Aerospace

Research

16 pages, 15763 KB

Open AccessArticle

Modification of a Scaled Flight Demonstrator for the Implementation and Experimental Investigation of an Energy Harvesting Powertrain in Distributed Electric Propulsion Systems

by Achim Kuhn, Eskil Jonas Nussbaumer, Jan Denzel, Dominique Paul Bergmann and Andreas Strohmayer

Aerospace 2026, 13(5), 435; https://doi.org/10.3390/aerospace13050435 - 6 May 2026

Viewed by 248

Abstract

Distributed electric propulsion (DEP) systems offer a wide range of options for arranging the propulsion units on an aircraft. In most cases, the position of the propulsion systems is optimized for one specific flight phase, e.g., takeoff or cruise. Taking advantage of the [...] Read more.

Distributed electric propulsion (DEP) systems offer a wide range of options for arranging the propulsion units on an aircraft. In most cases, the position of the propulsion systems is optimized for one specific flight phase, e.g., takeoff or cruise. Taking advantage of the high lift potential of the DEP also during descent and approach phases represents a challenge due to increased thrust. Energy harvesting propellers (EHPs) can be used to adapt the resulting thrust, by generation an additional drag force while regenerating a certain amount of energy back into the system. Therefore, the scaled flight demonstrator (SFD) e-Genius-Mod was modified to implement an energy harvesting powertrain in a DEP system. The energy harvesting wingtip propellers are integrated in a pusher configuration. It is possible to investigate different operation modes for recuperation, such as Windmilling and Opposite Pitch, by adjusting different propeller pitch angles. The electronics used for the wingtip propellers (WTPs) enable the control and measurement of the recuperation performance and furthermore to charge recuperated energy back into the battery. The energy harvesting system was tested in a wind tunnel to verify its functionality. In Windmilling mode, the maximum mean electrical power output is −25.7 W. In Opposite Pitch mode, the values were significantly higher, with a maximum mean electrical power of −184 W. This corresponds to up to seven times as much regenerated power in Opposite Pitch mode. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

28 pages, 19675 KB

Open AccessArticle

Technology Identification and Selection from Qualitative Solution Spaces in Conceptual Aircraft Design

by Vladislav T. Todorov, Dmitry Rakov and Andreas Bardenhagen

Aerospace 2026, 13(5), 434; https://doi.org/10.3390/aerospace13050434 - 6 May 2026

Viewed by 252

Abstract

Unconventional aircraft configurations are considered as potential solutions to achieve the ambitious emission reduction goals in aviation. However, the identification, selection, and synergetic combination of promising technologies remain a highly vague and uncertain process. This has been addressed in the framework for the [...] Read more.

Unconventional aircraft configurations are considered as potential solutions to achieve the ambitious emission reduction goals in aviation. However, the identification, selection, and synergetic combination of promising technologies remain a highly vague and uncertain process. This has been addressed in the framework for the advanced morphological approach (FAMA), which represents a structured design process for the generation and evaluation of unconventional aircraft configurations. It implies the decomposition of the task into subproblems, their analysis and the synthesis of concepts in a solution space. This general workflow has been further developed and adapted on three levels in aircraft design: (1) the qualitative idea generation; (2) the semi-quantitative concept selection from the generated ideas; and (3) the probabilistic estimation of design parameters and figures of merit for the most promising concepts from the previous level. The current paper focuses on the overview of the finalized methodology as well as levels one and two, while level three will be presented in more detail in future work. The first level is demonstrated on the concept generation for regional aerial transportation. The second level results in the percentual performance comparisons of promising technologies for the design of an energy-efficient long-range aircraft. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

67 pages, 3502 KB

Open AccessArticle

Gust Behaviour and Envelope Build-Up Process for Fixed-Wing Multi-Mission Remotely Piloted Aircraft

by Álvaro Gómez-Rodríguez, Carmelo-Javier Villanueva-Cañizares and Cristina Cuerno-Rejado

Aerospace 2026, 13(5), 428; https://doi.org/10.3390/aerospace13050428 - 2 May 2026

Viewed by 202

Abstract

The study of aircraft gust behaviour is essential in aerodynamic and structural design and analysis, as well as in airworthiness certification. The particularities of fixed-wing Remotely Piloted Aircraft (RPA) demand a specific study of gust effects on these vehicles and their implications in [...] Read more.

The study of aircraft gust behaviour is essential in aerodynamic and structural design and analysis, as well as in airworthiness certification. The particularities of fixed-wing Remotely Piloted Aircraft (RPA) demand a specific study of gust effects on these vehicles and their implications in RPA design and operation. The research presented here addresses the investigation of gust behaviour of RPA within the frame of conceptual design through three complementary approaches, which are respectively based on the assessment of gust and manoeuvring envelopes of RPA, the modelisation of multi-mission flight profiles of RPA towards the evaluation of the variations in gust load factor along the mission, and the analysis of the interaction of RPA conceptual design parameters with gust behaviour. These approaches are applied to various case studies, providing several key insights into the gust behaviour characteristics of RPA. These include the assessment of the operational conditions in which gust-induced stall may occur and the way in which they interact with typical mission conditions of RPA, the evaluation of the impact of mission parameters in RPA gust response along with the capability of identifying the most critical gust load factor condition for the set of considered design missions, and the ways in which undesirable gust effects may be mitigated in the conceptual design stage through the change in overall RPA design parameters. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

21 pages, 4916 KB

Open AccessArticle

Case Study of a Liquid-Hydrogen-Powered Aircraft Utilizing Cryogenic Conformal Wing Tanks

by Nils Roth, Marc Engelmann, Chang Xu and Barlas Türkyilmaz

Aerospace 2026, 13(5), 427; https://doi.org/10.3390/aerospace13050427 - 1 May 2026

Viewed by 336

Abstract

Liquid hydrogen (LH₂) has been identified as a potential solution to the ever-growing climate impact of the aviation sector. One of the key problems for the industry remains the provision of the necessary storage volume, which results from the low density [...] Read more.

Liquid hydrogen (LH₂) has been identified as a potential solution to the ever-growing climate impact of the aviation sector. One of the key problems for the industry remains the provision of the necessary storage volume, which results from the low density of hydrogen. The objective of this paper is to quantify the potential for structurally integrated conformal wing tanks for liquid hydrogen. The three wing tanks derived for the CHoSe project contain internal rib structures and are placed inside the center wingbox as well as from wing root to kink. The multidisciplinary aircraft design environment BLADE has been extended by the capabilities to complement liquid hydrogen fuselage tanks with wing tanks of varying area mass. Comparing short-to-medium range (SMR) aircraft with only fuselage tanks and with additional wing tanks resulted in key findings: for similar area mass assumptions for fuselage and wing tanks of 20 kg/m², no fuel burn benefit could be achieved. The decrease in fuselage length could not compensate for the increased structural tank masses. No significant load alleviation effect on the wing structure can be expected due to the limited mass and lever arm of the tanks inside the wing. Small efficiency gains can only be expected when synergistic stiffening effects with the load-carrying structure of the wings reduce the effective added area mass to lower values than for the fuselage tanks. Adding tanks further outbound than the wing kink deteriorates the performance, even for the most optimistic tank assumptions. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

19 pages, 4057 KB

Open AccessArticle

Experimental and Numerical Analysis of Laser-Welded GFRP–PBT Joints for Aerospace Components

by Ana-Teodora Untariu, Katarina Monkova, Liviu Marșavina, Nicușor-Alin Sîrbu and Sergiu-Valentin Galațanu

Aerospace 2026, 13(5), 426; https://doi.org/10.3390/aerospace13050426 - 1 May 2026

Viewed by 309

Abstract

This study investigates laser transmission welding of 30% glass fiber-reinforced polybutylene terephthalate (PBT-GF30). Injection-molded plates were used as base material, from which specimens were prepared, welded, and experimentally tested. The influence of key process parameters, including laser power, beam size, and scanning speed, [...] Read more.

This study investigates laser transmission welding of 30% glass fiber-reinforced polybutylene terephthalate (PBT-GF30). Injection-molded plates were used as base material, from which specimens were prepared, welded, and experimentally tested. The influence of key process parameters, including laser power, beam size, and scanning speed, on weld quality was systematically evaluated through an iterative optimization approach. An optimized parameter set (400 W laser power, reduced beam size, and increased scanning speed) enabled stable and repeatable weld formation with minimal thermal degradation. Experimental results were further supported by finite element analysis, showing good agreement between numerical and experimental data. The findings confirm the feasibility of laser welding for PBT-GF30 and its potential for aerospace applications requiring precision, weight reduction, and structural reliability. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

11 pages, 1394 KB

Open AccessArticle

RF Transmit-and-Receive MMIC Front-End for V-Band Inter-Satellite Link

by Giulio Venanzoni, Andrea Ricci, Mattia Riccardi, Patrick E. Longhi, Rocco Giofrè and Ernesto Limiti

Aerospace 2026, 13(5), 416; https://doi.org/10.3390/aerospace13050416 - 29 Apr 2026

Viewed by 190

Abstract

This research focuses on the design and simulation of a V-band single-chip transmit-and-receive front-end integrating an LNA, PA and switching functions for ISL terminals. Two technologies are compared: a 60 nm GaN/Si HEMT from MESC and a 100 nm GaAs HEMT from UMS. [...] Read more.

