Next Issue
Volume 6, December
Previous Issue
Volume 6, October

Table of Contents

Aerospace, Volume 6, Issue 11 (November 2019)

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
Cover Story (view full-size image) The integration of turbofans with transport aircraft will become a growing challenge with the [...] Read more.
Order results
Result details
Select all
Export citation of selected articles as:
Open AccessArticle
Minimum-Cost Drone–Nest Matching through the Kuhn–Munkres Algorithm in Smart Cities: Energy Management and Efficiency Enhancement
Aerospace 2019, 6(11), 125; https://doi.org/10.3390/aerospace6110125 - 17 Nov 2019
Abstract
The development of new concepts for smart cities and the application of drones in this area requires different architecture for the drones’ stations (nests) and their placement. Drones’ stations are designed to protect drones from hazards and utilize charging mechanisms such as solar [...] Read more.
The development of new concepts for smart cities and the application of drones in this area requires different architecture for the drones’ stations (nests) and their placement. Drones’ stations are designed to protect drones from hazards and utilize charging mechanisms such as solar cells to recharge them. Increasing the number of drones in smart cities makes it harder to find the optimum station for each drone to go to after performing its mission. In classic ordered technique, each drone returns to its preassigned station, which is shown to be not very efficient. Greedy and Kuhn–Munkres (Hungarian) algorithms are used to match the drone to the best nesting station. Three different scenarios are investigated in this study; (1) drones with the same level of energy, (2) drones with different levels of energy, and (3) drones and stations with different levels of energy. The results show that an energy consumption reduction of 25–80% can be achieved by applying the Kuhn–Munkres and greedy algorithms in drone–nest matching compared to preassigned stations. A graphical user interface is also designed to demonstrate drone–station matching through the Kuhn–Munkres and greedy algorithms. Full article
(This article belongs to the Special Issue Biomimetics in Aerospace Engineering)
Show Figures

Graphical abstract

Open AccessArticle
Constraint Replacement-Based Design for Additive Manufacturing of Satellite Components: Ensuring Design Manufacturability through Tailored Test Artefacts
Aerospace 2019, 6(11), 124; https://doi.org/10.3390/aerospace6110124 - 16 Nov 2019
Abstract
Additive manufacturing (AM) is becoming increasingly attractive for aerospace companies due to the fact of its increased ability to allow design freedom and reduce weight. Despite these benefits, AM comes with manufacturing constraints that limit design freedom and reduce the possibility of achieving [...] Read more.
Additive manufacturing (AM) is becoming increasingly attractive for aerospace companies due to the fact of its increased ability to allow design freedom and reduce weight. Despite these benefits, AM comes with manufacturing constraints that limit design freedom and reduce the possibility of achieving advanced geometries that can be produced in a cost-efficient manner. To exploit the design freedom offered by AM while ensuring product manufacturability, a model-based design for an additive manufacturing (DfAM) method is presented. The method is based on the premise that lessons learned from testing and prototyping activities can be systematically captured and organized to support early design activities. To enable this outcome, the DfAM method extends a representation often used in early design, a function–means model, with the introduction of a new model construct—manufacturing constraints (Cm). The method was applied to the redesign, manufacturing, and testing of a flow connector for satellite applications. The results of this application—as well as the reflections of industrial practitioners—point to the benefits of the DfAM method in establishing a systematic, cost-efficient way of challenging the general AM design guidelines found in the literature and a means to redefine and update manufacturing constraints for specific design problems. Full article
(This article belongs to the Special Issue Additive Manufacturing for Aerospace and Defence)
Show Figures

