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A Study of Paradrogue Aerodynamics

Forrest Jack Mobley
  • Technical Paper
  • 2020-01-0027
To be published on 2020-03-10 by SAE International in United States
Scaled paradrogue models were designed, built, and tested for the purpose of possible UAS aerial refueling application. Paradrogue chute gore patterns were changed between three models and studied using wind tunnel testing and computational fluid dynamics simulations. Drag coefficient values, as well as vortex shedding characteristics through POD and DMD analysis, were compared between the three models, with an emphasis on possible affects on flight stability.
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System integration in aircraft environment – Hydraulic performances through coupled simulations

Airbus Operations GmbH-Henning Witt lng
Airbus Operations India-Ashutosh Singh
  • Technical Paper
  • 2020-01-0004
To be published on 2020-03-10 by SAE International in United States
An Airbus methodology for the assessment of accurate hydraulic performance at early program stages in the complete aircraft and power consuming systems environment based on joint collaboration with Chiastek is presented. The aim is to comfort the prediction of an aircraft hydraulic performance in order to limit the need for a physical integration test bench and extensive flight test campaign but also to avoid late system redesign based on robust early stage model based engineering and to secure the aircraft entry-into-service
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An Approach to Verification of Interference Concerns for Multicore Systems (CAST-32A)

Rapita Systems, Inc., Ltd.-Steven H. VanderLeest, Christos Evripidou
  • Technical Paper
  • 2020-01-0016
To be published on 2020-03-10 by SAE International in United States
The avionics industry is moving towards the use of multicore systems to meet the demands of modern avionics applications. In multicore systems, interference can affect execution timing behavior, including worst case execution time (WCET), as identified in the FAA CAST-32A position paper. Examining and verifying the effects of interference is critical in the production of safety-critical avionics software for multicore architectures. Multicore processor hardware along with aerospace RTOS providers increasingly offers robust partitioning technologies to help developers mitigate the effects of interference. These technologies enable the partitioning of cores for different applications at different criticalities and make it possible to run multiple applications on one specific core. When incorporated into system-design considerations, these partitioning mechanisms can be used to reduce the effects of interference on software performance. In this paper we describe a novel approach to verifying the effectiveness of RTOS interference mitigation on the final hosted software. We showcase the use of the proposed approach on the NXP T2080 multicore board. The approach follows a V-model based methodology in which high- and low-level requirements…
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On Shedding Frequency and Aerodynamic Characteristics of a Rotating Wire-wrapped Cylinder

California State University-Long Beach-Hamid R. Rahai
  • Technical Paper
  • 2020-01-0028
To be published on 2020-03-10 by SAE International in United States
Numerical investigations of shedding frequency of rotating smooth and wire-wrapped cylinders, placed in steady flow have been performed. The freestream mean velocity was 10 m/sec. and the smooth cylinder diameter was 5 cm, which corresponds to an approximate Reynolds number based on cylinder’s diameter of 3.2x104. The wire wrapped cylinder had a wire diameter of 5 mm and the ratios of pitch spacing to the cylinder diameter, p/D, was 1.0. The cylinder length to diameter ratio was 20. The rotation rate (λ), the ratio of axial tangential mean velocity at the cylinder’s surface to the free stream mean velocity was 2.0. To obtain the shedding frequency, numerical probes were placed at 3D downstream, 0.5 D above the centerline, spaced at 0.5D along the spanwise direction for obtaining instantaneous axial velocity and shedding frequencies were obtained from spectra of the axial velocity. Results indicate that the lift for the wire-wrapped cylinder is nearly 150% of that of the smooth cylinder, however, it has higher drag force. The lift to drag ratio for the smooth rotating cylinder…
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Automated Inspection of Polished Skin

Kawasaki Heavy Industries, Ltd.-Naofumi Aoki, Takuya Ota, Masayoshi Zaitsu
  • Technical Paper
  • 2020-01-0032
To be published on 2020-03-10 by SAE International in United States
This report is about development result of an automatic defect detector for polished skins. The “polished skin” material is used for an outside plate of commercial airplanes. The polished skin is manufactured by polishing the surface of an aluminum clad material and it has a uniform high level of color, brightness, and reflectivity. It can be used without painting because the surface has a natural oxide layer which prevents corrosion. The polished skins are inspected with visual observation and it is large burden for inspectors to find minute defects on the large size materials. An automated inspection is not easy because the material has mirror surface and its size is large. Defects on the polished skin can be classified broadly into three categories: dent, bump and color change. Therefore, a defect detector has to be able to detect these defects, and measure surface profile of defects. This technical report presents the outcomes from a design and a manufacture of the defect detector which has been designed to be low cost and high performance. It has…
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Validation Testing of Lithium Battery Performance-Based Packaging for use in Air Transportation (SAE G-27)