This research focuses on the design and simulation of a V-band single-chip transmit-and-receive front-end integrating an LNA, PA and switching functions for ISL terminals. Two technologies are compared: a 60 nm GaN/Si HEMT from MESC and a 100 nm GaAs HEMT from UMS. In Tx mode, the proposed design targets a saturated output power of at least 20 dBm and a power-added efficiency of no less than 5%. In Rx mode, the goal is 4 dB noise figure. In both cases, the small signal gain must exceed 20 dB across the 59–71 GHz band. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

23 pages, 958 KB

Open AccessArticle

Unlocking the Future of Aircraft Manufacturing: The Environmental Benefits of Laser Patterning for Surface Enhancement of Aircraft-Certified Alloys

by Luis Antonio Sanchez de Almeida Prado, Selim Coskun, Anne-Laure Cadène, Ramon Angel Antelo Reguengo, Jake Carter, Kyle Ito, Minok Park and Vassilia Zorba

Aerospace 2026, 13(5), 414; https://doi.org/10.3390/aerospace13050414 - 29 Apr 2026

Viewed by 300

Abstract

Surface protection and functional modification of aircraft-certified aluminum alloys are essential for corrosion resistance, durability, and long-term airworthiness. At the same time, increasingly restrictive environmental regulations motivate the development of alternatives to legacy wet-chemical surface treatments. This study presents an integrated assessment of [...] Read more.

Surface protection and functional modification of aircraft-certified aluminum alloys are essential for corrosion resistance, durability, and long-term airworthiness. At the same time, increasingly restrictive environmental regulations motivate the development of alternatives to legacy wet-chemical surface treatments. This study presents an integrated assessment of ultrafast femtosecond laser surface texturing as a surface functionalization approach for Aluminum 6061 alloys within an aerospace manufacturing and sustainability context. Ultrashort-pulse laser processing enables controlled micro- and nano-scale surface topographical modification with limited thermal impact, allowing adjustment of wettability and surface functionality while preserving bulk material integrity. As a dry and contactless process, femtosecond laser treatment eliminates the use of hazardous chemicals, reduces consumable inputs, and generates minimal secondary waste. A streamlined cradle-to-gate life cycle assessment conducted in accordance with ISO 14040/14044 indicates a lower global-warming potential per functional unit compared with conventional surface treatments, including anodization, plasma-assisted coatings, and organic coating systems. Complementary qualitative analyses addressing environmental health and safety, supply-chain risk, and ESG alignment indicate potential advantages related to occupational safety, regulatory compliance, waste management, and end-of-life recyclability. The investigation is performed on planar Aluminum 6061 reference surfaces with a treated area of 25 mm², providing a controlled laboratory-scale basis for analyzing process behavior, functional surface modification, and associated environmental metrics. Within this defined scope, the results support further evaluation of femtosecond laser surface texturing as a surface engineering option for future aerospace manufacturing. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Graphical abstract

19 pages, 3631 KB

Open AccessArticle

Using Commercial Off-the-Shelf Camera Systems for Remote Sensing and Public Engagement on the Small Satellite ROMEO

by Dominik Starzmann, Thorben Loeffler, Kevin Waizenegger, Michael Lengowski and Sabine Klinkner

Aerospace 2026, 13(5), 411; https://doi.org/10.3390/aerospace13050411 - 28 Apr 2026

Viewed by 315

Abstract

The Research and Observation in Medium Earth Orbit (ROMEO) mission, developed at the University of Stuttgart‘s Institute of Space Systems, seeks to demonstrate a cost-effective exploitation of the medium Earth orbit (MEO) for sustainable access to space. It uses a green propulsion system [...] Read more.

The Research and Observation in Medium Earth Orbit (ROMEO) mission, developed at the University of Stuttgart‘s Institute of Space Systems, seeks to demonstrate a cost-effective exploitation of the medium Earth orbit (MEO) for sustainable access to space. It uses a green propulsion system with water as propellant to reach up to 2500 km altitude starting from a 450 km sun-synchronous orbit (SSO). This paper presents the design and intended use of the ROMEO satellite as well as its two in-house developed camera systems, the public relations (PR) and the near-infrared (NIR) camera system. The PR camera system features two silicon sensors with a Bayer color pattern in a compact, lightweight package and in a cold redundant setup to reduce the impact of radiation-related degradation. Their wide field of view (128 × 96°) allows imaging of the complete visible Earth in the mission‘s final orbit and supports calibration of the Earthshine telescope, which is the primary payload. The NIR camera system uses a commercial InGaAs sensor with a high quantum efficiency up to 1700 nm, coupled to a 100 mm focal length optics assembly that yields a ground sampling distance of 45 m in the initial orbit. Its scientific objectives include monitoring gas flares and wildfires, which are relevant to climate change research, and demonstrating an exoplanet transit detection—an unprecedented capability for a small satellite using a commercial off-the-shelf InGaAs sensor in the NIR spectrum. This paper demonstrates that ROMEO’s compact, low-mass camera systems meet mission constraints while enabling a broad spectrum of scientific and outreach activities. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

16 pages, 2346 KB

Open AccessArticle

Accelerated Refueling of Type IV Hydrogen Pressure Tanks by Passive Means: Thermal Material Characterization and Evaluation

by Nico Liebers and Sven Ropte

Aerospace 2026, 13(5), 403; https://doi.org/10.3390/aerospace13050403 - 24 Apr 2026

Viewed by 288

Abstract

The significant heat generated during the refueling of hydrogen pressure tanks may exceed the permissible 85 °C temperature limit for type IV tanks. Common countermeasures such as hydrogen pre-cooling or long filling times are energy- and time-consuming; hence, in this paper, passive means [...] Read more.

The significant heat generated during the refueling of hydrogen pressure tanks may exceed the permissible 85 °C temperature limit for type IV tanks. Common countermeasures such as hydrogen pre-cooling or long filling times are energy- and time-consuming; hence, in this paper, passive means through thermally better-suited materials are examined. State-of-the-art and alternative materials are first characterized and finally compared using a transient heat model. Different material combinations are compared in terms of the maximum temperature and weight in a typical filling scenario. As alternative liner materials, thermoplastics filled with short carbon fibers, minerals, and graphite were selected to improve thermal properties. For the composite overwrap, copper-coated carbon fibers were chosen. The findings show that the liner is the bottleneck while transferring heat from the inner to the outer tank surface. Using graphite-filled thermoplastics as the liner material shows the greatest potential regarding thermal optimization with only a slight weight increase. Using copper-coated carbon fibers additionally further reduces the maximum temperature but results in a significant weight increase. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

28 pages, 10687 KB

Open AccessArticle

Investigation of Liquid Hydrogen Tank Structural Integration Concepts for Regional Aircraft

by Panagiotis Gyftos, Ioannis Sioutis and George Lampeas

Aerospace 2026, 13(4), 388; https://doi.org/10.3390/aerospace13040388 - 20 Apr 2026

Viewed by 504

Abstract

Liquid hydrogen (LH₂) as an energy source is viewed as a potential path to achieve carbon neutral commercial aviation, albeit accompanied by a plethora of structural, thermal and safety challenges that still need to be resolved. With respect to a LH [...] Read more.

Liquid hydrogen (LH₂) as an energy source is viewed as a potential path to achieve carbon neutral commercial aviation, albeit accompanied by a plethora of structural, thermal and safety challenges that still need to be resolved. With respect to a LH₂ tank’s structural integration aspect, static, damage tolerance and impact/crashworthiness responses need to be investigated. Ιn the present work, an efficient structural integration concept of LH₂ tanks into a Regional Commercial Aircraft fuselage is proposed, analyzed and preliminary designed, as part of the Clean Aviation project HERFUSE. The main purpose of the work is the feasibility assessment of introducing adhesively bonded solutions in the connection of LH₂ tanks to the aircraft fuselage. The initial design of the potential mounting system configuration was investigated via a finite element parametric simulation model that was developed for this purpose and used to analyze different variations in the proposed concept, under certification relevant load cases. Different variations in the mounting system were assessed, considering their effect on the stress concentrations developed in the fuselage and the tank structure, as well as induced deformations and potential joints debonding. The results indicated that the utilization of adhesive bonding elements in the design of an LH₂ tank integration system is conceptually efficient, although the specific configuration-related shortcomings that were identified need to be tackled. As far as the preliminary design study results are concerned, the minimum required number of joining elements were identified and an initial mass prediction of the mounting system was performed to be used as initial value in the entire hybrid–electric novel aircraft design loop. Future studies on the detailed design and sizing of the mounting system, as well as to incorporate dynamic crash analyses and implementation of energy absorbing elements are needed. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

19 pages, 535 KB

Open AccessArticle

Life Cycle Assessment of Innovative Propulsion Technologies for Regional Aviation Within the HERA Project

by Felicia Molinaro and Marco Fioriti

Aerospace 2026, 13(4), 383; https://doi.org/10.3390/aerospace13040383 - 17 Apr 2026

Viewed by 423

Abstract

Hybrid-electric propulsion and alternative energy carriers are being considered to mitigate the climate impact of short-range regional aviation. Within this framework, the HERA (Hybrid Electric Regional Architecture) project investigates advanced propulsion architectures for a next-generation 72 passenger regional platform. This work presents a [...] Read more.

