This SAE Aerospace Information Report (AIR) contains Lessons Learned from aerospace actuation, control and fluid power systems technologies. The lessons were prepared by engineers from the aerospace industry and government services as part of the work of SAE Committee A-6, Aerospace Actuation, Control and Fluid Power Systems.
This Aerospace Information Report (AIR) provides information on the thrust vectoring flight control systems incorporated on various aircraft development programs and production military aircraft. This report includes V/STOL aircraft thrust vector applications in addition to recommendations for use of thrust vectoring for the improvement of low speed maneuverability in conventional aircraft. Descriptions of each aircraft are provided along with a summary of the thrust vector control system, and, mechanical design methodologies used. Block diagrams, system schematics, and, several system level components are presented.
This SAE Aerospace Information Report (AIR) was prepared by a panel of the SAE A-5 Committee. This document establishes the specifications for fluids used in landing gear shock struts with extreme pressure and antiwear additives that have been added for improved lubrication.
This SAE Aerospace Recommended Practice (ARP) establishes the requirements for the design, manufacture, and qualification of four hydraulic switching valves used in airborne applications. Two are pressure operated, Type IA and IB and two are solenoid/pilot operated, Type IIA and IIB. They are applicable to four pressure classes 3000, 4000, 5000 and 8000 psi. The equipment as designed is intended to be installed in hydraulic systems designed to AS5440 for military applications or ARP4752 and ARP4925 depending on the type of aircraft for commercial applications. Additional or refined requirements shall be contained in the detail (procurement) specification and these shall take precedence over any potentially conflicting requirements of this ARP or documents referenced by this ARP.
A hydraulic purifier is used in remediation of contaminated fluids by removing air, particulate and water to clean the fluid to within the requirements of the system where the fluid is being used. This standard provides requirements for standard tests to evaluate purifier performance so that users can determine the best purifier for their use.
This information report is intended to provide reference material for the selection and use of fire-resistant fluids in the hydraulic systems of off-road work machinery with separate hydraulic oil sump.
This SAE Aerospace Recommended Practice (ARP) presents a procedure for evaluating cleaning methods with respect to contaminant removal and element degradation particularly for metallic filter elements. A procedure for checking durability of cleaning equipment and a referee cleaning method are also included. It is applicable only to the evaluation of cleaning methods proposed for removal of service dirt and not for built-in dirt, liquid oxygen (LOX) cleaning, etc. Supporting information for use with the ARP is also included.
This SAE Aerospace Recommended Practice (ARP) establishes a method for evaluating the particulate matter extracted from theh working fluid of a hydraulic system or component using a membrane. The amount of particulate matter deposited on the membrane due to filtering a given quantity of fluid is visually compared against a standard membrane in order to provide an indication of the cleanliness level of the fluid. A particular feature of this method is the membrane preparation to achieve an even particulate distribution on the membrane suitable for other applications. Membrane evaluation using standard membranes, described in this document, is an alternative technique to counting with either an optical microscope (ARP598) or an automatic particle counter (ISO 11500). The latter particle counting procedures are considered more rpecise.
This document reviews briefly the subject of woven metal screens. Conditions that can promote damaging corrosion in stainless steel filter screens are discussed and recommendations are listed for minimizing corrosion damage. This is a general document only; for specific applications it is suggested that the reader refer to the technical literature, and selected references listed below.
This Recommended Practice establishes a uniform fluid specification for reference usage in specific documents, such as fluid power component test procedures, where a fluid designation is required.
In May 1979 Martin Marietta Aerospace, Denver Division, completed a survey of missile hydraulic system cleanliness and contamination control procedures and practices as several aerospace companies. The intent of this survey was to gather and assemble the data from companies that manufacture missiles with hydraulic systems, similar to the Titan III System, from a contamination control standpoint. The survey concentrated on 15 subject areas of interest.
This procedure will be generally applicable to three classes of hydraulic components as listed below: Class A - Motors, Pumps, Actuators, Accumulators, Reservoirs, and Non-metering Valves Class B - Servo Valves and Metering Valves Class C - Special short Life Duration Components
This SAE Aerospace Recommended Practice (ARP) provides guidance for the design and installation of a commercial aircraft hydraulic system to meet the applicable requirements, including the applicable airworthiness regulations that affect the hydraulic system design. This ARP also provides information and guidelines on the many factors that arise in the design process to provide cost effectiveness, reliability, maintainability and accepted design and installation practices.
This SAE Aerospace Recommended Practice (ARP) shall provide guidelines for the maintenance, inspection, and support of rotary and linear mechanical actuators on in-service and aging aircraft.
Much of the available long-term storage test data has been reviewed and topically separated to enable the independent discussion of storage effects on fluids, seals, hydraulic components, and hydraulic systems. Comments are made in Section 4 concerning the applicability of the test results and regarding design practices for storability. Conclusions are drawn in Section 5 regarding inactive storage of hydraulic systems for at least a 7 year period.
This SAE Aerospace Recommended Practice (ARP) provides analytical and test methods for determining pressure drop in fluid systems such as hydraulic, fluid, oil, and coolant used in aerospace vehicles. Determining pressure drop by analytical and test results will be discussed.
