Electric Aircraft Research Articles

Evaluating the Eco‐Efficiency of Urban Air Mobility: Understanding Environmental and Social Impacts for Informed Passenger Choices

AbstractFull electric aircraft with zero CO2 emissions during operations are a promising pathway towards achieving the Fly Net Zero by 2050 goal proposed by the International Air Transport Association (IATA). In this context, Urban Air Mobility (UAM) expects to offer an environmentally friendly alternative through electric Vertical Takeoff and Landing (eVTOL) aircraft. While eVTOLs produce no greenhouse gas emissions, the comprehensive eco‐efficiency of UAM goes beyond the flight phase. This paper delves into evaluating UAM operation's environmental and social impacts, considering the urban space, public perception, operational profiles, and power consumption. Employing causal loop analysis, the study uncovers the relationships that add value or increase impact, assessing UAM passenger transportation's eco‐efficiency. Moreover, the Unified Architecture Framework is used to model the UAM ecosystem and to propose strategies to balance values and impacts in achieving eco‐efficiency. By shedding light on the sustainability viewpoint, this study emphasizes the importance of holistically understanding UAM's operational impact and empowering users to make eco‐efficient choices when opting for UAM transportation. Finally, strategies to provide sustainability awareness to the user are discussed in the Mobility‐as‐a‐System (MaaS) context.

Fast as a plane, clean as a train? Prospective life cycle assessment of a hyperloop system

Today, options to reduce the climate impacts of high-speed passenger transport over hundreds of kilometres are limited to using low-carbon synthetic fuels in aviation and high-speed trains. In the future, alternatives like battery electric airplanes might be available. Further, vehicles operating in near-vacuum tubes, so-called “hyperloop systems”, could represent an alternative. Our first-of-its-kind environmental life cycle assessment (LCA), considering its construction, operation, and end-of-life, shows that such a hyperloop system is energy-efficient and can exhibit very low greenhouse gas emissions (<8 g CO2/pkm) if low-carbon sources provide electricity for its operation and relatively high occupation rates can be realised. The environmental performance of a hyperloop system can be regarded as very similar to that of a train offering the same transport service. Compared to air travel, environmental burdens can be substantially reduced (<5% impact on climate change compared to conventional aircraft). This fundamental finding holds despite uncertainties regarding technical properties and design choices, which reflect the current development status of the hyperloop.

Quasi-three-dimensional high-lift wing design approach considering three-dimensional effects of slipstream for distributed electric propulsion aircraft

The efficient utilization of propeller slipstream energy is important for improving the ultra-short takeoff and landing capability of Distributed Electric Propulsion (DEP) aircraft. This paper presents a quasi-three-dimensional (2.5D) high-lift wing design approach considering the three-dimensional (3D) effects of slipstream for DEP aircraft, aiming at maximizing the comprehensive lift enhancement benefit of the airframe-propulsion coupling unit. A high-precision and efficient momentum source method is adopted to simulate the slipstream effects, and the distributed propellers are replaced by a rectangular actuator disk to reduce the difficulty of grid generation and improve the grid quality. A detailed comparison of the 2.5D and 3D configurations based on the X-57 Mod Ⅳ is performed in terms of flow characteristics and computational cost to demonstrate the rationality of the above design approach. The optimization results of the high-lift wing of the X-57 Mod Ⅳ show that the aerodynamic performance of the landing configuration is significantly improved, for instance, the lift coefficient increases by 0.094 at the angle of attack of 7°, and 0.097 at the angle of attack of 14°. This novel approach achieves efficient and effective design of high-lift wings under the influence of distributed slipstream, which has the potential to improve the design level of DEP aircraft.

