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

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At least 55 records · Page 3

Radiated Emissions from a Remote-Controlled Airplane-Measured in a Reverberation Chamber

A full-vehicle, subscale all-electric model airplane was tested for radiated emissions, using a reverberation chamber. The mission of the NASA model airplane is to test in-flight airframe damage diagnosis and battery prognosis algorithms, and provide experimental data for other aviation safety research. Subscale model airplanes are economical experimental tools, but assembling their systems from hobbyist and low-cost components may lead to unforseen electromagnetic compatibility problems. This report provides a guide for accommodating the on-board radio systems, so that all model airplane systems may be operated during radiated emission testing. Radiated emission data are provided for on-board systems being operated separately and together, so that potential interferors can be isolated and mitigated. The report concludes with recommendations for EMI/EMC best practices for subscale model airplanes and airships used for research.

Ely, Jay J.↗

Development of a Maxwell X-57 High Lift Motor Reference Design

NASA's all-electric X-57 airplane will utilize 14 electric motors, of which 12 are exclusively for lift augmentation during takeoff and landing. This report covers the design and development process taken to create an open reference model representative of the 12 lift augmenting motors. A combined worst case scenario was used as the design point, which represents the simultaneously occurring worst case aspects of thermal, static stress, electromagnetic, and rotor dynamic conditions. This work also highlights the tightly coupled nature of aerospace electric motor design, requiring constant iteration between all disciplines involved. Further adding to the uniqueness is the cooling method, which is limited to nacelle skin forced convection cooling only, no internal air flow is permitted. The stator outer diameter limit of 156.45 mm greatly impacts the degree of coupling between the electromagnetic design with the thermal analysis. The permanent magnet synchronous motor developed here operates between 385 V and 538 V, at a peak current of 50 A. Detailed electromagnetic, thermal, static load, and rotordynamic analysis was completed for this electric motor; all of which are required for a full design. The rotordynamic analysis took into consideration the motor housing which is designed specifically for this motor. The final electric motor has a mass of 2.34 kg, produces 24.1 Nm of torque with a specific power of 5.56 kW/kg, and has an efficiency of 96.61% at the combined worst case design point.

Electric Aircraft↗

Subsonic Ultra Green Aircraft Research: Phase 2: Hybrid Electric Design Exploration - Volume 2

This report summarizes the hybrid electric concept design, analysis, and modeling work accomplished by the Boeing Subsonic Ultra Green Aircraft Research (SUGAR) team, consisting of Boeing Research and Technology, Boeing Commercial Airplanes, General Electric, and Georgia Tech.Performance and sizing tasks were conducted for hybrid electric versions of a conventional tube-and-wing aircraft and a hybrid wing body. The high wing Truss Braced Wing (TBW) SUGAR Volt was updated based on results from the TBW work (documented separately) and new engine performance models. Energy cost and acoustic analyses were conducted and technology roadmaps were updated for hybrid electric and battery technology. NOx emissions were calculated for landing and takeoff (LTO) and cruise. NPSS models were developed for hybrid electric components and tested using an integrated analysis of superconducting and non-superconducting hybrid electric engines. The hybrid electric SUGAR Volt was shown to produce significant emissions and fuel burn reductions beyond those achieved by the conventionally powered SUGAR High and was able to meet the NASA goals for fuel burn. Total energy utilization was not decreased but reduced energy cost can be achieved for some scenarios. The team was not able to identify a technology development path to meet NASA's noise goals

Bradley, Marty K.↗

X-57 Maxwell NASA’s First Electric X-Plane

NASA’s first all-electric experimental airplane! Some primary goals the X-57 has include reducing the energy required in flight; Use existing state-of-the-art technology; Learn about the integration challenges of electric aircraft.

