12th EASN International Conference on Innovation in Aviation & Space for Opening New Horizons

A special issue of Aerospace (ISSN 2226-4310).

Deadline for manuscript submissions: closed (28 February 2023) | Viewed by 49406

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Special Issue Editors


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Guest Editor
Honorary Chairman of the European Aeronautics Science Network Association (EASN); Professor Emeritus at the University of Patras, Panepistimioupolis Rion, 26500 Patras, Greece
Interests: aeronautical materials and structures; mechanical behavior of materials; structural integrity; damage mechanics; experimental fracture mechanics; fatigue of aircraft materials and structures; ageing aircraft; characterization and manufacturing processes of polymers, thermosetting and thermoplastic composites; nanocomposites and nanocrystalline alloys; multifunctional and self-healing materials
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Guest Editor
Chairman of the European Aeronautics Science Network Association (EASN), Head of Department Aircraft Design, Institute of Aircraft Design (IFB), University of Stuttgart, Pfaffenwaldring 31, 70569 Stuttgart, Germany
Interests: aircraft design; conventional and unconventional configurations; aircraft systems; operational aspects; certification; electric and hybrid-electric flight; alternative propulsion systems; flight testing; unmanned aerial vehicles; scaled flight testing
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
National Contact Point (NCP) for Spain of the European Aeronautics Science Network Association (EASN), Professor at the Physics Department, Aeronautics Division, Centre Internacional de Mètodes Numèrics en Enginyeria (CIMNE), Universitat Politècnica de Catalunya, c/Esteve Terrades 5, Edifici C3, Campus UPC-PMT, 08860 Castelldefels, Spain
Interests: optimization methods; uncertainty quantification; robust design optimization; multi-fluid flow; water management within the fuel cells channels, low-order and low-cost CFD methods; panel and vortex methods; airports; air operations; flight efficiency

Special Issue Information

Dear Colleagues,

This Special Issue is cooperating with the 12th EASN International Conference on "Innovation in Aviation & Space for opening New Horizons", which will be held by EASN Association and the Universitat Politecnica de Catalunya - BarcelonaTech (UPC), and will take place in Barcelona, Spain from the 18th to 21st of October 2022.

Similar to its predecessors, the 12th EASN International Conference on "Innovation in Aviation & Space for Opening New Horizons" will include a number of plenary talks by distinguished personalities of the European aviation and space sectors from the academic, industry, and research communities, as well as policy-makers. It will also include thematic sessions, along with technical workshops, where innovative ideas, breakthrough concepts, and disruptive technologies will be presented and discussed with the aim of establishing new research partnerships and possible synergies.

Furthermore, the conference is expected to be a major European dissemination event of aviation- and space-related research, as it will provide a forum for presenting the activities and accomplishments of EU-funded projects, discussing current trends and future needs, and attempting to identify possible collaborations with each other. Additionally, a number of policy development projects will also take to the floor to present the strategic priorities of the European aviation sector.   

Authors of outstanding papers related to the topic of aviation and space are invited to submit extended versions of their work to this Special Issue for publication.

We are looking forward to welcoming you to Barcelona and the 2022 EASN International Conference, and invite submissions of extended conference papers to this Special Issue. We hope that the conference will be another successful, in-person gathering of the EASN Association in these challenging times.

Prof. Dr. Spiros Pantelakis
Prof. Dr. Andreas Strohmayer
Prof. Dr. Jordi Pons-Prats
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Aerospace is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • aerostructures: materials, structures, manufacturing
  • maintenance, repair and overhaul (MRO)
  • flight physics
  • UAS and scaled flight testing
  • propulsion
  • hybrid electric flight
  • fuels and energy storage
  • small air transport (SAT) technologies
  • avionics, systems and equipment
  • air traffic management and airports
  • human factors
  • innovative concepts and scenarios
  • industry 4.0 and factories of the future
  • space technologies
  • space applications and operations
  • space policies
  • ecoDESIGN and sustainable productivity
  • safety, regulation and standards
  • synergies and technology transfer with the automotive industry
  • european policy actions in the field of aviation and space

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Published Papers (20 papers)