This SAE Aerospace Information Report (AIR) provides design data reliability information relative to the long-term storage of gas containers or pressure vessels charged with nitrogen or helium at pressures ranging from 6000 to 12 000 psi. The gas containers are cylindrical, spherical, or toroidal in shape. Internal volumes range up to 1385 in3. Applications for this type cold gas actuation system include tactical missiles, guided projectiles, and smart bombs. A typical system is described.
This document provides an overview of the tests, and issues related to testing, that are unique to Electromechanical Actuators (EMAs). The tests, and issues documented, are not necessarily all-inclusive. This document discusses both the tests applicable to EMAs and the test methodologies to accomplish the test objectives. EMAs may be used in a wide variety of applications such as utility, secondary flight controls and primary flight controls, in a wide variety of markets including manned and unmanned civil and military aircraft, small missile fin and thrust vector control applications up to high powered utility and flight controls. EMAs may also have either a rotary or a linear output, be servo controlled or use simple open loop point-to-point or other control topologies. As such this document covers a wide range of potential applications, the application of any given test requirement is determined by the application and the user.
The purpose of this SAE Aerospace Recommended Practice (ARP) is to provide guide lines for allowable leakage for in-service aircraft hydraulic components at a nominal 100 °F (38 °C) temperature and to outline the procedure for measuring such leakage. The limits to be applied to any specific aircraft should be adjusted before inclusion in a maintenance manual.
Recommendations for EHA Pump sizing based on considerations for various actuator performance requirements, including no-load speed, breakout torque, low temperature, stiffness, dynamic response, maximum pressure-velocity capability, and other conditions.
Aerospace - Procedure for the Determination of Particulate Contamination in Hydraulic Fluids By the Control Filter Gravimetric Procedure
This SAE Aerospace Recommended Practice (ARP) describes a gravimetric method for the determination of particulate contaminant in hydraulic fluids by the control filter technique. With this method detectable contamination levels down to 0.2 mg per sample can be obtained with a standard deviation of ±0.1 mg.
This SAE Aerospace Standard (AS) defines contamination classes and levels for particulate contamination of hydraulic fluids and includes methods of reporting related data (Appendix A). The contamination levels selected are based on the widely accepted NAS 1638 cleanliness classes. The conversion from NAS 1638 cleanliness class specifications to AS4059 class specifications is defined. The comparison of the NAS 1638 classes to AS4059 classes and levels is provided and are defined and the differences explained (Appendix B). NAS 1638 classes based on weight of particles are not applicable to these classes and are not included. A contamination code has been added to describe the contamination levels of the fluid at the specified particle size ranges.
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This document provides guidelines for sizing commercial aircraft hydraulic systems including determining the hydraulic flow demands for all phases of flight and hence sizing of the hydraulic pumps. In addition, details of sizing of hydraulic reservoirs and pipelines are also provided.
This specification covers manual pressure-generating brake control units as defined by specification MIL-H-5440.
This SAE Aerospace Recommended Practice (ARP) provides guidance in the design, development, qualification test, process control and production acceptance test for flight critical control valve (FCCV) design used in military flight control servoactuators where loss of single valve control could cause a catastrophic failure resulting in death, permanent total disability, and/or financial loss exceeding a defined contractual limit. The FCCV, which is one element of a flight control actuator servo control loop, is a variable position control valve which modulates fluid into and out of the servoactuator power stage cylinders. The FCCV may be mechanically driven by either a mechanical flight control system as shown in Figure 1 or hydraulically driven from electro-hydraulic servo valve (EHSV) modulation control flow as shown in Figure 2. This type of control valve is not an EHSV or a direct drive valve (DDV). The FCCV is used in military hydraulic systems which conform to AS5440.
This compendium is provided to facilitate the computation of compressible flow through restrictions. In addition, graphical data are provided for characterizing nitrogen, helium, and argon gases. The information presented is density, entropy, enthalpy, viscosity, and specific heat as functions of pressure and temperature.
This report summarizes data relative to liquid fluids and their properties which are of interest to Aerospace Fluid Power technologists.
Although there is controversy regarding the chemical form of chlorine and its relation to harmful effects in the hydraulic fluid (i.e., chloride ions versus organic chloro-compounds versus total chlorine in all forms), it is generally agreed that total chlorine content should be measured and controlled. In the near future, the ban on the manufacture of chlorinated solvents, out of concern for depletion of the ozone layer, may in itself diminish or eliminate chlorine contamination related aircraft malfunctions. It is generally accepted that hydraulic fluid contamination should be held to a minimum under all conditions. The benefits of low contamination levels are improved performance, lower maintenance due to lower wear, corrosion and erosion, longer fluid life, longer component life, etc.
This Aerospace Information Reportr will describe aircraft hydro-mechanical systems design related to the direct and indirect effects of lightning strikes. Stress and other design factors for hydraulic system components, electrical bonding, electrical control and monitoring, composite aircraft structures, and electromagnetic effects will be addressed.