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  • 1
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    Unknown
    In:  CASI
    Publication Date: 2018-04-21
    Description: No abstract available
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN54470 , AOSP R&D Partnership Workshop; 10 Apr. 2018; Moffett Field, CA; United States
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  • 2
    Publication Date: 2018-03-10
    Description: No abstract available
    Keywords: Aeronautics (General)
    Type: AFRC-E-DAA-TN53598 , 2018 FAA UAS Symposium; 6-8 Mar. 2018; Baltimore, MD; United States
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  • 3
    Publication Date: 2019-07-20
    Description: An overview of UTM (UAS (Unmanned Aircraft Systems) Traffic Management) and UAM (Urban Air Mobility).
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN58456 , International Conference on Research in Air Transportation (ICRAT 2018); Jun 26, 2018 - Jun 29, 2018; Barcelona; Spain
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  • 4
    Publication Date: 2019-07-12
    Description: The 9- by 15-Foot Low Speed Wind Tunnel has been used for acoustic testing for more than 40 years. The facility is principally used for testing aircraft engine propulsion components, for both aerodynamic performance and acoustics. The present report discusses the instrumentation and procedures currently used for the acquisition of high-quality acoustic data from aircraft engine fan models.
    Keywords: Aeronautics (General)
    Type: NASA/TM-2018-218874 , E-19531 , GRC-E-DAA-TN56180
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  • 5
    Publication Date: 2019-07-12
    Description: There is renewed interest in developing new supersonic transports after the discontinuation of the Concorde supersonic jet, which was mostly limited for flights over trans-oceanic routes due to the severe noise of the sonic boom. In order to avoid the sonic boom, more slender configurations, such as the Low Boom Flight Demonstrator (LBFD) configuration, are being considered. The aeroelastic characteristics of these new supersonic transports can significantly differ from conventional aircraft. Both rigid and flexible body modes can play a significant role in aeroelastic stability. For unconventional configurations, such as aircraft with forward swept wings, the short period oscillation (SPO) has been found to significantly impact the aeroelastic response. SPO can occur due to unanticipated events such as gusts, abrupt maneuvering, etc. During the design of the Concorde, the effects of SPO was considered in detail, though its impact is not publically disclosed. Assuring stability of supersonic aircraft, particularly during descent from the supersonic Mach regime to the transonic regime, is critical. An aircraft can deviate from its normal descent trajectory due to coupling between flows and body motions. The effect of SPO needs to be considered in aeroelastic responses. Preliminary studies using quasi-steady aerodynamics show that the presence of SPO can lead to unstable response. The well-established Reynolds Averaged Navier-Stokes (RANS) equations, which are computationally feasible with current supercomputers, have been in use for aeroelastic computations for the last three decades. Recently, such efforts have begun to include trajectory motions; for instance, the effect of phugoid motion on stability is studied in Ref. 9 using the RANS equations. In this paper, the effect of SPO on aeroelastic responses of a typical supersonic transport is studied.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN52950
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  • 6
    Publication Date: 2019-07-12
    Description: In 2015, the National Aeronautics and Space Administration (NASA) formed a multi-center, interdisciplinary team of engineers from three different aeronautics research centers who were tasked with improving NASA autonomy research capabilities. This group was subsequently named the Aeronautics Autonomy Testbed Capability (AATC) team. To aid in confronting the autonomy research directive, NASA contracted IDEO, a design firm, to provide consultants and guides to educate NASA engineers through the practice of design thinking, which is an unconventional method for aerospace design processes. The team then began learning about autonomy research challenges by conducting interviews with a diverse group of researchers and pilots, military personnel and civilians, experts and amateurs. Part of this design thinking process involved developing ideas for products or programs known as concepts that could enable real world fulfillment of the most important latent needs identified through analysis of the interviews. The concepts are intended to be sacrificial, intermediate steps in the design thinking process and are presented in this report to record the efforts of the AATC group. Descriptions are provided in present tense to allow for further ideation and imagining the concept as reality as was attempted during the teams discussions and interviews. This does not indicate that the concepts are actually in practice within NASA though there may be similar existing programs independent of AATC. These concepts were primarily created at two distinct stages during the design thinking process. After the initial interviews, there was a workshop for concept development and the resulting ideas are shown in this work as from the First Round. As part of succeeding interviews, the team members presented the First Round concepts to refine the understanding of existing research needs. This knowledge was then used to generate an additional set of concepts denoted as the Second Round. Some concepts were created by a single person in a few minutes while others were refined by the entire team over several weeks. Thus, certain ideas are more detailed than others but those from the second round are not necessarily more comprehensive than the first round concepts. Primarily, as reported here in the Second Round section, the designs serve to encompass more of the high level end user research needs which were not necessarily known to the team during the prior workshop. In the figures provided throughout this report, illustrations are often provided to represent a concept. Nearly all of the images are informal sketches or renderings and this casualness should, hopefully, not be held to negate the potential insights available within the concepts.
    Keywords: Aeronautics (General)
    Type: NASA/TM-2018-219759 , E-19471 , GRC-E-DAA-TN47481
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  • 7
    Publication Date: 2019-07-12
    Description: The purpose of this document is to introduce a new user to the procedures for overset CFD analysis by building scripts based on the CGT Script Library. Parameterized inputs are built into the steps of the process which include creation and manipulation of geometry, and surface and volume meshing. In preparation for performing computations in the flow solver, further steps are constructed for specification of inputs for domain connectivity, flow solver boundary conditions, and components for computation of aerodynamic forces/moments. The JCLV rocket will be used as an example geometry for this demonstration.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN57092
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  • 8
    Publication Date: 2019-07-20
    Description: The Layered and Extensible Aircraft Performance System (LEAPS) is a new sizing and synthesis tool being developed within the Aeronautics Systems Analysis Branch (ASAB) at NASA Langley Research Center. It is a modular, multidisciplinary, multi- fidelity sizing and synthesis tool for modeling advanced aircraft concepts and architectures such as electric/hybrid-electric propulsion, unconventional propulsion airframe integration, and non-traditional mission trajectories. The development of LEAPS is motivated by the lack of existing tools that meet the needs of ASAB. The Flight Optimization System (FLOPS) has been the primary sizing and synthesis tool of ASAB for three decades. However, FLOPS has a number of limitations that make it dicult to use for unconventional aircraft designs. Three high-level goals have been adopted to guide the LEAPS development pro- cess. LEAPS is being developed in Python with an architecture built to enable a exible and extensible analysis capability using the concept of an aircraft object that combines data and analysis models. Five challenge problems for LEAPS have been identi ed to measure progress: analysis of a conventional tube-and-wing aircraft using legacy methods, coupled aeroelastic analysis for weight estimation of a conventional tube-and-wing aircraft, analysis of an advanced hybrid-electric concept, analysis of the X-57 Maxwell distributed electric propulsion aircraft, and optimization of the trajectory of a supersonic vehicle to minimize sonic boom. LEAPS will be a publicly available capability of exceptional quality with modularity and extensibility that makes it a robust tool for design and analysis of current and future unconventional aircraft concepts.
    Keywords: Aeronautics (General)
    Type: NF1676L-27420 , AIAA SciTech 2018; Jan 08, 2018 - Jan 12, 2018; Kissimmee, FL; United States
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  • 9
    Publication Date: 2019-07-20
    Description: A brief update of the progress towards RVLT Milestone L490 Initial acoustic model for kW class electric motors. A quiet loading device has been created that will allow for acoustic testing of a motor with different loads applied. Testing has also begun on a larger motor, the Scorpion SII-4020. Description of the installation of this motor as well as initial measurements reported. These include acoustic spectra and beamforming for source localization.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN62182 , Acoustics Technical Working Group; Oct 16, 2018 - Oct 17, 2018; Cleveland, OH; United States|Urban Mobility Noise Working Group Meeting; Oct 18, 2018; Cleveland, OH; United States
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  • 10
    Publication Date: 2019-07-20
    Description: This presentation discusses high-level capabilities and interests in autonomy at NASA Ames, and describes some methods for collaboration.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN56092 , Annual HESTEMP Conference; May 05, 2018; Honolulu, HI; United States
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  • 11
    Publication Date: 2019-07-20
    Description: In response to a NASA request, Heathcoat Fabrics Limited has woven a new parachute fabric (Custom Design 1 G-60315-1800-Q01). This fabric was tested to obtain its permeability in air (i.e., flow-through volume of air per area per time) over a range of differential pressures from 0.146 to 25 psf (7 to 1197 Pa). The fabric met its specification permeability of 60 to 100 ft3/ft2/min (30.5 to 50.8 cm3/cm2/s) at the U.S. standard differential pressure of 0.5 inch of water (2.60 psf, 124 Pa). The permeability results were transformed into an effective porosity model for use in calculations related to the total porosity of parachutes. The tested fabric is being considered for use in parachutes for future missions to Mars. Calculations of drag coefficient were performed for two geometrically identical parachutes using either the new fabric or fabric woven to Parachute Industry Specification PIA-C-7020D Type I (Mars Science Laboratory Disk-Gap-Band parachute operating on Mars at a Mach number of 0.41). These calculations indicate essentially no difference in the drag coefficient between the two parachutes.
    Keywords: Aeronautics (General)
    Type: NASA/TM-2018-220112 , L-20891 , NF1676L-28522
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  • 12
    Publication Date: 2019-07-20
    Description: With the recent interest in Martian exploration using Unmanned Aerial Vehicles (UAV), an experimental study was conducted to investigate rotor performance at Martian atmospheric conditions. Both simulation and testing of rotors is vital for the evaluation of performance and behavior of a rotor, especially when subjected to a Marian atmosphere. One critical test that has not been performed to date is simulated helicopter forward flight in a Martian atmosphere. To achieve this, the test must be conducted in a facility which can be evacuated to the atmospheric pressure and density of Mars. A unique 40-in diameter rotor, roughly approximating a proposed design for a Mars Helicopter (MH), was tested in forward flight at Mars atmospheric pressure at the NASA Ames Planetary Aeolian Laboratory (PAL). The goal of this experiment was to collect rotor thrust, RPM, power, torque, and acoustics measurements. Subsequently, these results are compared with simulated cases using a mid-fidelity Computational Fluid Dynamics (CFD) approach. As expected, rotor thrust and power results are drastically reduced when under low atmospheric conditions. In addition, Reynolds number effects seem to play a vital role that cannot be neglected.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN51027 , AHS International Technical Meeting Aeromechanics Design for the Transformation Flight; Jan 16, 2018 - Jan 19, 2018; San Francisco, CA; United States
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  • 13
    Publication Date: 2019-07-20
    Description: No abstract available
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN57452 , Japan Aerospace Exploration Agency (JAXA); Jun 18, 2018; Chofu; Japan
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  • 14
    Publication Date: 2019-07-20
    Description: A high-lift propeller system is a distributed electric propulsion technology which dedicates an array of wing-mounted tractor propellers to actively augment wing lift during takeoff and landing. This paper describes the results of a wind tunnel experiment dedicated to investigating the effects of high-lift propeller installation geometry on lift generation. Variables investigated include propeller height, offset, and inclination. Results show that propeller height is the most critical variable and that the height for maximum lift depends highly on the angle of attack and flap deflection. In addition, a relationship between optimal propeller height and the wings unblown lift coefficient is discovered.