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Research

13 pages, 6623 KiB  
Article
Additive Manufacturing of 17-4PH Alloy: Tailoring the Printing Orientation for Enhanced Aerospace Application Performance
by Sandor Endre Kovacs, Tamas Miko, Enrico Troiani, Dionysios Markatos, Daniel Petho, Greta Gergely, Laszlo Varga and Zoltan Gacsi
Aerospace 2023, 10(7), 619; https://doi.org/10.3390/aerospace10070619 - 7 Jul 2023
Cited by 3 | Viewed by 1669
Abstract
Additive manufacturing (AM) is one of the fastest-growing markets of our time. During its journey in the past 30 years, its key to success has been that it can easily produce extremely complex shapes and is not limited by tooling problems when a [...] Read more.
Additive manufacturing (AM) is one of the fastest-growing markets of our time. During its journey in the past 30 years, its key to success has been that it can easily produce extremely complex shapes and is not limited by tooling problems when a change in geometry is desired. This flexibility leads to possible solutions for creating lightweight structural elements while keeping the mechanical properties at a stable reserve factor value. In the aerospace industry, several kinds of structural elements for fuselage and wing parts are made from different kinds of steel alloys, such as 17-4PH stainless steel, which are usually milled from a block material made using conventional processing (CP) methods. However, these approaches are limited when a relatively small element must withstand greater forces that can occur during flight. AM can bridge this problem with a new perspective, mainly using thin walls and complex shapes while maintaining the ideal sizes. The downside of the elements made using AM is that the quality of the final product is highly dependent on the build/printing orientation, an issue extensively studied and addressed by researchers in the field. During flight, some components may experience forces that predominantly act in a single direction. With this in mind, we created samples with the desired orientation to maximize material properties in a specific direction. The goal of this study was to demonstrate that an additively manufactured part, produced using laser powder bed fusion (LPBF), with a desired build orientation has exceptional properties compared to parts produced via conventional methods. To assess the impact of the build orientation on the LPBF parts’ properties, one-dimensional tensile and dynamic fracture toughness tests were deployed. Full article
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20 pages, 6315 KiB  
Article
Effect of Temperature on the Functionalization Process of Structural Self-Healing Epoxy Resin
by Luigi Vertuccio, Elisa Calabrese, Marialuigia Raimondo, Michelina Catauro, Andrea Sorrentino, Carlo Naddeo, Raffaele Longo and Liberata Guadagno
Aerospace 2023, 10(5), 476; https://doi.org/10.3390/aerospace10050476 - 18 May 2023
Cited by 1 | Viewed by 1401
Abstract
This work deals with developing a self-healing resin designed for aeronautical and aerospace applications. The bifunctional epoxy precursor was suitably functionalized to enhance its toughness to realize good compatibilization with a rubber phase dispersed in the hosting epoxy resin. Subsequently, the resulting mixture [...] Read more.
This work deals with developing a self-healing resin designed for aeronautical and aerospace applications. The bifunctional epoxy precursor was suitably functionalized to enhance its toughness to realize good compatibilization with a rubber phase dispersed in the hosting epoxy resin. Subsequently, the resulting mixture was loaded with healing molecules. The effect of the temperature on the epoxy precursor’s functionalization process was deeply studied. Fourier trans-former infrared (FT-IR) spectroscopy and dynamic mechanical analyses (DMA) evidenced that the highest temperature (160 °C) allows for obtaining a bigger amount of rubber phase bonded to the matrix. Elastomeric domains of dimensions lower than 500–600 nanometers were found well distributed in the matrix. Self-healing efficiency evaluated with the tapered double cantilever beam (TDCB) method evidenced a healing efficiency for the system functionalized at 160 °C higher than 69% for all the explored fillers. The highest value was detected for the sample with DBA, for which 88% was found. The healing efficiency of the same sample functionalized at 120 °C was found to decrease to the value of 52%. These results evidence the relevant role of the amount and distribution of rubber domains into the resin for improving the resin’s dynamic properties. The adopted strategy allows for optimizing the self-healing performance. Full article
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26 pages, 7150 KiB  
Article
Fast Sizing Methodology and Assessment of Energy Storage Configuration on the Flight Time of a Multirotor Aerial Vehicle
by Saad Chahba, Rabia Sehab, Cristina Morel, Guillaume Krebs and Ahmad Akrad
Aerospace 2023, 10(5), 425; https://doi.org/10.3390/aerospace10050425 - 30 Apr 2023
Cited by 3 | Viewed by 2360
Abstract
Urban air mobility (UAM), defined as safe and efficient air traffic operations in a metropolitan area for manned aircraft and unmanned aircraft systems, is being researched and developed by industry, academia, and government. This kind of mobility offers an opportunity to construct a [...] Read more.
Urban air mobility (UAM), defined as safe and efficient air traffic operations in a metropolitan area for manned aircraft and unmanned aircraft systems, is being researched and developed by industry, academia, and government. This kind of mobility offers an opportunity to construct a green and sustainable sub-sector, building upon the lessons learned over decades by aviation. Thanks to their non-polluting operation and simple air traffic management, electric vertical take-off and landing (eVTOL) aircraft technologies are currently being developed and experimented with for this purpose. However, to successfully complete the certification and commercialization stage, several challenges need to be overcome, particularly in terms of performance, such as flight time and endurance, and reliability. In this paper, a fast methodology for sizing and selecting the propulsion chain components of an eVTOL multirotor aerial vehicle was developed and validated on a reduced-scale prototype of an electric multirotor vehicle with a GTOW of 15 kg. This methodology is associated with a comparative study of energy storage system configurations, in order to assess their effect on the flight time of the aerial vehicle. First, the optimal pair motor/propeller was selected using a global nonlinear optimization in order to maximize the specific efficiency of these components. Second, five energy storage technologies were sized in order to evaluate their influence on the aerial vehicle flight time. Finally, based on this sizing process, the optimized propulsion chain gross take-off weight (GTOW) was evaluated for each energy storage configuration using regression-based methods based on propulsion chain supplier data. Full article
