Pumped Up: Hydraulic Systems in Aircraft
No matter their size, all aircraft require some kind of mechanism to power systems like landing gear, brakes, flaps, and various flight controls. All mechanical systems require some sort of medium through which they apply force and pressure, and in a hydraulic system, that medium is a liquid or oil. For comparison, pneumatic systems rely on compressed air or gas. In this blog, we’ll break down some of the most common applications for hydraulic systems, and how exactly they work.
Hydraulic systems enjoy several benefits over pneumatic systems: because they rely on liquids that are non-compressible, there is no delay in their movement, whereas a pneumatic system often has a delay as gasses are compressed. Additionally, because
hydraulic oil is non-compressible, hydraulics can offer more weight, whereas air and gas can cause a device to shake and move around when the air pressure fluctuates.
Hydraulic fluid must act as a coolant, lubricate parts of the system, and accurately transmit pressure. Hydraulic fluid comes in three different types:
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Mineral oil, dyed red and made from kerosene petrochemical products. Mineral oil inhibits foaming and corrosion, is chemically stable, and handles temperature changes well.
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Synthetic oil, made from phosphate ester and is typically dyed purple (can also be amber or green). The biggest drawback of synthetic oil is that it can eat away at insulation and degrade wiring, so safe storage is absolutely necessary.
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Vegetable oil is colored blue and made from alcohol and castor oil. Vegetable oil is only seen in older aircraft, as it can cause corrosion and sludge to build up.
Small aircraft will typically use mineral oil, but manufacturers will have their own recommendations.
The core of hydraulics revolves around Pascal’s Law, which states that if pressure is applied to liquid anywhere in a system, this action causes equal pressure to be distributed throughout the entire system. This means that a small device applying pressure in one area of the system can be transferred to other areas.
In aircraft, hydraulics are used in
Aircraft landing gear, both to raise and lower them from deployment, in braking systems, in manipulating flight control surfaces like ailerons, flaps, and elevators, to control thrust reversers, and a wide range of other tasks.
At ASAP Parts 360, owned and operated by ASAP Semiconductor, we can help you find all the hydraulic systems and parts for the aerospace, civil aviation, and defense industries. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at
sales@asapparts360.com or call us at
+1-708-387-7800.
