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Aviation Lubricant Tribology Evaluator (ALTE) Method to Determine the Lubricating Quality of Gas Turbine LubricantsARP6255A (Current)11/26/2025
Employing ‘ball-on-cylinder’ philosophy, a non-rotating steel ball is held in a vertically mounted chuck and using an applied load is forced against an axially mounted steel cylinder. The test cylinder is rotated at a fixed speed while being partially immersed in a lubricant reservoir. This maintains the cylinder in a wet condition and continuously transports a lubricating film of test fluid to the ball and cylinder interface. The diameter of the wear scar generated on the test ball is used as a measure of the fluid’s lubricating properties. The apparatus can be used, by adjusting the operating conditions, to reproduce two different wear mechanisms; mild and severe wear, the ALTE therefore has the ability to assess a lubricant’s performance in that regard.
E-34 Propulsion Lubricants Committee
Gas Turbine Engine Lubricant Specifications: Current Technical Review and Future DirectionAIR6056A (Current)11/26/2025
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.
E-34 Propulsion Lubricants Committee
A Review of Literature on the Relationship Between Gas Turbine Engine Lubricants and Aircraft Cabin Air QualityAIR5784A (Current)11/26/2025
There has been a recent upsurge in interest from the media concerning the quality of the environment within aircraft cabins and cockpits especially in the commercial world. This has included (although by no means been limited to) the air quality, with particular reference to the alleged effects of contamination from the aircraft turbine lubricant. Possible exposure to 'organophosphates' (OPs) from the oil has raised special concerns from cabin crew. Such is the concern that government organisations around the world, including Australia, USA and UK, have set up committees to investigate the cabin air quality issue. Concern was also voiced in the aviation lubricants world at the way in which OP additives in turbine lubricants were being blamed in some reports for the symptoms being experienced by air crew and passengers. SAE Committee E-34 therefore decided that it should gather as much available information on the subject as possible. This would then enable E-34 to participate in debates on the issue and help prevent a potentially erroneous decision regarding the future of OP based additives in turbine lubricants. It would also serve as an indicator of where any additional work may be necessary to properly gauge the role that turbine lubricants, and OP additives, play in cabin air quality. This report summarises recent documentation from the literature on this subject. The contents do not necessarily represent the views of the SAE or any of the members of the study group who produced this review. The literature falls into three categories: - Air quality (Section 5), which includes: future systems to improve air quality and research plans into investigating cabin air quality - Chemistry of turbine lubricants, phosphate esters (Section 6), including evaluation of products found in cabin air and thermal breakdown products of lubricants. - Toxicity evaluation of turbine oils and additives (Section 7).
E-34 Propulsion Lubricants Committee
NATO Next Generation Rotorcraft Capability Powerplant Concept StudyF-0081-2025-01875/20/2025
The purpose of the NATO Next Generation Rotorcraft Capability (NGRC) Support Partnership funded Novel Powerplant concept study was to identify, analyze, and compare novel powerplant concepts that could fulfill the NGRC need in a solution-agnostic approach. The outcome of the study provided NSPA and the NGRC participating nations with increased knowledge and understanding of the powerplant domain to inform assessment of future NGRC platforms. This study modeled four aircraft configurations to derive propulsion sizing requirements and compared propulsion configurations for each. The propulsion system configurations considered included three levels of conventional gas turbine technology (In-service GT, 2025 GT, and 2035 GT), hybrid electric (battery), hybrid hydrogen fuel cell, and hydrogen combustion. The results of the study considered both quantitative and qualitative evaluations. The quantitative analysis determined aircraft and propulsion system sizing to align with the expected NGRC need at different max cruise speeds, and compared performance along with recurring, non-recurring, and operational costs for each. The qualitative analysis investigated the impacts of wider technical, capability, and supportability considerations for each propulsion concept. Assuming a notional NGRC entry into service target date of 2035, this study shows that, when considering both quantitative analysis and a qualitative review, a modern gas turbine is the most reasonable solution space to deliver the performance and multi-mission capability expected.
Thorpe, Richard, Williams, Aimee, Geiger, Jim, Woodside, Nicholas, Luxford, Kevin
Hybrid-Electric Powertrain Design for Enhanced Vehicle PerformanceF-0081-2025-03695/20/2025
Electrification could improve full-size rotorcraft performance by reducing peak turbine power demand, reducing transmission system weight and complexity, and reducing operating costs. Integrating electric machines with mechanical powertrains requires careful consideration of the system-level weight and efficiency impacts. This paper presents an optimization framework for evaluating parallel hybrid powertrain configurations using Geometric Programming (GP). Both retrofit and clean-sheet vehicle designs are considered. The results show that high-speed electric motors integrated into a parallel hybrid configuration using batteries can reduce the sized gas turbine power, enabling more efficient engine operation at lower power levels. For retrofit designs, with a fixed vehicle gross weight, adding batteries and motors reduces usable fuel, decreasing mission capability. Clean-sheet designs offer additional flexibility to re-size the vehicle and rotor, resulting in energy savings for an equivalent design mission.