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16 pages, 1950 KiB  
Article
Influence of Electric Wing Tip Propulsion on the Sizing of the Vertical Stabilizer and Rudder in Preliminary Aircraft Design
by Alexander Albrecht, Andreas Bender, Philipp Strathoff, Clemens Zumegen, Eike Stumpf and Andreas Strohmayer
Aerospace 2023, 10(5), 395; https://doi.org/10.3390/aerospace10050395 - 25 Apr 2023
Cited by 1 | Viewed by 1622
Abstract
During preliminary aircraft design, the vertical tail sizing is conventionally conducted by the use of volume coefficients. These represent a statistical approach using existing configurations’ correlating parameters, such as wing span and lever arm, to size the empennage. For a more detailed analysis [...] Read more.
During preliminary aircraft design, the vertical tail sizing is conventionally conducted by the use of volume coefficients. These represent a statistical approach using existing configurations’ correlating parameters, such as wing span and lever arm, to size the empennage. For a more detailed analysis with regard to control performance, the vertical tail size strongly depends on the critical loss of thrust assessment. This consideration increases in complexity for the design of the aircraft using wing tip propulsion systems. Within this study, a volume coefficient-based vertical tail plane sizing is compared to handbook methods and the possibility to reduce the necessary vertical stabilizer size is assessed with regard to the position of the engine integration and their interconnection. Two configurations, with different engine positions, of a hybrid-electric 19-seater aircraft, derived from the specifications of a Beechcraft 1900D, are compared. For both configurations two wiring options are assessed with regard to their impact on aircraft level for a partial loss of thrust. The preliminary aircraft design tool MICADO is used to size the four aircraft and propulsion system configurations using fin volume coefficients. These results are subsequently amended by handbook methods to resize the vertical stabilizer and update the configurations. The results in terms of, e.g., operating empty mass and mission fuel consumption, are compared to the original configurations without the optimized vertical stabilizer. The findings support the initial idea that the connection of the electric engines on the wing tips to their respective power source has a significant effect on the resulting torque around the yaw axis and the behaviour of the aircraft in case of a power train failure, as well as on the empty mass and trip fuel. For only one out of the four different aircraft designs and wiring configurations investigated it was possible to decrease the fin size, resulting in a 53.7% smaller vertical tail and a reduction in trip fuel of 4.9%, compared to the MICADO design results for the original fin volume coefficient. Full article
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17 pages, 520 KiB  
Article
Sensitivity Analysis of a Hybrid MCDM Model for Sustainability Assessment—An Example from the Aviation Industry
by Dionysios N. Markatos, Sonia Malefaki and Spiros G. Pantelakis
Aerospace 2023, 10(4), 385; https://doi.org/10.3390/aerospace10040385 - 21 Apr 2023
Cited by 6 | Viewed by 1824
Abstract
When it comes to achieving sustainability and circular economy objectives, multi-criteria decision-making (MCDM) tools can be of aid in supporting decision-makers to reach a satisfying solution, especially when conflicting criteria are present. In a previous work of the authors, a hybrid MCDM tool [...] Read more.
When it comes to achieving sustainability and circular economy objectives, multi-criteria decision-making (MCDM) tools can be of aid in supporting decision-makers to reach a satisfying solution, especially when conflicting criteria are present. In a previous work of the authors, a hybrid MCDM tool was introduced to support the selection of sustainable materials in aviation. The reliability of an MCDM tool depends decisively on its robustness. Hence, in the present work, the robustness of the aforementioned tool has been assessed by conducting an extensive sensitivity analysis. To this end, the extent to which the results are affected by the normalization method involved in the proposed MCDM tool is examined. In addition, the sensitivity of the final output to the weights’ variation as well as to the data values variation has been investigated towards monitoring the stability of the tool in terms of the final ranking obtained. In order to carry out the analysis, a case study from the aviation industry has been considered. In the current study, carbon fiber reinforced plastics (CFRP) components, both virgin and recycled, are assessed and compared with regard to their sustainability by accounting for metrics linked to their whole lifecycle. The latter assessment also accounts for the impact of the fuel type utilized during the use phase of the components. The results show that the proposed tool provides an effective and robust method for the evaluation of the sustainability of aircraft components. Moreover, the present work can provide answers to questions raised concerning the adequacy of the CFRP recycled parts performance and their expected contribution towards sustainability and circular economy goals in aviation. Full article
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27 pages, 12112 KiB  
Article
Design and Preliminary Performance Assessment of a PHM System for Electromechanical Flight Control Actuators
by Antonio Carlo Bertolino, Andrea De Martin, Giovanni Jacazio and Massimo Sorli
Aerospace 2023, 10(4), 335; https://doi.org/10.3390/aerospace10040335 - 28 Mar 2023
Cited by 3 | Viewed by 6168
Abstract
The evolution toward “more electric” aircraft has seen a decisive push in the last decade due to growing environmental concerns and the development of new market segments (flying taxis). Such a push has involved both the propulsion components and the aircraft systems, with [...] Read more.