Electric aircraft motor↗

Fuel-Cell-Powered Electric Motor Drive Analyzed for a Large Airplane

Because of its high efficiency, fuel cell technology may be used to launch a new generation of more-electric aeropropulsion and power systems for future aircraft. Electric-motor-driven airplanes using fuel-cell powerplants would be beneficial to the environment because of fuel savings, low noise, and zero carbon-dioxide emissions. In spite of the fuel cell s efficiency benefit, to produce the same shaft drive power, a fuel cell- powered electric-drive system must be definitely heavier than a turbine-drive system. However, the fuel-cell system s overall efficiency from fuel-to-shaft power is higher than for a turbine-drive system. This means that the fuel consumption rate could be lower than for a conventional system. For heavier, fuel-laden planes for longer flights, we might achieve substantial fuel savings. In the airplane industry, in fact, an efficiency gain of even a few percentage points can make a major economic difference in operating costs.

Brown, Gerald V.↗

Hybrid Solid Oxide Fuel Cell/Gas Turbine Model Development for Electric Aviation

A thermodynamic model was developed and validated to analyze a high-performance solid oxide fuel cell and gas turbine (SOFC-GT) hybrid power system for electric aviation. This study used a process simulation software package (ProMax) to study the role of SOFC design and operation on the feasibility and performance of the hybrid system. Standard modules, including compressor, turbine, heat exchanger, reforming reactor, and combustor were used from the ProMax tool suite while a custom module was created to simulate the SOFC stack. The model used an SOFC test data set as an input. Additional SOFC stack performance effects, such as pressure, temperature, and utilization of air and fuel, were added from open source data. System performance predictors were SOFC specific power, fuel-to-electricity conversion efficiency, and hybrid system efficiency. Using these input data and predictors, a static thermodynamic performance model was created that can be modified for different system configurations and operating conditions. Prior to creating the final aircraft performance model, initial demonstration models were developed to validate output results. We used the NASA SOFC model as a benchmark, which was created with their Numerical Propulsion System Simulator (NPSS) software framework. Our output results matched within 1% of both the NASA model and open source SOFC performance data. With confidence gained in the accuracy of this model, a 1-MW SOFC-GT hybrid power system was constructed for an aircraft propulsion concept. Overall hybrid system efficiencies of > 75% FTE were observed during standard 36,000 feet cruise flight conditions.

30 DIRECT ENERGY CONVERSION↗

Flight study of a vehicle operational status and monitoring system

An analog onboard monitoring system was installed on a YF-12 airplane as the first phase of a program to monitor the engine inlet and portions of the airplane's electrical and fuel management subsystems in flight. The system provided data which were considered to form a suitable base for diagnostic test logic and decision criteria for the rest of the program. The data were also adequate for the purpose of maintaining the engine inlet and identifying malfunctions within it. The investigation showed that the requirements of an onboard monitoring system should be considered during the original design of the system to be monitored.

Love, J. E.↗

Subsonic Ultra Green Aircraft Research

This Final Report summarizes the work accomplished by the Boeing Subsonic Ultra Green Aircraft Research (SUGAR) team in Phase 1, which includes the time period of October 2008 through March 2010. The team consisted of Boeing Research and Technology, Boeing Commercial Airplanes, General Electric, and Georgia Tech. The team completed the development of a comprehensive future scenario for world-wide commercial aviation, selected baseline and advanced configurations for detailed study, generated technology suites for each configuration, conducted detailed performance analysis, calculated noise and emissions, assessed technology risks, and developed technology roadmaps. Five concepts were evaluated in detail: 2008 baseline, N+3 reference, N+3 high span strut braced wing, N+3 gas turbine battery electric concept, and N+3 hybrid wing body. A wide portfolio of technologies was identified to address the NASA N+3 goals. Significant improvements in air traffic management, aerodynamics, materials and structures, aircraft systems, propulsion, and acoustics are needed. Recommendations for Phase 2 concept and technology projects have been identified.

Bradley, Marty K.↗

Subsonic Ultra Green Aircraft Research Phase II: N+4 Advanced Concept Development

This final report documents the work of the Boeing Subsonic Ultra Green Aircraft Research (SUGAR) team on Task 1 of the Phase II effort. The team consisted of Boeing Research and Technology, Boeing Commercial Airplanes, General Electric, and Georgia Tech. Using a quantitative workshop process, the following technologies, appropriate to aircraft operational in the N+4 2040 timeframe, were identified: Liquefied Natural Gas (LNG), Hydrogen, fuel cell hybrids, battery electric hybrids, Low Energy Nuclear (LENR), boundary layer ingestion propulsion (BLI), unducted fans and advanced propellers, and combinations. Technology development plans were developed.