VanLandingham, Aaron, Hall, David, Smith, Edward, Bill, Robert
On-Board Fuel Sensing for UAS and Ground Vehicle Applications2024-01-41289/16/2024
Abstract The variability in fuel, particularly for fuel blends containing sustainable aviation fuels (SAFs), emphasizes the importance of understanding fuel properties for optimizing engine performance. This paper introduces spectroscopic fuel sensors capable of real-time estimation of jet fuel properties, mainly derived cetane number (DCN). While initially developed for unmanned aircraft systems (UAS), the paper explores their potential in ground vehicle applications: enhancing engine performance through sensing for feed-forward control and fuel property monitoring at fuel depots. The fuel sensing technologies are based on spectroscopic techniques coupled with machine learning (ML) approaches. The combination of these techniques demonstrates a promising solution for a wide spectrum of fuel applications.
Patel, Dev B., Sutar, Ashish, Abraham, Abhinav, Ambre, Dhananjay, Brezinsky, Kenneth, Lynch, Patrick T., Okada, Haruna, Stafford, Jacob M., Miganakallu, Niranjan, Sanders, Scott, Rothamer, David, Mayhew, Eric, Kim, Kenneth S.
QA Test for CSP-7037053020245/15/2024
QA Test
Airlines Electronic Engineering Committee
test download manager cache issue 12/27/2023 at 9 amSAE-PP-0908512/27/2023
test download manager cache issue 12/27/2023 at 9 am
Mutagaana, Festo
A Numerical Study on the Effect of a Pre-Chamber Initiated Turbulent Jet on Main Chamber Combustion2022-01-04693/29/2022
To elucidate the complex characteristics of pre-chamber combustion engines, the interaction of the hot gas jets initiated by an active narrow throated pre-chamber with lean premixed CH4/air in a heavy-duty engine was studied computationally. A twelve-hole KAUST proprietary pre-chamber geometry was investigated using CONVERGE software. The KAUST pre-chamber has an upper conical part with the spark plug, and fuel injector, followed by a straight narrow region called the throat and nozzles connecting the chambers. The simulations were run for an entire cycle, starting at the previous cycle's exhaust valve opening (EVO). The SAGE combustion model was used with the chemistry modeled using a reduced methane oxidation mechanism based on GRI Mech 3.0, which was validated against in-house OH chemiluminescence data from the optical engine experiments. Two different piston geometries, a flat piston geometry, and a more realistic bowl piston geometry were studied to understand the influence of jet on main chamber combustion. Varying the piston geometries results in different free jet times and hence main chamber combustion characteristics. Pre-chamber fuel ratio (PCFR) 6% of the total amount of fuel was investigated while keeping the global excess air ratios (λ) condition a constant value of 2.0. Both piston cases resulted in similar pre-chamber pressurization, with almost the same pre-chamber discharge and the equal pressure difference between pre-and main-chamber (ΔP) at the start of jet ejection. Different combustion behaviors were observed on analysis of the heat release rate in the main chamber. The importance of turbulence generated by the pre-chamber-initiated jets was further studied. It was observed that free jet time is a critical factor in developing turbulence in the main chamber. This increase in turbulence helps in increasing the burning velocity causing faster combustion. The influence of the jet-piston interaction is also analyzed as that determines the combustion behavior in the later CAD.
Sanal, Sangeeth, Echeverri Marquez, Manuel, Silva, Mickael, Cenker, Emre, Im, Hong G.
O-RING, MOLDED FROM AMS7379 RUBBER FOR USE WITH AS5202 PORTSAS6203A (Current)11/9/2021
A-6C2 Seals Committee
Aircraft Turbine Fuel Contamination History and Endurance Test RequirementsAIR4023C (Current)11/1/2021
This document discusses the history and development of endurance requirements, provides an analysis of test contaminant material and includes a discussion of future requirements.
AE-5B Aircraft and Engine Fuel and Lubricant Sys Components
Rubber: Fluorocarbon Elastomer (FKM) Aircraft Engine Oil, Fuel and Hydraulic Fluid Resistant 70 to 80 Shore Type A Hardness Low Temperature Sealing Tg -47 °F (-43.9 °C) for Elastomeric Seals in Aircraft Engine, Fuel and Hydraulic SystemsAMS7410 (Current)10/6/2021
This specification covers high temperature, compression set, and fluid resistant fluorocarbon (FKM) elastomer in the form of molded rings, compression seals, O-ring cord, and molded-in-place gaskets for aeronautical and aerospace applications.
AMS CE Elastomers Committee
Defining and Measuring Factors Affecting Helicopter Turbine Engine Power AvailableARP1702B (Current)10/1/2021
This SAE Aerospace Recommended Practice (ARP) identifies and defines a method of measuring those factors affecting installed power available for helicopter powerplants. These factors are installation losses, accessory power extraction, and operational effects. Accurate determination of these factors is vital in the calculation of helicopter performance as described in the RFM. It is intended that the methods presented herein prescribe and define each factor as well as an approach to measuring said factor. Only basic installations of turboshaft engines in helicopters are considered. Although the methods described may apply in principle to other configurations that lead to more complex installation losses, such as an inlet particle separator, inlet barrier filter (with or without a bypass system), or infrared suppressor, specialized or individual techniques may be required in these cases for the determination and definition of engine installation losses. Some rotorcraft may use an alternate source of propulsion system power to supplement engine output shaft power delivered. If RFM performance includes the contribution of a Supplemental Power Unit (SPU), then the installed power available of the SPU should also be defined and measured, for which the power loss factors and methods described in this document may be applicable.