The evolution toward “more electric” aircraft has seen a decisive push in the last decade due to growing environmental concerns and the development of new market segments (flying taxis). Such a push has involved both the propulsion components and the aircraft systems, with the latter seeing a progressive trend in replacing traditional solutions based on hydraulic power with electrical or electromechanical devices. Flight Control Systems (FCSs) are one of the aircraft systems affected the most since the adoption of Electromechanical Actuators (EMAs) would provide several advantages over traditional electrohydraulic or mechanical solutions, but their application is still limited due to their sensitivity to certain single points of failure that can lead to mechanical jams. The development of an effective and reliable Prognostics and Health Management (PHM) system for EMAs could help in mitigating the risk of a sudden critical failure by properly recognizing and tracking the ongoing fault and anticipating its evolution, thus boosting the acceptance of EMAs as the primary flight-control actuators in commercial aircraft. The paper is focused on the results of the preliminary activities performed within the CleanSky 2/Astib research program, dedicated to the definition of the iron bird of a new regional-transport aircraft able to provide some prognostic capabilities and act as a technological demonstrator for new PHM strategies for EMAs employed in-flight control systems. The paper is organized as follows. At first, a proper introduction to the research program is provided, along with a brief description of the employed approach. Hence the simulation models adopted for the study are presented and used to build synthetic databases to inform the definition of the PHM algorithm. The prognostic framework is then presented, and a preliminary assessment of its expected performance is discussed. Full article
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13 pages, 6050 KiB  
Article
A Novel Process to Produce Ti Parts from Powder Metallurgy with Advanced Properties for Aeronautical Applications
by Tamas Miko, Daniel Petho, Greta Gergely, Dionysios Markatos and Zoltan Gacsi
Aerospace 2023, 10(4), 332; https://doi.org/10.3390/aerospace10040332 - 27 Mar 2023
Cited by 1 | Viewed by 1695
Abstract
Titanium and its alloys have excellent corrosion resistance, heat, and fatigue tolerance, and their strength-to-weight ratio is one of the highest among metals. This combination of properties makes them ideal for aerospace applications; however, high manufacturing costs hinder their widespread use compared to [...] Read more.
Titanium and its alloys have excellent corrosion resistance, heat, and fatigue tolerance, and their strength-to-weight ratio is one of the highest among metals. This combination of properties makes them ideal for aerospace applications; however, high manufacturing costs hinder their widespread use compared to other metals such as aluminum alloys and steels. Powder metallurgy (PM) is a greener and more cost and energy-efficient method for the production of near-net-shape parts compared to traditional ingot metallurgy, especially for titanium parts. In addition, it allows us to synthesize special microstructures, which result in outstanding mechanical properties without the need for alloying elements. The most commonly used Ti alloy is the Ti6Al4V grade 5. This workhorse alloy ensures outstanding mechanical properties, demonstrating a strength which is at least twice that of commercially pure titanium (CP-Ti) grade 2 and comparable to the strength of hardened stainless steels. In the present research, different mixtures of both milled and unmilled Cp-Ti grade 2 powder were utilized using the PM method, aiming to synthesize samples with high mechanical properties comparable to those of high-strength alloys such as Ti6Al4V. The results showed that the fine nanoparticles significantly enhanced the strength of the material, while in several cases the material exceeded the values of the Ti6Al4V alloy. The produced sample exhibited a maximum compressive yield strength (1492 MPa), contained 10 wt.% of fine (milled) particles (average particle size: 3 μm) and was sintered at 900 °C for one hour. Full article
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30 pages, 2204 KiB  
Article
Comprehensive Comparison of Different Integrated Thermal Protection Systems with Ablative Materials for Load-Bearing Components of Reusable Launch Vehicles
by Stefano Piacquadio, Dominik Pridöhl, Nils Henkel, Rasmus Bergström, Alessandro Zamprotta, Athanasios Dafnis and Kai-Uwe Schröder
Aerospace 2023, 10(3), 319; https://doi.org/10.3390/aerospace10030319 - 22 Mar 2023
Cited by 2 | Viewed by 2442
Abstract
Economic viability of small launch vehicles, i.e., microlaunchers, is impaired by several factors, one of which is a higher dry to wet mass ratio as compared to conventional size launchers. Although reusability may reduce launch cost, it can drive dry and/or wet mass [...] Read more.
Economic viability of small launch vehicles, i.e., microlaunchers, is impaired by several factors, one of which is a higher dry to wet mass ratio as compared to conventional size launchers. Although reusability may reduce launch cost, it can drive dry and/or wet mass to unfeasibly high levels. In particular, for load-bearing components that are exposed to convective heating during the aerothermodynamic phase of the re-entry, the mass increase due to the presence of a thermal protection system (TPS) must be considered. Examples of such components are aerodynamic drag devices (ADDs), which are extended during the re-entry. These should withstand high mechanical loading, be thermally protected to avoid failure, and be reusable. Ablative materials can offer lightweight thermal protection, but they represent an add-on mass for the structure and they are rarely reusable. Similarly, TPS based on ceramic matrix composite (CMC) tiles represent an additional mass. To tackle this issue, so-called integrated thermal protection systems (ITPS) composed of CMC sandwich structures were introduced in the literature. The aim is to obtain a load-bearing structure that is at the same time the thermally protective layer. However, a comprehensive description of the real lightweight potential of such solutions compared to ablative materials with the corresponding sub-structures is, to the authors’ knowledge, not yet presented. Thus, based on the design of an ADD, this work aims to holistically describe such load bearing components and to compare different TPS solutions. Both thermal and preliminary mechanical designs are discussed. Additionally, a novel concept is proposed, which is based on the use of phase change materials (PCMs) embedded within a metallic sandwich structure with an additively manufactured lattice core. Such a solution can be beneficial due to the combination of both the high specific stiffness of lattice structures and the high mass-specific thermal energy storage potential of PCMs. The study is conducted with reference to the first stage of the microlauncher analysed within the European Horizon-2020 project named Recovery and Return To Base (RRTB). Full article