Bradley, Marty K.↗

Reducing Size, Weight, and Power (SWaP) of Perception Systems in Small Autonomous Aerial Systems

The objectives are to examine recent trends in the reduction of size, weight, and power (SWaP) requirements of sensor systems for environmental perception and to explore new technology that may overcome limitations in current systems. Improving perception systems to facilitate situation awareness is critical in the move to introduce increasing autonomy in aerial systems. Whether the autonomy is in the current state-of-the-art of increasing automation or is enabling cognitive decisions that facilitate adaptive behavior, collection of environmental information and fusion of that information into knowledge that can direct actuation is imperative to decisions resulting in appropriate behavior. Artificial sensory systems such as cameras, radar, LIDAR, and acoustic sensors have been in use on aircraft for many years but, due to the large size and weight of the airplane and electrical power made available through powerful engines, the SWaP requirements of these sensors was inconsequential. With the proliferation of Remote Piloted Vehicles (RPV), the trend is in significant reduction in SWaP of the vehicles. This requires at least an equivalent reduction in SWaP for the sensory systems. A survey of some currently available sensor systems and changing technology will reveal the trend toward reduction of SWaP of these systems and will predict future reductions. A new technology will be introduced that provides an example of a desirable new trend. A new device replaces multiple conventional sensory devices facilitating synchronization, localization, altimetry, collision avoidance, terrain mapping, and data communication in a single integrated, small form-factor, extremely lightweight, and low power device that it is practical for integration into small autonomous vehicles and can facilitate cooperative behavior. The technology is based on Ultra WideBand (UWB) radio using short pulses of energy rather than continuous sine waves. The characteristics of UWB yield several desirable characteristics to facilitate integration of perception for autonomous activities. The capabilities of this device and its limitations will be assessed.

Jones, Kennie H.↗

Subsonic Ultra Green Aircraft Research: Truss Braced Wing Design Exploration - Phase II - Volume I

This report summarizes the Truss Braced Wing (TBW) work accomplished by the Boeing Subsonic Ultra Green Aircraft Research (SUGAR) team, consisting of Boeing Research and Technology, Boeing Commercial Airplanes, General Electric, Georgia Tech, Virginia Tech, NextGen Aeronautics, and Microcraft. A multi-disciplinary optimization (MDO) environment defined the geometry that was further refined for the updated SUGAR High TBW configuration. Airfoil shapes were tested in the NASA TCT facility, and an aeroelastic model was tested in the NASA TDT facility. Flutter suppression was successfully demonstrated using control laws derived from test system ID data and analysis models. Aeroelastic impacts for the TBW design are manageable and smaller than assumed in Phase I. Flutter analysis of TBW designs need to include pre-load and large displacement non-linear effects to obtain a reasonable match to test data. With the updated performance and sizing, fuel burn and energy use is reduced by 54% compared to the SUGAR Free current technology Baseline (Goal 60%). Use of the unducted fan version of the engine reduces fuel burn and energy by 56% compared to the Baseline. Technology development roadmaps were updated, and an airport compatibility analysis established feasibility of a folding wing aircraft at existing airports.

Bradley, Marty K.↗

Propulsion Powertrain Real-Time Simulation Using Hardware-in-the-Loop (HIL) for Aircraft Electric Propulsion System