S-12 Powered Lift Propulsion Committee
Adapter Interface - Turbine Engine Blade Moment Weighing ScaleARP1134A (Current)9/15/2021
To provide a standard interface adapter flange on any blade classification instrument capable of meeting the sensitivity requirements for the specific class.
EG-1A Balancing Committee
Data Formats and Practices for Life Cycle Cost InformationARP4294A (Current)9/10/2021
This SAE Aerospace Recommended Practice (ARP)4294 is directed at life cycle cost (LCC) analysis of aerospace propulsion systems and supplements AIR1939. Specific topics addressed by ARP4294 are listed below: a Propulsion system LCC element structure. b Information exchange and relationships with: (1) Aircraft manufacturer (2) Equipment suppliers (3) Customer c The relationship of the LCC element structure to work breakdown structures. d The relationship between LCC analysis and other related disciplines (e.g., technical (performance analysis, weight control, component lives), reliability, availability and maintainability (RAM), integrated logistic support (ILS), production and finance). e Classification of the accuracy and applicability of LCC assessments.
LCLS Life Cycle Logistics Supportability
Aircraft Engine Life Cycle Cost GuideAIR1939A (Current)9/10/2021
AIR 1939 addresses communication of LCC data between equipment suppliers, aircraft engine producers, aircraft manufacturers, and users, as illustrated in Figure 1. The LCC data categories addressed include: research, development, test and evaluation (RDT&E); acquisition (initial procurement and investment); and operating and support (O&S) costs. While input and output formats are suggested, calculation procedures and cost methodology are specifically excluded since many LCC models preferred by the industry are company sensitive or proprietary (Figure 1). The relationship of LCC input data to program phase is described. Ground rules and assumptions are addressed. A glossary of LCC terms is provided. The LCC impact of propulsion systems on other aircraft systems is considered. This document was specifically developed for military propulsion system cost analysis. However, it is believed that a functional relationship exists between military and commercial Life Cycle Cost analysis and that with some interpretation, sections of AIR 1939 might be applicable to commercial propulsion systems as well. In summary, AIR 1939 provides a basis for LCC calculations, for monitoring of LCC status resulting from trade studies, and for tracking status against LCC goals in a consistent manner, thus permitting quantitative, comparable assessment. AIR 1939 guidelines recommend that a Life Cycle Cost presentation include consideration of overall cost rather than a sub-optimization of just one or a few cost elements.
LCLS Life Cycle Logistics Supportability
Measuring Aircraft Gas Turbine Engine Fine Fuel Filter Element PerformanceARP1827D (Current)7/23/2021
This SAE Aerospace Recommended Practice (ARP) delineates two complementary filter element performance parameters: (1) dirt capacity, and (2) filtration efficiency, and corresponding test procedures. It is intended for non-cleanable (disposable), fine fuel filter elements, rated at 25 µm(c) or finer, used in aviation gas turbine engine fuel systems.
AE-5B Aircraft and Engine Fuel and Lubricant Sys Components
Procedure for the Continuous Sampling and Measurement of Non-Volatile Particulate Matter Emissions from Aircraft Turbine EnginesARP6320A (Historical)5/19/2021
This SAE Aerospace Recommended Practice (ARP) describes recommended sampling conditions, instrumentation, and procedures for the measurement of non-volatile particle number and mass concentrations from the exhaust of aircraft gas turbine engines. Procedures are included to estimate sampling system loss performance. This ARP is not intended for in-flight testing, nor does it apply to engines operating in the afterburning mode. This ARP is intended as a guide toward standard practice and is subject to change to keep pace with experience and technical advances.
E-31P Particulate Matter Committee
Gas Turbine Engine Performance Presentation for Computer Programs Using FortranAS4191A (Current)5/13/2021
This SAE Aerospace Standard (AS) provides a method for gas turbine engine performance computer programs to be written using Fortran COMMON blocks. If a “function-call application program interface” (API) is to be used, then ARP4868 and ARP5571 are recommended as alternatives to that described in this document. When it is agreed between the program user and supplier that a particular program shall be supplied in Fortran, this document shall be used in conjunction with AS681 for steady-state and transient programs. This document also describes how to take advantage of the Fortran CHARACTER storage to extend the information interface between the calling program and the engine subroutine.