Hybrid-electric propulsion and alternative energy carriers are being considered to mitigate the climate impact of short-range regional aviation. Within this framework, the HERA (Hybrid Electric Regional Architecture) project investigates advanced propulsion architectures for a next-generation 72 passenger regional platform. This work presents a cradle-to-grave Life Cycle Assessment of two HERA reference configurations and compares them with a conventional 70 passenger turboprop representative of current service aircraft. The analysis focuses on lithium–sulphur batteries, proton exchange membrane fuel cells, liquid hydrogen storage tanks, and electric motors. The assessment is implemented through a parametric LCA tool supported by a detailed Life Cycle Inventory based on Ecoinvent v3.8 and evaluated using ReCiPe 2016 midpoint indicators. The system boundary includes raw material extraction, manufacturing and assembly, operation under defined mission profiles, maintenance with component replacement, and End-of-Life (EoL) treatment. Results show that the operational phase remains the main driver of climate change impacts, exceeding 95% of total CO₂ equivalent emissions across configurations. The battery-based hybrid reduces fuel consumption but increases manufacturing and maintenance burdens. The fuel cell configuration shows a more balanced life cycle profile, with platinum identified as a critical hotspot. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

39 pages, 2980 KB

Open AccessArticle

A Roadmap for Twin-Fuselage Aircraft Conceptual Design

by Álvaro Cobo-González and Cristina Cuerno-Rejado

Aerospace 2026, 13(4), 379; https://doi.org/10.3390/aerospace13040379 - 17 Apr 2026

Viewed by 576

Abstract

Unconventional aircraft configurations show significant potential to reduce aviation’s environmental footprint. Computerized conceptual design environments enable the design of unconventional aircraft concepts and the comparison of their performance and environmental impact against conventional Tube-And-Wing aircraft and other competing unconventional layouts. However, no environment [...] Read more.

Unconventional aircraft configurations show significant potential to reduce aviation’s environmental footprint. Computerized conceptual design environments enable the design of unconventional aircraft concepts and the comparison of their performance and environmental impact against conventional Tube-And-Wing aircraft and other competing unconventional layouts. However, no environment has yet been specifically developed to support the Twin-Fuselage configuration. This paper addresses this gap by analyzing the advantages of the Twin-Fuselage configuration, identifying a potentially relevant design space, and compiling the existing conceptual-level design methods applicable to this layout. Building on these results, a roadmap for the conception of computerized conceptual design environments supporting Twin-Fuselage aircraft is presented. A structured environment architecture is proposed considering current trends and limitations of state-of-the-art environments supporting other unconventional configurations. The proposed modules for each discipline are also outlined. Finally, the main research gaps in Twin-Fuselage aircraft conceptual design are identified, highlighting and prioritizing the developments needed to enable a fully operational Twin-Fuselage-supporting computerized conceptual design environment. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

24 pages, 17020 KB

Open AccessArticle

Operational Modal Analysis of Aeronautical Structures via Tangential Interpolation

by Gabriele Dessena, Marco Civera and Oscar E. Bonilla-Manrique

Aerospace 2026, 13(4), 378; https://doi.org/10.3390/aerospace13040378 - 16 Apr 2026

Viewed by 312

Abstract

Over the last decades, progress in modal analysis has enabled the increasingly routine use of modal parameters for applications such as structural health monitoring and finite element model updating. For output-only identification, or operational modal analysis (OMA), widely adopted approaches include stochastic subspace [...] Read more.

Over the last decades, progress in modal analysis has enabled the increasingly routine use of modal parameters for applications such as structural health monitoring and finite element model updating. For output-only identification, or operational modal analysis (OMA), widely adopted approaches include stochastic subspace identification (SSI) methods and the Natural Excitation Technique, combined with the Eigensystem Realization Algorithm (NExT-ERA). Nevertheless, SSI-based techniques may become cumbersome on large systems, while NExT-ERA fitting can struggle when measurements are contaminated by noise. To alleviate these, this work investigates an OMA frequency-domain formulation for aeronautical structures by coupling the Loewner Framework (LF) with NExT, yielding the proposed NExT-LF method. The method exploits the computational efficiency of LF, due to the effectiveness of tangential interpolation, together with the impulse response function retrieval enabled by NExT. NExT-LF is assessed on two experimental benchmarks: the eXperimental BeaRDS 2 high-aspect-ratio wing main spar and an Airbus Helicopters H135 bearingless main rotor blade. The identified modal parameters are compared against available experimental references and results obtained via SSI with a Canonical Variate Analysis and NExT-ERA. The results show that the modes identified by NExT-LF correlate well with benchmark data, particularly for high-amplitude tests and in the low-frequency range. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

24 pages, 1244 KB

Open AccessArticle

Selection Criteria for a Fuel-Cell-Based Propulsion Architecture of a Regional Box-Wing Aircraft

by Ulrich Carsten Johannes Rischmüller and Mirko Hornung

Aerospace 2026, 13(4), 358; https://doi.org/10.3390/aerospace13040358 - 13 Apr 2026

Viewed by 398

Abstract

To reduce the impact of aviation on the environment, a multitude of concepts must be evaluated to enable subsequent targeted developments. The reduction of on-board energy requirements through the aero-propulsive coupling of a box-wing configuration can represent one possible approach. It enables a [...] Read more.

To reduce the impact of aviation on the environment, a multitude of concepts must be evaluated to enable subsequent targeted developments. The reduction of on-board energy requirements through the aero-propulsive coupling of a box-wing configuration can represent one possible approach. It enables a decreased environmental impact by cutting the energy required and—in the configuration under consideration—by using hydrogen fuel cells as power generators. To fully exploit the advantages of such a concept, different propulsion system architectures were analyzed. Decision criteria were developed to select the most sensible powertrain architecture for the box-wing regional aircraft considering component and aircraft-level effects in a two-phased approach; following a qualitative preselection, a multi-criteria decision analysis was employed. Fuselage, fairing and nacelle-bound architecture options for the 70-passenger aircraft with a projection of its powertrain characteristics into the year 2045 are shown and compared. The placement of propulsion system components as well as their characteristics play a major role in the downselection of propulsion architecture options, especially considering the requirements placed by the liquid hydrogen energy storage. Due to low aerodynamic interference with the specific aero-propulsive arrangement, its high safety characteristics, synergistic potential with other systems, and not least, ease of integration, a compact propulsion system placement forward of the front hydrogen tank is considered most beneficial on aircraft level. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

30 pages, 5815 KB

Open AccessArticle

Engine Design Study for Free Double Piston Integrated Composite Cycle Engine

by Yu-Hsuan Lin, Gregory Uhl, Florian Winter, Alexandros Lessis, Fabio Witzgall and Arne Seitz

Aerospace 2026, 13(4), 354; https://doi.org/10.3390/aerospace13040354 - 10 Apr 2026

Viewed by 386

Abstract

The Composite Cycle Engine (CCE) enhances the conventional Joule/Brayton cycle by replacing the high-pressure compressor with a high-quality piston-based gas generator that enables extremely high compression, combustion, and expansion of the working fluid before entering the classic Joule burner. This piston-based topping cycle [...] Read more.

The Composite Cycle Engine (CCE) enhances the conventional Joule/Brayton cycle by replacing the high-pressure compressor with a high-quality piston-based gas generator that enables extremely high compression, combustion, and expansion of the working fluid before entering the classic Joule burner. This piston-based topping cycle unlocks much more efficient fuel utilization. This paper studies a CCE concept featuring a system of free double piston (FDP) units for a potential long-range (LR) application in 2045, benchmarked against an advanced turbofan engine representative of the same time frame. In-house-developed simulation tools for the piston system and the overall power plant, as well as aircraft non-linear trade factor analysis, are used for different levels of conceptual assessment. First, the cooling demand inside the FDP system is determined. An engine cycle parametric study is then performed for the design point top-of-climb (ToC). Off-design performance is further studied, demonstrating a 9.3% improvement in thrust-specific fuel consumption (TSFC) in cruise relative to the baseline engine. After incorporating the engine weight and nacelle geometry effects, the engine reaches a total mission fuel burn reduction of around 14.7% compared to the baseline engine. The concept evaluation shows the fuel burn potential of the CCE in the future LR aviation sector and lays the foundation for further climate impact analysis. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

27 pages, 6553 KB

Open AccessArticle

Scaled Test Program Strategy of Skin Heat Exchanger for Thermal Management in Hybrid Electric Regional Aircraft

by Benigno J. Lázaro and Ezequiel González-Martínez

Aerospace 2026, 13(4), 353; https://doi.org/10.3390/aerospace13040353 - 10 Apr 2026

Viewed by 296

Abstract

The strategy developed to carry out a scaled test program aimed at reproducing the behavior of skin heat exchangers to alleviate the heat dissipation requirements in future hybrid electric propulsion regional aircrafts is presented. The test program is intended to reproduce the dimensionless [...] Read more.

