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Viewing 31 to 60 of 22514
Technical Paper
2014-09-16
Yamina Boughari, Ruxandra Botez, Georges Ghazi, Florian Theel
The main goal of the flight control system is to achieve good performances with acceptable flying qualities within the specified flight envelope and to ensure robustness for models variations. In this research, the Cessna Citation X aircraft linear model is presented using different flight conditions to cover the aircraft’s flight envelope, on which a robust controller is designed using H-infinity method optimized by two different heuristic algorithms. The optimal controller was used to reach satisfactory dynamic characteristics for the lateral stability control augmentation systems with respect to flying qualities requirements for the Cessna Citation X aircraft. The weighting functions of the H-infinity method were optimised by using both genetic and the differential evolution algorithms. The evolutionary algorithms here used have given very good results. These algorithms were used in this form for the first time to optimize H_infinity controllers on a business aircraft control, using both flying qualities requirements and robustness criterion as objective function and to avoid using algorithms which are computationally complicated.
Technical Paper
2014-09-16
Teresa Donateo, Maria Grazia De Giorgi, Antonio Ficarella, Elisabetta Argentieri, Elena Rizzo
The aim of the present investigation is the implementation of a Matlab/Simulink environment to assess the performance (thrust, specific fuel consumption, aircraft/engine mass, cost, etc.) and environmental impact (greenhouse and pollutant emissions) of conventional and more electric aircrafts. In particular, the benefits of adopting more electric solutions for either aircrafts at given missions specifications can be evaluated. Each component is modeled as a black box that receives input (in terms of mass flow and energy) from the previous component and send its output variables to the next one after a balance of mass and energy content. The software includes a design workflow for the input of the aircraft specification, the choice of the architecture (e.g. series or parallel) and the specification of each component including energy converter (piston engine, turboprop, turbojet, fuel cell, etc.), energy storage systems (batteries, supercapacitors), auxiliaries and secondary power systems.
Technical Paper
2014-09-16
Tim C. O'Connell, Kevin McCarthy, Andrew Paquette, David McCormick, Paul Pigg, Peter T. Lamm
Validation of models is a critical component of Model Based Design (MBD). Without validation, the accuracy of the models is not certain, so the decisions made with those models may not be based on the best information. The Integrated Vehicle Energy Technology (INVENT) program is planning a series of hardware experiments that will be used to validate a large set of integrated models. While the task of validating such a large number of interacting models is daunting, it provides an excellent opportunity to test the limits of MBD. Model validation can take places in many ways, from direct model parameter measurement, to inferred measurements to dynamic signal comparisons. In addition, for complex systems like the ones being tested on INVENT, validation can happen at many levels, from individual unit construction all the way to integrated testing. A process for coordinating these varied validation efforts across multiple participants is needed. For INVENT, a plan to implement all the aspects of validation listed above has been created.
Technical Paper
2014-09-16
Martin Bradish, Obed Sands, Ted Wright, Casey Bakula, Daniel Oldham, William Ivancic, Michael Lewis, Joseph Klebau, Nicholas Tollis, Andrew Jalics
Author Name (s): William .D. Ivancic, Obed S. Sands, Casey J. Bakula, Daniel R. Oldham, Ted Wright, Martin A. Bradish, Joseph M. Klebau Mailing Address: Martin Bradish, NASA Glenn Research Center, 21000 Brookpark Road, MS 86-5, Cleveland, Ohio 44135 USA Telephone Number: (216) 433-3848 Fax Number: (216) 433-6382 eMail Address: martin.a.bradish@nasa.gov This paper summarizes the Power, Avionics and Software (PAS) 1.0 subsystem integration testing and test results that occurred in August and September of 2013. This paper covers the capabilities of each PAS assembly to meet integration test objectives for non-safety critical, non-flight, non-human-rated hardware and software development. This test report is the outcome of the first integration of the PAS subsystem and is meant to provide data for subsequent designs, development and testing of the future PAS subsystems. The two main objectives were to assess the ability of the PAS assemblies’ to exchange messages and to perform audio tests of both inbound and outbound channels.
Technical Paper
2014-09-16
Christine Ross, Michael Armstrong, Mark Blackwelder, Catherine Jones, Patrick Norman, Steven Fletcher
The NASA N3-X blended-wing body with turboelectric distributed propulsion (TeDP) concept is being studied to achieve N3-X goals such as reduced noise, NOx emissions, and improved energy efficiency. The gas turbine engines are used to provide rotational energy to generators which convert this energy to electrical. The electrical power output of the generators is rectified and distributed as a DC system to an array of propulsor motors each with their own inverter. The electrical distribution system is superconducting in order to maximize its efficiency and increase the power density of all associated components. An aspect of this concept currently under study is the protection of the electrical distribution system for propulsion. The protection of a superconducting DC network poses unique electrical and thermal challenges due to low impedance of the superconductor and operation in the superconducting or quenched states. For a fixed TeDP electrical system architecture with fixed power ratings, several protection strategies are investigated.