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17 pages, 679 KiB  
Article
A Model-Based Prognostic Framework for Electromechanical Actuators Based on Metaheuristic Algorithms
by Leonardo Baldo, Ivana Querques, Matteo Davide Lorenzo Dalla Vedova and Paolo Maggiore
Aerospace 2023, 10(3), 293; https://doi.org/10.3390/aerospace10030293 - 16 Mar 2023
Cited by 1 | Viewed by 1898
Abstract
The deployment of electro-mechanical actuators plays an important role towards the adoption of the more electric aircraft (MEA) philosophy. On the other hand, a seamless substitution of EMAs, in place of more traditional hydraulic solutions, is still set back, due to the shortage [...] Read more.
The deployment of electro-mechanical actuators plays an important role towards the adoption of the more electric aircraft (MEA) philosophy. On the other hand, a seamless substitution of EMAs, in place of more traditional hydraulic solutions, is still set back, due to the shortage of real-life and reliability data regarding their failure modes. One way to work around this problem is providing a capillary EMA prognostics and health management (PHM) system capable of recognizing failures before they actually undermine the ability of the safety-critical system to perform its functions. The aim of this work is the development of a model-based prognostic framework for PMSM-based EMAs leveraging a metaheuristic algorithm: the evolutionary (differential evolution (DE)) and swarm intelligence (particle swarm (PSO), grey wolf (GWO)) methods are considered. Several failures (dry friction, backlash, short circuit, eccentricity, and proportional gain) are simulated by a reference model, and then detected and identified by the envisioned prognostic method, which employs a low fidelity monitoring model. The paper findings are analysed, showing good results and proving that this strategy could be executed and integrated in more complex routines, supporting EMAs adoption, with positive impacts on system safety and reliability in the aerospace and industrial field. Full article
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20 pages, 3372 KiB  
Article
Prediction of Capacity Regulations in Airspace Based on Timing and Air Traffic Situation
by Francisco Pérez Moreno, Víctor Fernando Gómez Comendador, Raquel Delgado-Aguilera Jurado, María Zamarreño Suárez and Rosa María Arnaldo Valdés
Aerospace 2023, 10(3), 291; https://doi.org/10.3390/aerospace10030291 - 15 Mar 2023
Viewed by 1232
Abstract
The Air Traffic Control (ATC) system suffers from an ever-increasing demand for aircraft, leading to capacity issues. For this reason, airspace is regulated by limiting the entry of aircraft into the airspace. Knowledge of these regulations before they occur would allow the ATC [...] Read more.
The Air Traffic Control (ATC) system suffers from an ever-increasing demand for aircraft, leading to capacity issues. For this reason, airspace is regulated by limiting the entry of aircraft into the airspace. Knowledge of these regulations before they occur would allow the ATC system to be aware of conflicting areas of the airspace, and to manage both its human and technological resources to lessen the effect of the expected regulations. Therefore, this paper develops a methodology in which the final result is a machine learning model that allows predicting capacity regulations. Predictions shall be based mainly on historical data, but also on the traffic situation at the time of the prediction. The results of tests of the model in a sector of Spanish airspace are satisfactory. In addition to testing the model results, special emphasis is placed on the explainability of the model. This explainability will help to understand the basis of the predictions and validate them from an operational point of view. The main conclusion after testing the model is that this model works well. Therefore, it is possible to predict when an ATC sector will be regulated or not based mainly on historical data. Full article
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27 pages, 1031 KiB  
Article
Structured Expert Judgment Elicitation in Conceptual Aircraft Design
by Vladislav T. Todorov, Dmitry Rakov and Andreas Bardenhagen
Aerospace 2023, 10(3), 287; https://doi.org/10.3390/aerospace10030287 - 14 Mar 2023
Cited by 3 | Viewed by 1574
Abstract
Disruptive technologies and novel aircraft generations represent a potential approach to address the ambitious emission reduction goals in aviation. However, the introduction of innovative concepts is a time-consuming process, which might not necessarily yield an optimal design for a given flight mission and [...] Read more.
Disruptive technologies and novel aircraft generations represent a potential approach to address the ambitious emission reduction goals in aviation. However, the introduction of innovative concepts is a time-consuming process, which might not necessarily yield an optimal design for a given flight mission and within the defined time frame. In order to address the need for a structured and more exhaustive search for novel concept generations, the Advanced Morphological Approach (AMA) and its further enhancement was introduced earlier. It implies the decomposition of design problems into functional attributes and appropriate technological alternatives. Subsequently, these are evaluated and combined into solutions, which are then projected onto a solution space. The current paper focuses on the technology evaluation step by deriving and integrating structured expert judgment elicitation (SEJE) techniques into conceptual aircraft design with the AMA. For this purpose, the first aim of the work is to justify the developed method by giving an overview and discussing the most prominent SEJE methods and their applications in aerospace. Then, the derived SEJE concept is described and applied in the form of an expert workshop on the use case of wing morphing architecture. As a result, a solution space of wing morphing architecture configurations is generated and analyzed. The workshop conduction and the expert feedback serve as valuable findings for both the further AMA enhancement and similar research. Full article
