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This paper focuses on a case study to compare the performances of Fowler wing flaps that are used on the trailing edge of modern-day commercial airliners. The aim is to observe trends in coefficients of lift (Cl) and drag (Cd) with varying flap angles of release on a single-slotted Fowler flap and arrive at the most efficient flap configuration for flight. A series of two-dimensional analyses are carried out using computational fluid dynamics (CFD) to examine the flow separation and occurrence of stalls between the different angles of flap deflection. A two-equation, k-ω shear stress transport (SST) turbulence model is used as it helps in better prediction of flow separation and boundary layer studies. Since the study is carried out for such passenger carriers, the study focuses on the lower transonic ranges of Mach number 0.7-0.9 with a Reynolds number range of 400,000 to 500,000 considering a scaled-down model and upon taking inspiration from related literature.

Most of current jet aircraft circulate fuel on the airframe to match heat loads with available heat sink. The demands for thermal management in wide range of air vehicle systems are growing rapidly along with the increased mission power, vehicle survivability, flight speeds, and so on. With improved aircraft performance and growth of heat load created by Aircraft Mounted Accessory Drive (AMAD) system and hydraulic system, effectively removing the large amount of heat load on the aircraft is gaining crucial importance. Fuel is becoming heat transfer fluid of choice for aircraft thermal management since it offers improved heat transfer characteristics and offers fewer system penalties than air. In the scope of this paper, an AMESim model is built which includes airframe fuel and hydraulic systems with AMAD gearbox of a jet trainer aircraft. The integrated model will be evaluated for thermal performance.

The aerospace industry is undergoing a revolution with the large-scale development of eVTOL (Electric Vertical Take-Off & Landing) and MEA (More Electric Aircraft). These aerial vehicles, many of them unmanned vehicles (UAV), will serve a variety of service-related functions: Search and Rescue (SAR), Medivac, delivery and lift operations, aerial mapping, and, of course, human transportation [1]. Despite its numerous functionalities, this type of vehicle has a serious problem, which is its usual batteries, the main means for its operation. Due to its autonomy not being so effective compared to its charging time, generating a considerable loss of time. In this context, it is necessary to find forms of components that can replace these batteries, so that the effective development of these vehicles is possible. Studies done in other means of transportation point out that the use of hydrogen fuel cells has grown a lot.

Equipment used in aerospace non-destructive inspection presents opportunity for modernization. Many inspection cells in production operate using a widely available control system software that is suitable for most inspection applications with minimal customization. The size and complex geometry of airframe components demand more application-specific system design to ensure the reliability and cycle time required for an aerospace production schedule. Ordinary inspection systems require manual teaching for program generation and lack datum-finding systems required to rerun programs without modification. Integration of offline programming software and machine vision instruments can save inspection technicians hours or shifts per part by eliminating the need for program retraining due to variation in part delivery position. Modernized inspection cells will reduce labor burden on technicians and provide reliable cycle time information to production planners.

As the aerospace industry moves toward determinate assembly and ever-tighter manufacturing tolerances, there is a need for automated, high-precision milling, trimming and drilling equipment that is specialized for aerospace applications. Precision countersinking is a common requirement for aircraft parts, but this is not a process that typical general-purpose milling machines are able to accommodate without the use of specialty tools such as depth-stop tool holders. To meet this need, Electroimpact has designed a 5-axis milling machine with high-speed clamping capability for countersink depth control. A custom trunnion and head with a quill and an additional clamp axis provide clamping functionality similar in speed and precision to a riveting machine, while maintaining the accuracy and features of a conventional machining center.

Refueling operation of the aircraft fuel tanks has some limitations. One of the limitations is refueling time which restricts refueling duration for entire tank. Other one is overfilling situations which are also possible because of the wave damper designs in tank such as barriers and baffles resist against fuel creeping towards all sides of tank. Required refueling duration restricts refueling speed at a certain minimum value. On the other hand, baffle design restricts refueling speed at a certain maximum value. It should be the mathematical region between these two extremum points where the refueling mass flow rate can be defined. Minimum mass flow rate point can be adjusted with defining of mass flow rate depends of requirements easily but upper extremum point should be defined depends on design of baffles. It can only be changed with altering the design of interior wing tank.