Development of on-board power systems and the concept of a more electric aircraft

The article reviews the main stages of development of aircraft power systems. The basic features of the power node for the Mi-24 combat helicopter, a multi-tasking aircraft, are presented F-22 and the Boeing B-787 passenger airplane. The results of the analysis of methods for managing the distribution of electricity on both conventional aircraft and the most modern aircraft structures (A-380, B-787) are presented. The basic structures of the aircraft's on-board power network are presented, divided into three periods: the period until the 1960s (with the dominance of the direct current network with a voltage of 28.5 V), the period until 2000 (with the dominance of the three-phase alternating current network with a voltage of 3 x 115 V / 200 V, 400 Hz) and the most recent period, after 2000 (dominated by a 270 V direct current network, obtained by converting the voltage from a three-phase alternating current generator 3x 115 V / 200 V, 400 Hz using a transformer-rectifier block). The concept of a more electric aircraft was presented as the main direction of current construction works for MEA concept (More Electric Aircraft).

Low-velocity impact response optimization of the foam-cored sandwich panels with CFRP skins for electric aircraft fuselage skin application

Abstract Composite sandwich structures are widely used in the aerospace field due to their advantages of high strength, lightweight, and fatigue resistance. However, these structures are prone to damage with very-low-energy impacts. In order to improve the impact resistance of aircraft skin structure, a low-velocity impact resistance of sandwich structure specimens was tested by means of drop hammer impact, and the impact damage area was scanned by ultrasonic C-scan, and obtains the impact damage of specimens with different impact energies and different ply sequences. Combined with the Hashin failure criterion, the finite element equivalent model of composite sandwich structure under low-velocity impact was established. The errors between the simulation results and the C-scan results of the test piece were less than 10%, in which the experimental measurements and numerical predictions were in close agreement. Finally, the finite element equivalent model was applied to optimize the application of model sandwich, which was used for fuselage skin of a certain electric aircraft. The total thickness of the laminate structure remains unchanged before and after optimization, but the impact resistance was significantly enhanced. The ±45° lay-up was beneficial for the structure to absorb the impact energy.

Full Electric Aircraft and The Electrical Motors of The Propulsion Systems

Full Electric Aircraft and The Electrical Motors of The Propulsion Systems

Adaptive fault-tolerant control of distributed electric propulsion aircraft based on multivariable model predictive control

Distributed Electric Propulsion (DEP) aircraft presents a highly promising technology aligned with the demands of green aviation due to its superior flight efficiency, reduced energy loss, and diminished noise. This paper firstly designs and establishes a flight dynamics model for DEP aircraft, followed by an analysis of flying qualities, thus laying the foundation for control method design. Secondly, addressing the challenge of detecting subtle control surface faults, a deep learning fault diagnosis method based on Data Dimensionality Reduction (DDR) structure is devised, achieving an accuracy rate of 99.8 %. Finally, an adaptive fault-tolerant control method for the lateral motion mode of DEP aircraft is introduced, utilizing Constrained Multivariable-multiobjective Model Predictive Control (CMMPC). Notably, for the rudder complete fault, adaptive fault-tolerant control is achieved by switching controllers and utilizing differential thrust from distributed redundant propulsion units to mitigate yaw channel anomalies, thus showcasing the advantages of DEP aircraft. Simulation results validate the theoretical soundness of the proposed method, providing a theoretical basis for the future engineering application and advancement of control systems for DEP aircraft.

Multimodal transient topology optimization design of heat dissipation structure in electric aircraft power cabin

High power density electronic devices are widely installed in electric aircraft power cabin with finite space, which causes the heat to be dissipated difficultly. In this work, a multimodal transient topology optimization model based on the weight coefficient method is proposed to obtain a lightweight and efficient heat dissipation structure in electric aircraft power cabin. The proposed topology optimization model can consider all flight envelope including takeoff, cruise and landing processes. The effect of the topology weight coefficient on the heat dissipation capacity in all flight envelope is investigated. Results show that the heat dissipation efficiency of the topology optimization structure can be improved by 11.25%, 9.18%, and 11.27% in the takeoff, cruise and landing processes compared with that of the conventional heat dissipation structure, respectively. Increasing the topology weight coefficient by 6.67% can result in an 3.47% improvement in the heat dissipation efficiency during the takeoff and landing processes. The above findings can be used as a reference for the design of the lightweight and efficient heat dissipation structure in electric aircraft.