    Keywords: Aeronautics (General)
    Type: NF1676L-27395 , AIAA SciTech 2018; Jan 08, 2018 - Jan 12, 2018; Kissimmee, FL; United States
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  • 15
    Publication Date: 2019-07-20
    Description: No abstract available
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN63305 , Dr. Hassan A. Hassan Distinguished Lecture; Nov 16, 2018; Raleigh, NC; Afghanistan
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  • 16
    Publication Date: 2019-07-20
    Description: System safety and resilience is a critical concern in the air traffic domain. An important element of maintaining system safety and resilience is the ability of systems to degrade gracefully. However, previous research on the causes of system degradation in the air traffic domain are sporadic, and the potential interaction between the causes of degradation, and the resulting possible compound effect on the entire system, has been under-researched. An interview study was conducted with 12 retired controllers as participants. The results of a thematic analysis revealed the key causes of system degradation, and the associated impact on the ability of the controllers to prevent system degradation or recover the system. Findings have direct implications for identifying and mitigating potential risks of increasingly automated air traffic control systems.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN62819 , International Symposium on Human Mental Workload: Models and Applications (H-WORKLOAD 2018); Sep 20, 2018 - Sep 21, 2018; Amsterdam; Netherlands
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  • 17
    Publication Date: 2019-07-13
    Description: Carbon preforms used in Thermal Protection System (TPS) materials are 80 to 90% porous, allowing for boundary layer and pyrolysis gases to flow through the porous regions. The bulk material properties such as permeability and hydraulic tortuosity factor affect the transport of the boundary layer gases. The use of Direct Simulation Monte Carlo along with the Klinkenberg permeability formulation allows us to compute the continuum permeability and Knudsen correction factor for flow in the transition regime. In this work, we have computed the permeability for two types of carbon preforms, namely, Morgan Felt and FiberForm, and assessed the effect of orientation on the permeability. Since both the materials are anisotropic, the permeability was found to depend on orientation, wherein, the materials are more permeable in the in-plane orientation than the through-thickness orientation. The through-thickness orientation was also more tortuous compared to the in-plane material orientation. Compared to Morgan Felt, FiberForm is less permeable, in both, through thickness and in-plane directions.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN50011 , AIAA SciTech 2018; Jan 08, 2018 - Jan 12, 2018; Kissimmee, FL; United States
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  • 18
    Publication Date: 2019-07-13
    Description: This PowerPoint presentation will discuss Aura's current spacecraft and OMI insturment status, highlight anyperformance trends and impacts to OMI operations, identify any operational changes and express concerns or potential process improvements. Reviewed by Eric Moyer, ESMO Deputy Project Manager.
    Keywords: Aeronautics (General)
    Type: GSFC-E-DAA-TN60660 , OMI Science Team Meeting; Sep 11, 2018 - Sep 13, 2018; De Bilt; Netherlands
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  • 19
    Publication Date: 2019-07-13
    Description: During Mars atmospheric entry, the Mars Science Laboratory (MSL) was protected by a 4.5 meters diameter ablative heatshield assembled in 113 tiles [1]. The heatshield was made of NASA's flagship ablative material, the Phenolic Impregnated Carbon Ablator (PICA) [2]. Prior work [3] compared the traditional one-dimensional and three-dimensional material response models at different locations in the heatshield. It was observed that the flow was basically one-dimensional in the nose and flank regions, but three-dimensional flow effects were observed in the outer flank. Additionally, the effects of tiled versus monolithic heatshield models were also investigated. It was observed that the 3D tiled and 3D monolithic configurations yielded relative differences for in-depth material temperature up to 18% and 28%, respectively, when compared to the a 1D model.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN57503 , Annual International Planetary Probe Workshop; Jun 11, 2018 - Jun 15, 2018; Boulder, CO; United States
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  • 20
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN57279 , Advanced Modeling & Simulation Seminar Series; May 10, 2018; Moffett Field, CA; United States
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  • 21
    Publication Date: 2019-07-13
    Description: A modified and extended version of a convergence test for wind tunnel strain-gage balance load iterations was implemented. The test uses an upper bound of the Lipschitz constant to assess convergence characteristics of balance load predictions if the Iterative Method is applied. Convergence is expected within the use envelope of the balance whenever this upper bound is less than the threshold of one. It is explained in great detail how the convergence test can be applied to the two load iteration equation types that are currently being used in the aerospace testing community. In addition, the application of the test to balances with bi-directional output characteristics is discussed. It is also shown how numerical differentiation can be used in order to obtain partial derivatives that are needed for the calculation of the Lipschitz constant. Finally, machine calibration data of NASA's MC60E six-component force balance is selected to demonstrate both implementation and use of the convergence test.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN54238 , AIAA AVIATION Forum; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 22
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    In:  CASI
    Publication Date: 2019-07-13
    Description: This presentation includes the UAS-Enabled Market Categories used in Study, as well as the reason for the UAS-NAS NO Chase COA flight. It discusses the transitioning of a UA from different airspaces. UAS Integration is a community wide effort, and the FAA Symposium provides attendees with the opportunity to engage face-to-face with a cross-section of government and industry leaders and innovators about the latest industry developments, regulations, research, and other initiatives to safely integrate UAS into the National Airspace System (NAS).
    Keywords: Aeronautics (General)
    Type: AFRC-E-DAA-TN53416 , 2018 FAA UAS Symposium; Mar 06, 2018 - Mar 08, 2018; Baltimore, MD; United States
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  • 23
    Publication Date: 2019-07-13
    Description: The design of a modular multi-physics high-order space-time finite-element framework is presented together with its extension to allow monolithic coupling of different physics. One of the main objectives of the framework is to perform efficient high- fidelity simulations of capsule/parachute systems. This problem requires simulating multiple physics including, but not limited to, the compressible Navier-Stokes equations, the dynamics of a moving body with mesh deformations and adaptation, the linear shell equations, non-re effective boundary conditions and wall modeling. The solver is based on high-order space-time - finite element methods. Continuous, discontinuous and C1-discontinuous Galerkin methods are implemented, allowing one to discretize various physical models. Tangent and adjoint sensitivity analysis are also targeted in order to conduct gradient-based optimization, error estimation, mesh adaptation, and flow control, adding another layer of complexity to the framework. The decisions made to tackle these challenges are presented. The discussion focuses first on the "single-physics" solver and later on its extension to the monolithic coupling of different physics. The implementation of different physics modules, relevant to the capsule/parachute system, are also presented. Finally, examples of coupled computations are presented, paving the way to the simulation of the full capsule/parachute system.
    Keywords: Aeronautics (General)
    Type: AIAA Paper 2018-1400 , ARC-E-DAA-TN50876 , AIAA SciTech Forum; Jan 08, 2018 - Jan 12, 2018; Kissimmee, FL; United States
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  • 24
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    In:  CASI
    Publication Date: 2019-07-13
    Description: This presentation will cover the structure of the unmanned aircraft systems (UAS) integration into the national airspace system (NAS) project (UAS-NAS Project). The talk also details the motivation of the project to help develop standards for a detect-and-avoid (DAA) system, which is required in order to comply with requirements in manned aviation to see-and-avoid other traffic so as to maintain well clear. The presentation covers accomplishments reached by the project in Phase 1 of the research, and touches on the work to be done in Phase 2. The discussion ends with examples of the display work developed as a result of the Phase 1 research.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN54111 , Emergent Aircraft Systems and the Dispatcher Workshop; May 14, 2018; Moffett Field, CA; United States
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  • 25
    Publication Date: 2019-07-13
    Description: This is a pull-up banner of the Multifunctional Structures for High-Energy Lightweight Load-bearing Storage (M-SHELLS) technology that will be on display at the SciTech Conference in January 2018. Efforts in Multifunctional Structures for High Energy Load-Bearing Storage (M-Shells) are pushing the boundaries of development for hybrid electric propulsion for future commercial aeronautical transport. The M-Shells hybrid material would serve as the power/energy storage of the vehicle and provide structural integrity, freeing up usable volume and mass typically occupied by bulky batteries. The ultimate goal is to demonstrate a system-level mass savings with a multifunctional structure with energy storage.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN49576 , AIAA SciTech Forum; Jan 08, 2018 - Jan 12, 2018; Kissimmee, FL; United States
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  • 26
    Publication Date: 2019-07-13
    Description: Increasing demand for improved capabilities of small unmanned aircraft systems (sUAS) has generated interest in improving the design techniques for these vehicles. sUAS have typically been designed using iterative methods with multiple prototypes, but advancements in aircraft design software will make it possible to generate conceptual designs of very small VTOL aircraft with reduced hardware prototyping. This paper describes a research effort to generate a conceptual design of an approximately 6-lb quadcopter using the NASA rotorcraft design software NDARC. Wind tunnel and hover test data are used to validate and refine the conceptual design results. The effects of parametric design variations on vehicle scale are shown. The design study described herein shows that the NDARC software, which was designed for full-scale rotorcraft, can be used to design and evaluate sUAS vehicles.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN51087 , Transformative Vertical Flight Shop; Jan 16, 2018 - Jan 19, 2018; San Francisco, CA; United States|AHS International Technical Meeting Aeromechanics Design for the Transformation Flight; Jan 16, 2018 - Jan 19, 2018; San Francisco, CA; United States
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  • 27
    Publication Date: 2019-07-13
    Description: This paper adds data to help develop simulator motion guidelines for stall recovery training by identifying time-varying manual control behavior in a stall recovery task under different simulator motion conditions. A study was conducted in the NASA Ames Vertical Motion Simulator, where seventeen general aviation pilots performed a stall recovery task. Pilots had to follow a flight director through four stages of the stall recovery task. A time-varying identification method was used to quantify how pilots weigh position and velocity information throughout different stages of the task, in both roll and pitch. Four motion configurations were used: no motion, generic hexapod motion, enhanced hexapod motion and full motion. Pilot performance was highest for the enhanced hexapod and full motion conditions in both roll and pitch, and the lowest for the condition with no motion. The time-varying identification method revealed that, in the roll axis, pilot position gain did not significantly change between time segments, but was the lowest for the condition with no motion. The pilot velocity gain was significantly different between motion conditions, the largest difference being found at the beginning of the stall. The enhanced hexapod motion condition had the highest pilot velocity gain. In the pitch axis, the pilot position gain was significantly different between time segments but not between motion conditions. The pitch pilot velocity gain was highest for the full motion condition and increased at the beginning of the stall, but did not change significantly for the other motion conditions. Overall, pilot control behavior under enhanced hexapod motion was more similar to that under full aircraft motion compared to standard hexapod motion. This indicates that motion cueing on hexapod simulators might be improved for stall recovery training by using the enhanced hexapod motion developed in previous experiments.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN58412 , AIAA Aviation Forum; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 28
    Publication Date: 2019-07-13
    Description: NASA funded the preliminary design of a flight demonstrator aircraft with a greatly reduced sonic boom signature to enable supersonic flight over land. In 2017, two tests were performed at the NASA Glenn Research Center 8- by 6-foot Supersonic Wind Tunnel, an aerodynamic stability/control test and an inlet performance test. The inlet was unique due to the location on the vehicle, located on the top centerline near the rear of the aircraft. Test data provided a validation and performance dataset for engine integration on the demonstrator vehicle. The subject of this report is the subsonic and supersonic performance data collected for the centerline top-mounted inlet.
    Keywords: Aeronautics (General)
    Type: NASA/TM-2018-219956 , E-19567 , AIAA Paper 2018-2850 , GRC-E-DAA-TN59194 , AIAA Space Forum; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 29
    Publication Date: 2019-07-13
    Description: Tones were encountered in large-scale, multi-stream nozzle tests in the Aeoacoustics Propulsion Laboratory (AAPL). A different coaxial nozzle used in a past experiment also produced tones. In this paper, we present experimental and COMSOL results addressing the tone mechanism in the latter nozzle.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN58208 , AIAA/CEAS Aeroacoustics Conference; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 30
    Publication Date: 2019-07-13
    Description: A study has been performed to determine best practices for generating unstructured grids for Reynolds-Averaged Navier-Stokes (RANS) simulations of jet flows. The Axisymmetric Near-Sonic Jet Case from the Turbulence Modeling Resource was used for this study: a Mach 0.985 flow through the 2-in. diameter Acoustic Reference Nozzle (ARN2). Simulations were run with FUN3D and used the Menter Shear Stress Transport (SST-V), Spalart-Allmaras (S-A), and k-kL turbulence models. The axial velocity and turbulent kinetic energy fields in the jet plume of the unstructured grid solutions were compared to those of the baseline structured grid solution provided by the Turbulence Modeling Resource. Only solutions using grids with structured-like elements in the jet plume showed good agreement with the baseline structured grid solution. Using the SST-V turbulence model, the fully unstructured grid solutions predicted the jet potential core to decay upstream of the baseline solution. With the S-A turbulence model, the unstructured grid solutions predicted the jet potential core to decay upstream of the baseline solution. The solutions using the k-kL turbulence model seemed less sensitive to grid topology. Nozzle massflow and thrust performance were also compared for all simulations. Based on the results of this study, it is currently recommended that structured-like grid elements are used in the plumes of jet flows; unstructured grid elements can be used elsewhere.