It is essential to design a propulsion powertrain real-time simulator using the hardware-in-the-loop (HIL) system that emulates an electrified aircraft propulsion (EAP) systems power grid. This simulator would enable us to facilitate in-depth understanding of the system principles, to validate system model analysis and performance prediction, and to demonstrate the proof-of-concept of the EAP electrical system. This paper describes how subscale electrical machines with their controllers can mimic the power components in an EAP powertrain. In particular, three powertrain emulations are presented to mimic 1) a gas turbo-=shaft engine driving a generator, consisting of two permanent magnet (PM) motors with brushless motor drives, coupled by a shaft, 2) a motor driving a propulsive fan, and 3) a turbo-shaft engine driven fan (turbofan engine) operation. As a first step towards the demonstration, experimental dynamic characterization of the two motor drive systems, coupled by a mechanical shaft, were performed. The previously developed analytical motor models1 were then replaced with the experimental motor models to perform the real-time demonstration in the predefined flight path profiles. This technique can convert the plain motor system into a unique EAP power grid emulator that enables rapid analysis and real-time simulation performance using hardware-in-the-loop (HIL).

turbo-electric propulsion↗

Energy Storage for NASA Missions

The presentation is a part of Invited Panel discussion at ARPA-E IONICS program review. It very briefly covers the following topics: 1) Energy storage key needs and challenges, particularly those facets that are distinct for NASA. 2) NASA efforts to address those needs and challenges. 3) Any key things perspective external partners should know if they want to support NASA.

batteries↗

X-57 Maxwell Airworthiness Validation Plan

This report is a Final Airworthiness Validation Plan (AVP) and describes how an aircraft like X-57 does (and does not) meet current airworthiness standards. The objective of this report is to create an example certification basis, associated means of compliance (MoC), and method of compliance for a distributed electric propulsion airplane under 14 Code of Federal Regulations (CFR) Part 21, “Certification Procedures for Products and Articles,” and its associated relevant sections of 14 CFR for “Airworthiness Standards” of Part 23, “Normal Category Airplanes,” Part 33 “Aircraft Engines,” and Part 35 “Propellers.” The approach to meet the objective is to use NASA’s X-57 Modification (Mod) IV flight demonstrator as an example and categorize its applicability to the regulations and standards according to the following three conditions: 1. Identify, where applicable, that the MoC and methods of compliance can be associated with existing Standard Specifications and Standard Practices of (ASTM) Committee F39 on Aircraft Systems and ASTM Committee F44 on General Aviation Aircraft; 2. If relevant ASTM standards do not exist, identify means and-or methods of compliance from appropriate Federal Aviation Administration (FAA) Advisory Circulars and other sources to use for the X-57 Mod IV vehicle; or 3. If no relevant certification rule, MoC, or method of compliance exists, highlight this omission and provide recommendations.

Herbert W Schlickenmaier↗

X-57 Flight Systems Integration Path

The foundation for a safe and successful flight test of the National Aeronautics and Space Administration (NASA) X-57 Maxwell all-electric experimental airplane, or any X-Plane, is comprehensive system testing on the ground. This test campaign includes verification and validation (V&V) that the integrated system operates as designed and expected, as well as understanding how the system reacts and responds to failures that can occur during flight by performing failure modes and effects testing (FMET). The aircraft should be in the final flight configuration for these test activities because any modifications, even those that appear insignificant, could affect test outcomes. Although the plan was to perform V&V and FMET testing once the airplane was in the flight configuration, due to multiple component redesigns, concurrent software development, and other problems with on-aircraft testing, the X-57 Maxwell never made it into a full-flight configuration. As a result, a build-up approach was followed to test software and hardware as they became ready in order to continue making progress wherever possible. Using this approach revealed problems with the hardware and software faster than waiting for a full-flight configuration, allowing solutions to be found more quickly and in parallel with other project tasks. Other than unloaded motor testing in a lab setting, the only other test setup was on the airplane itself. On-aircraft testing was preferrable in order to test things as close to a flight configuration as possible but was time consuming due to the requirements for testing on the airplane. To overcome some of the on-aircraft barriers, off-aircraft test configurations, such as the Systems Integration Laboratory (SIL) and hardware-in-the-loop (HIL) setups, were used, but each of these setups had limitations to be considered. As a result, solutions found in the SIL or HIL configurations did not always work as expected on the airplane, resulting in an iterative process between on- and off-aircraft testing to find the final solution. Having a dedicated test platform such as an iron bird that closely represents the aircraft - without flight hardware - would have been the most effective off-aircraft test setup, which could have allowed the project to save time and money and potentially reach flight. This paper will highlight the V&V and FMET considerations and testing prerequisites, the build-up approaches to both software and system testing, the benefits and drawbacks to different test configurations, as well as battery testing and operations.