Technical Paper
2014-09-16
Andreas Himmler
Test systems for aircraft systems are crucial for reaching and ensuring the safety of passengers, crew and other persons in air traffic. In the past, the requirements to be met by aircraft systems regarding safety, environmental friendliness, reliability and comfort have already become significantly more extensive and complex. This trend will continue in the foreseeable future. In addition to the requirements on the aircraft systems, with each aircraft program, the requirements on the test systems for electronic control units (ECUs) has also increased, as both the number of systems to be tested and their complexity has grown. As a result, the number of necessary test systems for ECUs has also increased with each aircraft program. At the same time, each aircraft program causes an increase in the number of simulation models necessary for the tests. To make the development of complex aircraft systems manageable and economical, tests must be performed as early as possible in the development process.
Technical Paper
2014-09-16
Javier A. Parrilla
Current industry trends demonstrate aircraft electrification will be part of future platforms in order to achieve higher levels of efficiency in various vehicle level sub-systems. However, electrification requires a substantial change in aircraft design that is not suitable for re-winged or re-engined applications as some aircraft manufacturers are opting for today. Thermal limits arise as engine cores progressively get smaller and hotter to improve overall engine efficiency, while legacy systems still demand a substantial amount of pneumatic, hydraulic and electric power extraction. The environmental control system (ECS) provides pressurization, ventilation and air conditioning in commercial aircraft, making it the main heat sink for all aircraft loads with exception of the engine. To mitigate the architecture thermal limits in an efficient manner, the form in which the ECS interacts with the engine will have to be enhanced as to reduce the overall energy consumed and achieve an energy optimized solution.
Technical Paper
2014-09-16
Hidefumi Saito, Shoji Uryu, Norio Takahashi, Noriko Morioka, Hitoshi Oyori
In this study, we seek solution to energy optimization issue of Environmental Control System (ECS) for electric aircraft. Aircraft ECS must have three functions as pressurization, ventilation, and temperature control. Non-bleed ECS based on more electric aircraft makes it possible to distribute the three functions to equipment. Motor Driven Fresh Air Compressor (MDFAC) mainly takes charge of pressurization function and ventilation function, therefore selection of equipment for temperature control function is important. We select not Air Cycle System (ACS) but Vapor Cycle System (VCS) as the equipment for temperature control function, for minimization of energy consumption by higher Coefficient of Performance (COP). We try to clarify specifications, configuration and weight of the VCS suitable for the temperature control function of single aisle aircraft, which is a non-bleed type aircraft equipped with MDFACs. To keep increase of flight fuel consumption by additional weight negligible, weight and rated performance of the VCS are set as the same as those of the ACS.
Technical Paper
2014-09-16
Steven David Angus Fletcher, Patrick Norman, Stuart Galloway, Graeme Burt
Abstract The development of the More-Electric Engine (MEE) concept will see an expansion in the power levels, functionality and criticality of electrical systems within engines. However, to date, these more critical electrical systems have not been accounted for in existing engine certification standards. To begin to address this gap, this paper conducts a review of current engine certification standards in order to determine how these standards will impact on the design requirements of More-Electric Engine (MEE) electrical system architectures. The paper focuses on determining two key architectural requirements: the number of individual failures an architecture can accommodate and still remain functional and the rate at which these failures are allowed to occur. The paper concludes by discussing how the derived failure rates begin to define a set of design requirements for MEE electrical architectures, considering various operating strategies, and demonstrates their application to example MEE electrical system architecture designs.
Technical Paper
2014-09-16
Jennifer C. Shaw, Patrick Norman, Stuart Galloway, Graeme Burt
Abstract Radical new electrically propelled aircraft are being considered to meet strict future performance goals. One concept design proposed is a Turboelectric Distributed Propulsion (TeDP) aircraft that utilises a number of electrically driven propulsors. Such concepts place a new and significant reliance on an aircraft's electrical system for safe and efficient flight. Accordingly, in addition to providing certainty that supply reliability targets are being met, a contingency analysis, evaluating the probability of component failure within the electrical network and the impact of that failure upon the available thrust must also be undertaken for architecture designs. Solutions that meet specified thrust requirements at a minimum associated weight are desired as these will likely achieve the greatest performance against the proposed emissions targets. This paper presents a Fault Tree Analysis (FTA) based design approach for the electrical system and thrust reliability analysis of TeDP aircraft architectures.