    Keywords: Aeronautics (General)
    Type: NASA/TM-2018-219957 , AIAA Paper 2018-3223 , E-19568 , GRC-E-DAA-TN59207 , AIAA Aviation 2018; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 31
    Publication Date: 2019-07-13
    Description: The formation of ice over lifting surfaces can affect aerodynamic performance. The ability to predict ice accumulation and the resulting degradation in vehicle performance is essential to determine the limitations of aircraft in icing encounters. The consequences of underestimating performance degradation can be serious and so it is important to produce accurate predictions, particularly for severe icing conditions. The simulation of ice accretion is a challenging multidisciplinary problem that requires close collaboration between the computational and ground test communities. This paper describes three recent case studies and the lessons learned through collaborative experiments and computations in aircraft icing- one for large commercial transports, one for rotorcraft, and one dealing with icing on regional jets.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN56891 , 2018 Aviation Forum; Jun 23, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 32
    Publication Date: 2019-07-13
    Description: A study of the Weber Number effects on droplets in the NASA Icing Research Tunnel is described. The work focuses on examining the droplet Weber Number effects observed for droplets accelerated by air flow in the contraction section of the Icing Research Tunnel to the test section. These results will aid in Supercooled Large Drop facility design studies. Measurements acquired with the Phase Doppler Interferometer and High Speed Imaging Dual Range Flight Probes at a series of locations through the contraction are presented alongside a 1D numerical model developed during this study to aid interpretation of the experimental results. An estimate of the maximum Weber Number observed in the Icing Research Tunnel for varying drop sizes up to 1000 m is presented and provided for incorporation into future design studies. Finally, experimental results coupled with a numerical model indicate that breakup of drops up to 1000 m is not occurring in the NASA Icing Research Tunnel up to 129 m/s.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN57007 , AIAA Aviation Forum 2018; Jun 23, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 33
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    In:  CASI
    Publication Date: 2019-07-13
    Description: Efforts to improve operational safety often focus on preventing human error. But humans don't just make mistakes. They do, in fact, make a tremendous contribution to operational safety, and there is much to learn from what goes right. To support people in their role, the operation should be human-centered. To make the operation human-centered, the framework of the 4Ps can be used to create a clear, coherent, consistent and comprehensive guidance.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN58118 , Flight Operations Day Americas 2018; Sep 18, 2018 - Sep 19, 2018; Dallas, TX; United States
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  • 34
    Publication Date: 2019-07-13
    Description: The Mars Science Laboratory (MSL) was protected during its Mars atmospheric entry by an instrumented heatshield that used NASA's Phenolic Impregnated Carbon Ablator (PICA). PICA is a lightweight carbon fiber/polymeric resin material that offers excellent performances for protecting probes during planetary entry. The Mars Entry Descent and Landing Instrument (MEDLI) suite on MSL offers unique in-flight validation data for models of atmospheric entry and material response. MEDLI recorded, among others, time-resolved in-depth temperature data of PICA using thermocouple sensors assembled in the MEDLI Integrated Sensor Plugs (MISP). These measurements have been widely used in the literature as a validation benchmark for state-of-the-art ablation codes. The objective of this work is to perform an inverse estimate of the MSL heatshield material properties and aerothermal environment during Mars entry from the MISP flight data.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN57496 , Annual International Planetary Probe Workshop (IPPW-2018); Jun 11, 2018 - Jun 15, 2018; Boulder, CO; United States
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  • 35
    Publication Date: 2019-07-13
    Description: NASA's Airspace Technical Demonstration-2 (ATD-2) Integrated Arrival, Departure, and Surface (IADS) traffic management system integrates strategic and tactical scheduling tools for traffic sequencing from the gate to the overhead stream and back again for multi-airport, metroplex environments. The system is expected to increase airport efficiency, predictability, and throughout while improving information sharing among all airport operators. A series of knowledge elicitation sessions were conducted with commercial airline pilots and general aviation pilots to characterize airport operations and procedures. This presentation describes ATD-2 IADS-enabled Information Sharing impacts on the Flight Deck, benefits of that Information Sharing, pilot procedural changes, our pilot engagement/outreach efforts, use of a Mobile App to faciliate information flow in GA operations, and future IADS efforts at other airports/metroplexes.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN58698 , International Conference on Applied Human Factors and Ergonomics; Jul 22, 2018 - Jul 26, 2018; Orlando, FL; United States
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  • 36
    Publication Date: 2019-07-13
    Description: This study reports results from recent icing scaling tests conducted in the NASA Glenn Icing Research Tunnel (IRT) using recommended scaling methods that were developed for swept wing icing applications. The aluminum test articles used in this study were NACA 0012 Adjustable Sweep Airfoil Models. The reference and scale airfoils have a 36 inch and 15 inch chord measured normal to the leading edge, and a 60 inch and 24 inch span respectively. Reference tests were run with airspeeds of 100, 140.3 and 150 knot and MVD of 41.4, 44.4, 93 and 150 micron. All tests were set at 0 angle of attack (AOA) and 30 sweep angle. Results will be presented for stagnation freezing fractions ranging from 0.3 to 1.0. For non-dimensional reference & scale ice shape comparison, a new post-scanning ice shape digitization procedure was applied to extract 2-D "hand-tracing like" ice shape profiles, i.e. the Maximum Combined Cross Section or MCCS, at selected span-wise locations from the high fidelity 3-D scanned ice shapes obtained in the IRT. Preliminary assessment of ice shape comparison with MCCS showed that good scaling was achieved for the test conditions by using the recommended scaling methods developed for swept wing icing.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN55984 , AIAA Aviation Forum; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 37
    Publication Date: 2019-07-13
    Description: The problem of propagation of sound across the shear layer in a turbofan jet exhaust with an external center-body is discussed. The wave equation of interest is the compressible Rayleigh equation. Two forms of the equation are considered, and the Green's function solutions, subject to appropriate surface conditions on the center-body and flight condition in the ambient, are presented. Directivity studies in a heated exhaust at temperature ratio of 2.0 and Mach number 0.90 indicate that a rigid center-body tends to increase the sound propagation at forward angles relative to an exhaust without a center-body, while application of suitable surface liner may significantly reduce this enhancement.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN54929 , AIAA Aviation Forum; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 38
    Publication Date: 2019-07-13
    Description: Reynolds Averaged Navier-Stokes (RANS) simulations were performed on an N+2 conceptual commercial supersonic transport aircraft to explore the possibility of relocating the engines from below the wings to above the wings in order to capitalize upon potential noise shielding benefits. The simulations focused on the feasibility of the top-mounted propulsion configuration in terms of inlet performance and flow separation around the nacelles at climbout conditions for both 0deg and 8deg angle of attack. The results showed overall good inlet performance and little separation around the nacelles. The results were comparable to the engines in their original underwing configuration.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN56780 , AIAA Aviation Forum; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 39
    Publication Date: 2019-07-13
    Description: Boundary Layer Ingestion (BLI) for aircraft applications was first proposed by Apollo Smith and Howard Roberts in a 1947 paper that studied the use of jet intakes embedded in the boundary layer as a means to maintain laminar flow and reduce aircraft drag. While the use of BLI in aviation didn't catch on it was heavily studied and utilized for marine applications. In 1993 interest in BLI applications to aircraft design was renewed when Leyroy Smith published novel work using a boundary layer analysis combined with basic propulsion modeling to show the potential for significant fuel burn reduction. Smith identified the tightly coupled aero-propulsive nature of BLI as a key challenge in the analysis and design of the concept.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN56385 , AIAA Aviation Forum; Jun 25, 2018 - Jun 29, 2018; Atlanta, Ga; United States
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  • 40
    Publication Date: 2019-07-13
    Description: This paper deals with designing a thrust distribution strategy when a Turboelectric Distributed Propulsion (TeDP) system of 16 embedded propulsors is installed on an aerodynamically optimized hybrid wing-body configuration. This HWB previously designed to satisfy conditions of trim, longitudinally static stability and specific cargo space is employed as the baseline configuration for the current study of seeking an optimal propulsion/power system. According to the nature of the entrance flow condition for each distributed propulsion passage in hybrid wing-body aircraft, the ingested boundary layer thickness differs and results in different propulsive reaction. An optimal distribution of thrust and power output is determined by how the system utilizes the propulsive characteristics of each passage. The design space and the number of design variables are selected and described accordingly. An actuator disk model is employed to model thrust generation and shaft power from the propulsor. To carry out the optimization of the propulsion/power system on a computationally expensive CFD model, a Kriging method in conjunction with a Genetic Algorithm (GA) is applied. Throughout the design process, the propulsion performances of the sampled propulsion/power system are analyzed and compared to those of a clean flow engine. The performance metrics includes mass flow rate, fan pressure ratio besides the thrust and shaft power. Minimization of total shaft power from the distributed engine is performed at multiple thrust levels. The benefit of boundary layer ingestion propulsion system is quantified via comparison of thrust equivalent, shaft power and mass flow equivalent clean flow engines with CFD based system design.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN57008 , AIAA Aviation Forum; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 41
    Publication Date: 2019-07-13
    Description: Film cooling is used in a wide variety of engineering applications for protection of surfaces from hot or combusting gases. The design of more efficient thin film cooling geometries/configurations could be facilitated by an ability to accurately model and predict the effectiveness of current designs using computational fluid dynamics (CFD) code predictions. Hence, a benchmark set of flow field property data were obtained for use in assessing current CFD capabilities and for development of better turbulence models. Both Particle Image Velocimetry (PIV) and spontaneous rotational Raman scattering (SRS) spectroscopy were used to acquire high quality, spatially-resolved measurements of the mean velocity, turbulence intensity and also the mean temperature and normalized root mean square (rms) temperatures in a single injector cooling flow arrangement. In addition to flowfield measurements, thermocouple measurements on the plate surface enabled estimates of the film effectiveness. Raman spectra in air were obtained across a matrix of radial and axial locations downstream from a 68.07 mm square nozzle blowing heated air over a range of temperatures and Mach numbers, across a 30.48cm long plate equipped with a single injector cooling hole. In addition, both centerline streamwise 2-component PIV and cross-stream 3-component Stereo PIV data at 15 axial stations were collected in the same flows. The velocity and temperature data were then compared against Wind-US CFD code predictions for the same flow conditions. The results of this and planned follow-on studies will support NASA's development and assessment of turbulence models for heated flows.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN56253 , AIAA Aviation Forum; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 42
    Publication Date: 2019-07-13
    Description: Thermal stability is an important characteristic of alternative fuels that must be evaluated before they can be used in aviation engines. This characteristic is of great importance to the effectiveness of the fuel as a coolant and to the engine's combustion performance. The thermal stability of Gevo fuel, an alcohol to jet fuel made from plant feedstock was studied. This analysis was used to make comments on the effectiveness of the current thermal stability test standard. This work was performed using a spectroscopic ellipsometer to measure the thickness of deposits left on aluminum substrates. It was observed that Gevo deposit thickness increased slowly up to 375 C and much more rapidly after that point. Similar behavior was observed in JP-8 fuel. Comparisons were also made between color standard ratings and ellipsometric thickness measurements, and it was found that in some cases, darker colors did not indicate thicker deposits. Reference tubes were used to validate the optical models used in this work, and different optical constants were found to best model the results than what are published in the ASTM D3241 test method for thermal stability.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN55789 , American Society of Mechanical Engineers (ASME) Turbo Expo; Jun 11, 2018 - Jun 15, 2018; Lillestrom; Norway
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  • 43
    Publication Date: 2019-07-13
    Description: Data Exchange and Integration is necessary for progress towards an Integrated Arrival, Departure, and Surface (IADS) traffic management capability. In collaboration with the FAA, NASA has introduced new data exchange elements to Charlotte-Douglas International Airport air traffic facilities, including the American Airlines ramp, as part of the Airspace Technology Demonstration 2 (ATD2). This paper describes the new tools that deliver these elements, and the human factors impact of the tools as measured by post-bank surveys. Workload was unaffected by ATD2 tool use, and situational awareness was improved in the Tower and with Ramp controllers in the second round of surveys. Respondents described their tools as more helpful if they included ATD2 tools 1) in the Tower for insuring compliance for aircraft under a Traffic Management Initiative, 2) in the TRACON when actively used for many TRACON tasks, and 3) in the Ramp in the second round of surveys.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN56189 , International Conference on Applied Human Factors and Ergonomics; Jul 21, 2018 - Jul 25, 2018; Orlando, FL; United States