S-15 Gas Turbine Perf Simulation Nomenclature and Interfaces
Use of Health Monitoring Systems to Detect Aircraft Exposure to Volcanic EventsAIR6212 (Current)5/13/2021
This document collates the ways and means that existing sensors can identify the platform’s exposure to volcanic ash. The capabilities include real-time detection and estimation, and post flight determinations of exposure and intensity. The document includes results of initiatives with the Federal Aviation Administration (FAA), the European Aviation Safety Agency (EASA), the International Civil Aviation Organization (ICAO), Transport Canada, various research organizations, Industry and other subject matter experts. The document illustrates the ways that an aircraft can use existing sensors to act as health monitoring tools so as to assess the operational and maintenance effects related to volcanic ash incidents and possibly help determine what remedial action to take after encountering a volcanic ash (VA) event. Finally, the document provides insight into emerging technologies and capabilities that have been specifically pursued to detect volcanic ash encounters but are not yet a part of an airplane’s standard fit.
HM-1 Integrated Vehicle Health Management Committee
Liquid Filter Ratings, Parameters and TestsAIR887C (Current)4/29/2021
This SAE Aerospace Information Report (AIR) identifies and explains the meaning of various ratings and terms used to describe the physical characteristics of liquid filter elements. The significance of various filter parameters is discussed. In addition, a number of filter test methods are briefly described. This AIR and the data presented are only applicable where the system liquid wets the filter elements.
A-6C1 Contamination and Filtration Committee
EVALUATION OF HELICOPTER TURBINE ENGINE LINEAR VIBRATION ENVIRONMENTAIR1289A (Current)3/11/2021
This SAE Aerospace Information Report (AIR) outlines a recommended procedure for evaluation of the vibration environment to which the gas turbine engine powerplant is subjected in the helicopter installation. This analysis of engine vibration is normally demonstrated on a one-time basis upon initial certification, or after a major modification, of an engine/helicopter configuration. This AIR deals with linear vibration as measured on the basic case structure of the engine and not, for example, torsional vibration in drive shafting or vibration of a component within the engine such as a compressor or turbine airfoil. In summary, this AIR discusses the engine manufacturer’s "Installation Test Code" aspects of engine vibration and proposes an appropriate measurement method.
S-12 Powered Lift Propulsion Committee
ENGINE EXHAUST SYSTEM DESIGN CONSIDERATIONS FOR ROTORCRAFTARP4056 (Current)3/11/2021
Turbine engines installed in rotorcraft have an exhaust system that is designed and produced by the aircraft manufacturer. The primary function of the exhaust system is to direct hot exhaust gases away from the airframe. The exhaust system may consist of a tailpipe, which is attached to the engine, and an exhaust fairing, which is part of the rotorcraft. The engine manufacturer specifies a baseline "referee" tailpipe design, and guaranteed engine performance is based upon the use of the referee tailpipe and tailpipe exit diameter. The configuration used on the rotocraft may differ from the referee tailpipe, but it is intended to minimize additional losses attributed to the installation. This Aerospace Recommended Practice (ARP) describes the physical, functional, and performance interfaces to be considered in the design of the aircraft exhaust system.
S-12 Powered Lift Propulsion Committee
Helicopter Engine-Rotor System CompatibilityARP704A (Current)3/10/2021
This SAE Aerospace Recommended Practice (ARP) recommends a methodology to be used for the design, analysis and test evaluation of modern helicopter gas turbine propulsion system stability and transient response characteristics. This methodology utilizes the computational power of modern digital computers to more thoroughly analyze, simulate and bench-test the helicopter engine/rotor system speed control loop over the flight envelope. This up-front work results in significantly less effort expended during flight test and delivers a more effective system into service. The methodology presented herein is recommended for modern digital electronic propulsion control systems and also for traditional analog and hydromechanical systems.
S-12 Powered Lift Propulsion Committee
An Assessment of Planar WavesAIR5866A (Current)2/1/2021
“An Assessment of Planar Waves” provides background on some of the history of planar waves, which are time-dependent variations of inlet recovery, as well as establishing a hierarchy for categorizing various types of planar waves. It further identifies approaches for establishing compression-component and engine sensitivities to planar waves, and methods for accounting for the destabilizing effects of planar waves. This document contains an extensive list and categorization (see Appendix A) of references to aid both the newcomer and the practitioner on this subject. The committee acknowledges that this document addresses only the impact of planar waves on compression-component stability and does not address the impact of planar waves on augmenter rumble, engine structural issues, and/or pilot discomfort.
S-16 Turbine Engine Inlet Flow Distortion Committee
Design Considerations for Enclosed Turbofan/Turbojet Engine Test CellsAIR4869B (Current)2/1/2021
This SAE Aerospace Information Report (AIR) has been written for individuals associated with the ground-level testing of large and small gas turbine engines and particularly for those who might be interested in upgrading their existing or acquiring new test cell facilities.
EG-1E Gas Turbine Test Facilities and Equipment
Guidelines for Characterization of Gas Turbine Engine Total-Pressure, Planar-Wave, and Total-Temperature Inlet-Flow DistortionARP6420 (Historical)1/14/2021
The turbine-engine-inlet flow distortion descriptors summarized in this document apply to the effects of inlet total-pressure, planar-wave, and total-temperature distortions. Guidelines on stability margin, destabilizing influences, types and purposes of inlet data, AIP definition, and data acquisition and handling are summarized from AIR5866, AIR5867, ARP1420, and AIR1419. The degree to which these recommendations are applied to a specific program should be consistent with the complexity of the inlet/engine integration. Total-pressure distortion is often the predominant destabilizing element that is encountered and is often the only type of distortion to be considered, i.e, not all types of distortion need to be considered for all vehicles.