Figure 1

Open AccessArticle
A Brazilian Space Launch System for the Small Satellite Market
Aerospace 2019, 6(11), 123; https://doi.org/10.3390/aerospace6110123 - 12 Nov 2019
Abstract
At present, most small satellites are delivered as hosted payloads on large launch vehicles. Considering the current technological development, constellations of small satellites can provide a broad range of services operating at designated orbits. To achieve that, small satellite customers are seeking cost-effective [...] Read more.
At present, most small satellites are delivered as hosted payloads on large launch vehicles. Considering the current technological development, constellations of small satellites can provide a broad range of services operating at designated orbits. To achieve that, small satellite customers are seeking cost-effective launch services for dedicated missions. This paper deals with performance and cost assessments of a set of launch vehicle concepts based on a solid propellant rocket engine (S-50) under development by the Institute of Aeronautics and Space (Brazil) with support from the Brazilian Space Agency. Cost estimation analysis, based on the TRANSCOST model, was carried out taking into account the costs of launch system development, vehicle fabrication, direct and indirect operation cost. A cost-competitive expendable launch system was identified by using three S-50 solid rocket motors for the first stage, one S-50 engine for the second stage and a flight-proven cluster of pressure-fed liquid engines for the third stage. This launch system, operating from the Alcantara Launch Center, located at 2 20’ S, would deliver satellites from the 500 kg class in typical polar missions with a specific transportation cost of about US$39,000 per kilogram of payload at a rate of 12 launches per year, in dedicated missions. At a low inclined orbit, vehicle payload capacity increased, decreasing the specific transportation cost to about 32,000 US$/kg. Cost analysis also showed that vehicle development effort would claim 781 work year, or less than 80 million dollars. Vehicle fabrication accounted for 174 work year representing less than 23 million dollars per unit. The launch system based on the best concept would, therefore, deploy small satellite constellations in cost-effective dedicated launches, 224 work year per flight, from the Alcantara Launch Center in Brazil. Full article
Show Figures

Figure 1

Open AccessArticle
Simulation and Test of Discrete Mobile Surfaces for a RC-Aircraft
Aerospace 2019, 6(11), 122; https://doi.org/10.3390/aerospace6110122 - 05 Nov 2019
Abstract
Morphing structures suitable for unmanned aerial vehicles (UAVs) have been investigated for several years. This paper presents a novel lightweight, morphing concept based on the exploitation of the “lever effect” of a bistable composite plate that can be integrated in an UAV horizontal [...] Read more.
Morphing structures suitable for unmanned aerial vehicles (UAVs) have been investigated for several years. This paper presents a novel lightweight, morphing concept based on the exploitation of the “lever effect” of a bistable composite plate that can be integrated in an UAV horizontal tail. Flight dynamics equations are solved in Simulink environment, thus being able to simulate and compare different flight conditions with conventional and bistable command surfaces. Subsequently, bistable plates are built by using composite materials, paying particular attention to dimensions, asymmetric stacking sequence and total thickness needed to achieve bistability. NACA0011 airfoil is chosen for proving this concept. Wind tunnel tests demonstrate that the discrete surface is capable of withstanding the aerodynamic pressure. A remotely piloted vehicle is employed to test the discrete horizontal tail command during the take-off. The results show that, choosing a proper configuration of constraints, stacking sequence and aspect ratio for the bistable laminate, it is possible to tailor the snap-through mechanism. The proposed concept appears lighter and increases aerodynamic efficiency when compared to conventional UAV command surfaces. Full article
(This article belongs to the Special Issue Aircraft Design (SI-2/2020) )
Show Figures

Figure 1

Open AccessArticle
DLR TAU-Code uRANS Turbofan Modeling for Aircraft Aerodynamics Investigations
Aerospace 2019, 6(11), 121; https://doi.org/10.3390/aerospace6110121 - 03 Nov 2019
Abstract
In the context of an increased focus on fuel efficiency and environmental impact, turbofan engine developments continue towards larger bypass ratio engine designs, with Ultra-High Bypass Ratio (UHBR) engines becoming a likely power plant option for future commercial transport aircraft. These engines promise [...] Read more.
In the context of an increased focus on fuel efficiency and environmental impact, turbofan engine developments continue towards larger bypass ratio engine designs, with Ultra-High Bypass Ratio (UHBR) engines becoming a likely power plant option for future commercial transport aircraft. These engines promise low specific fuel consumption at the engine level, but the resulting size of the nacelle poses challenges in terms of the installation on the airframe. Thus, their integration on an aircraft requires careful consideration of complex engine–airframe interactions impacting performance, aeroelastics and aeroacoustics on both the airframe and the engine sides. As a partner in the EU funded Clean Sky 2 project ASPIRE, the DLR Institute of Aerodynamics and Flow Technology is contributing to an investigation of numerical analysis approaches, which draws on a generic representative UHBR engine configuration specifically designed in the frame of the project. In the present paper, project results are discussed, which aimed at demonstrating the suitability and accuracy of an unsteady RANS-based engine modeling approach in the context of external aerodynamics focused CFD simulations with the DLR TAU-Code. For this high-fidelity approach with a geometrically fully modeled fan stage, an in-depth study on spatial and temporal resolution requirements was performed, and the results were compared with simpler methods using classical engine boundary conditions. The primary aim is to identify the capabilities and shortcomings of these modeling approaches, and to develop a best-practice for the uRANS simulations as well as determine the best application scenarios. Full article
(This article belongs to the Special Issue Progress in Jet Engine Technology)
Show Figures