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  • 44
    Publication Date: 2019-07-13
    Description: This paper adds data to help the development of simulator motion cueing guidelines for stall recovery training by identifying time-varying manual control behavior in a stall recovery task under different simulator motion conditions. A study was conducted with seventeen general aviation pilots in the NASA Ames Vertical Motion Simulator. Pilots had to follow a flight director through four stages of a high-altitude stall task. A time-varying identification method was used to quantify how pilot manual control parameters change throughout different stages of the task in both roll and pitch. Four motion configurations were used: no motion, generic hexapod motion, enhanced hexapod motion and full motion. Pilot performance was highest for the enhanced hexapod and full motion configurations in both roll and pitch, and the lowest without motion. In the roll axis, the pilot position gain did not significantly change throughout the stall task, but was the lowest for the condition with no motion. The pilot roll velocity gain was significantly different between motion conditions, the largest difference being found close to the stall point. The enhanced hexapod motion condition had the highest pilot roll velocity gain. In the pitch axis, the pilot position gain was significantly different between time segments but not between motion conditions. The pilot pitch velocity gain was highest for the full motion condition and increased close to the stall point, but did not change significantly for the other motion conditions. Overall, pilot control behavior under enhanced hexapod motion was most similar to that under full aircraft motion. This indicates that motion cueing for stall recovery training on hexapod simulators might be improved by using the principles behind the enhanced hexapod motion configuration.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN57233 , AIAA Aviation Forum; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 45
    Publication Date: 2019-07-13
    Description: JENRE, a large eddy simulation code, is used to simulate an unheated, subsonic jet. Results are compared to experiment, with an emphasis on validating the acoustic power spectral density at the farfield. Problems encountered during the development of the simulations are discussed, with solutions to said problems.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN54609 , Acoustics Technical Working Group Meeting (ATWG); Apr 10, 2018 - Apr 11, 2018; Hampton, VA; United States
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  • 46
    Publication Date: 2019-07-13
    Description: The ability to monitor the health of the rotating components in aircraft engines is of major interest to aero community in improving safety and reliability. The use of instrumentation for these applications remains very challenging. It requires sensors and techniques that are highly accurate, able to operate in a high temperature environment, and sensitive enough to detect minute changes and hidden flaws before undesired events occur. The National Aeronautics and Space Administration (NASA), through several Aviation Safety Programs, has taken a leadership role in the development of new sensor technologies and techniques for the in-situ health monitoring of aircraft turbine engines. Along with the development of new instrumentation for aircraft engines, the Glenn Research Center has a diverse set of ground test facilities that are used to simulate the conditions that a vehicle would see in flight allowing new concepts to be safely developed and evaluated on the ground before progressing to actual flight. In this presentation Mark will give an overview of the NASA Glenn Research Center, discuss its past aviation safety initiatives, present some select sensors that have been developed for aircraft engine safety, and then conclude with some new measurement techniques that have been developed for use at the NASA Glenn test facilities, enabling better measurement and simulation of flight conditions. He will discuss current research and development efforts that he is working on at the NASA Glenn Research Center in the areas of new sensors and techniques for aircraft engine health monitoring. This work is being conducted in support of aviation safety.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN54758 , Kent State University Aeronautics Safety Day; Apr 12, 2018; Kent, OH; United States
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  • 47
    Publication Date: 2019-07-13
    Description: Increasing temperatures in aero gas turbines is resulting in oxidation and hot corrosion attack of turbine disks. Since disks are sensitive to low cycle fatigue (LCF), any environmental attack, and especially hot corrosion pitting, can seriously degrade the life of the disk. Application of metallic coatings is one means of protecting disk alloys from this environmental attack. However, since LCF is sensitive to surface conditions, pre- and post-coat processing can have a significant effect on the LCF life of coated bars. Various pre-and post-coating conditions were examined with a Ni-45wt. Cr coating applied by High-power impulse magnetron sputtering (HiPiMS) to a Ni-based disk alloy. Initial pre-coat surface conditions examined a grit blasted surface. Later pre-coat surface treatments involved wet blasting, two shot peening levels (8N-200 and 16N-200) and a highly polished surface. Post-coat treatments involved two shot peening levels (4N-100 and 16N-200) and a post-coat diffusion anneal in high purity Ar or a low PO2 environment to encourage chromia scale formation. Half of the coated and uncoated bars were LCF tested at 760C without further environmental exposure to evaluate the pre- and post-coat treatments. The second half of samples were either oxidized for 500 hours at 760C in air, hot corroded for 50 hours at 760C in air using a Na2SO4-MgSO4 salt, or subjected to both exposures. Results of the LCF testing and post-test characterization of the various coatings will be presented and future research directions discussed.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN55314 , International Conference on Metallurgical Coatings and Thin Films; Apr 23, 2018 - Apr 27, 2018; San Diego, CA; United States
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  • 48
    Publication Date: 2019-07-13
    Description: The DGEN AeroPropulsion Research Turbofan (DART) is a small engine representative of commercial transport propulsors. It is used at NASA to study, among other topics, core and combustor noise production mechanisms and propagation. This includes development/validation of robust and accurate instrumentation/techniques for evaluating noise production in the extreme environment of a turbofan core. This presentation highlights upcoming core-noise research activities contributing to or directly utilizing the DART facility during the remaining CY2018 and First Quarter CY 2019 period. The near-term aim is to further investigate features seen in the baseline DART core/combustor-noise test performed in the NASA GRC Aero-Acoustic Propulsion Laboratory (AAPL) during 2017 as well as to provide an improved documentation of the core noise emanating from the turbofan engine. The research is aligned with the NASA Ultra-Efficient Commercial Transport strategic thrust and is supported by the NASA Advanced Air Vehicle Program, Advanced Air Transport Technology Project, under the Aircraft Noise Reduction Subproject.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN54605 , Acoustics Technical Working Group (ATWG); Apr 10, 2018 - Apr 11, 2018; Hampton, VA; United States
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  • 49
    Publication Date: 2019-07-13
    Description: In this paper we discuss how team configuration may influence how infor-mation is shared among team members for low-altitude Unmanned Aircraft Systems (UAS) operations. NASA collected and analyzed observation data gathered during a series of field tests for the UAS Traffic Management (UTM) project. The field tests were part of a larger effort aimed at advancing the UTM concept, conducted at six test-sites spread across the USA. Ground control station (GCS) concepts, flight-crew composition, and crew-size var-ied within and across test-sites. Flight crews took two strategic approaches to organizing their teams. The first of the two approaches was implemented by one third of the flight crews. These crews integrated the role of UTM opera-tor into the duties of existing crew members, merging the current roles with this new one, keeping the UTM Operator collocated with the flight crew. The remaining two thirds implemented a distributed team configuration, where a single UTM operator distributed support across multiple crews. Results from our data collection efforts revealed that UTM Operator location influenced whether flight crews used verbal communication versus displays to acquire UTM information.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN54107 , International Conference on Applied Human Factors and Ergonomics; Jul 21, 2018 - Jul 25, 2018; Orlando, FL; United States
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  • 50
    Publication Date: 2019-07-13
    Description: The source of audible tones occurring with a coaxial nozzle in a range of low Mach numbers is explored experimentally as well as computationally. The hardware is comprised of an inner and an outer nozzle, without a center-body, that are held together by a set of four struts. With increasing jet Mach number (M(sub j)), first a tone occurred at about 2550 Hz around M(sub j)=0.06. At higher values of M(sub j) a tone at 5200 Hz dominated the noise spectra. The corresponding nondimensional frequency, based on effective thickness of the inner nozzle lip and jet exit velocity, turned out to be about 0.2, a value characteristic of Karmann vortex shedding. Thus, vortex shedding from the inner nozzle lip could be linked to the tones. From a comparison of the acoustic wavelengths and the nozzle dimensions, it was inferred that the vortex shedding excited a one-quarter-wave resonance within the divergent section of either the inner nozzle or the outer nozzle. This led to the generation of the sharp tones.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN55234 , AIAA Aviation Forum; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 51
    Publication Date: 2019-07-13
    Description: The optical and physical properties of spacecraft radiator coatings are dictated by orbital environmental conditions. For example, coatings must adequately dissipate charge buildup when orbital conditions, such as polar, geostationary or gravity neutral, result in surface charging. Current dissipation techniques include depositing a layer of ITO (indium tin oxide) on the radiator surface in a high temperature process. Other examples include the application of variable emittance coatings such as the use of VO2 to optimize radiator size, allowing for a decrease in heater power budget. The application of these enhanced coatings must be such that the properties in question are tailored to mission-specific requirements. Modification of these coatings can be accomplished during coating application preprocessing by using a deposition technique prevalent in the semiconductor micro processing industry called Atomic Layer Deposition (ALD). The preprocessing is rendered directly on the coating dry pigment before binding. ALD is a cost effective nano-manufacturing technique that allows for the conformal coating of substrates with atomic-level thickness control in a benign temperature and pressure environment. Through the introduction of paired precursor gases, thin films can be deposited on a myriad of substrates ranging from glass, polymers, aerogels, metals, powders, and other high aspect-ratio micro- and nano-structures. By providing atomic-level control, where single layers of atoms can be deposited, the fabrication of metal transparent films, precise nano-laminates, and coatings of nano-channels and pores is achievable. We have demonstrated a method for the ALD of In2O3 and ITO films on a variety of substrates from Si(100) wafers, glass slides, and on Z93P pigments (patent pending). The results indicate excellent growth of 4-22 nm thick films demonstrating an order of magnitude decrease in resistivity on the pigments.
    Keywords: Aeronautics (General)
    Type: GSFC-E-DAA-TN58724 , International Conference on Environmental Systems; Jul 08, 2018 - Jul 12, 2018; Albuquerque, NM; United States
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  • 52
    Publication Date: 2019-07-13
    Description: A set of empirical jet-surface interaction noise models, developed for single-stream round nozzles exhausting over a simple surface in a static ambient, are evaluated for use in more realistic applications that include multi-stream nozzle systems, multi-plane surface geometries, and a flight-steam. The simple-single-stream models have several advantages when used in system-level noise studies: they are robust, they are quickly computed, and they are generally applicable to a wide range of configurations. However, these models require simplifying assumptions when applied to more complex jet exhaust systems; for example, previous work on multi-stream jets used an empirical formula to compute a single-stream equivalent jet potential core length that could be used to predict the noise using simple-single-stream jet-surface interaction models. This paper considers the effect of flight and multi-plane surfaces using a similar approach: introducing assumptions to simplify the complex system, applying the simple-single-stream models, and evaluating the uncertainty.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN50855 , AIAA SciTech 2018 Conference; Jan 08, 2018 - Jan 12, 2018; Kissimmee, FL; United States
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  • 53
    Publication Date: 2019-07-13
    Description: This paper adds data to establish fidelity criteria for the simulator motion system diagnostic test now required during commercial aircraft simulator approval in the United States. Nineteen airline transport pilots flew three tasks under six different motion conditions in an experiment on the NASA Vertical Motion Simulator. The motion conditions allowed refinement of the initial fidelity criteria developed in previous experiments. In line with these previous experiments, the motion condition significantly affected (1) false motion cue pilot ratings, and sink rate and longitudinal deviation at touchdown in the approach and landing task, (2) false motion cue pilot ratings, roll deviations, and maximum pitch rate in the stall task, and (3) false motion cue pilot ratings, heading deviation, and pedal reaction time after an engine failure in the take-off task. Combining data from three experiments, significant differences in pilot-vehicle performance were used to define objective motion cueing criteria boundaries. These fidelity boundaries suggest that some hexapod simulators can possibly produce motion cues with improved fidelity in several degrees of freedom.