Mapping the hot stamping process through developing distinctive digital characteristics

Structural components produced through hot stamping of lightweight materials, such as aluminium alloys, play a pivotal role in mass reduction, leading to decreased CO2 emissions and enhanced fuel efficiency, especially in applications such as electric vehicles, high-speed trains, and aircraft. Concurrently, the hot stamping process is experiencing an exponential increase in data generation, stemming from ongoing production, research, and development activities. Yet, translating the inherent values of these voluminous metadata into scientific innovations and industrial breakthroughs requires the emerging expertise by consolidating the knowledge of hot stamping and data science. Here, the authors have conceptualised and developed the digital characteristics (DC) for manufacturing processes. The DC serves as the ‘DNA’ of every manufacturing process by encompassing its inherent and distinctive natures spanning over the design, manufacturing and application phases of the manufactured products. Focusing on the hot stamping process, the authors have developed the unique DC from voluminous hot stamping data derived from experimentally validated simulations and sensing networks. Results demonstrate that the DC revealed the distinct evolutionary thermo-mechanical characteristics of the hot stamping process in terms of representative geometric features, which facilitates the fundamental scientific understanding and unlocks the potential on implementing data-centric scientific innovations in advanced manufacturing paradigms.

Omics-enabled understanding of electric aircraft battery electrolytes

Omics-enabled understanding of electric aircraft battery electrolytes

Analysis of cooling structure of axial flux permanent-magnet synchronous motor for electric aircrafts

Analysis of cooling structure of axial flux permanent-magnet synchronous motor for electric aircrafts

Pathway to zero emissions in global tourism: opportunities, challenges, and implications

Human emissions must reach zero by 2050 to avoid dangerous climate change. Most sectors have achieved a downward path for their greenhouse gas emissions, but tourism’s emissions have continued to grow. We explore scenarios to reduce global tourism emissions and find only a narrow pathway to zero emissions tourism that could lead to net zero by 2050 while not severely damaging the tourism economy. Our study uses a system dynamics model. We describe the business-as-usual scenario, including its consequences for emissions and for tourism’s share of the remaining global carbon budgets if the world is to limit global temperature rise to 1.5 or 2 °C. We explore 45 possible policy approaches, like taxes and subsidies, infrastructure investments, off-sets, technology, behavioural changes, and sustainable aviation fuels. Key measures appear to be a mandate for e-fuel mixing up to 100% by 2050, and a multi-trillion USD investment in hydrogen-powered electric aircraft and high-speed rail infrastructure. We find that a limited renewable energy supply will constrain the growth of aviation if it is to be zero emissions in 2050. A risk-analysis explores the robustness of the policies. Finally, we discuss the consequences of the zero emissions tourism (ZET) scenario we propose.

Flight verification of cooling self-sustaining high-temperature superconducting motor

The global shift towards sustainable development and technological advancements has propelled the energy transition trend. Recognizing the substantial environmental impact of conventional commercial airplanes, there is a growing urgency to develop a sophisticated superconducting motor system for commercial aviation. The advent of high-temperature superconducting motors presents a transformative leap, offering significant advantages in power density and efficiency when compared to traditional motors. To validate the issues that future liquid-hydrogen superconducting electric airplanes may encounter, a kilowatt-class aerospace high-temperature superconducting motor is designed. Based on the requirements of airborne applications, critical parameters such as electromagnetic characteristics, operating characteristics, and AC losses have been analyzed. Furthermore, extensive research and testing have been conducted on the superconducting motor magnet, leading to the successful assembly of a prototype. The superconducting motor has a rated output power of 2.7 kW and a rated speed of 5000 rpm. Rigorous ground operation performance tests have also been conducted to ensure the feasibility and reliability of the motor in practical applications. Benefiting from the topological structure design, the superconducting motor has an excellent sealing performance at low temperatures. The superconducting motor can maintain low temperature and high vacuum for a long time, when the vacuum pump is removed and the liquid nitrogen inlet is closed after the motor is completely cooled. The culmination of these endeavors is the realization of a successful flight validation of an unmanned aerial vehicle equipped with a high-temperature superconducting motor, demonstrating a sustained flight of nearly one hour.