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22 pages, 3811 KiB  
Article
Decarbonised Future Regional Airport Infrastructure
by Markus Meindl, Cor de Ruiter, Valerio Marciello, Mario Di Stasio, Florian Hilpert, Manuela Ruocco, Fabrizio Nicolosi, Nils Thonemann, Karen Saavedra-Rubio, Louis Locqueville, Alexis Laurent and Martin Maerz
Aerospace 2023, 10(3), 283; https://doi.org/10.3390/aerospace10030283 - 13 Mar 2023
Cited by 5 | Viewed by 2280
Abstract
Sustainability and, especially, emission reductions are significant challenges for airports currently being addressed. The Clean Sky 2 project GENESIS addresses the environmental sustainability of hybrid-electric 50-passenger aircraft systems in a life cycle perspective to support the development of a technology roadmap for the [...] Read more.
Sustainability and, especially, emission reductions are significant challenges for airports currently being addressed. The Clean Sky 2 project GENESIS addresses the environmental sustainability of hybrid-electric 50-passenger aircraft systems in a life cycle perspective to support the development of a technology roadmap for the transition to sustainable and competitive electric aircraft systems. This article originates from the GENESIS research and describes various options for ground power supply at a regional airport. Potential solutions for airport infrastructure with a short (2030), medium (2040) and long (2050) time horizon are proposed. This analysis includes estimating the future energy demand per day, month and year. In addition, the current flight plan based on conventional aircraft is adapted to the needs of a 50-PAX regional aircraft. Thus, this article provides an overview of the energy demand of a regional airport, divided into individual time horizons. Full article
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20 pages, 7610 KiB  
Article
Enabling Green Approaches by FMS-AMAN Coordination
by Nils Ahrenhold, Izabela Stasicka, Rabeb Abdellaoui, Thorsten Mühlhausen and Marco-Michael Temme
Aerospace 2023, 10(3), 278; https://doi.org/10.3390/aerospace10030278 - 11 Mar 2023
Cited by 1 | Viewed by 1281
Abstract
Growing political pressure and widespread social concerns about climate change are triggering a paradigm shift in the aviation sector. Projects with the target of reducing aviation’s CO2 emissions and their impact on climate change are being launched to improve currently used procedures. [...] Read more.
Growing political pressure and widespread social concerns about climate change are triggering a paradigm shift in the aviation sector. Projects with the target of reducing aviation’s CO2 emissions and their impact on climate change are being launched to improve currently used procedures. In this paper, a new coordination process between aircraft flight management systems (FMSs) and an arrival manager (AMAN) was investigated to enable fuel-efficient and more sustainable approaches. This coordination posed two major challenges. Firstly, current capacity-centred AMANs’ planning processes are not optimised towards fuel-efficient trajectories. To investigate the benefit of negotiated trajectories with fixed target times for waypoints and thresholds, the terminal manoeuvring area was redesigned for an independent parallel runway system. Secondly, the FMS-AMAN negotiation process plan the trajectories based on time, whereas air traffic controllers guide traffic based on distance. Three tactical assisting tools were implemented in an air traffic controller’s working position to enable a smooth transition from distance-based to time-based coordination and guidance. The whole concept was implemented and tested in real-time human-in-the-loop studies at DLR’s Air Traffic Validation Center. Results showed that the new airspace design and concept was feasible, and a reduction in flown distance was measured. Full article
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23 pages, 3655 KiB  
Article
Hydrogen-Powered Aviation—Design of a Hybrid-Electric Regional Aircraft for Entry into Service in 2040
by Jona Eissele, Stefan Lafer, Cristian Mejía Burbano, Julian Schließus, Tristan Wiedmann, Jonas Mangold and Andreas Strohmayer
Aerospace 2023, 10(3), 277; https://doi.org/10.3390/aerospace10030277 - 11 Mar 2023
Cited by 7 | Viewed by 5698
Abstract
Over the past few years, the rapid growth of air traffic and the associated increase in emissions have created a need for sustainable aviation. Motivated by these challenges, this paper explores how a 50-passenger regional aircraft can be hybridized to fly with the [...] Read more.
Over the past few years, the rapid growth of air traffic and the associated increase in emissions have created a need for sustainable aviation. Motivated by these challenges, this paper explores how a 50-passenger regional aircraft can be hybridized to fly with the lowest possible emissions in 2040. In particular, the use of liquid hydrogen in this aircraft is an innovative power source that promises to reduce CO2 and NOx emissions to zero. Combined with a fuel-cell system, the energy obtained from the liquid hydrogen can be used efficiently. To realize a feasible concept in the near future considering the aspects of performance and security, the system must be hybridized. In terms of maximized aircraft sustainability, this paper analyses the flight phases and ground phases, resulting in an aircraft design with a significant reduction in operating costs. Promising technologies, such as a wingtip propeller and electric green taxiing, are discussed in this paper, and their potential impacts on the future of aviation are highlighted. In essence, the hybridization of regional aircraft is promising and feasible by 2040; however, more research is needed in the areas of fuel-cell technology, thermal management and hydrogen production and storage. Full article
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30 pages, 6647 KiB  
Article
Kriging-Based Framework Applied to a Multi-Point, Multi-Objective Engine Air-Intake Duct Aerodynamic Optimization Problem
by Przemysław S. Drężek, Sławomir Kubacki and Jerzy Żółtak
Aerospace 2023, 10(3), 266; https://doi.org/10.3390/aerospace10030266 - 9 Mar 2023
Cited by 2 | Viewed by 1687
Abstract