    Keywords: Aeronautics (General)
    Type: AIAA Paper 2018-2935 , ARC-E-DAA-TN58414 , AIAA Aviation 2018; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 54
    Publication Date: 2019-07-13
    Description: The integration of Unmanned Aircraft Systems (UAS) into the National Airspace System (NAS) poses a variety of technical challenges to UAS developers and aviation regulators. In response to growing demand for access to civil airspace in the United States, the Federal Aviation Administration (FAA) has produced a roadmap identifying key areas requiring further research and development. One such technical challenge is the development of a "detect and avoid" system (DAA) capable of providing a means of compliance with the "see and avoid" requirement in manned aviation. The purpose of the DAA system is to support the pilot, situated at a ground control station (GCS), in maintaining "DAA well clear" of nearby aircraft through the use of GCS displays and alerts. In addition to its primary function of aiding the pilot in maintaining well clear, the DAA system must also safely interoperate with existing NAS systems and operations, such as the airspace management procedures of air traffic controllers (ATC) and Collision Avoidance (CA) systems currently in use by manned aircraft, namely the Traffic alert and Collision Avoidance System (TCAS) II. It is anticipated that many UAS architectures will integrate both a DAA system and a TCAS II. It is therefore necessary to explicitly study the integration of DAA and TCAS II alerting structures and maneuver guidance formats to ensure that pilots understand the appropriate type and urgency of their response to the various alerts. This paper presents a concept of interoperability for the two systems. The concept was developed with the goal of avoiding any negative impact on the performance level of TCAS II while retaining a DAA system that still effectively enables pilots to maintain DAA well clear.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN58125 , AIAA Aviation 2018; Jun 26, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 55
    Publication Date: 2019-07-13
    Description: Concept vehicles are presented for air taxi operations, also known as urban air mobility or on-demand mobility applications. Considering the design-space dimensions of payload (passengers and pilot), range, aircraft type, and propulsion system, three aircraft are designed: a single passenger (250-lb payload), 50-nm range quadrotor with electric propulsion; a six-passenger (1200-lb payload), 4x50 = 200-nm range side-by-side helicopter with hybrid propulsion; and a fifteen-passenger (3000-lb payload), 8x50 = 400-nm range tiltwing with turbo-electric propulsion. These concept vehicles are intended to focus and guide NASA research activities in support of aircraft development for emerging aviation markets, in particular VTOL air taxi operations. Research areas are discussed, illustrated by results from the design of the concept vehicles.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN50731 , AHS Specialists'' Conference on Aeromechanics Design for Transformative Vertical Flight; Jan 16, 2018 - Jan 19, 2018; San Francisco, CA; United States
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  • 56
    Publication Date: 2019-07-13
    Description: The UAS-NAS Project hosted a Systems Integration Operationalization (SIO) Industry Day for the SIO Request for Information (RFI) on November 30, 2017 in San Diego, California. This presentation is being presented to the same group as a follow up regarding the progress that the UAS-NAS project has made on the SIO RFI. The presentation will be virtual with a teleconference
    Keywords: Aeronautics (General)
    Type: AFRC-E-DAA-TN53887 , SIO Industry Day Follow-up - Teleconference; Mar 15, 2018; Edwards, CA; United States
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  • 57
    Publication Date: 2019-07-13
    Description: Since 2006, when the Fundamental Aeronautics Program was instituted within NASA's Aeronautics Mission Directorate, there has been a Project looking at the technical barriers to commercial supersonic flight. Among the barriers is the noise produced by aircraft during landing and takeoff. Over the years that followed, research was carried out at NASA aeronautics research centers, often in collaboration with academia and industry, addressing the problem. In 2013, a high-level milestone was established, described as a Technical Challenge, with the objective of demonstrating the feasibility of a low-boom supersonic airliner that could meet current airport noise regulations. The Technical Challenge was formally called a Low Noise Propulsion for Low Boom Aircraft and was completed in late 2016. This paper reports the technical findings from this Technical Challenge, reaching back almost 10 years to review the technologies and tools that were developed along the way. It also discusses the final aircraft configuration and propulsion systems required for a supersonic civilian aircraft to meet noise regulations using the technologies available today. Finally, the paper documents the model-scale tests that validated the acoustic performance of the study aircraft.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN50748 , AIAA SciTech Forum; Jan 08, 2018 - Jan 12, 2018; Kissimmee, FL; United States
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  • 58
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN51285 , AIAA SciTech Forum; Jan 08, 2018 - Jan 12, 2018; Kissimmee, FL; United States
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  • 59
    Publication Date: 2019-07-13
    Description: In the proposed paper, the optimum wing shape of a highly flexible aircraft under varying flight conditions will be controlled by a linear parameter-varying approach. The optimum shape determined under multiple objectives, including flight performance, ride quality, and control effort, will be determined as well. This work is an extension of work done previously by the authors, and updates the existing optimization and utilizes the results to generate a robust flight controller.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN50215 , 2018 AIAA SciTech Forum; Jan 08, 2018 - Jan 12, 2018; Kissimmee, FL; United States
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  • 60
    Publication Date: 2019-07-13
    Description: The present research is aimed at providing a performance model for the Mars Helicopter (MH), to understand the complexity of the flow, and future regions of improvement. The Martian atmosphere's low density and the MH's relatively small rotor result in very low chord-based Reynolds number flows, Rec = O(10(exp 3)-10(exp 4)). The low density and subcritical Reynolds number reduce the lifting force and lifting efficiency, respectively. The high drag coefficients in subcritical flow, especially for thicker sections, are attributed to laminar separation from the rear of the airfoil. The goal is to generate a performance model for the MH rotor for a free wake analysis, since the computational budget for a complete Navier-Stokes solution for a rotating body-fitted rotor is substantial. In this study, a RANS-based approach is used to generate the airfoil deck using OVERFLOW with stitched experimental data for very high angles of attack. The model is presented through airfoil data tables (C81 files) that are used by comprehensive rotor analysis codes such as CAMRADII, or the mid-fidelity CFD solver RotCFD. These codes have proven to provide accurate performance predictions for all rotor operations at only a fraction of the computational expense of three- dimensional body-fitted viscous grids.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN53889 , Annual Forum and Technology Display; May 15, 2018 - May 17, 2018; Phoenix, AZ; United States
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  • 61
    Publication Date: 2019-07-13
    Description: NASA is exploring rotorcraft designs for VTOL air taxi operations, also known as urban air mobility (UAM) or on-demand mobility (ODM) applications. Several concept vehicles have been developed, intended to focus and guide NASA research activities in support of aircraft development for this emerging market. This paper summarizes the work conducted to date. To initially explore the broad design trade-space, three concept vehicles were designed: a quadrotor with electric propulsion; a side-by-side helicopter with hybrid propulsion; and a tiltwing with turbo-electric propulsion. Next a specific UAM mission was developed, accounting for the existing geography, population patterns, infrastructure, and weather in twenty-eight markets across the United States of America. Then in order to quantify the tradeoffs and performance targets necessary for practical implementation of the UAM vision, aircraft were designed to perform this mission, considering a range of aircraft types and propulsion system architectures: quadrotor aircraft, with turboshaft and all-electric propulsion; side-by-side aircraft, with turboshaft and all-electric propulsion; and lift+cruise aircraft with all-electric and turbo-electric propulsion. In examining these vehicles, performance targets and recurring technology themes emerged, which can guide investments in research and development within NASA, other government agencies, academia, and industry. In addition, results from the designs support observations about the trade-offs and key design decisions.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN60637 , Asian/Australian Rotorcraft Forum (ARF 2018); Oct 30, 2018 - Nov 01, 2018; Jeju Island; Korea, Republic of
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  • 62
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN58452 , International Symposium on Flow Visualization ISFV; Jun 26, 2018 - Jun 29, 2018; Zurich; Switzerland
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  • 63
    Publication Date: 2019-07-13
    Description: Lessons learned from past failures of launch vehicle developments and operations were used to create a new method to predict the probability of failure of conceptual systems. Existing methods such as Probabilistic Risk Assessments and Human Risk Assessments were considered but found to be too cumbersome for this type of system-wide application for yet-to-be-flown vehicles. The basis for this methodology were historic databases of past failures, where it was determined that various faulty human-interactions were the predominant root causes of failure rather than deficient component reliabilities evaluated through statistical analysis. This methodology contains an expert scoring part which can be used in either a qualitative or a quantitative mode. The method produces two products: a numerical score of the probability of failure and guidance to program management on critical areas in need of increased focus to improve the probability of success. In order to evaluate the effectiveness of this new method, data from a concluded vehicle program (USAF's Titan IV with the Centaur G-Prime upper stage) was used as a test case. The theoretical vs. actual probability of failure was found to be 4.46% vs. 6.67% respectively. Recommendations are made for future applications of this method to ongoing launch vehicle development programs.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN59930 , AIAA Space 2018; Sep 17, 2018 - Sep 19, 2018; Orlando, FL; United States
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  • 64
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN59743 , Cambridge Workshops of Cool Stars, Stellar Systems and the Sun (Cool Stars 20); Jul 29, 2018 - Aug 03, 2018; Cambridge, MA; United States
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  • 65
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-07-13
    Description: Multitasking is endemic in modern life and work: drivers talk on cell phones, office workers type while answering phone calls, students do homework while text messaging...but, nurses also prepare injections while responding to doctor's calls, and air traffic controllers direct aircraft in one sector while handling aircraft additional traffic in another. Whether in daily life or at work, we are constantly bombarded with multiple, concurrent interruptions and demands and we have all somehow come to believe in the myth that we can, and in fact are expected to, easily address them all - without any repercussions. Accumulating However, accumulating scientific evidence is now suggesting that multitasking increases the probability of human error. This talk presents a set of NASA studies that characterize concurrent demands in one work domain, routine airline cockpit operations, in order to illustrate the ways operational task demands together with the natural proclivity to manage them all concurrently make human performance in this and in any work domain vulnerable to potentially serious errors and to accidents.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN61073 , PGME Simulation Education and Research Symposium 2018; Oct 04, 2018; Calgary; Canada
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  • 66
    Publication Date: 2019-07-13
    Description: The injection of fully-developed turbulent heated air from a tube into a cooler turbulent duct flow is examined, as an analogy to film cooled turbine blades. A LES numerical model is developed and applied in which tube and duct turbulence inflow effects are emulated using a divergence-free synthetic eddy method (SEM). For direct comparison, a hot-wire experiment is conducted within the ERB test cell SW-6 at NASA Glenn Research Center. Results related to velocity, temperature, and heat flux are obtained numerically and experimentally for a blowing ratio of 1.2, involving a 36 K temperature difference. The relative effect on the solutions of tube and duct inflow turbulence is systematically evaluated. The impact of inherent low-pass filtering of temperature measurements and probe wire offset on the experimental results are addressed.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN56715 , AIAA Aviation Forum 2018; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 67
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-07-13
    Description: NASA is committed to transforming our aviation system to best meet demands and opportunities of the future. With a vision of safe, efficient, flexible, and environmentally sustainable air transportation, the NASA Aeronautics Research Mission Directorate is conducting research and development to address future needs of the aviation community, the Nation, and the world. While our NASA Aeronautics vision and strategy reaches into the next 25 years and beyond, we recognize that our vision and strategy must be responsive to new discoveries and emerging markets. For this reason, we are empowering our research community to redefine the future of aviation by dreaming up convergent/transformative ideas and studying if those ideas are possible. By modeling the new NASA Aeronautics' Convergent Aeronautics Solutions (CAS) Project after the venture capital community, we created opportunities for teams of intrapreneurs to mature their ideas into concepts through rapid feasibility studies. The CAS Project expects teams to consider the complexities and potential benefits of multi-disciplinary solutions and to leverage technology advances from outside the field of aeronautics. We also expect teams to explore their concepts in a rapid, iterative manner that allows them to learn and adjust their research approach. Within a year or two, teams are responsible for reporting on the feasibility of their concept. The findings inform NASA Aeronautics strategic planning and further investment. This presentation will give an overview of CAS.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN57971 , AIAA Aviation 2018; Jun 25, 2018 - Jun 29, 2018; Atlanta,GA; United States