A Power availablE Estimation Tool for real‐time estimation in aircraft generators

AbstractA systematic definition of an aircraft generator's “available power” (used to supply loads on its DC bus) is given, which is defined in the context of constraints on transient and steady‐state performance. Using a geometric, data‐driven approach, such a characterisation has been achieved, and a new method, called Power availablE Estimation Tool (PEET), has been developed to determine in real‐time whether a given load can be fulfilled at a given time while maintaining power quality. This is an important problem, especially for safety critical electrical systems such as more electric aircraft, for which it is imperative to know a priori whether an added load will result in voltage variations outside of allowed values. PEET is introduced and its conceptual framework is formalised. Lastly, it provides simulation results that illustrate its performance. The results show that the PEET method produces reliable a priori estimates of power availability, and that this can be achieved within time frames that make it applicable in a real‐time implementation.

Effects on the design of aeronautical fuel cell systems by inclusion of reliability requirements

The change towards carbon neutrality in air traffic involves a huge reduction of greenhouse gas emissions. This goal is beyond reach by the step wise improvement of conventional technologies. Hence, at present a solution which gains much of attraction are electric motors and electric aircraft systems in combination with fuel cells which can be run by green hydrogen. For a holistic comparison of various concepts the consideration of reliability aspects is required even at an early stage of design. In the scope of this work methods from reliability and safety engineering will be introduced and set in context of aeronautical fuel cell systems. On that basis the consequences arising by the requirement of redundancy are investigated on a system level approach. For this purpose, a model of an aeronautical fuel cell system will be set up in order to simulate a generic flight envelope at stationary points. The fuel cell system is chosen to be central-monolithic and its components are sized for the propulsion of a regional aircraft. With the aid of the system simulation, various failure scenarios are investigated from which mitigation strategies can be derived. Finally, the baseline design will be improved in terms of redundancy in order to last in a generic failure scenario. A comparison between the baseline and improved design shows that the additional redundancy comes with the cost of 4.6% weight increase and a 2.5% drop in cruise efficiency.

Transient voltage performance and protection design of variable frequency ac three-stage generator for more electric aircraft

Abstract Nowadays, variable frequency AC generation system is widely used on more electric aircraft because of their advantages of simple structure, high power density, and high reliability. However, a variable frequency system has a wide range of operating speeds and frequencies, and its exciter field is designed to be highly saturated at low speed. Under the condition of a saturated exciter field at high speed, the generator can produce a very high voltage, which will cause damage to aircraft utilization equipment, leading to catastrophic failures. Therefore, to protect the safety of the aircraft, transient voltage regulation performance and voltage protection design are critical in the system design of variable frequency AC generation. This paper focuses on the design of voltage regulation and protection of variable frequency electrical power systems that can meet airworthiness requirements.

Dynamic modeling of a cantilever reed valve considering squeeze flow with experimental validation