In this work we discuss the fault avoidance and the fault tolerance approaches for increasing the reliability of aerospace and automotive systems. This includes: the basic definitions/concepts (reliability, maintainability, availability, redundancy, etc.), and characteristics (a priori analysis, a posteriori analysis, physical/hardware redundancy, analytical/software redundancy, etc.) of both approaches, their mathematical background and models (exponential, Weilbull, etc.), their basic theory, their methods and techniques (fault trees, dependence diagrams, Markov chains, etc.), some of their standards (SAE-ARP4761, AC 25.1309, etc.) and simulation environments (Cafta, etc.), and their applications to the reliability analysis and reliability improvement of aerospace and automotive vehicles. This is illustrated by some examples driven from the aerospace and automotive industries.

With the growing complexity and integration of systems as satellites, automobiles, aircrafts, turbines, power controls and traffic controls, as prescribed by SAE-ARP-4754A Standard, the time de-synchronization can cause serious or even catastrophic failures. Time synchronization is a very important aspect to achieve high performance, reliability and determinism in networked control systems. Such systems operate in a real time distributed environment which frequently requires a consistent time view among different devices, levels and granularities. So, to guarantee high performance, reliability and determinism it is required a performance evaluation of time synchronization of the overall system. This time synchronization performance evaluation can be done in different ways, as experiments and/or model and simulation.

Aerospace Recommended Practice (ARP) 4754 Revision A (ARP4754A), Guidelines for Development of Civil Aircraft and Systems [1], and ARP4761, Guidelines and Methods for Conducting the Safety Assessment Process on Civil Airborne Systems and Equipment [2], together describe a complex set of intertwining processes which comprehensively prioritize development activities for a product's systems based on their safety criticality. These processes work at specific levels of detail (aircraft and system) and interact with a set of processes at lower levels of detail (item) defined by Radio Technical Commission for Aeronautics (RTCA) standards. The aircraft and system development process (ARP4754A) supplies functions, requirements, and architectural definitions to the System Safety process (ARP4761), which in turn supplies Development Assurance Levels back to the development process and on to the RTCA processes.

The advent of the Covid-19 pandemic that began at the end of 2019 accelerated technology to support remote work environments. While the technologies were not new, the capabilities of those technologies significantly increased. The number of users embracing the remote working technologies significantly increased within a very short timeframe. The expanded remote work capabilities have enabled new collaborating mechanisms that will carry-forth in the future, pandemic or not. SAE ARP 4761 [1] provides guidelines to perform a safety assessment. The Zonal Safety Assessment (ZSA) is one of the tools described in ARP 4761. An aspect of ZSA is an audit (or inspection) of the physical article. The remote work capabilities, along with cameras and software presenting a virtual environment, can allow individuals to participate in the physical audit without traveling to the site of the physical article.

This paper presents a summary of a university based research project sponsored by Honeywell for the development of sensorless control method for Brushless DC (BLDC) motors for industrial and aerospace applications. In particular, the development, test results and assessment of an advanced cost effective sensorless BLDC motor controller for aerospace applications are presented and discussed in detail. The motor is controlled by the method of detecting the back EMF instead of the usage of the rotor position or speed sensors. The implemented embedded controls utilize an ASIC with the main objective of enhancing reliability, fault-tolerance, power density and performance.

This paper first reviews the application of fault-tolerant machine drives as a means of reaching the necessary reliability levels in aerospace applications with minimum weight penalty. The requirements of such machines will be reviewed and different motor topologies will be compared. Three examples of fault-tolerant drive system demonstrators will then be described including a novel flux-switching, permanent magnet, synchronous machine topology.

This paper presents the design, fabrication, and testing of a 50HP, 30000 rpm induction motor for a next generation large aircraft spoiler. The motor is characterized by high power density, developing over 8.5 pounds per square inch of airgap surface area with only 13 pounds electromagnetic weight. Detailed designs, including magnetic material selection, electromagnetic parameters, and finite element thermal analyses are presented and compared to test data. Testing was obtained using a high speed hydraulic dynamometer with digital data acquisition. The motor and actuator are designed and built by AlliedSignal for participation in the NASA Redundant Effector Program and NASA Power-by-Wire Electromechanical Actuation (EMA) Spoiler Program. The program emphasizes the demonstration of power electronic motor drive and actuation technologies for aerospace applications.