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  • 68
    Publication Date: 2019-07-13
    Description: System resilience is critical to safety in air traffic control. An important element of maintaining resilience is the ability of systems to degrade gracefully. Of the available graceful degradation research, a majority of studies have focused primarily on technological causes of degradation only, limiting an ecologically valid understanding of the causes of degradation in air traffic control, and the preventative and mitigative strategies that enable graceful degradation. The current study aimed to address this research gap by investigating causes of degradation in air traffic control across the broad categories of technology, the environment, and the human operator, and the potential interactions between these causes. 12 retired controllers participated in semi-structured interviews focused on previous experience of causes of degradation and mitigation strategies. Findings provide an understanding of causation of degradation in air traffic control, and the prevention and mitigation strategies that moderate the relationship between cause and system effect. Findings confirmed that causes appear to interact to create compound, multiple effects on overall system performance. Findings also revealed prevention and mitigation strategies utilized to moderate the effect of the cause on the system. In order to gain an ecologically valid understanding of the causes of degradation, and effective prevention or mitigation strategies, causes from multiple categories, and the interactions between them, must be identified. Findings have implications for designers of future air traffic control systems to ensure the ability of the system to gracefully degrade, as well as risk assessment and system validation processes.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN58129 , AIAA Aviation Forum; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 69
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-07-13
    Description: The proposed research will determine the optimum relative locations for any pair of aircraft to fly in an extended formation and achieve fuel savings of up to 10%, saving the U.S. airline industry billions of dollars in aviation fuel costs.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN57776 , Ames Innovation Fair; Jun 14, 2018; Moffett Field, CA; United States
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  • 70
    Publication Date: 2019-07-13
    Description: The integration of Unmanned Aircraft Systems (UAS) into the National Airspace System (NAS) poses a variety of technical challenges to UAS developers and aviation regulators. In response to growing demand for access to civil airspace in the United States, the Federal Aviation Administration (FAA) has produced a roadmap identifying key areas requiring further research and development. One such technical challenge is the development of a "detect and avoid" system (DAA) capable of providing a means of compliance with the "see and avoid" requirement in manned aviation. The purpose of the DAA system is to support the pilot, situated at a ground control station (GCS), in maintaining "DAA well clear" of nearby aircraft through the use of GCS displays and alerts. In addition to its primary function of aiding the pilot in maintaining DAA well clear, the DAA system must also safely interoperate with existing NAS systems and operations, such as the airspace management procedures of air traffic controllers (ATC) and Collision Avoidance (CA) systems currently in use by manned aircraft, namely the Traffic Alert and Collision Avoidance System (TCAS II). It is anticipated that many UAS architectures will integrate both a DAA system and a TCAS II. It is therefore necessary to explicitly study the integration of DAA and TCAS II alerting structures and maneuver guidance formats to ensure that pilots understand the appropriate type and urgency of their response to the various alerts. This paper presents a concept of interoperability for the two systems. The concept was developed with the goal of avoiding any negative impact on the performance level of TCAS II while retaining a DAA system that still effectively enables pilots to maintain DAA well clear. The interoperability concept described in the paper focuses primarily on facilitating the transition from a late-stage DAA encounter (where a loss of DAA well clear is imminent) to a TCAS II Corrective Resolution Advisory (RA), which requires pilot compliance within five seconds of its issuance. The interoperability concept was presented to 10 participants (6 active UAS pilots and 4 active commercial pilots) in a medium-fidelity, human-in-the-loop simulation designed to stress different aspects of the DAA and TCAS II systems. Pilots' ability to maintain separation, their rate of compliance and response times using the interoperability concept are reported. Results indicated that pilots exhibited comprehension of, and appropriate prioritization within, the DAA-TCAS II combined alert structure. Pilots demonstrated a high rate of compliance with TCAS II RAs and were also seen to respond to corrective RAs within the five second requirement established for manned aircraft. The DAA system presented under test was also shown to be effective in supporting pilots' ability to maintain DAA well clear in the overwhelming majority of cases in which pilots had sufficient time to respond.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN56282 , 2018 AIAA Aviation Forum; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 71
    Publication Date: 2019-07-13
    Description: Over the course of four years, a team of aerospace engineers at the National Aeronautics and Space Administration Armstrong Flight Research Center completed four projects, each with the objective to research sonic-boom signatures from a ground-and building-level perspective. The relatively compressed timeline of these projects resulted in many lessons learned. With each successive project, these lessons have been more relied upon and referenced. This paper provides a high-level overview of the teams relevant lessons learned and the importance of these lessons for future projects.
    Keywords: Aeronautics (General)
    Type: AFRC-E-DAA-TN56431 , AIAA Aviation and Aeronautics Forum and Exposition (AVIATION 2018); Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 72
    Publication Date: 2019-08-13
    Description: No abstract available
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN53491 , CFD Prediction Error Assessment Workshop 2018; Mar 20, 2018 - Mar 22, 2018; Suffolk, VA; United States
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  • 73
    Publication Date: 2019-08-13
    Description: The development of optical non-intrusive measurement techniques that can make global surface measurements in aero flow fields with increased temporal and spatial resolution is of major interest to the aeronautical research community. The ability to globally measure quantities such as velocity, temperature, density and pressure can provide better insight into the complex flow characteristics associated with the aero vehicle and aero propulsion concepts being investigated by NASA. In addition, these measurements are needed to validate Computational Fluid Dynamic (CFD) codes that are being developed to model aero phenomena and predict system performance. This presentation will give an overview of the advanced optical techniques that are being developed at the NASA Glenn Research Center (GRC) for the measurement of flow field and surface parameters in the GRC aeronautical test facilities.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN59075 , NASA Technical Interchange Meeting (TIM) on Active Optical Systems; Jul 31, 2018; Columbia, MD; United States
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  • 74
    Publication Date: 2019-07-12
    Description: The Elytron 4S Unmanned Aerial Vehicle (UAV) Concept was developed to combine the advantages of fixed- and rotary-wing technology. The 4S Concept is a box-wing configuration with rotors mounted on a centrally located tiltwing. The UAV is intended to be capable of both conventional takeoff and landing (CTOL) and vertical takeoff and landing (VTOL), and is envisioned to excel in UAV performance because of the combined efficiency of fixed-wing aircraft and the hover and VTOL capabilities of regular drones or quadcopters. A mid-fidelity Unsteady Reynolds-Averaged Navier-Stokes (URANS) approach using Rotorcraft CFD (RotCFD) is performed to analyze and characterize the performance of the aircraft. The flow field is coupled with a rotor model based on blade-element momentum theory to model the 4S UAV rotors. Turbulence is modeled using a realizable k- turbulence model with special wall function. The code is used to generate aerodynamic forces and moments on the body at cruise conditions, and during VTOL. The results and their uncertainties are characterized, and an angle- of-attack and sideslip sweep are computed, both with and without rotors on. Simulations are compared with the wind tunnel tests in the 7- by 10-Foot U.S. Army Wind Tunnel at NASA Ames Research Center, performed in 2017. Results show promising comparison with experimental data, despite a late change in rotor size and rudder size of the physical model that cause the expected deviations from the simulation. A slight change in the net thrust value, when rotors are modeled, is observed because of the rotor diameter increase on the physical model. A noticeable difference in the directional stability was observed because of the increased rudder surface and added strakes. These changes were implemented to improve on the design as simulated, which is observed in the results. The simulation results paved the way to the first successful flight of the UAV Concept.
    Keywords: Aeronautics (General)
    Type: NASA/TM-2018ý219788 , ARC-E-DAA-TN53886
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  • 75
    Publication Date: 2019-07-12
    Description: The NASA Jet Propulsion Laboratory (JPL) designed the Mars Helicopter (MH) in collaboration with AeroVironment Inc., NASA Ames Research Center, and NASA Langley Research Center to explore the possibility of a vertical takeoff and landing (VTOL) Unmanned Aerial Vehicle (UAV) for flight on Mars. A 40-inch-diameter Aeolian Wind Tunnel (AWT) rotor, roughly approximating the proposed MH design by JPL, was tested in forward flight at Mars atmospheric pressure at the NASA Ames Planetary Aeolian Laboratory (PAL) in support of MH research efforts. This report describes the generation of the rotor model used to correlate with that experimental effort as reported by Ament and Koning. The 40-inch-diameter rotor was 3D-scanned and transformed into an airfoil deck. The scanned rotor airfoil sections are analyzed using C81 Generator (C81Gen) to generate the sectional aerodynamic coefficients for comprehensive analyses. A mid-fidelity computational fluid dynamics (CFD) simulation using Rotorcraft CFD (RotCFD) is pursued to efficiently estimate rotor hover and forward flight performance. Simulations at two pressures, 7 mbar (approximate Martian atmospheric pressure) and 1018 mbar (1 atmosphere), are performed to gain an understanding of the performance differences and Reynolds number effects observed. Experimental 1-atmosphere thrust for single- and dual-rotor isolated hover cases correlate well with the modeled rotor. Performance results at reduced pressure (7 mbar) show a drastic decrease in lift for equivalent RPMs tested at 1 atmosphere. Although this is primarily due to pressure reduction, Reynolds number effects also contribute to this decrease, as airfoil lift and drag coefficients are affected when compared with 1-atmosphere results. Further, simulated rotor power coefficient shows drastic increases at reduced pressures, attributed to laminar boundary layer separation, as described in Koning et al. for the MH rotor analysis. PAL experimental Martian Surface Wind Tunnel (MARSWIT) results are presented in the paper by Ament and Koning. The very low Reynolds number range is currently not well understood and presents various challenges for both experimentation and simulation.
    Keywords: Aeronautics (General)
    Type: NASA/CR-2018ý219737 , ARC-E-DAA-TN50404
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  • 76
    Publication Date: 2019-07-12
    Description: Arthritis, osteoporosis, and other bone diseases and defects are common medical issues worldwide. By utilizing ceramic biomaterials as bone substitutes to treat these diseases, bone regeneration can be promoted and toxicity from the substitute material can be limited. Calcium phosphate (CaP) ceramics have become popular as bone substitutes due to their biocompatibility and similarity in composition to natural bone. The purpose of this research was to investigate the physical properties and biological responses of CaP-based bone substitutes, doped with metal ions. Some metal ions are present in natural bone in small amounts, and recent studies show they affect the biological responses of CaPs significantly. Dopants such as magnesium (Mg), strontium (Sr), silicon (Si) and iron (Fe) alter the phase composition, mechanical properties, osteogenesis and angiogenesis properties of CaPs, depending on their concentration and method of addition. In the present study, the effects of cobalt (Co) and copper (Cu) on the physical and biological properties of two main CaP materials, brushite cement (BrC) and tricalcium phosphate (TCP), have been investigated. Different concentrations of dopants in forms of oxide and/or chloride were selected and their effect on phase composition, sintering behavior, density, setting time, compressive strength and in vitro interaction with osteosarcoma and osteoblast cells were studied. Different techniques of sample preparation, challenges during cement preparation and compact sample pressing, sintering, and methods of dopant addition are discussed. The presence of Cu in tricalcium phosphate was found to increase thermal stability of the material and decrease the impact of sintering temperature on porosity. In addition, Cu caused a reduction in expression of inflammatory gene markers by human osteoblast cells and an increased expression at early time points due of osteoinductive markers.The addition of Cu and Co to brushite cement caused an increase in thermal stability of the material, and the addition of Cu caused significant increase in setting time. Small dopant amounts of Co caused decrease in setting time, but higher amounts caused an increase. In addition, Cu dopant in small amounts resulted in an increase of compressive strength. Both Cu and Co led to a decrease in expression of inflammatory gene markers by osteoblast and osteosarcoma cells respectively, and Cu also caused an increase in osteoinductive marker expression. Thus, these results indicate that Cu and Co have a positive impact on the physical, mechanical and biological properties of calcium phosphate biomaterials.