Figure 1

Open AccessArticle
The Diagnosis of Communication and Trust in Aviation Maintenance (DiCTAM) Model
Aerospace 2019, 6(11), 120; https://doi.org/10.3390/aerospace6110120 - 01 Nov 2019
Abstract
In this research paper a new conceptual model is introduced—the Diagnosis of Communication and Trust in Aviation Maintenance (DiCTAM) model. The purpose of this model is to recognise, measure and predict the relationship between communication and trust in the aviation maintenance field. This [...] Read more.
In this research paper a new conceptual model is introduced—the Diagnosis of Communication and Trust in Aviation Maintenance (DiCTAM) model. The purpose of this model is to recognise, measure and predict the relationship between communication and trust in the aviation maintenance field. This model was formed by combining a conceptual cyclical process and two established survey tools, adapted and incorporated in a single question set. The implementation of each phase of the DiCTAM model is performed with the use of qualitative and quantitative research methods. This includes the use of content analyses of accident/incident investigation reports and training material, a survey and a hypothetical case study. The predictive functionality of the DiCTAM model has been investigated through the hypothetical case study. The obtained results indicate a positive relationship between communication and trust according to the aviation maintenance employees’ perception and accidents/incidents reports, even though basic training includes communication without direct mention of trust. Full article
(This article belongs to the Special Issue Civil and Military Airworthiness: Recent Developments and Challenges)
Show Figures

Figure 1

Open AccessArticle
Impact of Energy Dependence on Ground Level and Avionic SEE Rate Prediction When Applying Standard Test Procedures
Aerospace 2019, 6(11), 119; https://doi.org/10.3390/aerospace6110119 - 01 Nov 2019
Abstract
Single event effects (SEEs) in ground level and avionic applications are mainly induced by neutrons and protons, of which the relative contribution of the latter is larger with increasing altitude. Currently, there are two main applicable standards—JEDEC JESD89A for ground level and IEC [...] Read more.
Single event effects (SEEs) in ground level and avionic applications are mainly induced by neutrons and protons, of which the relative contribution of the latter is larger with increasing altitude. Currently, there are two main applicable standards—JEDEC JESD89A for ground level and IEC 62396 for avionics—that address the procedure for testing and qualifying electronics for these environments. In this work, we extracted terrestrial spectra at different altitudes from simulations and compared them with data available from the standards. Second, we computed the SEE rate using different approaches for three static random access memory (SRAM) types, which present a strong SEE response dependence with energy. Due to the presence of tungsten, a fissile material when interacting with high energy hadrons, the neutron and proton SEE cross sections do not saturate after 200 MeV, but still increase up to several GeV. For these memories, we found standard procedures could underestimate the SEE rate by a factor of up to 4-even in ground level applications—and up to 12 times at 12 km. Moreover, for such memories, the contribution from high energy protons is able to play a significant role, comparable to that of neutrons, even at commercial flight altitudes, and greater at higher altitudes. Full article
(This article belongs to the Special Issue Single Event Effect Prediction in Avionics)
Show Figures