The forecasted growth in dynamic global air fleet size in the coming decades, together with the need to introduce disruptive technologies supporting net-zero emission air transport, demands more efficient design and optimization workflows. This research focuses on developing an aerodynamic optimization framework suited [...] Read more.
The forecasted growth in dynamic global air fleet size in the coming decades, together with the need to introduce disruptive technologies supporting net-zero emission air transport, demands more efficient design and optimization workflows. This research focuses on developing an aerodynamic optimization framework suited for multi-objective studies of small aircraft engine air-intake ducts in multiple flight conditions. In addition to the refinement of the duct’s performance criteria, the work aims to improve the economic efficiency of the process. The optimization scheme combines the advantages of Kriging-based Efficient Global Optimization (EGO) with the Radial Basis Functions (RBF)-based mesh morphing technique and the Chebyshev-type Achievement Scalarizing Function (ASF) for handling multiple objectives and design points. The proposed framework is applied to an aerodynamic optimization study of an I-31T aircraft turboprop engine intake system. The workflow successfully reduces the air-duct pressure losses and mitigates the flow distortion at the engine compressor’s front face in three considered flight phases. The results prove the framework’s potential for solving complex multi-point air-intake duct problems and the capacity of the ASF-based formulation to guide optimization toward the designer’s preferred objective targets. Full article
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15 pages, 3689 KiB  
Article
Concepts for Increased Energy Dissipation in CFRP Composites Subjected to Impact Loading Conditions by Optimising Interlaminar Properties
by Moritz Kuhtz, Jonas Richter, Jens Wiegand, Albert Langkamp, Andreas Hornig and Maik Gude
Aerospace 2023, 10(3), 248; https://doi.org/10.3390/aerospace10030248 - 3 Mar 2023
Viewed by 1258
Abstract
Carbon fibre-reinforced plastics (CFRP) are predestined for use in high-performance components due to their superior specific mechanical properties. In addition, these materials have the advantage that the material properties and in particular, the failure behaviour can be adjusted. Fibre-dominated failure modes are usually [...] Read more.
Carbon fibre-reinforced plastics (CFRP) are predestined for use in high-performance components due to their superior specific mechanical properties. In addition, these materials have the advantage that the material properties and in particular, the failure behaviour can be adjusted. Fibre-dominated failure modes are usually brittle and catastrophic. In contrast, delaminations successively absorb energy and retain in-plane structural integrity. Previous investigations have shown that interface modifications can be used to selectively adjust the interlaminar properties, which decisively influence the delamination behaviour and the associated failure behaviour of structures. However, a systematic analysis of the influences of the positioning and characteristics of the interface modifications on the structural failure behaviour is still missing. Based on existing experimental investigations on the energy dissipation of CFRP impact-loaded beams, the failure behaviour is described here with the help of numerical simulations. The structural failure behaviour and the energy dissipation are represented in a three-dimensional, parameterised finite element analysis (FEA) model. Furthermore, the parameterised models are used to maximise the energy absorption of the three-point bending test through three concepts of interface modification. The large number of model input parameters requires a metamodel-based description of the correlation between the positioning and characteristics of the interface modification and the energy dissipation. Within the scope of the present work, a procedure is therefore developed which enables an efficient design of interface-modified CFRP under impact loads. Full article
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15 pages, 5743 KiB  
Article
Comparative Analysis of Flame Propagation and Flammability Limits of CH4/H2/Air Mixture with or without Nanosecond Plasma Discharges
by Ghazanfar Mehdi, Maria Grazia De Giorgi, Sara Bonuso, Zubair Ali Shah, Giacomo Cinieri and Antonio Ficarella
Aerospace 2023, 10(3), 224; https://doi.org/10.3390/aerospace10030224 - 25 Feb 2023
Cited by 3 | Viewed by 1853
Abstract
This study investigates the kinetic modeling of CH4/H2/Air mixture with nanosecond pulse discharge (NSPD) by varying H2/CH4 ratios from 0 to 20% at ambient pressure and temperature. A validated version of the plasma and chemical kinetic [...] Read more.
This study investigates the kinetic modeling of CH4/H2/Air mixture with nanosecond pulse discharge (NSPD) by varying H2/CH4 ratios from 0 to 20% at ambient pressure and temperature. A validated version of the plasma and chemical kinetic mechanisms was used. Two numerical tools, ZDPlasKin and CHEMKIN, were combined to analyze the thermal and kinetic effects of NSPD on flame speed enhancement. The addition of H2 and plasma excitation increased flame speed. The highest improvement (35%) was seen with 20% H2 and 1.2 mJ plasma energy input at ϕ = 1. Without plasma discharge, a 20% H2 blend only improved flame speed by 14% compared to 100% CH4. The study found that lean conditions at low flame temperature resulted in significant improvement in flame speed. With 20% H2 and NSPD, flame speed reached 37 cm/s at flame temperature of 2040 K at ϕ = 0.8. Similar results were observed with 0% and 5% H2 and a flame temperature of 2200 K at ϕ = 1. Lowering the flame temperature reduced NOx emissions. Combining 20% H2 and NSPD also increased the flammability limit to ϕ = 0.35 at a flame temperature of 1350 K, allowing for self-sustained combustion even at low temperatures. Full article
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30 pages, 9014 KiB  
Article
Innovative Integration of Severe Weather Forecasts into an Extended Arrival Manager
by Marco-Michael Temme, Olga Gluchshenko, Lennard Nöhren, Matthias Kleinert, Oliver Ohneiser, Kathleen Muth, Heiko Ehr, Niklas Groß, Annette Temme, Martina Lagasio, Massimo Milelli, Vincenzo Mazzarella, Antonio Parodi, Eugenio Realini, Stefano Federico, Rosa Claudia Torcasio, Markus Kerschbaum, Laura Esbrí, Maria Carmen Llasat, Tomeu Rigo and Riccardo Biondiadd Show full author list remove Hide full author list
Aerospace 2023, 10(3), 210; https://doi.org/10.3390/aerospace10030210 - 24 Feb 2023