During its flight an aircraft can be struck by lightning and the induced high current will require a highly conductive airframe skin structure in order for it to propagate through with minimum damage. However an aircraft skin is generally coated with paint and the airframer does not always have control on the paint thickness. Paint thickness generates heightened concerns for lightning strike on aircraft, mainly because most of coatings dedicated to that purpose are non-conductive. Using insulating material or non-conductive coating with certain thickness may contribute to or increase damage inflicted by the swept stroke lightning energy, even on metallic structures Due to its high relative permittivity, a non-conductive paint or coating on a fuselage skin surface will contribute to slow down the lightning current propagation through structure. With this comes the risk of increasing heat that will favor structural damage and possible melt through.

Surface engineering is becoming increasingly crucial for several automotive and aerospace components that involve intense surface interactions. Friction stir processing (FSP) has emerged as an effective surface modification and hardening technique in recent days. The technique also allows the incorporation of reinforcement into the modified surface to enhance the strength and hardness further. This work applied FSP to develop a pure Ti particulate reinforced AA6061 metal matrix composite (MMC). Six different strategies were adapted (in the form of micro grooves, micro drills on the surface) to effectively infuse reinforcement on the alloy surface. Microstructural changes before and after FSP were studied using SEM and EBSD. Other tests such as post-mortem EDS, XRD, hardness, and compression were also done to examine the performance of developed composite.

Materials play a key role in our day to day life and have shaped the industrial revolution to a great extent. Right selection of material for meeting a particular objective is the key to success in today’s world where the cost as well as sustainability of any equipment or a system have assumed greater significance than ever before. In automotive industry, materials have a definitive role as far as the mobility and safety is concerned. Materials that can absorb the required energy or impact can be manufactured through different manufacturing as well as metallurgical processes which involves appropriate heat treatment and bringing correct chemical compositions etc. However, they can also be formed by simpler methods such as combining certain materials together in the form of layered combinations to form light weight composites.

The overall goal of this program was the development of a 10 m. diameter, self-deployable antenna based on an open-celled rigid polyurethane foam system. Advantages of such a system relative to current inflatable or self-deploying systems include high volumetric efficiency of packing, high restoring force, low (or no) outgassing, low thermal conductivity, high dynamic damping, mechanical isotropy, infinite shelf life, and easy fabrication with methods amenable to construction of large structures (i.e., spraying). As part of a NASA Phase II SBIR, Adherent Technologies and its research partners, Temeku Technologies, and NASA JPL/Caltech, conducted activities in foam formulation, interdisciplinary analysis, and RF testing to assess the viability of using open cell polyurethane foams for self-deploying antenna applications.

This review summarizes the latest developments in diesel emissions regarding regulations, engines, NOx (nitrogen oxides) control, particulate matter (PM) reductions, and hydrocarbon (HC) and CO oxidation. Regulations are advancing with proposals for 70% tightening of fleet average light-duty (LD) criteria emissions likely to be proposed in California for ~2016-22. CO₂ regulations in both the heavy- and light-duty sectors will also tighten and impact diesel engines and emissions, probably long into the future. Engine technology is addressing these needs. Light-duty diesel engines are making incremental gains with combustion enhancements that allow downsizing for CO₂ savings. Heavy-duty (HD) engine show trade-offs between hardware recipes, exhaust deNOx control, and fuel consumption.

Dents on the aircraft skin are frequent and may easily go undetected during airworthiness checks, as their inspection process is tedious and extremely subject to human factors and environmental conditions. Nowadays, 3D scanning technologies are being proposed for more reliable, human-independent measurements, yet the process of inspection and reporting remains laborious and time consuming because data acquisition and validation are still carried out by the engineer. For full automation of dent inspection, the acquired point cloud data must be analysed via a reliable segmentation algorithm, releasing humans from the search and evaluation of damage. This paper reports on two developments towards automated dent inspection. The first is a method to generate a synthetic dataset of dented surfaces to train a fully convolutional neural network. The training of machine learning algorithms needs a substantial volume of dent data, which is not readily available.

Most emerging electric vertical takeoff and landing (eVTOL) aircraft feature distributed electric propulsion systems with automation features that simplify operations for future pilots. In theory, increasing automation levels should reduce pilot workload, decrease training time, and improve performance consistency. Air Education and Training Command Detachment 62 (AETC/Det 62) sought to test this theory as part of a larger study involving 70+ participants, two eVTOL platform simulators, and multimodal assessments of flight performance. In the present report, we compared expert ratings of flight performance of pilots who do not have prior pilot experience or training (herein referred to as ab initio pilots; i.e., 0 flight hours) to those of experienced pilots (i.e., >300 flight hours) in either a semi-automated or highly-automated simulated eVTOL platform.