Aircraft Hydraulic System Design pptx

© 2008 Eaton Corporation. All rights reserved. Aircraft Hydraulic System Design Peter A. Stricker, PE Product Sales Manager Eaton Aerospace Hydraulic Systems Division August 20, 2010 2 Purpose • Acquaint participants with hydraulic system design principles for civil aircraft • Review examples of hydraulic system architectures on common aircraft 3 Agenda • Introduction • Review of Aircraft Motion Controls • Uses for and sources of hydraulic power • Key hydraulic system design drivers • Safety standards for system design • Hydraulic design philosophies for conventional, “more electric” and “all electric” architectures • Hydraulic System Interfaces • Sample aircraft hydraulic system block diagrams • Conclusions 4 Introduction As airplanes grow in size, so do the forces needed to move the flight controls … thus the need to transmit larger amount of power Ram Air Turbine Pump Hydraulic Storage/Conditioning Engine Pump Electric Generator Electric Motorpump Flight Control Actuators Air Turbine Pump Hydraulic system transmits and controls power from engine to flight control actuators 2 Pilot inputs are transmitted to remote actuators and amplified 1 3 Pilot commands move actuators with little effort 4 Hydraulic power is generated mechanically, electrically and pneumatically 5 Pilot Inputs 5 Introduction • Aircraft’s Maximum Take-Off Weight (MTOW) drives aerodynamic forces that drive control surface size and loading • A380 – 1.25 million lb MTOW – extensive use of hydraulics • Cessna 172 – 2500 lb MTOW – no hydraulics – all manual 6 Controlling Aircraft Motion Primary Flight Controls Definition of Airplane Axes 1 Ailerons control roll 2 Elevators control pitch 3 Rudder controls yaw 1 3 2 7 Controlling Aircraft Motion Secondary Flight Controls High Lift Devices: ► • Flaps (Trailing Edge), slats (LE Flaps) increase area and camber of wing • permit low speed flight Flight Spoilers / Speed Brakes: permit steeper descent and augment ailerons at low speed when deployed on only one wing Ground Spoilers: Enhance deceleration on ground (not deployed in flight) Trim Controls: • Stabilizer (pitch), roll and rudder (yaw) trim to balance controls for desired flight condition 8 Example of Flight Controls (A320) REF: A320 FLIGHT CREW OPERATING MANUAL CHAPTER 1.27 - FLIGHT CONTROLS PRIMARY SECONDARY 9 Why use Hydraulics? • Effective and efficient method of power amplification • Small control effort results in a large power output • Precise control of load rate, position and magnitude • Infinitely variable rotary or linear motion control • Adjustable limits / reversible direction / fast response • Ability to handle multiple loads simultaneously • Independently in parallel or sequenced in series • Smooth, vibration free power output • Little impact from load variation • Hydraulic fluid transmission medium • Removes heat generated by internal losses • Serves as lubricant to increase component life 10 HYDR. MOTOR TORQUE TUBE GEARBOX Typical Users of Hydraulic Power • Landing gear • Extension, retraction, locking, steering, braking • Primary flight controls • Rudder, elevator, aileron, active (multi-function) spoiler • Secondary flight controls • high lift (flap / slat), horizontal stabilizer, spoiler, thrust reverser • Utility systems • Cargo handling, doors, ramps, emergency electrical power generation Flap DriveSpoiler Actuator Landing Gear Nosewheel Steering [...]... Hydraulic System Architecture: Arrangement and interconnection of hydraulic power sources and consumers in a manner that meets requirements for controllability of aircraft 12 Considerations for Hydraulic System Design to meet System Safety Requirements • Redundancy in case of failures must be designed into system • • • • Any and every component will fail during life of aircraft Manual control system requires... emergency conditions – retract / extend / steer 19 Aircraft Hydraulic Architectures Comparative Aircraft Weights Increasing Hydraulic System Complexity 20 Aircraft Hydraulic Architectures Mid-Size Jet Example Block Diagrams – Learjet 40/45 