S-16 Turbine Engine Inlet Flow Distortion Committee
Measurement of Far Field Noise from Gas Turbine Engines During Static OperationARP1846B (Current)12/21/2020
Recommendations presented in this document are intended primarily for the acquisition of far-field noise data. The test engine is to be appropriately configured and operated so that the sound pressure levels obtained are consistent with the specific objectives of the test. The principal output of the data reduction system is one-third octave band sound pressure levels. However, when appropriate, data may be recorded for purposes of broader or narrower bandwidth analysis.
A-21 Aircraft Noise Measurement Aviation Emission Modeling
Aerospace Auxiliary Power SourcesAIR744D (Current)11/19/2020
This SAE Aerospace Information Report (AIR) is a review of the general characteristics of power sources that may be used to provide secondary, auxiliary, or emergency power for use in aircraft, space vehicles, missiles, remotely piloted vehicles, air cushion vehicles, surface effect ships, or other vehicles in which aerospace technology is used. The information contained herein is intended for use in the selection of the power source most appropriate to the needs of a particular vehicle or system. The information may also be used in the preparation of a power source specification. Considerations for use in making a trade study and an evaluation of the several power sources are included. More detailed information relating to specific power sources is available in other SAE Aerospace Information Reports or in Aerospace Recommended Practices.
A-6C4 Power Sources Committee
Performance Testing of Lubricant Filter Elements Utilized in Aircraft Power and Propulsion Lubrication SystemsAIR1666C (Current)11/12/2020
This SAE Aerospace Information Report (AIR) reviews performance testing parameters for non-cleanable (often referred to as disposable) filter elements utilized in aircraft power and propulsion lubrication systems, including gas turbine engines and auxiliary power units (APUs), propulsion and transmission gear boxes, and constant speed drives and integrated drive generators (IDGs). This document is confined to laboratory testing of filter element performance to qualify the filtration medium and filter element construction as opposed to qualification of the complete filter assembly. The testing discussed here is usually followed by laboratory and on-engine testing of the entire lube filter assembly (including filter element, housing, valving, etc.), which is outside the scope of this AIR.
AE-5B Aircraft and Engine Fuel and Lubricant Sys Components
Turbine Flowmeter Fuel Flow CalculationsARP4990B (Current)10/22/2020
This SAE Aerospace Recommended Practice (ARP) provides to the aerospace industry a procedure for the consistent and accurate calculation of fuel flow using turbine flowmeters during development, production, and post overhaul/repair gas turbine engine testing.
EG-1E Gas Turbine Test Facilities and Equipment
Design Considerations for Enclosed Turbofan/Turbojet Engine Test CellsAIR4869A (Historical)10/22/2020
This SAE Aerospace Information Report (AIR) has been written for individuals associated with the ground-level testing of large and small gas turbine engines and particularly for those who might be interested in upgrading their existing or acquiring new test cell facilities.
EG-1E Gas Turbine Test Facilities and Equipment
Test Cell InstrumentationAIR5026B (Current)10/21/2020
This document discusses, in broad general terms, typical present instrumentation practice for post-overhaul gas turbine engine testing. Production engine testing and engine development work are outside the scope of this document as they will typically use many more channels of instrumentation, and in most cases will have requirements for measurements that are never made in post-overhaul testing, such as fan airflow measurements, or strain measurements on compressor blades. The specifications for each parameter to be measured, in terms of measurement range and measurement accuracy, are established by the engine manufacturers. Each test cell instrument system should meet or exceed those requirements. Furthermore, each instrument system should be recalibrated regularly, to ensure that it is still performing correctly.
EG-1E Gas Turbine Test Facilities and Equipment
Configuration Control for Maintaining Correlation of Gas Turbine Engine Test CellsARP6028A (Current)10/21/2020
The FAA has issued Advisory Circular, AC43-207, that recommends re-correlation, trending or period checks. The FAA, AC43-207 bases their recommendation on ARP741. This paper describes a recommended practice and procedure for the configuration control requirements to maintain test cell correlation status. This is necessary to maintain performance measurement integrity, particularly when correlation approval is achieved by statistical trending. The configuration of a test facility that exists at the time when a correlation is being carried out should be "base lined" as a condition of correlation approval acceptance, and, be maintained during the time period that the respective correlation approval lasts. This defines test facility configuration control. This is due to the fact that a change in configuration may have the potential to change the established correlation factors and measured engine performance. If such a change occurs then this should be judged by the respective OEMs or designated correlation approval authorities Subject Matter Expert (SME). In some cases, this may involve consultation with the engine project customer or airworthiness authorities. The purpose of this paper is to recommend a means of identifying, recording, documenting and maintaining the configuration status of all correlations, including those where re-approval is achieved by using statistical trending methods rather than physical back-to-back type testing. This paper can be considered applicable to all types and standards of test facilities in the aero, marine and industrial gas turbine engine businesses.
