Hydraulic Systems in Aircraft

To transmit power from one place to another

It is transmitted equally and undiminished to all parts of the container

Pounds per square inch (PSI)

Engine driven or electrically driven hydraulic pumps

To accomplish work, such as raising or lowering the landing gear or flaps

To control the flow of fluid under pressure

They are relatively lightweight and efficient

To store energy in the form of pressurized fluid

Power (P) = Gallons per minute x pounds per square inch x 0.000583

Ease of transmitting force over large distances and into sealed compartments, and large gain in mechanical advantage through varying piston sizes

Larger pistons increase the mechanical advantage by multiplying the input force

It displaces one cubic inch of fluid and produces a pressure of one pound per square inch

Not mentioned in the provided content (but typically it stores energy and supplements pump flow during peak demand)

In gallons per minute

Pounds per square inch (psi)

Not mentioned in the provided content (but typically it controls the flow of fluid)

Pascal's Law, which states that when there is an increase in pressure at any point in a confined fluid, there is an equal increase in pressure throughout the fluid in all directions, allowing it to generate, control, and transmit power.

A hydraulic filter removes contaminants and particulate matter from the fluid, ensuring clean and efficient fluid flow, which in turn affects system performance by preventing damage to components and maintaining optimal operating conditions.

An accumulator stores energy in the form of compressed fluid, allowing it to absorb pressure surges and maintain a steady pressure supply, which benefits system operation by providing a stable and reliable power source.

An actuator is a mechanical device that converts fluid power into mechanical energy, using the pressurized fluid to generate motion or force, which enables the system to perform specific tasks and functions.

A valve controls fluid flow by regulating pressure, direction, and flow rate, allowing the system todirect fluid to specific components and control the flow of fluid to achieve desired system performance.

To protect the system from excess pressure delivered from the engine driven pumps.

The key difference is that hydraulic systems use incompressible fluid, while pneumatic systems use compressible air, which affects system operation by requiring different component designs and operational considerations.

Pascal's Law enables hydraulic systems to transmit fluid power efficiently, as the pressure increase at one point in the system is equally transmitted throughout the system, allowing for effective power transmission and control.

It supplies a limited amount of hydraulic fluid under pressure to run the system, e.g. emergency brakes.

Mechanical advantage refers to the amplification of force or motion, which is critical in hydraulic systems as it enables the system to perform tasks that would otherwise be impossible or impractical, thereby improving system performance and efficiency.

It dampens any pulsating pressures generated by the pump output.

It informs the aircrew of the operating pressure of the system.

An actuator.

To provide power that is transmitted and used to control the movement of an actuator.

The one cubic inch of fluid displaced when the small piston moves down one inch spreads out under all 20 square inches of the large piston, moving it up only 1/20-inch.

A source of power, a means of transmitting this power, and a device to use the power.

to generate flow of fluid under pressure

hand pumps

Not specified in the text, but generally, single acting pumps create pressure in one direction, while double acting pumps create pressure in both directions

to avoid accidents or injury

to restore fluid under pressure

to charge with oil

pressure is generated when there is a restriction to the flow of fluid generated by the pump

to avoid accidents or injury due to improper procedure