Jean-Charles Maré is Professor at the National Institute of Applied Sciences (INSA) in Toulouse, France.

• Introduction ixNotations and Acronyms xiiiChapter 1. General Considerations 11.1. Power transmission in aircraft 11.1.1. Needs and requirements for secondary power and power flows 11.1.2. Actuation functions 21.1.3. Actuation needs and constraints 51.2. Primary and secondary power transmission functions for actuators 81.2.1. Primary functions 101.2.2. Secondary functions 121.2.3. Signal approach and power approach 131.2.4. Types of actuators 141.3. Hydraulic power actuation 161.3.1. Units and reference values 161.3.2. Energy transport by a liquid 181.3.3. Historical evolution of power and pressure use 221.3.4. Potential advantages and disadvantages of hydraulic technology 271.3.5. Overall hydraulic circuit architecture 31Chapter 2. Reliability  332.1. Risks and risk acceptance 332.2. Response to failure 362.2.1. Resistance to failure 372.2.2. Tolerance to failure 382.2.3. Examples 402.3. Redundancy 402.3.1. Static redundancy 442.3.2. Dynamic redundancy 482.4. Feared events and failure rates in actuation 512.5. Fundamentals of reliability calculation 522.5.1. Variables used in reliability calculation 522.5.2. Generic failure rate models 552.5.3. Reliability of element associations 572.6. Short glossary of technical terms pertaining to reliability 60Chapter 3. Hydraulic Fluid and its Conditioning 633.1. Needs and constraints 633.1.1. Opportunities and constraints in hydrostatic power transmission 633.1.2. Actual hydraulic fluid 643.1.3. Physical properties 663.2. Fluid conditioning 683.2.1. Fluid in sufficient quantity 683.2.2. Pressurization and charging 703.2.3. Filtration 733.2.4. Thermal management 763.2.5. External leakage collection 813.3. Monitoring and maintaining the fluid in working conditions 813.3.1. Fluid quantity 823.3.2. Cleanliness 823.3.3. Pressurization – depressurization 833.3.4. Examples 833.4. Energy phenomena caused by the fluid 843.4.1. Hydraulic resistance 843.4.2. Hydraulic capacitance 843.4.3. Hydraulic inertia 873.4.4. Speed of sound in the hydraulic fluid 87Chapter 4. Hydromechanical Power Transformation  894.1. Hydromechanical power transformation  894.2. Functional perspective 944.3. Technological shortcomings 954.3.1. Energy losses 964.3.2. Compressibility of the hydraulic fluid 974.3.3. Wall deformation 974.3.4. Pulsations 974.3.5. Drainage 994.4. Pump driving 1004.4.1. Driving performed by main engines: Engine Driven Pump (EDP)  1004.4.2. Driving performed by an electric motor: Electro Mechanical Pump (EMP) or Alternative Current Motor Pump (ACMP)  1024.4.3. Driving performed by a hydraulic motor: Power Transfer Unit (PTU) 1024.4.4. Dynamic air driving: Ram Air Turbine (RAT) or Air Driven Pump (ADP) 1044.4.5. Driving performed by a gas turbine: Solid Propellant Gas Generator (SPGG) or Monofuel Emergency Power Unit (MEPU) 1044.4.6. Fluid supply under pressure 105Chapter 5. Power Metering in Hydraulics 1075.1. Power metering principles 1075.2. Power-on-Demand 1105.2.1. Metering by pump drive adjustment 1105.2.2. Metering by displacement adjustment 1115.3. Metering by hydraulic restriction 1145.3.1. Functional configuration 1155.3.2. Types of distribution 1205.4. Impact of restriction configuration and properties on the metering function 1225.4.1. Fixed hydraulic restriction 1225.4.2. Variable hydraulic restriction 1255.5. Servovalves 1395.5.1. Architecture 1395.5.2. Incremental improvements of servovalve performances  1435.5.3. Power supply of the electromagnetic motor 1455.5.4. Concepts of pilot stages 1455.5.5. Direct drive valve 151Chapter 6. Power Management in Hydraulics 1576.1. Power distribution 1576.2. Providing power 1576.2.1. Transporting fluid 1576.2.2. Isolating 1626.2.3. Sequencing user power supplies 1656.2.4. Merging sources 1656.2.5. Sharing sources 1666.2.6. Storing/restoring energy 1686.2.7. Adjusting the pressure level 1716.3. Protecting 1726.3.1. Protecting against overpressure/overload 1736.3.2. Protecting against cavitation and desorption 1766.3.3. Protecting against over-consumptions 1786.4. Managing the load 1806.4.1. Locking the load in position 1806.4.2. Ensuring irreversibility 1816.4.3. Releasing the load 1826.4.4. Damping the load 183Chapter 7. Architectures and Geometric Integration of Hydraulically-supplied Actuators 1897.1. Introduction 1897.2. Arrangement of actuation functions 1907.3. Architecture and routing of hydraulic power networks 1917.3.1. Architecture 1917.3.2. Routing 1937.4. Integration of components and equipment 1937.4.1. In-line integration 1947.4.2. Manifold integration 1947.4.3. Sub-system integration 1977.5. Integration of actuators in the airframe  2007.5.1. Controls 2007.5.2. Structural integration 203Bibliography 209Index 219