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Journal Article

Demonstration of a Compact Hydrogen Fuel Cell Power System for UAS Propulsion

2014-09-16
2014-01-2223
We have assembled and demonstrated a prototype power system that uses an innovative hydrogen generator to fuel an ultra-compact PEM fuel cell that is suitable for use in small unmanned aerial system (UAS) propulsion systems. The hydrogen generator uses thermal decomposition of ammonia borane (AB) to produce hydrogen from a very compact and lightweight package. ...The fuel cell plant utilized in the power system prototype has been flown as part of several small UAS development programs and has logged hundreds of hours of flight time. The plant was designed specifically to be readily integrated with a range of hydrogen fueling subsystems and contains the balance of plant necessary to facilitate stand-alone operation.
Technical Paper

Nonlinear Slender Beam-Wise Schemes for Structural Behavior of Flexible UAS Wings

2015-09-15
2015-01-2462
The innovative highly flexible wings made of extremely light structures, yet still capable of carrying a considerable amount of non- structural weights, requires significant effort in structural simulations. The complexity involved in such design demands for simplified mathematical tools based on appropriate nonlinear structural schemes combined with reduced order models capable of predicting accurately their aero-structural behaviour. The model presented in this paper is based on a consistent nonlinear beam-wise scheme, capable of simulating the unconventional aeroelastic behaviour of flexible composite wings. The partial differential equations describing the wing dynamics are expanded up to the third order and can be used to explore the effect of static deflection imposed by external trim, the effect of gust loads and the one of nonlinear aerodynamic stall.
Article

Advanced simulation using the digital twin to achieve electromagnetic compatibility and electrification management in a modern UAS

2022-01-13
The aerospace industry is facing immense challenges due to increased design complexity and higher levels of integration, particularly in the electrification of aircraft. These challenges can easily impact program cost and product time to market. System electrification and electromagnetic compatibility (EMC) have become critical issues today. In the context of 3D electromagnetics, EMC electromagnetic compatibility ensures the original equipment manufacturer (OEM) that radiated emissions from various electronic devices, such as avionics or the entire aircraft for that matter, do not interfere with other electronic products onboard the aircraft.
Journal Article

Optimization of an Unmanned Aerial System' Wing Using a Flexible Skin Morphing Wing

2013-09-17
2013-01-2095
In this paper, we describe a practically efficient methodology of improving the aerodynamic characteristics of an UAS's wing using a morphing approach. We have replaced a part of the original wings' upper and lower surfaces with a flexible, composite material skin whose shape can be modified, according to the variable airflow conditions, using internally placed actuators. ...We have used the optimization tool to decrease the overall drag coefficient of a military grade UAS' wing equipped with the flexible skin. We have obtained good quality solutions for only a fraction of the computational cost needed when performing viscous flow field calculations.
Technical Paper

Development of Small Internal Combustion Engine Thrust Stand/Dynamometer

2010-04-12
2010-01-0658
Current US military small unmanned aircraft systems (UAS) rely on engines and propellers sourced from the hobby radio-controlled (RC) aircraft industry. ...Torque, thrust, power, brake specific fuel consumption, (BSFC) and propeller efficiency data for a UAS engine are presented.
Journal Article

Projecting the Impact of Aircraft Design Decisions on the Performance of a Fuel Cell Power and Energy System in Unmanned Aircraft Systems

2012-10-22
2012-01-2178
Fuel Cells provide an attractive alternative to battery powered Unmanned Aircraft Systems (UAS) as they maintain the simplicity of an all-electric vehicle architecture while taking advantage of highly energy-dense fuels. ...These outside requirements play a particularly important role in the design of Small UAS (SUAS) P&E systems where the fixed weight of the fuel cell plant may approach or exceed the weight of the fuel utilized. ...As the UAS design concept matures additional dependencies emerge, particularly due to the impact of mission requirements such as the required environmental operating envelope.
Journal Article

Hybrid-Electric, Heavy-Fuel Propulsion System for Small Unmanned Aircraft

2014-09-16
2014-01-2222
A series hybrid-electric propulsion system has been designed for small rapid-response unmanned aircraft systems (UAS) with the goals of improving endurance, providing flexible and responsive electric propulsion, and enabling heavy fuel usage. ...An energy-dense rechargeable battery pack was used to store energy and allow the UAS to operate with the engine shut off, which provided an engine-off operating mode. The ISA allowed re-starting the engine in flight without the need for a separate starter motor. ...The series hybrid UAS outfitted with the custom diesel engine demonstrated endurance improvements, due to additional benefits netted from the improved engine efficiency.
Magazine

