altitude ER-2 aircraft (NASA 706). Through dedicated instrumentation installed on the aircraft and repeated calibrations, the MMS provides accurate in situ measurements of free-stream pressure, temperature, and the wind vector. The MMS has participated in two major high-altitude scientific expeditions, the Stratosphere-Troposphere Exchange Project (STEP) based in northern Australia and the Airborne Antarctic Ozone Experiment (AAOE) based in southern Chile. Key MMS subsystems are described. The MMS consists of a dedicated inertial navigation system (INS), a randome differential pressure system, a data acquisition system, and air data instrumentation. The MMS incorporates a high-resolution INS (Litton LIN-72RH model), which is specially configured and is updated at 25 Hz. The differential pressure system, consisting of two sets of pressure ports and transducers, is installed in the ER-2 radome to provide sensitive measurements of the airflow angles (angle of attack and angle of sideslip). The data acquisition system was designed to meet aircraft requirements of compactness and light weight (2 cu ft 50 lb) and for MMS requirements to sample, control, process, and store 45 parameters (some redundant) at a sampling rate up to 10 Hz. The MMS data are stored both in a tape recorder (20 MB) and a hermatically-sealed winchester hard disc (10 MB). Special and redundant instrumentation for temperature and pressure measurements were also installed on the aircraft.

Scott, Stan G.↗
NASA NTRS1994

Aircraft-borne, laser-induced fluorescence instrument for the in situ detection of hydroxyl and hydroperoxyl radicals

The odd-hydrogen radicals OH and HO2 are central to most of the gas-phase chemical transformations that occur in the atmosphere. Of particular interest is the role that these species play in controlling the concentration of stratospheric ozone. This paper describes an instrument that measures both of these species at volume mixing ratios below one part in 10(exp 14) in the upper troposphere and lower stratosphere. The hydroxyl radical (OH) is measured by laser induced fluorescence at 309 nm. Tunable UV light is used to pump OH to the first electric state near 282 nm. the laser light is produced by a high-repetition rate pulsed dye-laser powered with all solid-state pump lasers. HO2 is measured as OH after gas-phase titration with nitric oxide. Measurements aboard a NASA ER-2 aircraft demonstrate the capability of this instrument to perform reliably with very high signal-to-noise ratios (greater than 30) achieved in short integration times (less than 20 sec).

Wennberg, P. O.↗