The strategy developed to carry out a scaled test program aimed at reproducing the behavior of skin heat exchangers to alleviate the heat dissipation requirements in future hybrid electric propulsion regional aircrafts is presented. The test program is intended to reproduce the dimensionless thermal response characterizing the skin heat exchanger on a predefined nominal cruise flight operation, while conducting the tests in a wind tunnel operating at low velocities and near-standard atmospheric conditions. For that purpose, dimensional analysis is used to define the geometrical scale and approach flow conditions in the wind tunnel test program, so that the dimensionless parameters describing the skin heat exchanger thermal response resemble the ones taking place under nominal flight conditions. The validation of the scaling strategy is achieved by comparing dimensionless parameters characterizing the turbulent momentum and heat transfer processes taking place at the skin heat exchanger/airflow interface surface in the flight and wind tunnel environments, by using CFD analysis based on two-equation

k - ϵ

and SST RANS turbulence modeling. The comparison reveals that the adopted wind tunnel strategy is indeed capable of closely reproducing the heat transfer process taking place in the flight environment, thus paving the way to achieve mid TLR validation of the skin heat exchanger technology. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

32 pages, 4275 KB

Open AccessArticle

Steps Towards the Validation of the Simplified Automated Approach for a Preliminary Safety Assessment via Scaled Flight Testing

by Alexander Kieß, Joachim Siegel, Eskil Jonas Nussbaumer and Andreas Strohmayer

Aerospace 2026, 13(4), 343; https://doi.org/10.3390/aerospace13040343 - 7 Apr 2026

Viewed by 316

Abstract

This study presents the application of an in-house developed safety assessment method on the scaled flight demonstrator e-Genius-Mod, which is equipped with distributed electric propulsion. Thereby, simplified aerodynamic and propulsive models are derived from existing flight test data. The safety assessment method is [...] Read more.

This study presents the application of an in-house developed safety assessment method on the scaled flight demonstrator e-Genius-Mod, which is equipped with distributed electric propulsion. Thereby, simplified aerodynamic and propulsive models are derived from existing flight test data. The safety assessment method is extended by modeling approaches for spanwise lift distribution and propeller slipstream effects on lift generation to incorporate an approximation of aero-propulsive effects. Selected failure case scenarios, namely single propulsor failures, are used to define suitable flight test scenarios as preparation for future validation of model predictions against flight test data. The application of the safety assessment method is shown to yield valuable predictions of failure effects on top-level aircraft performance and indicates that yaw moment-related failure effects are still dominant. Therefore, the effect of reducing vertical tail size on aircraft controllability and performance is examined. Model predictions indicate that propulsor failures at high thrust and low speed may exceed the yaw control authority of the aircraft, especially for the configurations with reduced vertical tail size. Furthermore, a simplified non-dimensionalised failure case depiction is presented to ease the transfer of insights to larger-scale aircraft designs and different powertrain architectures. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

13 pages, 4494 KB

Open AccessArticle

Global Impact of Aviation Contrails

by Octavian Thor Pleter and Cristian Emil Constantinescu

Aerospace 2026, 13(4), 324; https://doi.org/10.3390/aerospace13040324 - 31 Mar 2026

Viewed by 1680

Abstract

Avoiding contrails is one of the recent trends in ATM. Aviation contrails are considered a significant non-CO₂ environmental factor worth avoiding even with a CO₂ increase (lower-level cruise or horizontal avoidance, both burning more fuel). This paper is a study of [...] Read more.

Avoiding contrails is one of the recent trends in ATM. Aviation contrails are considered a significant non-CO₂ environmental factor worth avoiding even with a CO₂ increase (lower-level cruise or horizontal avoidance, both burning more fuel). This paper is a study of the global impact of aviation on global warming considering contrails and CO₂ trade-offs. In the literature, there are two concepts on why contrails are detrimental to the environment: (i) Daytime persistent contrails have a positive effect by reflecting the Sun’s rays back, whereas the contrails persisting into nighttime need to be avoided because they block the cooling of the planet by radiation—the overall impact is negative; (ii) too much humidity is injected into the tropopause by aircraft regardless of the type of contrails, persistent or not, and even by the flights without contrails. In hypothesis (ii), contrail avoidance is not the issue, since humidity is generated by the turbine engines regardless of the visibility of the water molecules (ice crystals or water droplets). Regarding hypothesis (i), the study analysed the Earth’s reflections contributing to albedo and the Earth’s emissions at the top of the atmosphere in infrared (day and night) over 25 years (2000–2025) from CERES data and found correlations with the two pandemic years, when the number of flights was significantly reduced, to understand the real environmental impact of aviation. The conclusion is that most of the time, contrails increase the Earth’s albedo, having a positive environmental impact. The damage to the environment comes mostly from 2% of flights, mainly over Europe, and the paper puts forward some practical proposals to regulate these flights, instead of complex contrail avoidance applied at the ATM level for all flights. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

25 pages, 2080 KB

Open AccessArticle

Design and Simulation Analysis of Attitude Control Algorithms for OPS-SAT-1

by Juan Carlos Crespo, María Royo, Álvaro Bello, Karl Olfe, Victoria Lapuerta and José Miguel Ezquerro

Aerospace 2026, 13(4), 320; https://doi.org/10.3390/aerospace13040320 - 29 Mar 2026

Viewed by 483

Abstract

This work presents the design of an attitude control experiment for onboard OPS-SAT-1 satellite execution, conceived with inherent extensibility to future mission architectures. OPS-SATs are ESA nanosatellite mission series designed as an in-orbit testbed for validating novel software and control techniques under real [...] Read more.

This work presents the design of an attitude control experiment for onboard OPS-SAT-1 satellite execution, conceived with inherent extensibility to future mission architectures. OPS-SATs are ESA nanosatellite mission series designed as an in-orbit testbed for validating novel software and control techniques under real space conditions, OPS-SAT-1 being the first mission. Equipped with an advanced payload computer, OPS-SAT-1 enabled experimentation with innovative mission operations, including real-time attitude control strategies. Two attitude control algorithms, a modified Proportional–Integral–Derivative (mPID) and a fuzzy logic controller, were designed and implemented for the OPS-SAT-1. The design methodology applied to these controllers consisted of (i) modelling the space environment and satellite characteristics, (ii) assessing actuator feasibility, (iii) determining the operational ranges for attitude error and angular velocity, (iv) parametrizing controllers within these ranges, (v) fine-tuning controllers using multi-objective genetic optimization, and (vi) robustness analysis using the Monte Carlo method. Despite the technical issues related to communication with the OPS-SAT-1 hardware, which prevented the execution of the experiment in orbit, this work presents the simulation results that were obtained. These results indicate that fuzzy logic controllers may outperform PID controllers in terms of the accumulated error, settling time and steady-state error, whereas power efficiency appears to be less robust than in the PID. This suggest that a large uncertainty in the model could lead the PID to become more efficient. Near the nominal scenario, the fuzzy controller achieves superior error–cost trade-offs, enabling precise attitude stabilization with lower energy consumption. These findings suggest the potential advantages of modern control approaches compared to classical methods, which will be further assessed through future in-orbit experiments. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

21 pages, 6850 KB

Open AccessArticle

Design and Simulation-Based Evaluation of the FuzzyBuzz Attitude Control Experiment on the Astrobee Platform

by María Royo, Juan Carlos Crespo, Ali Arshadi, Cristian Flores, Karl Olfe and José Miguel Ezquerro

Aerospace 2026, 13(4), 317; https://doi.org/10.3390/aerospace13040317 - 28 Mar 2026

Viewed by 405

Abstract

Recent space missions demand higher pointing accuracy, smoother attitude transitions and lower energy consumption than those typically achievable with conventional control approaches. This motivates the exploration of intelligent and nonlinear control methods. The FuzzyBuzz experiment investigates the application of fuzzy logic for spacecraft [...] Read more.