WIP Standard
2014-08-27
This SAE Standard specifies the test requirements in addition to those given in ISO 3046-1 for determining the power, at a single point or as a power curve, of marine propulsion engines or systems for recreational craft and other small craft using similar propulsion equipment of less than 24 m length of the hull. It also provides the means for documenting and checking the declared (rated) power published by the manufacturer.
Standard
2014-08-26
This set of criteria shall be utilized by accredited Certification Bodies (CBs) to establish compliance, and grant certification to AS5553A, Aerospace Standard; Counterfeit Electronic Parts; Avoidance, Detection, Mitigation, and Disposition.
WIP Standard
2014-08-26
The SAE Recommended Practice applies to all commercial, self- propelled motor vehicles which transport property or passengers when: gross weight~the vehicle has a gross weight rating of more than 4540 kg (10 000 lb); fuel~the fuel used has a boiling point above 0 °C (32 °F) at normal atmospheric pressure.
WIP Standard
2014-08-22
This Aerospace Recommended Practice (ARP) establishes a method of testing, and criteria for comparative evaluation of the abrasion resistance of chafe guard, and also establishes standard test equipment to be used in conducting these tests. This ARP establishes a standard test criteria for the evaluation of chafe guards intended to afford protection from abrasion and chafing of hose assemblies and adjacent components. For test purposes, a stainless steel wire braided hose assembly, such as MIL-H-25579, shall be used. The information obtained from testing will be applicable to any hose assembly because testing ceases when the chafe guard has worn through to the test assembly.
Standard
2014-08-20
This AIR describes the current scientific and engineering principles of gas turbine lubricant performance testing per AS5780 and identifies gaps in our understanding of the technology to help the continuous improvement of this specification.
Standard
2014-08-13
Various SAE vehicle sound level measurement procedures require use of a sound level meter which meets the Type 1 or Type 2 requirements of ANSI S1.4-1983 (see 2.1.1.1), or an alternative system which can be proved to provide equivalent test data. The purpose of this SAE Recommended Practice is to provide a procedure for determining if a sound data acquisition system (SDAS) has electro-acoustical performance equivalent to such a meter. By assuring equivalent performance of the test instrumentation, the equivalence of test data is assured. Two general configurations of sound data acquisition systems will be encompassed (see Figure 1). The first configuration consists of instrument sections which perform as a sound level meter. The second configuration is a system which records data for later processing. The intent of this document is to establish guidelines which permit the test engineer to insure equivalence of sound data acquisition systems to a sound level meter. It requires that the test engineer have a working knowledge of the characteristics of the sound data being measured.
Standard
2014-08-12
The specifications contained in this SAE Standard pertain to high tension ignition cable used in road vehicle engine ignition systems.
WIP Standard
2014-08-11
Crimping tool for AS39029/27, /28, and /75 contacts
WIP Standard
2014-08-11
Hand Crimping tool for AS39029/76, /77 and /78 contacts
WIP Standard
2014-08-11
AS23190 is a procurement specification that covers a series of plastic and metal components and devices used for the tying, positioning, and supporting cable, cable assemblies, wire, and wire bundles in electrical, electronic and communication equipment, and in interconnection systems.
Standard
2014-08-11
This SAE Standard specifies the general requirements and test methods for nonshielded high-tension ignition cable assemblies.
Standard
2014-08-11
SAE J1979 / ISO 15031-5 set includes the communication between the vehicle's OBD systems and test equipment implemented across vehicles within the scope of the legislated emissions-related OBD.
WIP Standard
2014-08-07
This test procedure provides a standard method for evaluating the side stand retraction performance of a side stand/motorcycle combination. This test procedure applies to any two-wheeled motorcycle without a sidecar, equipped with a side stand, and intended for highway use. (See SAE J213.) This SAE Recommended Practice is intended as a guide toward standard practice but may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering the use of this document.
WIP Standard
2014-08-07
These requirements define minimum recommended levels of side stand retraction performance of a new side stand/motorcycle combination when tested according to the procedures of SAE J1578. These requirements apply to any new two-wheeled motorcycle without a sidecar, equipped with a side stand, and intended for highway use. (See SAE J213). This SAE Recommended Practice is intended as a guide toward standard practice but may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering use of this document.
Viewing 31 to 60 of 22514

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