Aerospace & Defense Technology: October 2023

2023-10-05
DoD to Deploy Thousands of Low Cost Autonomous Systems Under Replicator Program Top Productivity Improvement Tips for Manufacturing Turbine Discs FACE Technical Standard Offers MOSA Lessons for Safety-Critical Software in Any Sector Adamant: A Soon-to-be Open Source, Mission-Critical Flight Software Framework Written in Ada Benefits and Challenges of Direct-RF Sampling for Avionic Platforms More Airports Test RF as Counter Measure for UAS in Restricted Airspace Adapting U.S. Army Acquisition to Ensure the Reliability and Safety of Autonomous Vehicles This report presents several challenges that the U.S.
Magazine

Aerospace & Defense Technology: October 2022

2022-10-01
Optimal UAS Assignments and Trajectories for Persistent Surveillance and Data Collection from a Wireless Sensor Network Developing a methodology for multiple unmanned aircraft assigned to fly optimal trajectories in order to survey and collect a pre-specified amount of data from a fixed, ground-based wireless sensor network.
Journal Article

Real-Time Powertrain Models of Hybrid Electric Vehicles

2014-10-13
2014-01-2893
Hybrid electric powertrains are developed for reducing the fuel consumption and consequently the emission of carbon dioxide. The fuel consumption of those systems depends significantly on the topology of the powertrain and the applied control strategy. For testing and improving the control strategy in terms of the overall system efficiency, Hardware-in-the-Loop (HIL) simulation can be applied. In order to operate the corresponding electronic control units in a virtual environment, it emulates the behavior of the actuator and sensor signals by a real-time simulation of the powertrain. Developing those powertrain models is a time-consuming task, due to high dynamics and high switching frequencies of the electrical subsystem and due to the large diversity of powertrain configurations.
Article

SAE International

2018-04-12
Last month, AeroVironment, Inc. began accepting orders for their new Puma 3 UAS. As an “all environment” UAS, Pumas have operated effectively in some of the harshest climates on Earth.
Event

AeroTech® Digital Summit

2024-05-19
New for 2022, AeroTech® will deliver even more robust programming by teaming up with AeroMat to deliver learning opportunities dedicated to: Additive Manufacturing and Materials, Environment and Sustainable Aviation (Sustainability), Autonomy and AI, Safety and Human Factors, Modeling, Simulation and Testing, Cybersecurity / Cyber-Physical Security, Industry 4.0 Smart Manufacturing and Assembly, IDEAL Summit (inclusion, diversity, equity, accessibility and leadership), Advanced Air Mobility (AAM) and Multimodal Mobility (M3)
Technical Paper

Emission Reduction Potential by Means of High Boost and Injection Pressure at Low- and Mid-Load for a Common Rail Diesel Engine under High EGR Rates

2013-10-14
2013-01-2541
The emission reduction potential of high boost and high injection pressures was investigated on a 4-cylinder small bore diesel engine at high rates of exhaust gas recirculation. For this reason an external boosting system was built up, which allowed to generate the desired boost pressure independent from the engine's operating point. In order to simulate conditions comparable to a real turbocharged engine, also the influence of the turbine on the exhaust back pressure was considered. The whole measurement campaign was carried out at two load points (low- and mid-load), which represent characteristic engine operating points of the Urban Driving Cycle (UDC). On the one hand could be shown, that there is an enormous potential in the reduction of particulate matter (PM) up to 75 % and of carbon monoxide (CO) up to 15 % at the mid-load point by increasing the boost pressure.
Journal Article

A New Measurement Technique for Online Oil Dilution Measurement

2013-10-14
2013-01-2521
New trends in the development of combustion engines lead to changed engine operating conditions which also result in changed loads of the engine parts and functional components. The application of regenerative fuels and new exhaust after- treatment systems can for example lead to an increased input of fuel into the engine oil. Oil dilution is an issue that impacts the engine operation and life cycle and therefore gains importance during the development process of combustion engines. In order to improve oil dilution to preclude destructive amounts of fuel in the oil it is necessary to investigate and optimize the fuel in oil sorption and desorption processes. At the University of Applied Sciences Regensburg a new measurement technique has been developed that realizes the online analysis of the fuel quantity in the engine oil.
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