Recent space missions demand higher pointing accuracy, smoother attitude transitions and lower energy consumption than those typically achievable with conventional control approaches. This motivates the exploration of intelligent and nonlinear control methods. The FuzzyBuzz experiment investigates the application of fuzzy logic for spacecraft attitude control using NASA’s Astrobee robotic system aboard the International Space Station. Unlike traditional control methods, fuzzy logic introduces a rule-based approach capable of handling uncertainties and nonlinearities inherent in space environments, making it particularly suited for autonomous operations in microgravity. The objective of FuzzyBuzz is to evaluate the effectiveness of fuzzy controllers compared to traditional linear ones, such as Proportional–Integral–Derivative (PID) and

H_{\infty}

controllers. In addition, a comparison with a nonlinear controller based on a Model Predictive Control (MPC) strategy is considered. The controllers will be tested through predefined attitude maneuvers, evaluating precision, energy efficiency, and real-time adaptability. This work presents the design of the FuzzyBuzz experiment, including the software architecture, simulation environment, experiment protocol, and the development of a fuzzy logic-based attitude control system for Astrobee robots. The proposed fuzzy controller and a PID controller are optimized using a Multi-Objective Particle Swarm Optimization (MOPSO) method, providing a range of operational points with different trade-offs between two metrics, related to convergence time and energy consumption. Results show that the PID controller is better suited for scenarios demanding low convergence times, whereas the fuzzy controller provides smoother responses, reduced steady-state error, and maintains convergence under significant parametric uncertainties. Results from

H_{\infty}

and MPC controllers will be reported once the in-orbit experiment is performed. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

14 pages, 16685 KB

Open AccessArticle

Operability Implications of Speed Variability in Hybridised Vaneless Counter-Rotating Axial Compressor Concepts

by Jan Nittka and Dieter Peitsch

Aerospace 2026, 13(4), 304; https://doi.org/10.3390/aerospace13040304 - 25 Mar 2026

Viewed by 340

Abstract

The aviation sector faces the challenge of reducing emissions while meeting growing demand for passenger transport. Recent research has proposed a hybridised axial compressor concept using a vaneless, counter-rotating configuration with independently electrically driven rotors. Earlier work showed the aerodynamic feasibility of this [...] Read more.

The aviation sector faces the challenge of reducing emissions while meeting growing demand for passenger transport. Recent research has proposed a hybridised axial compressor concept using a vaneless, counter-rotating configuration with independently electrically driven rotors. Earlier work showed the aerodynamic feasibility of this approach and identified the need for extended compressor maps to capture performance variations with hybridisation degree and speed ratio. This study explores the operational potential of such compressors in greater depth, focusing on how variable rotor speeds can unlock aerodynamic benefits and expand the operating envelope for hybrid-electric propulsion in regional aircraft and rotorcraft. Using mean line analysis, it is shown that independently driven rotors can operate effectively across a wide range of speed ratios. This flexibility enables the compressor to maintain high efficiency over diverse operating conditions, including part-load scenarios, typical of hybrid-electric missions. Independent speed control also offers a means of actively managing compressor stability. Compared to the conventional design the operating range can be significantly increased without relying on traditional stability measures such as variable stator vanes or bleed valves, reducing system weight and complexity. In this way the operating range of the hybrid compressor could be increased by up to 50%, while the number of blade rows could be reduced by up to 30% and the mass flow range increased by up to 33%. Together with the potential efficiency gains of counter-rotating concepts, this underscores its promise for future low-emission propulsion systems. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

27 pages, 1222 KB

Open AccessArticle

A Revised Shear Panel Formulation for Parallelogram Panels

by Moritz Bäß and Kai-Uwe Schröder

Aerospace 2026, 13(4), 301; https://doi.org/10.3390/aerospace13040301 - 24 Mar 2026

Viewed by 303

Abstract

The growing complexity of large-scale, thin-walled structures can be managed through the use of hierarchical modelling approaches. In aeroelastic wing design, efficient models are needed during the concept and preliminary design phases, as a large design space must be explored. However, in structural [...] Read more.

The growing complexity of large-scale, thin-walled structures can be managed through the use of hierarchical modelling approaches. In aeroelastic wing design, efficient models are needed during the concept and preliminary design phases, as a large design space must be explored. However, in structural engineering, these models are often reduced-order models that use time-consuming CAD-based FEM models to capture important detail. Shear panel theory has historically been used for such problems, even though it has been reported that the method cannot model the bending-induced torsion of swept wings. Additionally, the assumptions used to derive the parallelogram panel have been criticised for being inconsistent, resulting in deviations in stiffness and stresses. This paper presents a novel formulation for parallelogram shear panels and a novel smearing approach for normal stiffness that does not lead to an overestimation of in-plane bending stiffness. These new formulations are validated through comparisons with FEM reference models of single panels and swept and unswept wings. The results demonstrate that the stiffness and stress state of the new panel formulation match those of the reference model, and that using the formulation achieves the desired bending–torsion coupling of swept wings. Furthermore, the proposed smearing approach allows wing sections to be modelled with the fewest possible degrees of freedom while avoiding the overestimation of bending stiffness. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

39 pages, 1539 KB

Open AccessArticle

Systematic Identification of Stakeholder Needs for the Design of Sustainable Long-Range Aircraft of 2050

by Dionysios Markatos, Harry Psihoyos, Bram Peerlings, Ligeia Paletti, Luca Boggero, Panagiotis Pantelas, Elise Scheers, Lukas Söffing, James Page, Spiros Pantelakis, Arianna Pasqualone and Angelos Filippatos

Aerospace 2026, 13(4), 299; https://doi.org/10.3390/aerospace13040299 - 24 Mar 2026

Viewed by 1894

Abstract

Designing long-range aircraft for 2050 is a complex, multi-disciplinary challenge requiring integration of technical performance with sustainability objectives, including environmental responsibility, economic viability, circularity, and social acceptance. Existing studies on stakeholder needs in aviation are limited, focusing on specific groups, technical requirements, or [...] Read more.

Designing long-range aircraft for 2050 is a complex, multi-disciplinary challenge requiring integration of technical performance with sustainability objectives, including environmental responsibility, economic viability, circularity, and social acceptance. Existing studies on stakeholder needs in aviation are limited, focusing on specific groups, technical requirements, or individual aircraft concepts, resulting in a fragmented understanding of sustainability-driven needs. This study addresses this gap by systematically identifying stakeholders who influence long-range aircraft development and deriving 191 stakeholder needs, organized into coherent categories spanning manufacturers, operators, passengers, regulators, communities, and energy suppliers. Needs were classified across technical, environmental, economic, circular, and social dimensions, based on a comprehensive review of academic and grey literature, regulatory documents, and industry sources. The resulting framework provides a structured, reproducible approach to support conceptual aircraft design and requirement definition within the European EXAELIA project. By integrating multi-dimensional stakeholder expectations early in the design process, this approach facilitates aircraft development that is technically robust, environmentally sustainable, economically viable, circular, and socially inclusive, demonstrating the value of a stakeholder-driven method for sustainable systems engineering. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

22 pages, 37782 KB

Open AccessArticle

Fast Data-Driven Noise Prediction for an Aircraft in Unconventional Configuration Using Flight Test Data

by Dominik Eisenhut and Andreas Strohmayer

Aerospace 2026, 13(3), 292; https://doi.org/10.3390/aerospace13030292 - 19 Mar 2026

Viewed by 401

Abstract

New, highly integrated, disruptive aircraft concepts are being devised to reduce aviation’s environmental footprint, but their performance is oftentimes challenging for the aircraft designer to assess. Furthermore, these novel aircraft often introduce new risks, such as noise, that cannot be addressed quickly by [...] Read more.

New, highly integrated, disruptive aircraft concepts are being devised to reduce aviation’s environmental footprint, but their performance is oftentimes challenging for the aircraft designer to assess. Furthermore, these novel aircraft often introduce new risks, such as noise, that cannot be addressed quickly by available methods. Overall, in the pursuit of more environmental friendly aircraft configurations and the lack of methods to design such aircraft, aircraft-level trade-offs between noise and performance are challenging. The present study aims to close this gap by using a machine learning-based approach for one unconventional aircraft to investigate usability in the early stages of aircraft design. Based on overflight noise measurements, noise models for this aircraft are created with different approaches and base models. The single-output models show good performance, with mean absolute errors around 1 dB, good rank correlations and R² scores above 0.9. Support vector regression provides reasonably good agreement from experiments requiring only a small effort to set up; Neural Networks achieve better performance, but increased effort is required to obtain the model. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

16 pages, 3521 KB

Open AccessArticle

Shape Optimization of Aircraft Outflow Valve for Maximum Thrust Recovery

by Tasos Karageorgiou, Pela Katsapoxaki, Michael Moeller and El Hassan Ridouane

Aerospace 2026, 13(3), 288; https://doi.org/10.3390/aerospace13030288 - 18 Mar 2026

Viewed by 345

Abstract

The present study demonstrates a step-by-step method for optimizing the outflow valve geometry and maximizing thrust generation. In this system, the skin-mounted OutFlow Valve (OFV) acts as a convergent–divergent nozzle and, as such, the De Laval nozzle equations are considered as guidance for [...] Read more.