Kassidy M. Mclaughlin↗

X-57 Flight Systems Integration Path

The foundation for a safe and successful flight test of the National Aeronautics and Space Administration (NASA) X-57 Maxwell all-electric experimental airplane, or any X-Plane, is comprehensive system testing on the ground. This test campaign includes verification and validation (V&V) that the integrated system operates as designed and expected, as well as understanding how the system reacts and responds to failures that can occur during flight by performing failure modes and effects testing (FMET). The aircraft should be in the final flight configuration for these test activities because any modifications, even those that appear insignificant, could affect test outcomes. Although the plan was to perform V&V and FMET testing once the airplane was in the flight configuration, due to multiple component redesigns, concurrent software development, and other problems with on-aircraft testing, the X-57 Maxwell never made it into a full-flight configuration. As a result, a build-up approach was followed to test software and hardware as they became ready in order to continue making progress wherever possible. Using this approach revealed problems with the hardware and software faster than waiting for a full-flight configuration, allowing solutions to be found more quickly and in parallel with other project tasks. Other than unloaded motor testing in a lab setting, the only other test setup was on the airplane itself. On-aircraft testing was preferrable in order to test things as close to a flight configuration as possible but was time consuming due to the requirements for testing on the airplane. To overcome some of the on-aircraft barriers, off-aircraft test configurations, such as the Systems Integration Laboratory (SIL) and hardware-in-the-loop (HIL) setups, were used, but each of these setups had limitations to be considered. As a result, solutions found in the SIL or HIL configurations did not always work as expected on the airplane, resulting in an iterative process between on- and off-aircraft testing to find the final solution. Having a dedicated test platform such as an iron bird that closely represents the aircraft - without flight hardware - would have been the most effective off-aircraft test setup, which could have allowed the project to save time and money and potentially reach flight. This paper will highlight the V&V and FMET considerations and testing prerequisites, the build-up approaches to both software and system testing, the benefits and drawbacks to different test configurations, as well as battery testing and operations.

Kassidy McLaughlin↗

In situ measurements of thunderstorm electrical properties

An airplane sensor to measure the charge, size and two dimensional shape of precipitation particles and large cloud particles was developed. The basic design of the instrument includes: the transducers and analog electronics, the analog to digital conversion electronics and a microprocessor based system to run the electronics and load the digital data onto magnetic tape. Prototype instrumentation for the proposed lightning mapper satellite was tested by flying it in a U-2 aircraft over severe storms in Oklahoma. Flight data are compared to data from ground based instruments.

Marshall, T. C.↗

Nighttime observations of thunderstorm electrical activity from a high altitude airplane

Nocturnal thunderstorms were observed from above and features of cloud structure and lightning which are not generally visible from the ground are discussed. Most, lightning activity seems to be associated with clouds with strong convective cauliflower tops. In both of the storms lightning channels were visible in the clear air above the cloud. It is shown that substances produced by thunderstorm electrical discharges can be introduced directly into the stratosphere. The cause and nature of the discharges above the cloud are not clear. They may be produced by accumulations of space charge in the clear air above the cloud. The discharges may arise solely because of the intense electric fields produced by charges within the cloud. In the latter case the ions introduced by these discharges will increase the electrical conductivity of the air above the cloud and increase the conduction current that flows from the cloud to the electrosphere. More quantitative data at higher resolution may show significant spectral differences between cloud to ground and intracloud strokes. It is shown that electric field change data taken with an electric field change meter mounted in an airplane provide data on lightning discharges from above that are quite similar to those obtained from the ground in the past. The optical signals from dart leaders, from return strokes, and from continuing currents are recognizable, can be used to provide information on the fine structure of lightning, and can be used to distinguish between cloud to ground and intracloud flashes.

Brook, M.↗