What are Hydraulic Systems in Aircraft & How Do They Work?

First introduced in World War ll, aircraft hydraulic systems were a minor part of flight operations for a while. However, with their growing capabilities and advantages, this technology became a mandatory part of critical operations in planes, choppers, and military aircraft over time.

Hydraulic systems provide many functions in aircraft, including assisting primary flight controls, flap drives, landing gear, nose wheel steering, thrust reversers, spoilers, rudders, cargo doors, and emergency electrical generators.

Despite their complicated design, hydraulic technology is used in military aircraft gun drives, weapons-bay doors, and fan heat exchangers driven by hydraulic motors. The factors that can affect the performance of an airplane’s hydraulic pressure systems include high-pressure conditions, temperature extremes, excess weight, speed, materials, and more.

What Is an Aircraft Hydraulic System?

The aircraft hydraulic system is responsible for moving and actuating landing gears, flaps, and brakes using pressurized fluids or gas. The hydraulic system has several benefits, including part reliability and efficiency. However, they are not completely similar to pneumatic systems as they are not lightweight.

How Do Aircraft Hydraulic Systems Work?

Aircraft hydraulic systems function on the principle of fluid power. According to this principle, a fluid transmits power from one point to another equally and without loss when under pressure. In the case of aviation, aircraft hydraulic systems use oil (vegetable, synthetic, or mineral), ethylene glycol, water, or temperature-resistant fluids as a pressurized fluid to enforce movement in specific aircraft components from one position to another in real-time.

Whenever a pilot needs to move or operate a particular component, they activate the hydraulic system through flight control devices. Once the hydraulic system is activated, the pump starts running, causing the actuator to move toward the device that needs to be moved, creating pressure on the device and its surroundings. When the system needs to move in the reverse direction, all one needs to do is release the pressure.

Components and Benefits of Aircraft Hydraulic Systems

Aircraft hydraulic systems support several apparatuses such as braking systems, landing gear, wing flaps, flight-control surfaces, engine pumps, air turbines, and many others. Additionally, hydraulic systems can also be found in multiple industries like the automobile, electronic, real estate, and aeronautic sectors.

Aircraft hydraulic systems consist of the following components:

Reservoir

The reservoir is used to store fluids utilized by the hydraulic system. The capacity of a reservoir depends on the actuator volume or thermal usage of the contained fluid.

Pump

Pumps are the heart of the hydraulic system. Their purpose is to pump fluid from the reservoir and pressurize it to generate power for the movement of the component.

Pressure-Relief Valve

Pressure relief valves are safety valves provided along a hydraulic system to release excess pressure if it surpasses the optimal level.

Actuating Cylinder

The function of actuating cylinders is to convert fluid power into mechanical energy to perform specific actions in aircraft, such as raising or lowering wing flaps.

Heat Exchanger

Heat exchangers ensure that the fluid in the actuator or reservoir remains at a safe, working temperature.

Conclusion

As aircraft hydraulic systems are crucial components for the safe operation of an airplane, it is always important that operators understand them well and take care of their existing systems. ASAP Aero Supplies is a premier aerospace and NSN parts supply solution and go-to platform for aviation parts and civil aircraft parts. We offer more than 2 billion NSN parts from over 5000 industry-leading manufacturers. Feel free to contact us for any part-related query or requirements. 

1. gary anderson
2. Posted on March 29, 2022
aviation

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