The present study demonstrates a step-by-step method for optimizing the outflow valve geometry and maximizing thrust generation. In this system, the skin-mounted OutFlow Valve (OFV) acts as a convergent–divergent nozzle and, as such, the De Laval nozzle equations are considered as guidance for the shape optimization. The performance of the skin-mounted flapped OFV optimized designs is assessed with a combination of analytical equations and Computational Fluid Dynamics (CFD) methods. The three-dimensional Reynolds-Averaged Navier–Stokes (RANS) yield reliable thrust recovery estimates and reveal key aspects of the aerodynamic flow behaviour through the valve, highlighting the interaction between the skin-mounted flapped OFV components. The results compare well with the analytical approach, providing a basis upon which a skin-mounted flapped OFV can be tailored for a specific mission. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

25 pages, 2898 KB

Open AccessArticle

A Multi-Fidelity Aeroelastic Toolchain: From UAVs to Hydrogen Transport Aircraft

by Fanglin Yu, Carlos Sebastia Saez and Mirko Hornung

Aerospace 2026, 13(3), 286; https://doi.org/10.3390/aerospace13030286 - 18 Mar 2026

Viewed by 388

Abstract

The increasing adoption of high-aspect-ratio wings to improve aerodynamic efficiency introduces significant structural flexibility, necessitating the integration of aeroelastic considerations into the earliest design stages. While critical, existing frameworks often lack the multi-fidelity modeling capabilities and automated workflows required to bridge conceptual design [...] Read more.

The increasing adoption of high-aspect-ratio wings to improve aerodynamic efficiency introduces significant structural flexibility, necessitating the integration of aeroelastic considerations into the earliest design stages. While critical, existing frameworks often lack the multi-fidelity modeling capabilities and automated workflows required to bridge conceptual design and high-fidelity verification. This paper presents the Flexible Aero-Structural Toolbox (FAST), a modular framework supporting both beam and shell structural modeling and integrated with MSC NASTRAN for industry-standard aeroelastic simulation. The toolbox’s capabilities are demonstrated through modal, flutter, and static aeroelastic analyses across three distinct configurations: the P-FLEX UAV, the Ventus sailplane, and an A320-like transport aircraft, including its hydrogen-powered derivative. Results show that FAST accurately captures the aeroelastic characteristics of high-aspect-ratio wings and effectively predicts loads for large-scale flexible airframes. Notably, analysis of the hydrogen configuration reveals a significant 25% increase in wing bending moments for the “dry” wing condition compared to standard kerosene configurations. Furthermore, the tool’s ability to model unconventional mass distributions, such as cryogenic fuel tanks, highlights its adaptability for disruptive aircraft technologies. The study concludes that FAST provides a versatile, physics-based decision-making environment that significantly improves efficiency in the aeroelastic analysis process without compromising simulation fidelity. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

19 pages, 6023 KB

Open AccessArticle

Conceptual Study of a Manned European Martian Rotorcraft for Passenger and Cargo Transport in Future Mars Missions

by Jakub Kocjan, Robert Rogólski, Stanisław Kachel and Łukasz Kiszkowiak

Aerospace 2026, 13(3), 280; https://doi.org/10.3390/aerospace13030280 - 17 Mar 2026

Viewed by 451

Abstract

This work presents a space-oriented extension of an existing research program focused on developing innovative approaches and design solutions for rotorcraft. The study builds upon recent research conducted at the Military University of Technology, where new methods for main rotor optimization using parametric [...] Read more.

This work presents a space-oriented extension of an existing research program focused on developing innovative approaches and design solutions for rotorcraft. The study builds upon recent research conducted at the Military University of Technology, where new methods for main rotor optimization using parametric modeling were developed. The primary objective of this research is to investigate the feasibility of designing a rotorcraft capable of operating in the Martian environment. The proposed vehicle is intended to perform vertical takeoff, flight, and landing; sustain at least two hours of continuous operation; and transport a pilot with either a passenger or an equivalent payload of 100 kg. Additionally, the rotorcraft should be capable of being restored to an airworthy condition after each mission and prepared for reuse while maintaining its operational capabilities. Preliminary performance analyses were conducted based on Martian atmospheric conditions. Analytical models implemented in dedicated computational tools were used to estimate rotor dimensions, performance, and trim requirements. Several rotor configurations were evaluated to assess the feasibility of manned flight with an additional payload under extraterrestrial conditions. The results identify key limitations, risks, and technological challenges, while also highlighting potential design opportunities. The study culminates in a conceptual design proposal for a future Martian rotorcraft mission. The findings demonstrate the applicability of the proposed methodology and provide a foundation for further research and development in planetary rotorcraft systems. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

29 pages, 35494 KB

Open AccessArticle

Future Highly Efficient Engines with Solid Oxide Fuel Cell–Gas Turbine Coupling: System Modeling Study and Comparison of Directly and Indirectly Coupled SOFC–GT Systems

by Pascal Köhler, Jan Hollmann, Anis Taissir, Marc P. Heddrich and Stephan Kabelac

Aerospace 2026, 13(3), 263; https://doi.org/10.3390/aerospace13030263 - 11 Mar 2026

Cited by 1 | Viewed by 914

Abstract

This study investigates hybridization of a solid oxide fuel cell with a gas turbine (SOFC–GT) for application in an ATR 72 regional aircraft. Several challenges hinder its viability, including the low gravimetric power density of SOFC stacks and stringent heat integration constraints. A [...] Read more.

This study investigates hybridization of a solid oxide fuel cell with a gas turbine (SOFC–GT) for application in an ATR 72 regional aircraft. Several challenges hinder its viability, including the low gravimetric power density of SOFC stacks and stringent heat integration constraints. A steady-state model sweeps the cell voltage, overall pressure ratio (OPR), and a bounded turbine inlet temperature (TIT). This study introduces a new corrected power-share metric. This metric accounts for operating-point-dependent SOFC power density. It also enables weight-relevant comparisons. We analyze two types of coupling: direct and indirect. In the direct coupling, SOFC cooling fixes the core airflow and a TIT ceiling imposes a minimum power share. In the indirect coupling, a bypass decouples SOFC and gas turbine operation, incurring an efficiency penalty. We compare two heat-integration architectures: preheating with SOFC cathode exhaust versus low-pressure turbine (LPT) exhaust. Results show that direct coupling achieves efficiencies above 65% at high-corrected power shares, whereas indirect coupling offers greater operational flexibility but lower efficiency. Cathode exhaust preheating improves feasibility and outperforms LPT recuperation by more than 15% efficiency at low-to-mid-corrected power shares. However, LPT recuperation attains higher peak efficiency only at high-corrected power shares and within a narrow OPR window, which is limited by recuperator pinch. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

23 pages, 4907 KB

Open AccessArticle

Sustainable Waste Heat Utilization in Jet Engines via Integrated Guide Vane Heat Exchanger

by Gernot Burghard Hedjri-Peyfuss and Helmut Mad

Aerospace 2026, 13(3), 253; https://doi.org/10.3390/aerospace13030253 - 9 Mar 2026

Viewed by 422

Abstract

High-performance geared turbofan engines generate significant heat within the planetary power gearbox. This study presents the thermal design of an integrated fan guide vane heat exchanger aimed at recovering gearbox heat losses with minimal pressure loss and converting them into useful propulsive energy [...] Read more.

High-performance geared turbofan engines generate significant heat within the planetary power gearbox. This study presents the thermal design of an integrated fan guide vane heat exchanger aimed at recovering gearbox heat losses with minimal pressure loss and converting them into useful propulsive energy via the Junkers–Meredith Effect. Hot gearbox oil is routed through hollow fan static guide vanes, enabling heat transfer to the bypass airflow while simultaneously reducing oil temperature and augmenting thrust. A comprehensive analytical framework is applied, incorporating heat transfer modeling, guide vane geometry reconstruction, lubrication flow sizing, and propulsion performance evaluation for both take-off and cruise flight conditions, using the PW1127G-JM geared turbofan as the reference engine. The results indicate that the proposed system can achieve a thrust increase of up to 6.4% at the end of take-off and deliver a thrust-specific fuel consumption reduction of up to 5.6% during take-off and approximately 2% during cruise. While sufficient heat dissipation is achieved under cruise conditions, take-off operation requires a higher transient oil temperature. Overall, this study demonstrates that integrating heat recovery into existing engine structures offers a promising pathway to enhance propulsion efficiency, reduce fuel consumption, and support more sustainable aircraft engine designs. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

21 pages, 3194 KB

Open AccessArticle

Extended Comparative Analysis of Aircraft Energy Management Strategies for Improvements in Energy Expenditure, Hydrogen Savings, and Battery Lifecycle Assessment

by Ayesha R. E. Wise, Sharmila Sumsurooah, Seang Yeoh, Serhiy Bozhko and Osama Hebala

Aerospace 2026, 13(3), 251; https://doi.org/10.3390/aerospace13030251 - 9 Mar 2026

Viewed by 445

Abstract

Sustainable aviation requires electrical power systems that can deliver both high energy and high power. Hybrid fuel cell–battery architectures offer a promising solution to meet these demands, and their overall performance can be significantly enhanced through the application of energy management strategies (EMSs). [...] Read more.