Cited by 1 | Viewed by 1874
Abstract
In the H2020 project “Satellite-borne and INsitu Observations to Predict The Initiation of Convection for ATM” (SINOPTICA), an air traffic controller support system was extended to organize approaching traffic even under severe weather conditions. During project runtime, traffic days with extreme weather events [...] Read more.
In the H2020 project “Satellite-borne and INsitu Observations to Predict The Initiation of Convection for ATM” (SINOPTICA), an air traffic controller support system was extended to organize approaching traffic even under severe weather conditions. During project runtime, traffic days with extreme weather events in the Po Valley were analyzed, an arrival manager was extended with a module for 4D diversion trajectory calculation, two display variants for severe weather conditions in an air traffic controller primary display were developed, and the airport Milano Malpensa was modelled for an air traffic simulation. On the meteorological side, three new forecasting techniques were developed to better nowcast weather events affecting tactical air traffic operations and used to automatically organize arrival traffic. Additionally, short-range weather forecasts with high spatial resolution were elaborated using radar-based nowcasting and a numerical weather prediction model with data assimilation. This nowcast information was integrated into the extended arrival manager for the sequencing and guiding of approaching aircraft even in adverse weather situations. The combination of fast and reliable weather nowcasts with a guidance support system enables severe weather diversion coordination in combination with a visualization of its dynamics on traffic situation displays. Full article
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21 pages, 2592 KiB  
Article
Methodology for Determining the Event-Based Taskload of an Air Traffic Controller Using Real-Time Simulations
by María Zamarreño Suárez, Rosa María Arnaldo Valdés, Francisco Pérez Moreno, Raquel Delgado-Aguilera Jurado, Patricia María López de Frutos and Víctor Fernando Gómez Comendador
Aerospace 2023, 10(2), 97; https://doi.org/10.3390/aerospace10020097 - 18 Jan 2023
Cited by 2 | Viewed by 1643
Abstract
The study of human factors in aviation makes an important contribution to safety. Within this discipline, real-time simulations (RTS) are a very powerful tool. The use of simulators allows for exercises with controlled air traffic control (ATC) events to be designed so that [...] Read more.
The study of human factors in aviation makes an important contribution to safety. Within this discipline, real-time simulations (RTS) are a very powerful tool. The use of simulators allows for exercises with controlled air traffic control (ATC) events to be designed so that their influence on the performance of air traffic controllers (ATCOs) can be studied. The CRITERIA (atC event-dRiven capacITy modEls foR aIr nAvigation) project aims to establish capacity models and determine the influence of a series of ATC events on the workload of ATCOs. To establish a correlation between these ATC events and neurophysiological variables, a previous step is needed: a methodology for defining the taskload faced by the ATCO during the development of each simulation. This paper presents the development of this methodology and a series of recommendations for extrapolating the lessons learnt from this line of research to similar experiments. This methodology starts from a taskload design, and after RTS and through the use of data related to the subjective evaluation of workload as an intermediate tool it allows the taskload profile experienced by the ATCO in each simulation to be defined. Six ATCO students participated in this experiment. They performed four exercises using the SkySim simulator. As an example, a case study of the analysis of one of the participants is presented. Full article
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18 pages, 6521 KiB  
Article
Determination of the Parachute Harness Critical Load Based on Load Distribution into Individual Straps with Respect of the Skydiver’s Body Position
by Robert Grim, Robert Popela, Ivo Jebáček, Marek Horák and Jan Šplíchal
Aerospace 2023, 10(1), 83; https://doi.org/10.3390/aerospace10010083 - 14 Jan 2023
Viewed by 2251
Abstract
This article evaluates the redistribution of forces to the parachute harness during an opening shock load and also defines the ultimate limit load of the personal parachute harness by specifying the weakest construction element and its load capacity. The primary goal of this [...] Read more.
This article evaluates the redistribution of forces to the parachute harness during an opening shock load and also defines the ultimate limit load of the personal parachute harness by specifying the weakest construction element and its load capacity. The primary goal of this research was not only to detect the critical elements but also to gain an understanding of the force redistribution at various load levels, which could represent changes in body mass or aerodynamic properties of the parachute during the opening phase. To capture all the phenomena of the parachutist’s body deceleration, this study also includes loading the body out of the steady descending position and asymmetrical cases. Thus, the result represents not only idealized loading but also realistic limit cases, such as asymmetric canopy inflation or system activation when the skydiver is in a non-standard position. The results revealed a significant difference in the strength utilization of the individual components. Specifically, the back webbing was found to carry a fractional load compared to the other webbing used in the design in most of the scenarios tested. Reaching the maximum allowable strength was first achieved in the asymmetric load test case, where the total force would be equal to the value of 7.963 kN, which corresponds to the maximum permissible strength of the carabiner on the measuring element three. In the same test case, the second weakest point would reach the limiting load force when the entire harness is loaded with 67.89 kN. This information and the subsequent analysis of the individual nodes provide a great opportunity for further strength and weight optimization of the design, without reducing the load capacity of the harness as a system. The findings of this study will be used for further testing and possible harness robustness optimization for both military and sport parachuting. Full article
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