Journey of the Dream to Fly

In this Edition, we are going to learn about the vital role of Hydraulics in Aircraft Safety and Performance. So, let us start!

Aircraft have relied on hydraulic systems to power critical flight controls and functions for decades. Hydraulics play a vital role in keeping aircraft and their passengers’ safe in the air. However what exactly is Hydraulic system.

The word “hydraulics” originates from the ancient Greek word “hydraulikos” meaning water (hydor) pipe (aulos).

Hydraulic systems transmit force, making tough jobs more manageable. They transmit force and motion through the use of hydraulic fluids. Hydraulic systems amplify a small input force into a significantly larger force, which is an important feature for heavy-duty tasks like lifting heavy objects in construction, controlling high performance vehicles, etc

Let’s see in this small video, how a small force can be multiplied many times using the Pascal’s law.

How Hydraulic Systems Work in Aircraft:-

Hydraulic systems in aircraft use pressurized liquid, typically hydraulic fluid, to transfer power from one location to another. This liquid is pumped through a network of pipes, hoses, actuators and valves to provide the force needed to operate key systems.

For example the landing gear, flight controls like ailerons and flaps, and brakes are all operated by hydraulic power. When the pilot moves the flight controls, hydraulic pressure is used to physically move the control surfaces and steer the aircraft.

Advantages of Hydraulic systems

The Origins of Aircraft Hydraulics

The use of hydraulics in aircraft dates back to the early days of aviation. One of the first applications was in the Wright brothers’ 1903 Wright Flyer, which used a simple pneumatic (compressed air) system to control the wing-warping mechanism. As aircraft grew larger and more complex through the 1920s and 1930s, the need for more powerful and precise control systems led to the adoption of hydraulic systems. Hydraulics provided the necessary power and responsiveness to operate the flight controls of larger, faster planes.

The Importance of Hydraulics for Aircraft Safety

Hydraulic systems are critical to the safe operation of an aircraft. If a hydraulic system were to fail, it could result in the loss of control of the plane’s flight surfaces, landing gear or brakes. This would create an extremely dangerous situation for the crew and passengers. That is why aircraft are designed with redundant, backup hydraulic systems. There are usually two or more completely separate hydraulic systems, each powered by its own pump and reservoir. This ensures that even if one system fails, the other(s) can still provide the necessary hydraulic power to maintain control of the aircraft.

Additionally, planes have various warning systems and checklists to alert pilots to any issues with the hydraulic systems. Pilots are trained to quickly diagnose and respond to hydraulic problems in flight. As aircraft technology has advanced, hydraulic systems have continued to play a central role. Modern fly-by-wire flight control systems still rely on hydraulic actuators to physically move the control surfaces, even though the pilot’s inputs are electronically transmitted.

Efficiency

One of the main reasons hydraulics are so popular is their efficiency, because they rely on fluid for transmitting power. a hydraulic system can pack a lot of force into a relatively small amount of space. This makes hydraulics great for jobs that involve lifting heavy objects. Adding to their convenience, certain parts of a hydraulic system like pumps and motors can be located a significant distance away from the actuator. This makes them versatile and easier to install.

Constant Force

Another advantage of hydraulic systems is their constant application of force. Since they rely on incompressible fluid, hydraulics can apply the same consistent amount of force for the duration of extending and compressing a piston. They can even reverse the direction of force quickly without coming to an abrupt stop.

Easy to Control

As hydraulics rely on constant circulation of fluid rather than a rising and falling motion, they are easy to operate at the push of a button. Users can quickly adjust the speed and range of a hydraulic piston.

Though mechanical systems are capable of operating at a higher accuracy and maximum speed, they are required to operate at a fixed rate and adjusting mechanical systems can be a cumbersome process. Machines powered by electrical motors also have a higher danger of overheating and additional precautions are needed when using these systems in areas where flammable material is present.

Disadvantages of Hydraulic systems

Components like fluid lines, valves and seals can leak or drop in performance due to wear and need to be checked and maintained regularly. Internal leaks are more difficult to detect, and often require a certified specialist to repair. Alongside other maintenance, hydraulic fluid also needs to be replaced regularly to prevent contamination, loss of viscosity, and other issues.

If a seal or line does fail, hydraulic fluid can leak and spread before anyone notices and cleanup can cost time and money. Additionally, since hydraulic fluid is a blend of oil and other hazardous chemicals, a serious leak can pose risks to health and the environment.

As these systems rely on liquid, hydraulic systems are also subject to temperature issues. They may freeze in very cold conditions or overheat at high temperatures. Operating hydraulics in these types of environments requires purchasing specialized hydraulic fluid.

Hydraulics remain an essential component of aircraft design, helping to ensure the safe and reliable operation of these complex flying machines. The pressurized liquid power of hydraulic systems will likely remain a vital part of aviation for many years to come.

Below is the link to watch how Boeing 737 hydraulics work