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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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All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Experimental Studies of Open Rotor Installation Effects

Open rotor propulsion technologies offer an opportunity for reducing fuel burn. At the same time, great challenges arise from this radically different engine architecture in terms of aircraft system integration. The aeroacoustic effects of integration are one of those key challenges and, furthermore, can offer the possibility for total aircraft system noise reduction. The inter-relationship of the aerodynamic and aeroacoustic system integration effects is particularly important to enable future application. An extensive model scale test campaign was conducted to investigate a broad range of these open rotor installation effects for both a conventional and an unconventional airframe. The experimental campaign was conducted in the Boeing Low Speed Aeroacoustic Facility with specially designed modifications for efficient positioning of the open rotor rig relative to the airframe. The airframe was traversed remotely relative to the fixed open rotor rig providing for the investigation of a large number of installation positions. Eight positions around the main wing of the conventional airframe and eleven positions above the hybrid wing body airframe were documented. Other parameters investigated in the test campaign included forward flight simulation Mach number, angle of attack, rotor speed, and airframe control surface deployment. In addition, both airframes were modified for alternate configurations. The conventional airframe was configured with both a T and a U tail while the unconventional hybrid wing body airframe was configured with different vertical control surfaces. An extensive instrumentation package was deployed. The acoustics were documented with a fixed array of far field microphones, a traversing array of in-flow microphones, an out-of-flow traversing phased array, and unsteady pressure transducers mounted flush on the surface of the airframes. In addition, mean flow surveys were measured with an articulating arm traversing system. The flow field surveys were particularly valuable in documenting flow distortion effects for the various installation positions and those created by angle of attack. This presentation will report the key results obtained for open rotor installation effects and discuss future prospects with the perspective of these results.

Michael J Czech↗
NASA NTRS1993

Design aspects in small aircraft gas turbine fuel injectors

The causes of fuel injector spray deterioration and the effects of this deterioration on engine durability and performance are discussed. Small aircraft gas turbine fuel injectors present special design challenges due to low fuel flow rates involved and the physical size limitations. The principal fuel injector performance requirements are discussed in relation to their effect on the hydraulic, aerodynamic, and thermal design of aerating fuel injectors.

K Mccaldon↗
NASA NTRS2026

Assessment of Aircraft Electric Engine Regulatory Special Conditions

This report provides a regulatory gap assessment of the Federal Aviation Administration (FAA) and the European Union Aviation Safety Agency (EASA) Special Conditions (SC) for electric engines. This information is presented to support ongoing international harmonization efforts for electric engine certification, to establish a level of safety consistent across regulatory bodies and equivalent to that of existing combustion engines. HS Advanced Concepts LLC assembled a team of subject-matter experts to develop a comprehensive comparison of the regulatory text of EASA SC E-19 and the FAA special conditions for the certification of electric engines. The team included Mr. Chris Baczynski of BAC Aerospace Inc. and Mr. Zach Kaufman, formerly with magniX.

aircraft certification↗
NASA NTRSDate not supplied

Battery Cell-to-Pack Scaling Laws for Electric Aircraft

Battery pack gravimetric energy density is one of the most important, yet often miss-estimated design parameters for sizing all-electric aircraft. Proper accounting for thermal, structural, and operational safety margins are frequently lost when extrapolating performance from the cell level to the aircraft level. This paper summarizes the relevant engineering and certification details needed to better account for the penalties associated when assembling battery packs. The relationship between the cell and pack energy density is not linear, as is often assumed. Furthermore, the relationship varies depending on pack requirements, cell chemistry, and architecture. Parametric, high-fidelity models are used to determine optimal battery pack sizes over a range of conditions to better quantify technology scaling effects.

Battery Electric Aircraft↗
NASA NTRSDate not supplied

Battery Cell-to-Pack Scaling Trends for Electric Aircraft

Battery pack gravimetric energy density is one of the most important, yet often miss- estimated design parameters for sizing all-electric aircraft. Proper accounting for thermal, structural, and operational safety margins are frequently lost when extrapolating performance from the cell level to the aircraft level. This paper summarizes the relevant engineering and certification details needed to better account for the penalties associated when assembling battery packs. The relationship between the cell and pack energy density is not linear, as is often assumed. Furthermore, the relationship varies depending on pack requirements, cell chemistry, and architecture. Parametric, high-fidelity models are used to determine optimal battery pack sizes over a range of conditions to better quantify technology scaling effects.

Battery Electric Aircraft↗
NASA NTRS1976

NASA's Advanced Control Law Program for the F-8 Digital Fly-By-Wire Aircraft

This paper briefly describes the NASA F-8 Digital Fly-By-Wire (DFBW) program and Langley Research Center's role in investigating and promoting advanced control laws for possible flight experimentation. The primary purpose of the paper is to provide background material for papers describing some of the F-8 DFBW adaptive control law studies. The paper provides a brief description of the Phase II DFBW F-8 aircraft and its control system, discusses some of the advanced control law study objectives and guidelines, and provides some mathematical models which are useful in the control analysis problem.