Sustainable aviation requires electrical power systems that can deliver both high energy and high power. Hybrid fuel cell–battery architectures offer a promising solution to meet these demands, and their overall performance can be significantly enhanced through the application of energy management strategies (EMSs). This paper develops several EMSs approaches, including rule-based state machine, equivalent consumption minimisation strategy (ECMS), and dynamic programming (DP) for a hybrid fuel cell–battery aircraft targeting specific objectives, such as improving system efficiency, reducing hydrogen consumption and extending battery lifetime. The EMS approaches are then evaluated across both nominal missions and a fuel cell-failure scenario to assess their effectiveness in meeting their defined objectives. Results show that while ECMS achieves the lowest cost per mission, it does not maximise system efficiency. DP provides the highest overall energy efficiency and longest battery lifetime but is limited to offline implementation. To bridge this gap, a hybrid DP–ECMS strategy is introduced and evaluated. The results show that the approach delivers globally optimal performance under nominal conditions, accounting for the trade-offs between cost, efficiency, and battery ageing, while also preserving real-time responsiveness during unforeseen events. This demonstrates the benefits of combining offline optimisation with real-time control for hybrid electric aircraft. Software-in-the-loop (SIL) further validates the real-time applicability and robustness of the proposed strategy. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

16 pages, 9782 KB

Open AccessArticle

Concept of Composite Folded Core Skin Heat Exchanger with Experimental Investigation of Surface Temperatures Using Temperature-Sensitive Paints

by Marvin Tigre Larschow, Simon Thissen, Jakob Gugliuzza, Stefan Zistler, Stefan Carosella, Peter Middendorf and Rico Poser

Aerospace 2026, 13(3), 246; https://doi.org/10.3390/aerospace13030246 - 6 Mar 2026

Cited by 1 | Viewed by 454

Abstract

With the increasing integration of low-temperature waste heat systems in aviation, large areas are needed for heat dissipation without causing significant pressure losses. Large-area skin heat exchangers (SHXs) are coming into focus as a possible solution. SHXs based on composite materials offer a [...] Read more.

With the increasing integration of low-temperature waste heat systems in aviation, large areas are needed for heat dissipation without causing significant pressure losses. Large-area skin heat exchangers (SHXs) are coming into focus as a possible solution. SHXs based on composite materials offer a promising approach due to their weight-saving potential. This article presents a structure-integrated SHX with a folded core using modern materials and design strategies. An analytical 1D heat transfer model, validated by measurements with temperature-sensitive paints (TSPs), was derived to efficiently identify the optimal parameter set in the design process of an SHX. The model focuses on transverse heat conduction effects in the facesheet for lateral heat distribution and uses these specifically for the overall mass-optimized configuration of the SHX. It is shown that with an optimally selected distance between the cooling channels in the case considered here, up to 12% more energy can be dissipated in relation to the total mass of the SHX. This article concludes with a sensitivity analysis of the analytical model. The influence of heat transfer, thermal conductivity in two spatial directions, and facesheet thickness on the optimal channel spacing is examined. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

26 pages, 975 KB

Open AccessArticle

On the Design and Operation of the Thermal Management System of PEMFC-Powered Aircraft

by Marius Nozinski, Patrick Meyer, Fabian Delony, Jens Friedrichs, Jan Göing and Stephan Kabelac

Aerospace 2026, 13(3), 243; https://doi.org/10.3390/aerospace13030243 - 4 Mar 2026

Cited by 1 | Viewed by 930

Abstract

Hydrogen fuel-cell-powered all-electric aircraft are promising for decarbonizing short-range aviation, but the substantial low-temperature waste heat demands a compact thermal management system (TMS). This study presents a methodological framework for the integrated co-design of the TMS and powertrain using multi-objective optimization and holistic [...] Read more.

Hydrogen fuel-cell-powered all-electric aircraft are promising for decarbonizing short-range aviation, but the substantial low-temperature waste heat demands a compact thermal management system (TMS). This study presents a methodological framework for the integrated co-design of the TMS and powertrain using multi-objective optimization and holistic mission-level analysis to identify optimal TMS designs and operating strategies. Changes in TMS net drag translate into changes in required aircraft thrust, while changes in powertrain, TMS, and fuel mass affect the available payload under a constant maximum take-off mass assumption. This iterative process yields performance metrics across TMS cooling architectures (parallel or series), heat exchanger mass-drag characteristics, coolant temperature targets (50, 70, or 90 °C), and installation objectives (minimizing mass or ram-air duct length). The optimal design is a parallel cooling architecture that balances mass-specific heat rejection of 4.77 kW kg⁻¹ at hot-day take-off with drag-specific heat rejection of 1.29 kW N⁻¹ at standard-day cruise. A reduction in coolant temperature at standard-day missions entails no significant performance penalties and could improve the efficiency of electrical components. A shorter ram-air duct significantly decreases the available payload by 630 kg but may facilitate nacelle integration. The findings underscore that holistic TMS-powertrain co-design and optimization is essential for rigorous design of sustainable all-electric aircraft. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

17 pages, 1713 KB

Open AccessArticle

Conceptual Design of Metal Hydride Cartridges with Systematic Alloy Selection and Sizing Guidelines for Boil-Off-Gas Recovery from Liquid Hydrogen

by Florian Franke and Stefan Kazula

Aerospace 2026, 13(3), 242; https://doi.org/10.3390/aerospace13030242 - 4 Mar 2026

Viewed by 379

Abstract

Hydrogen has huge potential for sustainable future industries, but the formation of hydrogen boil-off gas (BOG) is a main drawback of liquid hydrogen (LH2) applications as BOG venting raises safety issues and leads to significant hydrogen loss. A promising approach for BOG recovery [...] Read more.

Hydrogen has huge potential for sustainable future industries, but the formation of hydrogen boil-off gas (BOG) is a main drawback of liquid hydrogen (LH2) applications as BOG venting raises safety issues and leads to significant hydrogen loss. A promising approach for BOG recovery is a system with exchangeable cartridges filled with metal hydride (MH). Previous studies focus on the macroscopic level of the interaction between the cartridges with the boil-off sources and the consumers. A detailed investigation of the cartridge design remains necessary to assess the potential of this novel BOG recovery system. This study elaborates design concepts for the individual cartridge. A thorough material selection for suitable MH alloys is conducted and requirements for the cartridge design are derived. The key design features of the cartridges are determined and summarized in a morphological box. Four explicit design concepts are elaborated and illustrated. These results provide the baseline for upcoming studies to explicitly design and manufacture an MH cartridge demonstrator for testing, assisting the transformation to an even more sustainable LH2 industry. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

13 pages, 1406 KB

Open AccessArticle

Centralized Landing Flow Merging for Drones Using Deep Reinforcement Learning

by Sasha Vlaskin, Jan Groot, Emmanuel Sunil, Joost Ellerbroek, Jacco Hoekstra and Dennis Nieuwenhuisen

Aerospace 2026, 13(3), 234; https://doi.org/10.3390/aerospace13030234 - 3 Mar 2026

Viewed by 414

Abstract

Drones are expected to support applications such as emergency response, parcel delivery, and infrastructure monitoring in dense urban airspaces, creating traffic levels that are unmanageable for human operators. Autonomous separation management is therefore essential, combining strategic and tactical control to prevent conflicts. This [...] Read more.

Drones are expected to support applications such as emergency response, parcel delivery, and infrastructure monitoring in dense urban airspaces, creating traffic levels that are unmanageable for human operators. Autonomous separation management is therefore essential, combining strategic and tactical control to prevent conflicts. This paper addresses the tactical landing phase by introducing a centralized landing flow manager—a reinforcement learning (RL) agent that adjusts drone speed and heading to merge landing flows safely and efficiently prior to a final approach fix. The objective of the work was to demonstrate the potential of reinforcement learning in this novel context, by implementing and evaluating it in simulation and testing its capabilities with 10 concurrent landing drones. The RL agent learns to successfully separate traffic, thereby lowering intrusion counts compared to the baseline autopilot, but is outperformed in safety by the decentralized Modified Voltage Potential (MVP) method due to outlier scenarios. Nevertheless, the RL-based system achieves faster scenario completion and thus a higher overall throughput, by speeding up the vehicles towards the final approach fix. Future work will explore improved network architectures, transfer learning across varied scenarios, and algorithmic fine-tuning to further enhance safety performance. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

15 pages, 14508 KB

Open AccessArticle

Aircraft Ditching by Simulation: A Contribution to Support Virtual Analysis Using a Meshfree Pointset Method

by Christian Leon Muñoz, Dieter Kohlgrüber and Michael Petsch

Aerospace 2026, 13(3), 226; https://doi.org/10.3390/aerospace13030226 - 28 Feb 2026

Viewed by 431

Abstract

The investigation of the emergency situation of an aircraft landing on water is mandatory for the certification of novel aircraft. In this context, computer-aided methods are becoming more relevant to support physical testing and to extend the analysis to further impact conditions. In [...] Read more.