EG-1E Gas Turbine Test Facilities and Equipment
Prognostics for Aerospace Propulsion SystemsAIR5871A (Current)10/14/2020
This document applies to prognostics of aerospace propulsion systems. Its purpose is to define the meaning of prognostics in this context, explain their potential and limitations, and to provide guidelines for potential approaches for use in existing condition monitoring environments. This document also includes some examples. The current revision does not provide specific guidance on validation and verification, nor does it address implementation aspects such as computational capability or certification.
E-32 Aerospace Propulsion Systems Health Management
Procedure for Measurement of Gaseous Emissions from Aircraft Gas Turbine Engines Using Fourier Transform Infrared AnalysisAIR5917 (Current)10/9/2020
This Aerospace Information Report (AIR) describes the use of FTIR analyzers for measurements of gaseous emissions from aircraft gas turbine engines and combustion rigs. The use of FTIR analyzers can be demonstrated as a suitable and cost-effective equivalent to NDIR and chemiluminescence analyzers as prescribed in ARP1256 for the measurement of CO, CO2, NO, and NO2, where NOx is closely approximated by the sum of NO and NO2 concentrations. FTIR analyzers may be proven suitable for equivalency of analyzers used in current emission testing. Additionally, FTIR analyzers have potential for equivalent measurements of “total” hydrocarbon (THC) as currently defined in ARP1256.
E-31G Gaseous Committee
T55 Gas Turbine Engine Bleed Band Actuator Housing Re-DesignF-0076-2020-1628110/5/2020
The continual replacement of the bleed band actuator caused a supply shortage resulting in production work stoppage. A re-design effort restored the actuator housing through rework modification of a sleeve repair. The re-design substantion is presented along with the qualification test and manufacturing process. Significant value engineering savings and increased supply readiness resulted from the re-design effort for the U. S. Army. However, the re-designed sleeved actuator housing became costly and inefficient over time and subsequently stopped. The overhaul discrepancy is still present on the newer T55 gas turbine engine model. A review of new repair technology available identified another solution that does not generate hazardous industrial waste. That solution is cold spray technology. Cold spray solid state additive technology is evaluated for re-design of the housing as comparison to the existing sleeve re-design. Cost decrease and manufacturing efficiency increase are both a result from this evaluation. Two cold spray powders presented are options for the re-design housing. While both powders provide a better overall solution to the sleeve re-design, the cold spray hard coat powder appears to provide improved wear resistance, e.g. 20 times better than hexavalent chrome plating.
Cass, Wesley
Embedded Sensing for Gas Turbine Engine Component Health MonitoringF-0076-2020-1633910/5/2020
Current rotorcraft gas turbine engines typically use titanium alloys and steel for compressor section and single-crystal nickel superalloys for the hot-section turbine stator vanes and rotor blades. However, these material selections are rapidly changing due to increased requirements on power-density and efficiency. Future Army gas turbine engines will be using ceramic matrix composites for many high temperature engine components due to their low density and improved durability in high temperature environment. The gas turbine industry is also actively developing adaptive concept technologies for production and assembly of modular gas turbine engine components with integrated sensing. In order to actively monitor engine components for extended seamless operation and improved reliability, it is essential to have intelligent embedded sensing to monitor the health of critical components in engines. Under this U.S. Army Foreign Technology Assessment Support (FTAS) program funded research project, surface bonded and embedded sensor patches from a U.K.-based company, Epsilon Optics Ltd., were experimentally evaluated to measure temperature responses on typical propulsion component material coupons. The temperature responses from this foreign technology sensor were assessed using a thermomechanical fatigue tester with a built-in furnace to conduct thermal cycling durability experiments. The experimental results obtained from the durability performance of this fiber-optic based embedded sensor are reported in this paper. This sensor technology upon maturation to higher TRL (Technology Readiness Level) levels can greatly reduce the lifecycle cost of future Army gas turbine engines.
Murugan, Muthuvel, Caesley, Roger, Ghoshal, Anindya, Walock, Michael, Knapp, Robert
Acceptance Test Procedures and Standards to Ensure Clean Fuel System ComponentsARP1953B (Current)10/1/2020
To describe general guidelines for achieving selected levels of cleanliness in gas turbine engine fuel system components and to describe laboratory methods for measuring and reporting the contamination level of the wetted portion of fuel system components. As in SAE J1227 (covering hydraulic components) this practice includes guidelines for levels of acceptance but does not attempt to set those levels.
AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee
Balancing Machines - Verification Test RequirementsAS8617 (Current)8/25/2020
This document specifies instructions to verify proper calibration of all balancing machines used for processing gas turbine rotors. Detailed test procedures and test log samples are provided to evaluate the condition of the machine under test. These performance and test requirements may be used for new installations, periodic surveillance, or following repairs that may have affected machine performance. Calibration of the balancing machine is an activity done prior to verification testing and is outside the scope of this document. Troubleshooting of difficulties during the verification tests is also outside the scope of this document; this document is purely an instructive procedure.