MTOW: 21,750 lb Flight Controls: Manual MAIN SYSTEM EMERGENCY SYSTEM Key Features • One main system fed by 2 EDP’s • Emergency system fed by DC electric pump • Common partitioned... hydraulic systems + one electric system (backup) Primary hydraulic power supplied by 4 EDP’s per system All primary flight controls have 3 channels – 2 hydraulic + 1 electric 4 engines provide sufficient redundancy for engine-out cases • • • REF.: EATON C5-37A 06/2006 • 25 Conclusions • • • Aircraft hydraulic systems are designed for high levels of safety using multiple levels of redundancy Fly-by-wire systems... Key Hydraulic System Design Drivers • High Level certification requirement per aviation regulations: Maintain control of the aircraft under all normal and anticipated failure conditions • Many system architectures* and design approaches exist to meet this high level requirement – aircraft designer has to certify to airworthiness regulators by analysis and test that his solution meets requirements * Hydraulic. .. in system 3 to retract LG Rotorburst: Three systems sufficiently segregated All Power-out: RAT pump powers center system; LG extends by gravity LEFT SYSTEM CENTER SYSTEM RIGHT SYSTEM • • • • • • • REF.: AIR5005 (SAE) 24 Wide Body Aircraft Hydraulic Architectures Example Block Diagrams – Airbus A380 MTOW: 1,250,000 lb Flight Controls: FBW (2H + 1E channel) Key Features / Redundancies Two independent hydraulic. .. workload, major damage to aircraft and possible injury and deaths Extremely remote P ≤ 10-7 Catastrophic Loss of aircraft with multiple deaths Extremely improbable P ≤ 10-9 Examples Minor: Single hydraulic system fails Major: Two (out of 3) hydraulic systems fail Hazardous: All hydraulic sources fail, except RAT or APU (US1549 Hudson River A320 – 2009) Catastrophic: All hydraulic systems fail (UA232 DC-10... actuators will like remain hydraulic, using Electro-Hydrostatic Actuators (EHA) or local hydraulic systems, consisting of • Miniature, electrically driven, integrated hydraulic power generation system • Hydraulic actuator controlled by electrical input 17 Fly-by-Wire (FBW) Systems Conventional Mechanical • • • • Fly-by-Wire Pilot input mechanically connected to flight control hydraulic servo-actuator... power from system #1 to #2 to retract LG Rotorburst: Emergency Rudder System is located outside burst area All Power-out: ERS runs off battery; others manual; LG extends by gravity • • • • 22 Aircraft Hydraulic Architectures Single-Aisle Example Block Diagrams – Airbus A320/321 MTOW (A321): 206,000 lb Flight Controls: Hydraulic FBW Key Features 3 independent systems 2 main systems with EDP 1 main system. .. on Civil Airborne Systems and Equipment ARP 4754: Certification Considerations for Highly-Integrated or Complex Aircraft Systems Aerospace Information Reports (SAE) AIR5005: Aerospace - Commercial Aircraft Hydraulic Systems Radio Technical Committee Association (RTCA) DO-178: Software Considerations in Airborne Systems and Equipment Certification (incl Errata Issued 3-26-99) DO-254: Design Assurance... WING BOEING 757 AILERON SYSTEM 18 Principal System Interfaces Design Considerations Electrical System Flight Controls Flow under normal and all emergency conditions – priority flow when LG, flaps are also demanding flow Electric motors, Solenoids Power on Demand Electrical power variations under normal and all emergency conditions (MIL-STD-704) Hydraulic System Power on Demand Hydraulic power from EDP . reserved. Aircraft Hydraulic System Design Peter A. Stricker, PE Product Sales Manager Eaton Aerospace Hydraulic Systems Division August 20, 2010 2 Purpose • Acquaint participants with hydraulic system. Aircraft Motion Controls • Uses for and sources of hydraulic power • Key hydraulic system design drivers • Safety standards for system design • Hydraulic design philosophies for conventional, “more. aircraft 13 Considerations for Hydraulic System Design to meet System Safety Requirements • Redundancy in case of failures must be designed into system • Any and every component will fail during life of aircraft • Manual