Optimal Control↗
NASA NTRS1977

NASA's Advanced Control Law Program for the F-8 Digital Fly-By-Wire Aircraft

This paper briefly describes the NASA F-8 Digital Fly-By-Wire (DFBW) and Langley Research Center's role in investigating and promoting advanced control laws for possible flight experimentation. The primary purpose of the paper is to provide background material for the papers that follow which describe some of the F-8 DFBW adaptive control law studies. The paper provides a brief description of the Phase II DFBW F-8 aircraft and its control system, discusses some of the advanced control law study objectives and guidelines, and provides some mathematical models which are useful in the control analysis problem.

Aerospace Materials↗
NASA NTRS1968

Advances in Tactical Rocket Propulsion

An AGARD Colloquium on 'Progress in Tactical Rocket Propulsion' was held at La Jolla, California, on April 22 and 23, 1965. The unclassified papers, or unclassified versions of classified papers, presented at this meeting form the contents of the present AGARD conference proceedings, which has been identified by a new title that reflects more properly the scope of the remaining technical papers. The articles contained in this volume represent significant evaluations of the status of solid-propellant, liquid-propellant and hybrid-propellant rocket development. Together with the reviews, they should provide a useful reference source for research workers and students alike.

S S Penner↗
NASA NTRSDate not supplied

Impact of Technology and Mission Variations on Aircraft Designed for Advanced Air Mobiity

NASA is conducting investigations in Advanced Air Mobility (AAM) aircraft and operations, including the development of Urban Air Mobility (UAM) aircraft designs that can be used to focus and guide research activities in support of AAM. This report is an investigation of the impact of technology and mission variations on several of the NASA AAM concept aircraft: quadrotor, quiet single main rotor, side-by-side, and tiltrotor configurations, with turboshaft and electric propulsion variants for each. First, the mission and aircraft models of the baseline designs were reassessed and updated, including rotor geometry optimization, update of the rotor performance models, and disk loading optimization. For these eight designs, technology and mission excursions were performed. Relative to the calibration cases that can be considered examples of good design practice, the impact of the weight technology factors is significant. For the electric aircraft, there is a very large impact of battery specific energy (Wh/kg), and correspondingly a very large impact of mission range. The vision of Advanced Air Mobility is driven by missions that will enable new transportation capabilities. Hence it is appropriate to compare Concept Vehicles of different lift and propulsive architectures, all designed to accomplish the same UAM mission. It is also useful however to consider specific missions that can take advantage of the strengths of individual aircraft configurations. So alternate designs were also developed for the concept vehicles: for turboshaft aircraft, longer unrefueled range, including faster cruise speed for the tiltrotor; for electric aircraft, shorter range and more realistic battery weight.

Technology↗
NASA NTRSDate not supplied

Conclusions of a Cryogenic Motor Configuration Study for Aircraft Propulsion

Cryogenic electric machines are a promising technology for multi megawatt electric aircraft drivetrains. Superconducting stators that make use of low AC loss superconducting wires are considered to be a key component for these cryogenic machines. This paper shares the lessons learned from a design study that evaluated several configurations of a 5 MW cryogenic motor for this application. The lessons are drawn from a qualitative study of 16 configurations and a quantitative study of 8 down selected configurations. The quantitative study involved using analytical calculations (electromagnetic, thermofluid, mechanical, and motor sizing) to determine each configuration’s Pareto front of total efficiency and total specific power. The conclusions from a preliminary assessment of different stator conductors (superconductors and cryogenic metals) are also presented. One motor configuration is down selected for future detailed design and demonstration at the multi megawatt level.

Electrified aircraft propulsion↗
NASA NTRS2026

Center for High-Efficiency Electrical Technologies for Aircraft: Phase I Final Report

Under the University Leadership Initiative (ULI), the Center for High-Efficiency for Electrical Technologies (CHEETA) was established to develop and mature early-stage technologies pertaining to hydrogen-electric power and energy systems for aircraft. In particular, integration of these technologies on an aircraft system is envisioned to leverage the high specific energy content of liquid hydrogen (LH2) with fuel cell energy conversion and an electrically driven ducted fan system to provide an ultra-efficient propulsion drivetrain. For this concept, the LH2 system is not just used as an energy storage mechanism, but also as a cryogen to enable highly efficient superconducting electric systems. The end result of this concept is an integrated aircraft system with a quiet, efficient propulsion architecture that produces zero CO2, NOx, SOx, and particulate matter emissions at the vehicle level.

Hydrogen↗