Piezoelectric hydraulic pumps play a pivotal role in more electric aircraft and all-electric aircraft utilizing power-by-wire technology, owing to their high power density and reliability. The cantilever reed valve (CRV) serves as a crucial component within these pumps, and its dynamic behavior within the fluid directly impacts the pumps' output power. A precise mathematical model of the CRV is essential for understanding its motion mechanisms. However, existing models for the CRV inadequately capture its dynamics and fail to explain the observed motion phenomena. Further exploration into dynamic modeling of the CRV is warranted. This paper employs finite element analysis to investigate CRV's dynamics, revealing the significant impact of squeeze flow on CRV's dynamics and identifying the cause of slow closure. Based on this, a novel lumped parameter model incorporating squeeze force is proposed to accurately depict CRV's dynamics, particularly focusing on the phenomenon of slow closure. To validate the proposed model's accuracy, an experimental system capable of independently driving the CRV is constructed to eliminate interference resulting from integrating the CRV into the pumps. The results show that the dynamic response during closure, as predicted by the proposed model, is in good agreement with the outcomes from finite element analysis. Notably, the proposed model exhibits an 11.11% higher prediction accuracy for experimental closing times compared to the traditional model that neglects squeeze forces. This study offers guidance for optimizing CRV's dynamics and improving the performance of piezoelectric hydraulic pumps in future applications.

A Fault Protection Strategy Based on Z-Source Solid State Circuit Breaker for More Electric Aircraft

A Fault Protection Strategy Based on Z-Source Solid State Circuit Breaker for More Electric Aircraft

Green Horizons Ahead: Navigating Carbon Neutrality in European Transportation by Sky and Sea

Abstract Research purpose. As carbon neutrality gains momentum, industries worldwide are navigating the challenges and opportunities posed by sustainability goals. This article delves into the strategies undertaken by airlines and maritime companies to achieve carbon neutrality by 2050 in the European Union (EU). The aim of the research is to explore how the aviation and maritime industries in Europe can effectively transition towards carbon neutrality by 2050, considering their similar technological challenges and opportunities. The objective of this research was to identify and compare currently utilized sustainability initiatives in aviation and maritime companies. The focus is on new insight from airline and maritime companies concentrating on their sustainability practices. Common hurdles, innovative solutions, and shared opportunities in the pursuit of environmental sustainability are explored. Design / Methodology / Approach. The selected research method was qualitative research, which was conducted with in-depth and semi-structured interviews and content analysis. Interviews were conducted with airline company and association representatives and maritime company, research, and education experts. The content analysis was based on sustainability reports and sustainability sections of annual reports. Key findings were synthesized into a theoretical framework and this research explores practical initiatives for a sustainable transformation process. Findings. The call to reduce carbon emissions has been initiated by the EU affecting the transportation sector, particularly aviation and maritime industries where the path to achieving carbon neutrality is constrained by significant technical limitations. Despite these challenges, both sectors share a unified objective according to EU climate targets. Both the aviation and maritime industries face challenges on the path to carbon neutrality. Airlines struggle with the limitations of current aviation technology, hindering the feasibility of large-scale technological advancements. Similarly, maritime companies confront regulatory complexities and infrastructure limitations in the adoption of alternative fuels and emission-reduction technologies since the commonly used tactics of reducing fuel consumption by optimizing speed, routes and scheduling are no longer adequate ways and the energy needs of the shipping industry cannot be met only with battery technology. Originality / Value / Practical implications. These challenges offer opportunities for innovation and collaboration. Investments in research and development are driving advancements in electric and hydrogen aircraft, while the maritime industry is also trying to find hydrogen-based solutions for greener development, but the technologies are not widely available. This leads towards combining bio-oils and technological innovations related to the fleet. Case study 1 sheds light on airline sustainability in Europe, revealing strategies and initiatives that European airlines are currently utilizing in their sustainable transformation journey. Case study 2 explores different means of achieving carbon neutrality in the maritime industry, in particular the potential of common reed (Phragmites australis) as a carbon offset tool for reaching net zero. Both industries are making significant strides towards carbon neutrality through a combination of technological innovation, operational efficiencies, and strategic partnerships. Towards green horizons as transport industries converge on the path to carbon neutrality.

A Modified 72-Pulse Rectifier for Harmonic Suppression in More Electric Aircraft Applications

A Modified 72-Pulse Rectifier for Harmonic Suppression in More Electric Aircraft Applications