The Role of Solenoid Valves in Aircraft Hydraulic Systems

There are many systems that contribute to the seamless operation of an aircraft, with the hydraulic system playing a significant role in powering various essential functions. Central to the operation of aircraft hydraulic systems are solenoid valves, which are responsible for controlling the flow of hydraulic fluid to actuators. In this blog, we will delve into the significance of solenoid valves in aircraft hydraulic systems, covering everything from their basic functionality to their specific applications in flight control and landing gear operations.

Essentially, a solenoid valve is an electromechanical device that manages fluid or gas flow by moving a plunger within the valve. When an electric current passes through a solenoid’s coil, it creates a magnetic field that either pulls or pushes a plunger inside the valve body. In the context of hydraulic systems, this movement either allows or restricts the flow of fluid traversing through hydraulic lines to hydraulic actuators that convert fluid pressure into mechanical motion. The ability to accurately control hydraulic fluid flow is vital for facilitating the correct operation of various mechanical components on aircraft.

Solenoid valves can be designed in various ways to control fluid flow for specific hydraulic system functions, common options including direct acting, pilot-operated, or two-way, three-way, and four-way configurations. Two-way solenoid valves are commonly used for simple on/off control of fluid flow, where when the solenoid is energized, the valve opens to allow fluid to pass through. When the solenoid is de-energized, the valve closes to stop flow. Three-way solenoid valves, on the other hand, are often employed in more complex systems where a change in the direction of fluid flow is required. These valves have three ports, and depending on the configuration, they can either direct fluid from one port to another or shut off one port while opening another. Four-way solenoid valves are even more advanced and are typically used in systems that require the actuation of double-acting hydraulic cylinders, which are common in flight control and landing gear systems.

In flight control systems, three-way and four-way solenoid valves play a crucial role in managing the flow of hydraulic fluid to the actuators that move control surfaces like ailerons, rudders, and elevators. Three-way solenoid valves in particular are often used to alternate the flow of hydraulic fluid between different circuits, allowing for precise control of actuators based on a pilot's commands. By accurately managing the flow of hydraulic fluid to these surfaces, these solenoid valves ensure that aircraft can efficiently maneuver and respond to inputs instantaneously.

Solenoid valves are also critical for landing gear actuation, which is a complex process that requires precise timing and coordination of multiple components. When a pilot commands the landing gear to retract or extend, hydraulic power units generate the necessary pressure to move the gear assembly. Four-way solenoid valves are typically employed to control the flow of hydraulic fluid to landing gear actuators, managing the extension and retraction of gear with smooth and efficient operation in both directions. Additionally, solenoid valves are involved in locking the landing gear in extended and retracted positions, further ensuring the safety and stability of an aircraft during all phases of flight.

In conclusion, solenoid valves are essential components within aircraft hydraulic systems, their ability to precisely control hydraulic fluid flow being what enables many of the complex maneuvers required in aviation. If you are in the market for solenoid valves that are strictly sourced from manufacturers you can trust, look to NSN Sourcing. We present over 2 billion parts on our website that range from new to obsolete condition, allowing us to meet a diverse set of needs. Moreover, we regularly offer competitive pricing and rapid lead times on our entire inventory, as well as are happy to accommodate our customers’ unique requirements and restrictions alike. As such, do not hesitate to explore our website and get in contact with a representative to discuss how we can dependably serve your needs.