How Hydraulic Pumps are used on Aircrafts
Hydraulic systems are used on aircraft to move and actuate landing gear, flaps and brakes.
On larger aircrafts, these systems are also used for controls, spoilers and thrust reversers.
For our latest blog, we are going to look at how hydraulic pumps are used in the aerospace sector.
Why Use Hydraulic Pumps?
The reasons hydraulics are used, is because they transmit a very high pressure or force with a relatively small volume of fluid (i.e. hydraulic oil).
One application where you will see hydraulics is their power-assisted brakes plus in most small and ultralight aircraft.
They are also extremely reliable, with its systems virtually incompressible and they are able to transmit high pressures.
Aircraft manufacturers will often put together their own brake systems for planes to gain a better understanding of how hydrodynamics function and how they can be handled safely during installation and maintenance.
Understanding Basic Hydrodynamics
Hydrodynamics is the study of how fluids can be used to help in moving mechanical heavy or hard to move components like ailerons, rudder or flaps against aerodynamics forces when in flight.
Pascal’s principle of transmission of fluid pressure states,
‘Pressure exerted anywhere in a confined incompressible fluid is transmitted equally in all directions throughout the fluid such that the pressure ratio (initial difference) remains the same.’
Pascal’s law used the same principles also used in aircraft toe or hand brakes.
The Use of Hydraulic Fluid
Hydraulic fluid must transmit the pressure, lubricate the parts of the hydraulic system whilst acting as a coolant at the same time. Oil used this way, has a low viscosity for easy filling of all lines and aluminium pipes. The oil will also heat up while retaining these properties over a vast temperature range.
There are three types of hydraulic oil, which have their own properties and requirements for special applications.
Vegetable – Made from castor oil and alcohol and is primarily used on older aircraft where natural rubber seals are used.
Mineral – It has good lubricating properties with additives inhibiting corrosion and foaming.
Synthetic – A less-flammable fluid than the mineral type, with its base on synthetic phosphate ester.