    Keywords: Aeronautics (General)
    Type: NASA/TM-2018-220015 , ARC-E-DAA-TN60380
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  • 77
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-07-12
    Description: Throughout history the same question has been asked by many mentors, from blacksmiths and cobblers to engineers and scientists. Now, at NASA Ames Research Center, it has been answered once again. Over the summer of 2018, the aeromechanics branch at NASA Ames Research Center was overrun by 53 Interns with backgrounds ranging from physics and engineering to education, from high school students to graduate students, causing this branch's population to grow by 50 percent. The Aeromechanics Office at NASA Ames Research Center is responsible for aeromechanics research activities that directly support the civil competiveness of the U.S. helicopter industry and the vertical lift requirements of the Department of Defense. The interns were set off to assist with work related to vertical take-off and landing (VTOL) technology and vertiport counterparts, computational fluid dynamics (CFD), 3D modeling (CAD), and projects that may even escape this world to Earth's neighbors Mars and Venus. More than 20,000 man-hours were dedicated to completing over 41 projects.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN61461
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  • 78
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    Unknown
    In:  CASI
    Publication Date: 2019-07-12
    Description: This memoir covers the first eight years of my 37 year career in VTOL aircraft design. It starts with family and how I came to be an engineer with a passion for aviation and a desire to make a difference. At MIT I acquired a solid understanding of basic physics, learned the basics of the various engineering disciplines and gained design experience. After over a decade on the East Coast I was homesick for Northern California. I decided to take a chance on working for the government instead of industry in order to return home. I was hired by Dr. Richard M. Carlson in March 1975 and joined a wonderful Army/NASA technical environment. The Interservice Helicopter Commonality Study was an important introduction to Joint Service aircraft design. The Advanced Attack Helicopter Source Selection Evaluation Board was an opportunity to learn acquisition system fundamentals and to lead a small team in a major technical evaluation. The Advanced Scout Helicopter Concept Formulation was an opportunity to learn how an aircraft development program is created and it formed a partnership between Dr. Carlson's Labs and Charlie Crawford's Development and Qualification directorate. The Army was Executive Service for the first year (1982) of the Joint Services Advanced Vertical Lift Aircraft (JVX) program. The JVX Joint Technology Assessment concluded that there was at least one design configuration, the tilt rotor, which could satisfy all JVX mission requirements with a high degree of inter-service commonality. The Navy became Executive Service at the end of the year and promptly released a JVX RFP to industry. This RFP resulted in the V-22 Osprey tilt rotor as the third type of VTOL aircraft to enter production and service. I was very lucky to have a useful role early in this program.
    Keywords: Aeronautics (General)
    Type: NASA/TP-2018-219981 , ARC-E-DAA-TN60420
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  • 79
    Publication Date: 2019-07-12
    Description: The RADI system described in this technical memorandum outlines a framework that can be used to fuse a variety of data including surveillance recordings, environmental observations, and procedural information to produce features that would otherwise not be observable by any single data source. The process is designed with scalability in mind so that large scale batch processing can be executed on a typical distributed cluster environment. This process was initially developed as a prototype to quickly assess adherence and iterate and engineer relevant features of interest that can assist in determining factors for non-adherence to procedural requirements.
    Keywords: Aeronautics (General)
    Type: NASA/TM-2018-219964 , ARC-E-DAA-TN58838
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  • 80
    Publication Date: 2019-07-12
    Description: The concept of boundary layer ingestion (BLI) has been proposed by NASA researchers and other groups for improving the performance of a number of future aircraft concepts. These future aircraft concepts include the STARC-ABL, D8 and N-3X among other examples. While BLI technology appears to be promising for improving the aircraft performance by reducing fuel burn, the benefits and challenges of using this technology are not well understood. As a result, there are a number of e orts ongoing within NASA which are attempting to model BLI and determine its overall bene t. Despite their common goal, there seems to be significant differences in the modeling approaches used in each e ort, with limited communication and collaboration between these groups. The purpose of this report is to document NASA's in-house BLI modeling e orts and their associated methodologies. Furthermore, the report will identify strengths and weaknesses of each methodology, specifically in regards to each method's application in conceptual design.
    Keywords: Aeronautics (General)
    Type: NASA/TM-2018-219926 , E19542 , GRC-E-DAA-TN57522
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  • 81
    Publication Date: 2019-07-12
    Description: Computational fluid dynamic (CFD) simulations of models tested in wind tunnels require a high level of fidelity and accuracy particularly for the purposes of CFD validation efforts. Considerable effort is required to ensure the proper characterization of both the physical geometry of the wind tunnel and recreating the correct flow conditions inside the wind tunnel. The typical trial-and-error effort used for determining the boundary condition values for a particular tunnel configuration are time and computer resource intensive. This paper describes a method for calculating and updating the back pressure boundary condition in wind tunnel simulations by using a proportional-integral-derivative controller. The controller methodology and equations are discussed, and simulations using the controller to set a tunnel Mach number in the NASA Langley 14- by 22-Foot Subsonic Tunnel are demonstrated.
    Keywords: Aeronautics (General)
    Type: NASA/TM-2018-219812 , L-20913 , NF1676L-29535
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  • 82
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    In:  CASI
    Publication Date: 2019-07-12
    Description: The Overview PowerPoint presentation offers a broad view of the aeronautics research done at NASA Ames Research Center, with an emphasis on VTOL and eVTOL research.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN57148 , VTOL to eVTOL Roundtable - Silicon Valley Chapter Event; San Carlos, CA
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  • 83
    Publication Date: 2019-07-12
    Description: This report describes an analysis of current transport aircraft system-management displays and the initial development of a set of display concepts for providing information about aircraft system status. The new display concepts are motivated by a shift away from the current approach to aircraft system alerting that reports the status of physical components, and towards displaying the implications for mission capability. Specifically, the proposed display concepts describe transport airplane component failures in terms of operational consequences of aircraft system degradations. The research activity described in this report is an effort to examine the utility of different representations of complex systems and operating environments to support real-time decision making during off-nominal situations. A specific focus is to develop display concepts that provide more highly integrated information to allow pilots to more easily reason about the operational consequences of the off-nominal situations. The work can also serve as a foundational element to autonomy-supported decision making since we are developing ideas for integrating information from the airplane and the operational environment to support decision making.
    Keywords: Aeronautics (General)
    Type: NASA/TM-2018-219774 , ARC-E-DAA-TN52885
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  • 84
    Publication Date: 2019-08-14
    Description: For many years, the concept of routinely flying unmanned aircraft systems (UAS) within the national airspace system (NAS) has been a long-term goal with numerous known and unknown technology and policy obstacles. Just within the last few years, the efforts and advancements from government, industry, and academia-sponsored research and development have greatly shortened the distance to the goal. The National Aeronautics and Space Administration (NASA) Aeronautics Research Mission Directorate (ARMD) has recognized that it is uniquely positioned to play a lead role in addressing the remaining UAS airspace integration (AI) challenges. To fully understand the magnitude and scope of these challenges, NASA ARMD initiated a study in 2015 to identify what would be needed to enable full integration of UAS for civil/commercial operations within the NAS by 2025. The desired outcome was a comprehensive analysis framework that ARMD could use to develop a research portfolio focused on retiring the remaining gaps and challenges standing in the way of full UAS integration. This document is a comprehensive assessment of UAS integration research to date.
    Keywords: Aeronautics (General)
    Type: AFRC-E-DAA-TN51123 , NASA/TM--2018-219751
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  • 85
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN62603 , Annual Meeting of the APS Division of Plasma Physics; Nov 05, 2018 - Nov 09, 2018; Portland, OR; United States
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  • 86
    Publication Date: 2019-07-13
    Description: This presentation serves as an overview of test plans for an upcoming DGEN Aeropropulsion Research Turbofan (DART) test entry at the NASA GRC AeroAcoustic Propulsion Laboratory (AAPL). The test entry includes: (1) a fan intra-stage velocity field survey, which will be compared to a Computational Fluid Dynamics (CFD) survey of DART, (2) an exploratory noise study of DART with several objectives focused on measurement projection to the far-field, source identification improvements and development of a barrier wall for isolation of various sources, (3) advancement of core/combustor noise research on DART using more extensive engine-mounted instrumentation, and (4) high-temperature pressure sensor technology-readiness-level (TRL) advancement.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN62110 , Acoustics Technical Working Group; Oct 16, 2018 - Oct 17, 2018; Cleveland, OH; United States
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  • 87
    Publication Date: 2019-07-13
    Description: Direct measurements of turbofan engine core unsteady pressure is complicated by the extreme thermal environment within the engine, preventing currently available transducers from operating. It is necessary to use a remote measurement configuration such as an infinite-tube-probe (ITP) configuration in which the transducer is teed into a line pneumatically coupled with the location of interest and the other end of the ITP contains an "infinite" waveguide designed to prevent any reflections. This configuration has become a standard method for experiments concerning core noise. In order to relate the spectral pressure measurements obtained remotely with the ITP, a transfer (frequency response) function needs to be calculated based on a known pressure field. This is accomplished using a normal impedance tube at Glenn Research Center, where a flush-mounted microphone is used as a reference to the ITP signal in the calculation of the ITP's transfer function.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN62138 , NASA Acoustics Technical Working Group Meeting; Oct 16, 2018 - Oct 17, 2018; Cleveland, OH; United States
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  • 88
    Publication Date: 2019-07-13
    Description: The increased interest in electric motors for aircraft propulsion systems has driven interest in quantifying the contribution of electric motor noise to the overall sound levels and possibly human annoyance of the propulsion system. This work presents acoustic measurements of electric motors used for small quadcopters to quantify the sound produced by a number of outrunner motors with different types of controllers. Results are presented for loaded and unloaded motors as well as installed and uninstalled configurations. Motor resonance frequencies were measured and computed. Current probe measurements showed significant harmonic content in the supply current from the controllers for both the conventional and sinewave controllers. Acoustic results showed motor noise is typically radiated at frequencies near that for azimuthal vibration mode number 2 of the rotor which occurs at roughly 5000 Hz. Electric motor noise was evident in the spectra produced by many of the motor-controller combinations for motors loaded with propellers with levels often greater than those for the motor alone due to increases in the stator magnetic flux density with increased current. An installed quadcopter configuration produced increases in acoustic radiation over that of the uninstalled motor in a frequency range near the 1200 Hz azimuthal vibration mode 1 of the rotor.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN57549 , AIAA Aviation Forum; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 89
    Publication Date: 2019-07-13
    Description: To present a summary of frequency domain and time domain procedures for aeroelasticity by using non-linear flow equations
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN58359 , Symposium on Classical to Computational Aeroelasticity; Sep 10, 2018 - Sep 13, 2018; Bangalore; India
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  • 90
    Publication Date: 2019-07-13
    Description: A multidisciplinary design optimization procedure has been developed and applied to rotorcraft simulations involving tightly-coupled, high-fidelity computational fluid dynamics and comprehensive analysis. A discretely-consistent, adjoint-based sensitivity analysis available in the fluid dynamics solver provides sensitivities arising from unsteady turbulent flows on unstructured, dynamic, overset meshes, while a complex-variable approach is used to compute structural sensitivities with respect to aerodynamic loads. The multidisciplinary sensitivity analysis is conducted through integrating the sensitivity components from each discipline of the coupled system. Accuracy of the coupled system for high-fidelity rotorcraft analysis is verified; simulation results exhibit good agreement with established solutions. A constrained gradient-based design optimization for a HART-II rotorcraft configuration is demonstrated. The computational cost for individual components of the multidisciplinary sensitivity analysis is assessed and improved.