The investigation of the emergency situation of an aircraft landing on water is mandatory for the certification of novel aircraft. In this context, computer-aided methods are becoming more relevant to support physical testing and to extend the analysis to further impact conditions. In this work, the meshless Lagrangian Finite Pointset Method was integrated into an aircraft pre-design process chain and used for the simulation of the interaction between the water and the structure during ditching. To assess the applicability of the method, results from simulations were compared with experimental data from water impact tests of curved panels and scaled models. In addition, the method was implemented in ditching simulations using a generic mid-range aircraft model. Results are analyzed in terms of accuracy, flexibility, and performance. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

22 pages, 1637 KB

Open AccessArticle

Insights into Conflict Detection and Resolution Integration in AI-Enhanced Air Traffic Control Systems

by Javier A. Pérez-Castán, Álvaro Albalá Pedrera, Lidia Serrano-Mira, Tomislav Radišić, Ivan Tukarić, Kristina Samardžić and Luis Pérez Sanz

Aerospace 2026, 13(3), 213; https://doi.org/10.3390/aerospace13030213 - 27 Feb 2026

Viewed by 812

Abstract

Artificial intelligence (AI) is a cutting-edge technology that can replicate knowledge, operation and, at some point, understanding at a human-like level. The AWARE project aims to develop an AI assistant application (ASA) designed to support air traffic control (ATC) operations by building a [...] Read more.

Artificial intelligence (AI) is a cutting-edge technology that can replicate knowledge, operation and, at some point, understanding at a human-like level. The AWARE project aims to develop an AI assistant application (ASA) designed to support air traffic control (ATC) operations by building a platform based on enhanced artificial situational awareness. One of the pillars of the ASA system is to develop a set of functionalities that mimic the behavior of human actions based on the development of technical tools. Regarding safety issues, conflict detection and resolution (CD&R) is the pillar to identify conflicts and avoid mid-air collisions. The goal is to build a CD&R that can be embedded into the ASA system and generate outputs that can be usable and valuable for ATC. CD&R tool is based on two subsystems: The CD component identifies potential separation minima infringements, while the CR module produces explainable resolution maneuvers with standardized syntax for seamless ATCO integration. CD uses a deterministic algorithmic approach grounded in trajectory prediction models, while CR implements a hierarchical decision-making architecture that emulates expert ATCO cognitive processes within a client-service paradigm where pilots serve as end-users. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

28 pages, 970 KB

Open AccessArticle

From Firm-Level Alignment to Institutional Coordination: European and National Funding in Spanish Aviation

by Juan-Francisco Reyes-Sánchez, Gustavo Alonso and Gustavo Morales-Alonso

Aerospace 2026, 13(2), 205; https://doi.org/10.3390/aerospace13020205 - 22 Feb 2026

Viewed by 588

Abstract

This study explores entities’ strategy to combine multiple governmental funding sources to complement their research and innovation activities. It focuses on the case of Spanish aeronautics entities and their participation in both European and national research and innovation programs over two successive periods. [...] Read more.

This study explores entities’ strategy to combine multiple governmental funding sources to complement their research and innovation activities. It focuses on the case of Spanish aeronautics entities and their participation in both European and national research and innovation programs over two successive periods. Using a mixed-methods approach, this study combines qualitative interviews with three representative entities and a quantitative analysis of project-level data. The interviews are first used to identify key variables and analytical categories, such as entity type, Joint Undertaking membership, technological focus, and temporal evolution, which then guide the quantitative analysis. Quantitative data on budgets, funding, participation, and technologies are analyzed across both periods and programs, including pairwise correlation analysis. The findings show that Spanish entities actively seek to align national and European funding at both financial and technological levels, although with uneven success in some cases. Joint Undertaking membership and position within the aeronautical value chain strongly influence the ability to participate in both programs and to accumulate funding. While many entities develop informal alignment strategies, these efforts often exceed their organizational capacity, particularly in the second period. The results highlight the need for formal, government-level coordination mechanisms to support effective alignment between European and national aeronautics funding programs. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

44 pages, 1966 KB

Open AccessArticle

Experimental Aircraft: Comparative Analysis of Governance, Funding, and Business Models

by Dionysios Markatos, Harry Psihoyos, Thomas Kalampoukas, Pierluigi Iannelli, Lorenzo Pellone, Marco Armbrust, Andreas Strohmayer, Spiros Pantelakis and Angelos Filippatos

Aerospace 2026, 13(2), 181; https://doi.org/10.3390/aerospace13020181 - 13 Feb 2026

Viewed by 997

Abstract

Decarbonizing aviation, particularly for long-range operations, is critical for meeting international climate targets, yet it remains technically and operationally challenging. Experimental aircraft (EA) serve to enable flying research infrastructures that provide realistic flight environments for validating emerging technologies and bridging the gap between [...] Read more.

Decarbonizing aviation, particularly for long-range operations, is critical for meeting international climate targets, yet it remains technically and operationally challenging. Experimental aircraft (EA) serve to enable flying research infrastructures that provide realistic flight environments for validating emerging technologies and bridging the gap between research and future operational aircraft. While motivated by long-range aviation decarbonization, the study analyses experimental aircraft across multiple scales and missions, focusing on governance structures, funding mechanisms, and business models rather than technical performance metrics. Beyond their technical role, the success and sustainability of EA programs depend strongly on how they are governed, financed, and operated—dimensions that remain comparatively underexplored in the literature, which has primarily emphasized technical performance and flight-test results. To address this gap, this study adopts a structured, multi-method qualitative research approach combining desk-based investigation, a systematic literature review, and comparative case study analysis. The paper reviews and classifies 74 experimental aircraft programs worldwide, with a primary analytical focus on Europe and the United States, examining governance models, funding structures, and business models alongside contextual factors such as platform scale, sectoral orientation, and stakeholder involvement. The results show that most experimental aircraft function as technology demonstration and strategic innovation platforms, supported predominantly by public and public–private funding due to the high-risk and long-term nature of flight research infrastructures. Governance arrangements vary with mission and scale, balancing public oversight, industrial leadership, and academic participation. These findings support the EXAELIA project and provide a reference framework for future experimental aircraft programs. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

20 pages, 5308 KB

Open AccessArticle

Bayesian Forward Design Methodology for Laminar Transonic Airfoils with Cross Flow Attenuation at Large Sweep Angles

by Samarth Kakkar, Thomas Streit, Arne Seitz and Rolf Radespiel

Aerospace 2026, 13(2), 171; https://doi.org/10.3390/aerospace13020171 - 11 Feb 2026

Viewed by 560

Abstract

Drag reduction forms a key area of focus in aerodynamics with a significant emphasis on delaying the laminar-to-turbulent transition of boundary layers over the wings of aircraft. There is enough evidence to suggest that achieving such transition delays is particularly challenging for backward-swept [...] Read more.

Drag reduction forms a key area of focus in aerodynamics with a significant emphasis on delaying the laminar-to-turbulent transition of boundary layers over the wings of aircraft. There is enough evidence to suggest that achieving such transition delays is particularly challenging for backward-swept wings with large leading-edge sweep angles, which give rise to crossflow and attachment-line instabilities, in addition to Tollmien–Schlichting waves. The sustenance of extended laminar flow regions at high sweep angles has been demonstrated in recent studies, by designing airfoils with specially curated leading-edge profiles, which generate pressure distributions that can suppress crossflow. Such airfoils are called Crossflow Attenuating Natural Laminar Flow (CATNLF) airfoils. However, the design of such airfoils is presently restricted to inverse methodologies due to the inability of the conventional geometry parameterization techniques in representing the specialized leading-edge profiles of CATNLF airfoils. The aim of this study is to illustrate that a parametric representation of CATNLF airfoils can be realized using Bezier curves, thereby enabling their forward multi-point design using gradient-free Bayesian optimization. The developed design framework in terms of geometry parameterization and optimization formulation is able to deliver airfoils that can sustain natural laminar flow up to around 50% chord length on the upper surface, with a leading-edge sweep angle greater than 27 degrees at a Mach number of 0.78 and a Reynolds number of 20 million within a range of lift coefficients

C_{l} = 0.5 \pm 0.1

, making them a suitable design choice for a medium-range transport aircraft. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

► Show Figures

Figure 1

Journal Menu

Journal Browser

15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Related Special Issues

Published Papers (39 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI