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Aerospace, Volume 4, Issue 4 (December 2017)

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Research

Open AccessArticle Optimization of Air Traffic Control Training at the Federal Aviation Administration Academy
Aerospace 2017, 4(4), 50; doi:10.3390/aerospace4040050
Received: 23 September 2017 / Revised: 15 October 2017 / Accepted: 25 October 2017 / Published: 28 October 2017
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Abstract
This paper investigates current and future uses of simulation in the Federal Aviation Administration (FAA) Academy’s Air Traffic Control (ATC) training program to identify potential improvement areas in the areas of simulation technologies and course content. Once identified, recommendations for changes to the
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This paper investigates current and future uses of simulation in the Federal Aviation Administration (FAA) Academy’s Air Traffic Control (ATC) training program to identify potential improvement areas in the areas of simulation technologies and course content. Once identified, recommendations for changes to the current training program are made. A literature review of the current training techniques used at the FAA Academy and training centers was conducted. In addition, interviews were held and surveys were distributed to collect data regarding a variety of ATC training interest areas, such as virtual reality, current maintenance schedules, and simulator features. Finally, a cost-benefit analysis was conducted to determine the potential improvement areas with the highest feasibility for implementation and the highest potential to reduce training costs and/or time. The primary findings of this research revealed three feasible improvement areas to the current training process and simulation technologies: (1) reducing the dependence on instructors during simulation training, (2) utilizing web-based training methods, and (3) updating current simulator systems to include new features, such as recording and playback features. These changes were recommended to be implemented first, with voice recognition and virtual reality improvement areas being recommended as priority focus areas for future studies and/or implementation. Full article
(This article belongs to the Special Issue Air Transportation—Operations and Management)
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Open AccessArticle Air Traffic Security: Aircraft Classification Using ADS-B Message’s Phase-Pattern
Aerospace 2017, 4(4), 51; doi:10.3390/aerospace4040051
Received: 27 September 2017 / Revised: 20 October 2017 / Accepted: 27 October 2017 / Published: 30 October 2017
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Abstract
Automatic Dependent Surveillance-Broadcast (ADS-B) is a surveillance system used in Air Traffic Control. With this system, the aircraft transmits their own information (identity, position, velocity, etc.) to any equipped listener for surveillance scope. The ADS-B is based on a very simple protocol and
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Automatic Dependent Surveillance-Broadcast (ADS-B) is a surveillance system used in Air Traffic Control. With this system, the aircraft transmits their own information (identity, position, velocity, etc.) to any equipped listener for surveillance scope. The ADS-B is based on a very simple protocol and does not provide any kind of authentication and encryption, making it vulnerable to many types of cyber-attacks. In the paper, the use of the airplane/transmitter carrier phase is proposed as a feature to perform a classification of the aircraft and, therefore, distinguish legitimate messages from fake ones. The feature extraction process is described and a classification method is selected. Finally, a complete intruder detection algorithm is proposed and evaluated with real data. Full article
(This article belongs to the collection Feature Papers in Aerospace)
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Open AccessArticle Design, Development and Testing of Shape Shifting Wing Model
Aerospace 2017, 4(4), 52; doi:10.3390/aerospace4040052
Received: 19 August 2017 / Revised: 20 October 2017 / Accepted: 30 October 2017 / Published: 1 November 2017
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Abstract
The design and development of morphing (shape shifting) aircraft wings—an innovative technology that has the potential to increase the aerodynamic efficiency and reduce noise signatures of aircrafts—was carried out. This research was focused on reducing lift-induced drag at the flaps of the aerofoil
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The design and development of morphing (shape shifting) aircraft wings—an innovative technology that has the potential to increase the aerodynamic efficiency and reduce noise signatures of aircrafts—was carried out. This research was focused on reducing lift-induced drag at the flaps of the aerofoil and to improve the design to achieve the optimum aerodynamic efficiency. Simulation revealed a 10.8% coefficient of lift increase for the initial morphing wing and 15.4% for the optimized morphing wing as compared to conventional wing design. At angles of attack of 0, 5, 10 and 15 degrees, the optimized wing has an increase in lift-to-drag ratio of 18.3%, 10.5%, 10.6% and 4% respectively when compared with the conventional wing. Simulations also showed that there is a significant improvement on pressure distribution over the lower surface of the morphing wing aerofoil. The increase in flow smoothness and reduction in vortex size reduced pressure drag along the trailing edge of the wing as a result an increase in pressure on the lower surface was experienced. A morphing wing reduced the size of the vortices and therefore the noise levels measured were reduced by up to 50%. Full article
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Open AccessArticle Experimental Investigation of the Wake and the Wingtip Vortices of a UAV Model
Aerospace 2017, 4(4), 53; doi:10.3390/aerospace4040053
Received: 5 October 2017 / Revised: 28 October 2017 / Accepted: 30 October 2017 / Published: 1 November 2017
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Abstract
An experimental investigation of the wake of an Unmanned Aerial Vehicle (UAV) model using flow visualization techniques and a 3D Laser Doppler Anemometry (LDA) system is presented in this work. Emphasis is given on the flow field at the wingtip and the investigation
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An experimental investigation of the wake of an Unmanned Aerial Vehicle (UAV) model using flow visualization techniques and a 3D Laser Doppler Anemometry (LDA) system is presented in this work. Emphasis is given on the flow field at the wingtip and the investigation of the tip vortices. A comparison of the velocity field is made with and without winglet devices installed at the wingtips. The experiments are carried out in a closed-circuit subsonic wind tunnel. The flow visualization techniques include smoke-wire and smoke-probe experiments to identify the flow phenomena, whereas for accurately measuring the velocity field point measurements are conducted using the LDA system. Apart from the measured velocities, vorticity and circulation quantities are also calculated and compared for the two cases. The results help to provide a more detailed view of the flow field around the UAV and indicate the winglets’ significant contribution to the deconstruction of wing-tip vortex structures. Full article
(This article belongs to the collection Unmanned Aerial Systems)
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Open AccessArticle An Efficient Application of the MOEA/D Algorithm for Designing Noise Abatement Departure Trajectories
Aerospace 2017, 4(4), 54; doi:10.3390/aerospace4040054
Received: 2 October 2017 / Revised: 24 October 2017 / Accepted: 27 October 2017 / Published: 1 November 2017
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Abstract
In an effort to allow to increase the number of aircraft and airport operations while mitigating their negative impacts (e.g., noise and pollutant emission) on near-airport communities, the optimal design of new departure routes with less noise and fuel consumption becomes more important.
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In an effort to allow to increase the number of aircraft and airport operations while mitigating their negative impacts (e.g., noise and pollutant emission) on near-airport communities, the optimal design of new departure routes with less noise and fuel consumption becomes more important. In this paper, a multi-objective evolutionary algorithm based on decomposition (MOEA/D), which recently emerged as a potential method for solving multi-objective optimization problems (MOPs), is developed for this kind of problem. First, to minimize aircraft noise for departure routes while taking into account the interests of various stakeholders, bi-objective optimization problems involving noise and fuel consumption are formulated where both the ground track and vertical profile of a departure route are optimized simultaneously. Second, in order to make the design space of vertical profiles feasible during the optimization process, a trajectory parameterization technique recently proposed is employed. Furthermore, some modifications to MOEA/D that are aimed at significantly reducing the computational cost are also introduced. Two different examples of departure routes at Schiphol Airport in the Netherlands are shown to demonstrate the applicability and reliability of the proposed method. The simulation results reveal that the proposed method is an effective and efficient approach for solving this kind of problem. Full article
(This article belongs to the Special Issue Air Transportation—Operations and Management)
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Open AccessArticle High Fidelity Multi-Objective Design Optimization of a Downscaled Cusped Field Thruster
Aerospace 2017, 4(4), 55; doi:10.3390/aerospace4040055
Received: 27 September 2017 / Revised: 1 November 2017 / Accepted: 11 November 2017 / Published: 18 November 2017
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Abstract
The Cusped Field Thruster (CFT) concept has demonstrated significantly improved performance over the Hall Effect Thruster and the Gridded Ion Thruster; however, little is understood about the complexities of the interactions and interdependencies of the geometrical, magnetic and ion beam properties of the
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The Cusped Field Thruster (CFT) concept has demonstrated significantly improved performance over the Hall Effect Thruster and the Gridded Ion Thruster; however, little is understood about the complexities of the interactions and interdependencies of the geometrical, magnetic and ion beam properties of the thruster. This study applies an advanced design methodology combining a modified power distribution calculation and evolutionary algorithms assisted by surrogate modeling to a multi-objective design optimization for the performance optimization and characterization of the CFT. Optimization is performed for maximization of performance defined by five design parameters (i.e., anode voltage, anode current, mass flow rate, and magnet radii), simultaneously aiming to maximize three objectives; that is, thrust, efficiency and specific impulse. Statistical methods based on global sensitivity analysis are employed to assess the optimization results in conjunction with surrogate models to identify key design factors with respect to the three design objectives and additional performance measures. The research indicates that the anode current and the Outer Magnet Radius have the greatest effect on the performance parameters. An optimal value for the anode current is determined, and a trend towards maximizing anode potential and mass flow rate is observed. Full article
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Open AccessArticle The Impact of Volute Aspect Ratio on the Performance of a Mixed Flow Turbine
Aerospace 2017, 4(4), 56; doi:10.3390/aerospace4040056
Received: 27 October 2017 / Revised: 16 November 2017 / Accepted: 20 November 2017 / Published: 23 November 2017
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Abstract
Current trends in the automotive industry towards engine downsizing mean turbocharging now plays a vital role in engine performance. A turbocharger increases charge air density using a turbine to extract waste energy from the exhaust gas to drive a compressor. Most turbocharger applications
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Current trends in the automotive industry towards engine downsizing mean turbocharging now plays a vital role in engine performance. A turbocharger increases charge air density using a turbine to extract waste energy from the exhaust gas to drive a compressor. Most turbocharger applications employ a radial inflow turbine. However, mixed flow turbines can offer non-zero blade angles, reducing leading edge (LE) separation at low velocity ratios. The current paper investigates the performance of a mixed flow turbine with three different volute aspect ratio (AR) designs (AR = 0.5, 1 and 2). With constant A/r (ratio of volute area to centroid radius), the AR = 0.5 volute design produced a 4.3% increase in cycle averaged mass flow parameter (MFP) compared to the AR = 2 design. For the purpose of performance comparison, it was necessary to manipulate the volute A/r’s to ensure constant MFP for aerodynamic similarity. With the volute A/r’s manipulated to ensure constant MFP for aerodynamic similarity, the maximum variation of cycle averaged normalized efficiency measured between the designs was 1.47%. Purely in the rotor region, the variation in normalized cycle averaged efficiency was 1%. The smallest tested volute aspect ratio showed a significant increase in volute loss while the ARs of 1 and 2 showed similar levels of loss. The smallest AR volute showed significant secondary flow development in the volute. The resulting variation in LE incidence was found to vary as a result. Full article
(This article belongs to the collection Feature Papers in Aerospace)
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Open AccessArticle Comparative Study of Aircraft Boarding Strategies Using Cellular Discrete Event Simulation
Aerospace 2017, 4(4), 57; doi:10.3390/aerospace4040057
Received: 6 November 2017 / Revised: 23 November 2017 / Accepted: 25 November 2017 / Published: 28 November 2017
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Abstract
Time is crucial in the airlines industry. Among all factors contributing to an aircraft turnaround time; passenger boarding delays is the most challenging one. Airlines do not have control over the behavior of passengers; thus, focusing their effort on reducing passenger boarding time
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Time is crucial in the airlines industry. Among all factors contributing to an aircraft turnaround time; passenger boarding delays is the most challenging one. Airlines do not have control over the behavior of passengers; thus, focusing their effort on reducing passenger boarding time through implementing efficient boarding strategies. In this work, we attempt to use cellular Discrete-Event System Specification (Cell-DEVS) modeling and simulation to provide a comprehensive evaluation of aircraft boarding strategies. We have developed a simulation benchmark consisting of eight boarding strategies including Back-to-Front; Window Middle Aisle; Random; Zone Rotate; Reverse Pyramid; Optimal; Optimal Practical; and Efficient. Our simulation models are scalable and adaptive; providing a powerful analysis apparatus for investigating any existing or yet to be discovered boarding strategy. We explain the details of our models and present the results both visually and numerically to evaluate the eight implemented boarding strategies. We also compare our results with other studies that have used different modeling techniques; reporting nearly identical performance results. The simulations revealed that Window Middle Aisle provides the least boarding delay; with a small fraction of time difference compared to the optimal strategy. The results of this work could highly benefit the commercial airlines industry by optimizing and reducing passenger boarding delays. Full article
(This article belongs to the Special Issue Air Transportation—Operations and Management)
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Open AccessArticle An Overview of Cube-Satellite Propulsion Technologies and Trends
Aerospace 2017, 4(4), 58; doi:10.3390/aerospace4040058 (registering DOI)
Received: 30 September 2017 / Revised: 21 November 2017 / Accepted: 29 November 2017 / Published: 9 December 2017
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Abstract
CubeSats provide a cost effective means to perform scientific and technological studies in space. Due to their affordability, CubeSat technologies have been diversely studied and developed by educational institutions, companies and space organizations all over the world. The CubeSat technology that is surveyed
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CubeSats provide a cost effective means to perform scientific and technological studies in space. Due to their affordability, CubeSat technologies have been diversely studied and developed by educational institutions, companies and space organizations all over the world. The CubeSat technology that is surveyed in this paper is the propulsion system. A propulsion system is the primary mobility device of a spacecraft and helps with orbit modifications and attitude control. This paper provides an overview of micro-propulsion technologies that have been developed or are currently being developed for CubeSats. Some of the micro-propulsion technologies listed have also flown as secondary propulsion systems on larger spacecraft. Operating principles and key design considerations for each class of propulsion system are outlined. Finally, the performance factors of micro-propulsion systems have been summarized in terms of: first, a comparison of thrust and specific impulse for all propulsion systems; second, a comparison of power and specific impulse, as also thrust-to-power ratio and specific impulse for electric propulsion systems. Full article
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