Learn about the advantages and disadvantages of hydraulic systems in aircraft, as well as the basic principles, components, and types of hydraulic systems.

A good operating system will obviously have a disadvantage. But efficiencies and advantages are much more then the few downsides. Power from Hydraulic systems moves the landing gears, flaps, slats and spoilers. In heavy aircrafts, they assist pilots in moving flight controls. Hydraulic systems are there for a variety of good reasons and will be a reliable source in years ahead.

What are the advantages and disadvantages of hydraulic systems in aircraft?

Hydraulic systems are widely used in aircraft to control various functions, such as landing gear, brakes, flaps, spoilers, and flight control surfaces. They use pressurized fluid to transmit power and force from one point to another. But how do they work, and what are their advantages and disadvantages compared to other systems? In this article, you will learn about the basic principles, components, and types of hydraulic systems in aircraft, as well as their benefits and drawbacks.

1 How hydraulic systems work

A hydraulic system consists of four main elements: a reservoir, a pump, a valve, and an actuator. The reservoir stores the hydraulic fluid, which is usually oil or synthetic fluid. The pump draws the fluid from the reservoir and delivers it to the valve at a high pressure. The valve regulates the flow and direction of the fluid to the actuator, which converts the fluid pressure into mechanical motion. The actuator can be a cylinder, a motor, or a servo. The fluid then returns to the reservoir through a filter and a cooler.

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SAJAL KUMAR DAS GUPTA

Retired from ACC Ltd as Joint manager (Mechanical) after serving the company for 39 yrs
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And of course a prime mover to power the pump ,pipings and various other control valves as required. Depending upon the function of the hydraulic systems,it may may include accumulator, on line heater/cooler,various indicators analog/digital for various parameters like pressure, temperature ,online filters and extent of clogging of filters etc

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Jussara Motta

Proprietária
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Vantagens dos sistemas hidráulicos em aeronaves incluem alta eficiência e precisão no controle de componentes como flaps e lemes, além de proporcionarem uma operação suave e com grande capacidade de força. Esses sistemas permitem respostas rápidas e precisas, essenciais para a segurança e desempenho da aeronave.

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2 Components of hydraulic systems

Hydraulic systems in aircraft are composed of various components that each perform a different function. A pressure regulator maintains the pressure of the system within a specified range and prevents overpressure, while a pressure relief valve releases excess pressure in case of a malfunction or emergency. Additionally, a check valve allows the fluid to flow in one direction only and prevents backflow, and a selector valve controls the direction of the fluid to the actuator according to the pilot's input. An accumulator stores pressurized fluid and provides extra power when needed, and a servo valve modulates the fluid flow to the actuator with high precision and responsiveness.

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SAJAL KUMAR DAS GUPTA

Retired from ACC Ltd as Joint manager (Mechanical) after serving the company for 39 yrs
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Although I Don't have experience with particular reference to aircraft hydraulic systems, I do have some experience with industrial hydraulic systems. Considering criticality of the hydraulic systems with particular reference to aircraft, there must be some foolproof additional safety measures like backup of the system incase of failure of the operating system. Also,there will be many automated controls for maneuvering the aircraft

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3 Types of hydraulic systems

Aircraft use three main types of hydraulic systems: open-loop, closed-loop, and hybrid. The open-loop system is the simplest and most common type. It has a single pump supplying fluid to all actuators through a common pipeline, then returning to the reservoir. This system is easy to maintain and operate, but has low efficiency and reliability. It is mainly used for low-demand functions, such as landing gear and brakes. The closed-loop system is more complex and advanced. It has two pumps supplying fluid to each actuator separately, then returning to the same pump through a feedback loop. This system has high efficiency and reliability, but is more expensive and difficult to maintain and operate. It is mainly used for high-demand functions, such as flight control surfaces and spoilers. The hybrid system combines open-loop and closed-loop systems with a primary pump supplying fluid to the main actuators through a closed-loop system, and a secondary pump supplying fluid to the auxiliary actuators through an open-loop system. This type of system has the advantages of both systems, but it is also more complex and costly. It is mainly used for modern and sophisticated aircraft, such as fighter jets and helicopters.

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4 Advantages of hydraulic systems

Hydraulic systems in aircraft offer several advantages when compared to other systems, such as pneumatic, electrical, and mechanical systems. For instance, they have a high power-to-weight ratio, meaning they can produce a large amount of force and torque with a small and lightweight pump and actuator. This not only reduces the weight and size of the system but also increases the performance and fuel efficiency of the aircraft. Additionally, hydraulic systems are highly flexible and adaptable, allowing for easy configuration and modification to suit different functions and requirements. They can also be integrated with electronic and computer systems to boost the control and feedback of the system. Furthermore, hydraulic systems provide high safety and redundancy due to their multiple backup and fail-safe features, such as pressure regulators, relief valves, accumulators, and dual or triple pumps. These features ensure the safety and reliability of the system in case of a failure or emergency while also allowing it to operate at reduced or partial capacity if necessary.

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SAJAL KUMAR DAS GUPTA

Retired from ACC Ltd as Joint manager (Mechanical) after serving the company for 39 yrs
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All credit goes to Pascal who brought revolution in the industrial sector.Its use has made life easier,more productive saving cost,saving in human energy and a user-friendly environment Today it is being extensively used in industry, transportation, medical,domestic appliances, warfare.

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5 Disadvantages of hydraulic systems

Hydraulic systems in aircraft have some disadvantages that limit their applications and performance. These include high maintenance and cost, as frequent inspection, cleaning, and replacement of the fluid, filters, seals, and hoses is required. Additionally, there is a high risk of leakage and contamination of the fluid which can cause loss of pressure, corrosion, erosion, and wear of the components. Additionally, hydraulic systems are complex and generate a lot of noise and vibration that can affect the comfort and communication of crew and passengers. All of these factors increase the maintenance time and cost of the system while reducing its availability and lifespan.

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Suresh Bista

Senior Captain. Examiner/Instructor.
(edited)
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A good operating system will obviously have a disadvantage. But efficiencies and advantages are much more then the few downsides. Power from Hydraulic systems moves the landing gears, flaps, slats and spoilers. In heavy aircrafts, they assist pilots in moving flight controls. Hydraulic systems are there for a variety of good reasons and will be a reliable source in years ahead.

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6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?

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SAJAL KUMAR DAS GUPTA

Retired from ACC Ltd as Joint manager (Mechanical) after serving the company for 39 yrs
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Although it has been highlighted about some problems in hydraulic systems I feel that by continually improving material quality,Avoiding leakage by quality inspection and maintenence, online automatic inspection by using latest instrumentation will minimize the occurrence of Leakage Also,scheduled inspection and repair should not be compromised. We should honestly weigh between advantages and disadvantages and I am sure that wisdom will vote for advantages only.As regards problems being faced with respect to maintenence ,it can definitely be solved with the edge of technology which is ever improving day by day

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What are the advantages and disadvantages of hydraulic systems in aircraft?

1

2

3

4

5

6

1 How hydraulic systems work

2 Components of hydraulic systems

3 Types of hydraulic systems

4 Advantages of hydraulic systems

5 Disadvantages of hydraulic systems

6 Here’s what else to consider

Mechanical Engineering

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What are the advantages and disadvantages of hydraulic systems in aircraft?

1

2

3

4

5

6

1 How hydraulic systems work

2 Components of hydraulic systems

3 Types of hydraulic systems

4 Advantages of hydraulic systems

5 Disadvantages of hydraulic systems

6 Here’s what else to consider

Mechanical Engineering

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