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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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223 records · Page 13

NASA AREAL Testbed and UE Power Quality Testing

A large number of electrified aircraft propulsion systems currently in development consist of high-voltage direct current (HVDC) power systems and utilization equipment (UE). There is a need for industry consensus standards and guidelines in order to support the development and verification of these rapidly maturing systems, user equipment, and associated technologies. To support the aforementioned need, the National Aeronautics and Space Administration (NASA) Revolutionary Vertical Lift Technology (RVLT) Project is performing ongoing power quality testing on HVDC power systems and associated UE. The testing described in this paper describes the UE testing completed to date in the NASA Advanced Reconfigurable Electrified Aircraft Lab (AREAL).

electrified aircraft↗

Development of Candidate Airspace Procedures for Urban Air Mobility in the Dallas Area

As the concept of on-demand electric air taxis gains popularity and begins to take shape, many research efforts are underway to address the challenges of integrating this new class of passenger-carrying air vehicles into the already congested U.S. National Airspace System. Through collaborations between the National Aeronautics and Space Administration (NASA), the Federal Aviation Administration, and industry, this concept, commonly referred to as Urban Air Mobility (UAM), envisions a safe, reliable, and efficient mode of transportation traversing metropolitan and urban areas. Among the many challenges being tackled, airspace procedures and information requirements are critical areas of research that need to be addressed. In a joint effort between NASA and Joby Aviation, a human-in-the-loop study was conducted at the NASA Ames Research Center to evaluate initial and midterm operations with air traffic controllers and on-board UAM pilots in the Dallas area. This area was chosen due to its complex Class Bravo Airspace that extends to the surface over a relatively large area. To achieve the goals and objectives of the study, multiple preceding efforts were conducted to develop the candidate procedures and information requirements. This paper provides an overview of the operational concept used for the study, the process that was followed, and the findings from the two tabletop meetings and a shakedown activity. The combination of these led to a set of airspace procedures, letters of agreement, and information requirements that were evaluated in the human-inthe-loop study.

Urban Air Mobility↗

High Level Architecture (HLA) as a Research Tool for Advanced Air Mobility (AAM)

In this document, a NASA investigation into the High-Level Architecture (HLA) standard for distributed simulation as a means of furthering Advanced Air Mobility (AAM) research is illustrated along with a description of the evolution of distributed simulation leading to the HLA standard. HLA enables efficient definition and insertion of components and participants in simulation sessions. Novel concepts can be added or removed as the work evolves. A general history of the HLA standard is described to show past needs for improved methods of distributed simulation, particularly among participating laboratories in separate locations, as well as previous applications of HLA simulation to airspace research. These examples from the past illustrate how new and emerging concepts can be simulated by layering notional ideas over simulated current-day systems and capabilities in a controlled environment for examination. In the 1990s, the Federal Aviation Administration (FAA) and the MITRE Corporation performed joint research into then-emergent capabilities in the National Airspace System (NAS). In the early 2000s, the MITRE Corporation developed an open, extendable set of objects and protocols designed for global and collaborative aviation research called AviationSimNet, which has HLA as its foundation. This led to NASA and the FAA using AviationSimNet to connect laboratories for AAM research, resulting in the NASA/FAA Laboratory Integrated Test Environment (NFLITE). The underlying capabilities of HLA enabled testing a notional interaction between AAM and legacy ATC systems that resulted in AAM vehicles receiving beacon codes for identification on ATC screens in Class C airspace. The potential next steps in this work include defining and examining notional interactions between AAM and legacy ATC systems within Class B airspace.

UAM↗

Aerodynamic Performance and Acoustic Impacts of Varying Tip Speeds and Tripping Conditions on Small Rotors in an Anechoic Hover Chamber

Performance and acoustic measurements were taken in a hover chamber for various optimum hovering rotors (OPT2) and a commercial-off-the-shelf (COTS) rotor. A total of 10 rotors are included in this report, all of which have two blades and a tip radius of 0.1905 m (7.5 in.). For the OPT2, results for three additive manufacturing methods of fabrication are presented: stereolithography(SLA) using Accura Xtreme, SLA using FormLabs 10K resin, and selective laser sintering (SLS) using mineral-filled PA12 nylon material. All but one set of rotors were designed with a trailing edge bluntness that is 3% of the chord length, and one set was designed with a bluntness that is 1% of the chord length. Spanwise boundary layer trips were applied to the SLA, FormLabs and COTS rotors. Performance comparisons between untripped and tripped configurations demonstrate the impact of boundary layer state on rotor efficiency. Acoustic results, including periodic and broadband noise components, are presented. The effects of tripping these rotors near the leading edge are also presented. For some of the rotors, acoustic spectra of tip speed sweeps are presented to show how the frequency content changes with tip speed. Amplitude and frequency scaling methods are used to collapse broadband spectra at various tip speeds towards a unified curve. These findings contribute to the understanding of small rotor aeroacoustics and provide valuable datasets for computational model validation in urban air mobility applications.

eVTOL↗