EG-1A Balancing Committee
Gas Turbine Engine Real Time Performance Model PresentationARP4148C (Current)8/17/2020
This SAE Aerospace Recommended Practice (ARP) provides guidance for the presentation of gas turbine engine transient performance models with the capacity to be implemented as computer programs operating in real time and is intended to complement AS681. Such models will be used in those applications where a transient program must interface with physical systems. These applications are characterized by the requirement for real time transient response. These models require attention to unique characteristics that are beyond the scope of AS681. This document is intended to facilitate the development of mathematical models and the coordination of their requirements with the user. It will not unduly restrict the modeling methodology used by the supplier. The objective of this document is to define a recommended practice for the delivery of mathematical models intended for real time use. Models used in this application may also be contained in deliverable computer programs covered by AS681.
S-15 Gas Turbine Perf Simulation Nomenclature and Interfaces
Procedure for the Continuous Sampling and Measurement of Non-Volatile Particle Emissions from Aircraft Turbine EnginesAIR6241A (Current)7/28/2020
This Aerospace Information Report (AIR) is a historical technical record describing procedures, required continuous sampling conditions, and instrumentation for the measurement of non-volatile particle number and mass concentrations from the exhaust of aircraft gas turbine engines. Procedures are included to calculate sampling loss performance. This AIR is not intended for in-flight testing, nor does it apply to engine operating in the afterburning mode. This Aerospace Information Report is a historical technical record of the initial document detailing the measurement of non-volatile particle emissions at the exit plane of aircraft gas turbine engines. This methodology was adopted by ICAO into Annex 16 Vol II and updated into Aerospace Recommended Practice ARP6320. Future updates of this document may include explanations of the reasoning and assumptions used to develop this measurement methodology.
E-31P Particulate Matter Committee
Environmental Control System ContaminationAIR1539C (Current)5/29/2020
This SAE Aerospace Information Report (AIR) includes a discussion of liquid and particulate contaminants which enter the aircraft through the environmental control system (ECS). Gaseous contaminants such as ozone, fuel vapors, sulphates, etc. are also covered in this AIR. This publication is concerned with contamination sources which interface with ECS and fuel tank inerting systems, and the effects of this contamination on equipment. Methods of control will be limited to the equipment and interfacing ducting which normally falls within the responsibility of the ECS designer.
AC-9 Aircraft Environmental Systems Committee
Rubber: Fluorocarbon Elastomer (FKM) Low Temperature Sealing Tg -40 °F (-40 °C) 70 to 80 Type ‘A’ Hardness For Elastomeric Seals in Aircraft Engine Oil, Fuel and Hydraulics SystemsAMS7379A (Current)5/18/2020
This specification covers a fluorocarbon (FKM) rubber in the form of O-rings, compression seals, O-ring cord, and molded-in-place gaskets for aeronautical and aerospace applications. For sheet, strip, tubing, extrusions, and molded shapes use the AMS3353 specification which is intended for that use.
AMS CE Elastomers Committee
Aircraft Fuel System Vapor-Liquid Ratio ParameterAIR1326A (Current)4/29/2020
The AIR is limited to a presentation of the historical background, the technical rationale which generated the V/L fuel condition interface requirement in specifications between the aircraft fuel delivery system and the aircraft engine fuel system, and limitations in the usage of the V/L concept.
AE-5B Aircraft and Engine Fuel and Lubricant Sys Components
Compound, Rust Inhibiting Aircraft Engine ComponentsAMS3060B (Current)4/29/2020
This specification covers a rust-inhibiting compound in the form of a liquid concentrate or a water soluble powder.
AMS J Aircraft Maintenance Chemicals and Materials Committee
Determination of Costs and Benefits from Implementing an Engine Health Management SystemARP4176A (Current)4/28/2020
This ARP provides an insight into how to approach a cost benefit analysis (CBA) to determine the return on investment (ROI) that would result from implementing a propulsion Prognostics and Health Management (PHM) system on an air vehicle. It describes the complexity of features that can be considered in the analysis, the different tools and approaches for conducting a CBA and differentiates between military and commercial applications. This document is intended to help those who might not necessarily have a deep technical understanding or familiarity with PHM systems but want to either quantify or understand the economic benefits (i.e., the value proposition) that a PHM system could provide.
E-32 Aerospace Propulsion Systems Health Management
Pre-design Investigation of Resonant Frequency Effects on Gas Exchange Efficiencies of a One-kW Natural-Gas Linear Engine Alternator2020-01-04884/14/2020
Performance of a natural gas two-stroke engine incorporated in a 1-kW free-piston oscillating Linear Engine Alternator (LEA) - a household electricity generator - was investigated under different resonant frequencies for pre-design phase purposes. To increase the robustness, power density, and thermal efficiencies, the crank mechanism in free-piston LEA is omitted and all moving parts of the generator operate at a fixed resonant frequency. Flexure springs are the main source of the LEA’s stiffness and the mass-spring dynamics dominates the engine’s speed. The trade-off between the engine’s performance, mass-spring system limits, and power and efficiency targets versus the LEA speed is very crucial and demands a careful investigation specifically at the concept design stages to find the optimum design parameters and operating conditions. CFD modeling was performed to analyze the effects of resonant frequency on the engine’s gas exchange behavior. To take combustion effects into account, a semi-empirical method was employed to obtain the initial and boundary conditions during the gas exchange from experiments and imported into CFD simulation. The numerical results of the gas exchange were validated at the engine speed of 5400 RPM with the experimental results. The semi-empirical method eliminated the complicated combustion simulation and significantly reduced the computational time and well-matched with experiments within 1 % error. Results showed enhanced trapping efficiency of 7.1% per 1000 RPM, and reduced scavenging efficiencies of 5.5% per 1000 RPM as speed engine’s speed increased. Comparison of the trapping and scavenging efficiencies showed an improved fuel/power efficiency equal to about 1.45 % per each 15 Hz increase in the LEA resonant frequency.
