Aircraft Systems: Aircraft Hydraulic System

Aircraft Hydraulic System

operation of hydraulic system
The word “hydraulics” is based on the Greek word for water and originally meant the study of the physical behavior of water at rest and in motion. Today, the meaning has been expanded to include the physical behavior of all liquids, including hydraulic fluid. Hydraulic systems are not new to aviation. Early aircraft had hydraulic brake systems. As aircraft became more sophisticated, newer systems with hydraulic power were developed.

Hydraulic systems in aircraft provide a means for the operation of aircraft components. The operation of landing gear, flaps, flight control surfaces, and brakes is largely accomplished with hydraulic power systems. Hydraulic system complexity varies from small aircraft that require fluid only for manual operation of the wheel brakes to large transport aircraft where the systems are large and complex. To achieve the necessary redundancy and reliability, the system may consist of several subsystems. Each subsystem has a power generating device (pump) reservoir, accumulator, heat exchanger, filtering system, etc. System operating pressure may vary from a couple hundred pounds per square inch (psi) in small aircraft and rotorcraft to 5,000 psi in large transports.

Hydraulic systems have many advantages as power sources for operating various aircraft units; they combine the advantages of light weight, ease of installation, simplification of inspection, and minimum maintenance requirements. Hydraulic operations are also almost 100 percent efficient, with only negligible loss due to fluid friction.

Hydraulic Fluids

Types of Hydraulic Fluids

Basic Hydraulic Systems and Hydraulic Power Systems

Hydraulic Reservoirs

Hydraulic Filters

Hydraulic Pumps

Hydraulic Valves

Hydraulic Accumulators

Hydraulic Actuators

Power Transfer Unit (PTU)

Ram Air Turbine & Hydraulic Motor-Driven Generator

Hydraulic Seals

Large Aircraft Hydraulic Systems