    Keywords: Aeronautics (General)
    Type: NF1676L-27742 , Aeromechanics Design for Transformative Vertical Flight; Jan 16, 2018 - Jan 18, 2018; San Francisco, CA; United States
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  • 91
    Publication Date: 2019-07-13
    Description: The Flight Operational Quality Assurance (FOQA) programs have been implemented in US and Europe to identify anomalous flights based on data recorded on board an aircraft in an effort to improve flight safety. Numerous methods have been developed to support the analysis of FOQA data. However, it is unclear how FOQA data relates to the performance of the pilot. We sought to characterize the frequency and type of flight exceedances extracted from FOQA data during a controlled pilot schedule in order to determine whether patterns of exceedances related to human control of the aircraft would change according to scheduling factors.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN56137 , Annual Scientific Meeting of the Aerospace Medical Association; May 06, 2018 - May 10, 2018; Dallas, TX; Afghanistan
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  • 92
    Publication Date: 2019-07-13
    Description: Lean direct injection (LDI) is a combustion concept to reduce oxides of nitrogen (NOx) for next generation aircraft gas turbine engines. These newer engines have cycles that increase fuel efficiency through increased operating pressures, which increase combustor inlet temperatures. NOx formation rates increase with higher temperatures, and the LDI strategy is to avoid high temperature by staying fuel lean and away from stoichiometric burning. Thus, LDI relies on rapid and uniform fuel/air mixing. Additionally, in combustors for smaller core engines, the area and volume bring about mixing and time scale challenges not found in larger engines. As part of our parametric study in which we vary swirler angle and orientation and look at their effect on fluid mixing and combustion, we examine one configuration of a 7-point lean direct injector by looking at the non-combusting 2-D velocity field using PIV, and combusting system for chemical species using chemiluminescent imaging and flame spectroscopy. The circular 7-point array consists of axial swirlers, with the center 60 swirler surrounded by six 52 swirlers. The velocity results for this configuration show that the outer swirlers serve to isolate the center flow field near the injector exit. A recirculation zone forms downstream of the center swirler, but not behind the outer swirlers. The combusting results also show an isolated zone directly downstream of the center injector. The flame spectra show variation in speciation of combustion species such as OH*, C3*, CH*, and C2* as a function of position within the combustor.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN56856 , Spring Technical Meeting of the Central States Section of the Combustion Institute (CSSCI); May 20, 2018 - May 22, 2018; Minneapolis, MN; United States
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  • 93
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    In:  CASI
    Publication Date: 2019-07-13
    Description: This presentation discusses lessons learned from flight and technique testing.
    Keywords: Aeronautics (General)
    Type: AFRC-E-DAA-TN59199 , EAA AirVenture Oshkosh 2018; Jul 23, 2018 - Jul 29, 2018; Oshkosh, WI; United States
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  • 94
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    Unknown
    In:  CASI
    Publication Date: 2019-07-13
    Description: This presentations describes the career and current projects of the Center Chief Pilot.
    Keywords: Aeronautics (General)
    Type: AFRC-E-DAA-TN59076 , EAA AirVenture Oshkosh; Jul 23, 2018 - Jul 29, 2018; Oshkosh, WI; United States
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  • 95
    Publication Date: 2019-07-13
    Description: This paper presents the evaluation of a thermodynamic ice crystal icing model, previously presented to describe the possible mechanisms of icing within the core of a turbofan jet engine. It has been proposed that there are two types of distinct ice accretions based on a surface energy balance: freeze-dominated icing and melt-dominated icing. In the former, ice accretion occurs where a freeze fraction (0 to 1) of melted ice crystals freezes on a surface, along with the existing ice of the impinging water and ice mass. This freeze-dominated icing is characterized by having strong adhesion to the surface. In the latter, icing occurs from accumulated unmelted ice on a surface, where a melt fraction (0 to 1) dictates the amount of unmelted impinged ice. This melt-dominated icing is characterized by weakly bonded surface adhesion. The experimentally observed ice growth rates suggest that only a small fraction of the impinging ice remains on the surface, implying a mass loss mechanism such as splash, runback, bounce, or erosion. This mass loss parameter must be determined in conjunction with the fraction of freezing liquid water or fraction of melting ice on an icing surface. This loss parameter, however, along with the freeze and melt fraction, are the only experimental parameters that are currently not measured directly. Using reported icing growth rates from published ice crystal icing experiments, a methodology is proposed to determine these unknown parameters. This work takes reported ice accretion data from tests conducted by the National Aeronautics and Space Administration (NASA) in 2016 and tests NASA collaborated on with the National Research Council (NRC) of Canada in 2012 that examined the fundamental physics of ice crystal icing. Those research efforts sought to generate icing conditions representative of those that occur inside a jet engine when ingesting ice crystals. This paper presents the fundamental equations of the thermodynamic model, the methodology used to determine the aforementioned unknown icing parameters, and results from model evaluation using experimental data. In addition, this paper builds on the previously proposed model by adding a transient conduction term to explain ice growth behavior at the onset of experimental tests that was observed to be different from steady-state ice growth that occurred later in the test run.With the addition of this energy term, this becomes a quasi-steady model. A key finding from this work suggests that mass loss fractions can exceed 0.90 for steady ice growth periods. In addition, due to conductive heat fluxes when using a warmer-than-freezing airfoil, lower mass loss fraction values were calculated during the initial transient period.
    Keywords: Aeronautics (General)
    Type: E-19518 , GRC-E-DAA-TN55658 , 2018 Atmospheric and Space Environments Conference; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 96
    Publication Date: 2019-07-13
    Description: Between 2012 and 2017, parachutes for four NASA Projects were tested in the 80- by 120-Ft test section of the National Full-Scale Aerodynamic Complex (NFAC) at NASA Ames Research Center. These projects were: (1) Low-Density Supersonic Decelerator (LDSD); (2) Capsule Parachute Assembly System (CPAS, for Orion); (3) Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight, a Mars mission); and (4) Mars 2020. In all tests stereo photogrammetry was used to measure time-dependent positions of features on the canopies. For the LDSD and CPAS tests, where the purpose was to study the trade-off between stability and drag of different parachute designs, the pendulum motion of the canopies about the riser attachment point was measured by calibrated cameras in the diffuser. The CPAS test also included static measurements where the inflated parachutes were pulled to the side by a system of tethers. The Insight tests were structural qualification tests where each canopy was packed in a bag and launched from a mortar. Cameras in the diffuser measured the trajectory of the bag and the stripping of the bag from the canopy. The Mars 2020 test was a workmanship verification test where the canopies were either launched from a mortar or deployed from a sleeve stretched along the tunnel axis. The deployments were recorded from many directions by thirteen high-speed cameras distributed in the diffuser and test section. Photogrammetry was not planned; however, after a tunnel-related accident ended the test prematurely, photogrammetric measurements were bootstrapped from the images to support the accident investigations. This paper describes how the photogrammetry measurements were made in each test and presents typical results.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN56612 , AIAA Applied Aerodynamics Conference; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 97
    Publication Date: 2019-07-13
    Description: Rotorcraft gearbox transmissions are required to efficiently transfer power from the turbine engine to the main and tail rotor blades. Losses in transmission efficiency impact mission payload and aircraft range. These systems are expected to deliver high power with high gear pitch line velocities. More recently, shrouding has been employed to reduce windage power losses associated with the high gear rotational speeds. However, recent experimental results from tests conducted by the authors show the negative impact of close clearance shrouds on windage power loss, particularly at the meshed region where flow is ejected, or jetted, from the collapsing tooth spaces. A literature review was conducted to gain further insight into the phenomenon of gear mesh jetting and strategies to mitigate and control the associated losses. An analysis was conducted on windage losses in the mesh region. Test results are given for a modified shroud configuration. Finally, a discussion on observed trends follows with suggestions on future research.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN54362 , AHS International''s Annual Forum and Technology Display; May 15, 2018 - May 17, 2018; Phoenix, AZ; United States
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  • 98
    Publication Date: 2019-07-13
    Description: The Boundary Layer Ingestion poster is an overview of the technology.
    Keywords: Aeronautics (General)
    Type: GRC-E-DAA-TN49573 , SciTech Conference; Jan 08, 2018 - Jan 12, 2018; Kissimmee, FL; United States
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  • 99
    Publication Date: 2019-07-13
    Description: Automation is playing an increasingly important role in many operations. It is often cheaper faster and more precise than human operators. However, automation is not perfect. There are many situations in which a human operator must step in. We refer to these instances as contingencies and the act of stepping in contingency management. Here we propose coupling Human Autonomy Teaming (HAT) with contingency management. We describe two aspects to HAT, bi-directional communication, and working agreements (or plays). Bi-directional communication like Crew Resource Management in traditional aviation, allows all parties to contribute to a decision. Working agreements specify roles and responsibilities. Importantly working agreements allow for the possibility of roles and responsibilities changing depending on environmental factors (e.g., situations the automation was not designed for, workload, risk, or trust). This allows for the automation to "automatically" become more autonomous as it becomes more trusted and/or it is updated to deal with a more complete set of possible situations. We present a concrete example using a prototype contingency management station one might find in a future airline operations center. Automation proposes reroutes for aircraft that encounter bad weather or are forced to divert for environmental or systems reasons. If specific conditions are met, these recommendations may be autonomously datalinked to the affected aircraft.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN54114 , Emergent Aircraft Systems and the Dispatcher Workshop; Mar 14, 2018; Moffett Field, CA; United States
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  • 100
    Publication Date: 2019-07-13
    Description: The Revolutionary Vertical Lift Technology (RVLT) Project is one of six projects in the Advanced Air Vehicles Program (AAVP) of the NASA Aeronautics Research Mission Directorate. The overarching goal of the RVLT Project is to develop and validate tools, technologies, and concepts to overcome key barriers for vertical lift vehicles. The project vision is to enable the next generation of vertical lift vehicles with aggressive goals for efficiency, noise, and emissions, to expand current capabilities and develop new commercial markets. The RVLT Project invests in technologies that support conventional, non-conventional, and emerging vertical-lift aircraft in the very light to heavy vehicle classes. Research areas include acoustic, aeromechanics, drive systems, engines, icing, hybrid-electric systems, impact dynamics, experimental techniques, computational methods, and conceptual design. The project research is executed at NASA Ames, Glenn, and Langley Research Centers; the research extensively leverages partnerships with the US Army, the Federal Aviation Administration, industry, and academia. The primary facilities used by the project for testing of vertical-lift technologies include the 14- by 22-Ft Wind Tunnel, Icing Research Tunnel, National Full-Scale Aerodynamics Complex, 7- by 10-Ft Wind Tunnel, Rotor Test Cell, Landing and Impact Research facility, Compressor Test Facility, Drive System Test Facilities, Transonic Turbine Blade Cascade Facility, Vertical Motion Simulator, Mobile Acoustic Facility, Exterior Effects Synthesis and Simulation Lab, and the NASA Advanced Supercomputing Complex. To learn more about the RVLT Project, please stop by booth #1004 or visit their website at https://www.nasa.gov/aeroresearch/programs/aavp/rvlt.
    Keywords: Aeronautics (General)
    Type: ARC-E-DAA-TN52390 , AHS Annual Forum and Technology Display; May 14, 2018 - May 17, 2018; Phoenix, AZ; United States
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