Zamani Meymian, Nima, Darzi, Mahdi, Johnson, Derek, Famouri, Parviz
Initial Investigations into the Benefits and Challenges of Eliminating Port Overlap in Wankel Rotary Engines2020-01-02804/14/2020
The Wankel rotary engine historically found limited success in automotive applications due in part to poor combustion efficiency and challenges around emissions. This is despite its significant advantages in terms of power density, compactness, vibrationless operation, and reduced parts count in relation to the 4-stroke reciprocating engine, which is now-dominant in the automotive market. A large part of the reason for the poor fuel economy and high hydrocarbon emissions of the Wankel engine is that there is a very significant amount of overlap when the ports are opened and/or closed by the rotor apices (so-called peripheral ports). This paper investigates the benefits of zero overlap from a production engine with this characteristic and the effect of configuring a peripherally-ported Wankel engine in such a manner. As discussed in the paper, arranging this condition for peripherally-ported engines unfortunately reduces the trapped compression and/or expansion ratios significantly, such that when naturally-aspirated operation is simulated, a large reduction in performance ensues. In order to demonstrate the potential of zero port overlap in Wankel engines with respect to emissions, a 2007 model year Mazda RX-8 was rebuilt, run-in, degreened, and tested on a chassis dynamometer. As standard, the engine in this vehicle is configured with no port overlap through the adoption of side intake and exhaust ports. This testing was performed in order to see subjectively how successful such an approach could be in controlling emissions. The vehicle easily met Euro 5 limits for all criteria emissions and was even better in terms of hydrocarbon emissions versus Euro 6 on the WLTP cycle, giving the lie to the belief that a Wankel engine can no longer meet current automotive emissions targets. The analytical work reported here studies the result of eliminating overlap on the performance of a peripherally-ported single-rotor Wankel engine using a 1-D model. This was implemented and correlated to the in-production Advanced Innovative Engineering (UK) Ltd 225CS engine used in the UK government-funded ADAPT project. The initial port study focused on advancing and retarding the exhaust and intake port respectively to achieve zero port overlap and then sweeping their zero-overlap positions together around the trochoid housing. The best location for the ports was then identified; this was essentially an “Otto” timing set, with broadly equal compression and expansion ratios. Notwithstanding this, potential performance was found to be severely curtailed, as was to be expected given the marked reduction in trapped compression and/or expansion ratios necessary due to peripheral porting. Countermeasures to this reduction are discussed. Those that will be studied later in the project will be reported in a later publication.
Turner, James, Turner, Matthew, Vorraro, Giovanni, Thomas, Toby
The Effects of Thick Thermal Barrier Coatings on Low-Temperature Combustion2020-01-02754/14/2020
An experimental study was conducted on a Ricardo Hydra single-cylinder light-duty diesel research engine. Start of Injection (SOI) timing sweeps from -350 deg aTDC to -210 deg aTDC were performed on a total number of five pistons including two baseline metal pistons and three coated pistons to investigate the effects of thick thermal barrier coatings (TBCs) on the efficiency and emissions of low-temperature combustion (LTC). A fuel with a high latent heat of vaporization, wet ethanol, was chosen to eliminate the undesired effects of thick TBCs on volumetric efficiency. Additionally, the higher surface temperatures of the TBCs can be used to help vaporize the high heat of vaporization fuel and avoid excessive wall wetting. A specialized injector with a 60° included angle was used to target the fuel spray at the surface of the coated piston. Throughout the experiments, the equivalence ratio, ϕ, was maintained constant at 0.4; the combustion phasing was consistently matched at 6.8 ± 0.4 deg aTDC. It can be concluded that the thick TBC cases achieved 1 to 2 percentage points improvement in combustion efficiency, and generally, a ~2 percentage points increase in indicated engine efficiency. It is also noticed that applying a dense top sealing layer to the TBC further improves the UHC emissions compared to the TBC coated piston with an unsealed surface. From the heat release analysis, it can be concluded that the TBCs have no significant impact on the heat release process and knock intensity while matching the combustion phasing; however, it reduces the intake temperature requirement by up to 20 K. The exhaust gas temperatures were expected to increase for the TBC cases, but the expected increase in exhaust temperature was not conclusive from the results observed in this study.
Yan, Ziming, Gainey, Brian, Gohn, James, Hariharan, Deivanayagam, Saputo, John, Schmidt, Carl, Caliari, Felipe, Sampath, Sanjay, Lawler, Benjamin
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