National Research Council Canada-Khalid Fatih, Manuel Hernandez
Transport Canada-Ian Whittal, Kiran Shoib
  • Technical Paper
  • 2020-01-0042
To be published on 2020-03-10 by SAE International in United States
The SAE G-27 committee was tasked by ICAO to develop a performance-based packaging standard for lithium batteries transported as cargo on aircraft. The standard details test criteria to qualify packages of lithium batteries & cells for transportation as cargo on-board passenger aircraft. Lithium batteries and cells have been prohibited from shipment as cargo on passenger aircraft since 2016. This paper summarizes the results of the tests conducted by Transport Canada and National Research Council Canada to support the development of this standard with evidence-based recommendations. It includes a description of the test specimens, the test set up, instrumentation used, and test procedures following the standard as drafted to date. The study considered several lithium-ion battery and cell chemistries that were tested under various proposed testing scenarios in the draft standard. The aim was to assess the feasibility of proposed tests, and to determine whether the tests are able to accurately capture hazards which may arise from a catastrophic battery or a cell failure within the package. Laboratory results were also simulated with Computational Fluid Dynamics…
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Performance of Isolated UAV Rotors at Low Reynolds Number

Georgia Institute of Technology-Yashvardhan Tomar, Narayanan Komerath
Indian Institute of Technology-Dhwanil Shukla
  • Technical Paper
  • 2020-01-0046
To be published on 2020-03-10 by SAE International in United States
Vertical takeoff and landing vehicle platforms with many small rotors are gaining importance for small UAVs as well as distributed electric propulsion for larger vehicles. To predict vehicle performance, it must be possible to gauge interaction effects. These rotors operate in the less-known regime of low Reynolds number, with different blade geomety. As a first step, two identical commercial UAV rotors from a flight test program, are studied in isolation, experimentally and computationally. Load measurements were performed in Georgia Tech’s 2.13m x 2.74m wind tunnel. Simulations were done using the RotCFD solver which uses a Navier-Stokes wake computation with low-Reynolds number blade section data. It is found that in hover, small rotors available in the market vary noticeably in performance at low rotor speeds, the data converging at higher RPM and Reynolds number. This may be indicative of the high sensitivity of low-Re rotor flows to minor geometrical differences/imperfections in the rotors. It requires proper handling in computations. CFD results show a higher deviation from the experimental thrust data at low rotor speeds. While thrust…
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Delivery of Mixed Reality Tools Training in the Modern Production Environment

Boeing Co.-Mark Friesen, Lorrie Sivich
  • Technical Paper
  • 2020-01-0052
To be published on 2020-03-10 by SAE International in United States
Since the early development of Mixed Reality (MR) technologies for the gaming industry, Boeing Research and Technology has been a leader in applying the technology to the production environment. Mixed Reality technologies have matured in size reduction and cost enabling a wide variety of visualization tools into the factory today. They include: tablets, Microsoft’s HoloLens, Google Glasses, Vive, and Oculus to name a few. These digital productivity tools allow the factory worker to perform work through installation, quality inspection, and trouble shooting.
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In-Process Hole and Fastener Inspection Using a High-Accuracy Laser Sensor

Electroimpact Inc.-Zachary Luker, Erin Stansbury
  • Technical Paper
  • 2020-01-0015
To be published on 2020-03-10 by SAE International in United States
Electroimpact has produced a new in-process inspection system for use on drilling and fastening systems. The system uses a high-accuracy, non-contact, laser system to measure the flushness of installed fasteners. The system is also capable of measuring part normality and providing feedback to the machine for correction. One drawback to many automatic inspection systems is measurement error. Many sources of measurement error exist in a production environment, including drilling chips, lubrication, and fastener head markings. Electroimpact’s latest system can create a visualization of the measured fastener for the operator to interpret. This allows the operator to determine the cause of a failed measurement, thus reducing machine downtime due to false negatives. Electroimpact created a custom C# WPF application that queries the point-cloud data and analyzes the raw data. A custom “circle Hough transform” scoring algorithm is used to find the center of the nosepiece (pressure foot). A best fit plane is calculated from the point cloud data to find the panel surface. This plane is then used to output panel normality in the A and…
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Development of a Novel Hybrid-Piston for Application in High Performance Two-Stroke Engines

Fraunhofer IWS, 01277 Dresden, Germany-Axel Jahn, Frieder Zimmermann, Uwe Stamm
Mahle König Kommanditgesellschaft GmbH & Co KG, 6830 Ran-Christian Bechter, Thomas Herb
  • Technical Paper
  • 2019-32-0508
To be published on 2020-01-24 by Society of Automotive Engineers of Japan in Japan
The current development trends for high performance two-stroke engines have been identified in raising combustion pressures and therefore higher cylinder temperatures [1] [2]. Thus, the requirements on piston assembly are increased in such a way that pistons based on aluminium-silicon alloys – as most commonly used in high performance two-stroke engines - reach their application limit. A suitable solution has been shown by research work such as that conducted by Mahle König, by using a piston consisting of different materials. With this approach, the higher stressed piston crown consists of steel, while the lower stressed piston skirt is made out from aluminium. Previous basic examinations showed the high potential of the hybrid piston concept in terms of pressure and temperature increase, while also showing the need for a temperature-stable and pressure-tight joint between crown and skirt.This paper will focus on the development of two novel hybrid-piston concepts, where the piston crown and the piston skirt are connected in different ways. The first hybrid concept presented uses the piston pin in order to realize a plugconnection…