Figure 1

Open AccessArticle
MeznSat—A 3U CubeSat for Monitoring Greenhouse Gases Using Short Wave Infra-Red Spectrometry: Mission Concept and Analysis
Aerospace 2019, 6(11), 118; https://doi.org/10.3390/aerospace6110118 - 31 Oct 2019
Abstract
Climate change and global warming are attributed to the increased levels of greenhouse Gases in the atmosphere. Miniature low-cost, lightweight instruments on-board low-cost nanosatellite platforms such as CubeSats could be used to provide precise measurements of greenhouse gases levels. CubeSats, which usually have [...] Read more.
Climate change and global warming are attributed to the increased levels of greenhouse Gases in the atmosphere. Miniature low-cost, lightweight instruments on-board low-cost nanosatellite platforms such as CubeSats could be used to provide precise measurements of greenhouse gases levels. CubeSats, which usually have a narrow field of view, cost a fraction of what more expensive satellites with wide swaths cost. MeznSat is a 3U CubeSat that will carry a shortwave infrared (SWIR) micro-spectrometer as its primary payload, with the aim of deriving greenhouse gas concentrations in the atmosphere by making observations in the 1000–1650 nm wavelength region. The satellite, which is planned for launch in March 2020, is the result of a collaborative project between Khalifa University of Science and Technology (KUST) and the American University of Ras Al-Khaimah (AURAK) with a fund from the United Arab Emirates Space Agency (UAE-SA). The primary payload, Argus 2000, is a miniature, low-cost, space-qualified spectrometer that operates in the shortwave infrared (SWIR) bands. Argus 2000 is a ruggedized unit with a mass of less than 230 g and power consumption of less than 1 W. Also, the Argus 2000 has 0.15 degrees viewing angle and 15 mm fore-optics. The secondary payload will consist of a high definition (HD) camera that will allow post-processing to achieve the high geolocation accuracy required for the SWIR spectrometer data. The RGB combination of visible and SWIR bands setup makes MeznSat a unique CubeSat mission that will generate an interesting dataset to explore atmospheric correction algorithms, which employ SWIR data to process visible channels. This paper describes the mission feasibility, mission analysis, design, and status of MeznSat. Full article
Show Figures

Figure 1

Open AccessReview
Recent Advances in Anomaly Detection Methods Applied to Aviation
Aerospace 2019, 6(11), 117; https://doi.org/10.3390/aerospace6110117 - 30 Oct 2019
Abstract
Anomaly detection is an active area of research with numerous methods and applications. This survey reviews the state-of-the-art of data-driven anomaly detection techniques and their application to the aviation domain. After a brief introduction to the main traditional data-driven methods for anomaly detection, [...] Read more.
Anomaly detection is an active area of research with numerous methods and applications. This survey reviews the state-of-the-art of data-driven anomaly detection techniques and their application to the aviation domain. After a brief introduction to the main traditional data-driven methods for anomaly detection, we review the recent advances in the area of neural networks, deep learning and temporal-logic based learning. In particular, we cover unsupervised techniques applicable to time series data because of their relevance to the aviation domain, where the lack of labeled data is the most usual case, and the nature of flight trajectories and sensor data is sequential, or temporal. The advantages and disadvantages of each method are presented in terms of computational efficiency and detection efficacy. The second part of the survey explores the application of anomaly detection techniques to aviation and their contributions to the improvement of the safety and performance of flight operations and aviation systems. As far as we know, some of the presented methods have not yet found an application in the aviation domain. We review applications ranging from the identification of significant operational events in air traffic operations to the prediction of potential aviation system failures for predictive maintenance. Full article
(This article belongs to the collection Air Transportation—Operations and Management)
Show Figures

Figure 1

Open AccessArticle
Development and Testing of Woven FRP Flexure Hinges for Pressure-Actuated Cellular Structures with Regard to Morphing Wing Applications
Aerospace 2019, 6(11), 116; https://doi.org/10.3390/aerospace6110116 - 23 Oct 2019
Abstract
Shape-variable structures can change their geometry in a targeted way and thus adapt their outer shape to different operating conditions. The potential applications in aviation are manifold and far-reaching. The substitution of conventional flaps in high-lift systems or even the deformation of entire [...] Read more.
Shape-variable structures can change their geometry in a targeted way and thus adapt their outer shape to different operating conditions. The potential applications in aviation are manifold and far-reaching. The substitution of conventional flaps in high-lift systems or even the deformation of entire wing profiles is conceivable. All morphing approaches have to deal with the same challenge: A conflict between minimizing actuating forces on the one hand, and maximizing structural deflections and resistance to external forces on the other. A promising concept of shape variability to face this challenging conflict is found in biology. Pressure-actuated cellular structures (PACS) are based on the movement of nastic plants. Firstly, a brief review of the holistic design approach of PACS is presented. The aim of the following study is to investigate manufacturing possibilities for woven flexure hinges in closed cellular structures. Weaving trials are first performed on the material level and finally on a five-cell PACS cantilever. The overall feasibility of woven fiber reinforced plastics (FRP)-PACS is proven. However, the results show that the materials selection in the weaving process substantially influences the mechanical behavior of flexure hinges. Thus, the optimization of manufacturing parameters is a key factor for the realization of woven FRP-PACS. Full article
(This article belongs to the Special Issue Aeronautical Systems for Flow Control)
Show Figures

Graphical abstract

Previous Issue
Next Issue
Back to TopTop