Hydraulic Systems Flashcards
Equations Needed For Exam:
F=PA
P=F/A
Force = Pressure X Area Pressure = Force / Area
What does a hydraulic system do?
Hydraulic Systems use fluids to do work.
What are some uses of hydraulics in aircraft?
• Flight Controls
o Primary flight controls
o Flaps
o Leading edge devices
• Landing Gear
• Brakes
• NW Steering
• Thrust Reversers
• Air Stairs
Cargo DoorsARROW SPECIFIC HYDRAULIC SYSTEM USES: (4)
• Landing Gear
• Brakes
• Propeller
• Gear Oleo Sruts (Landing Gear Struts)
(hydraulic fluid flows to take some of the impact)Fluid: What happens in a hydraulic system.
Flows, and a fluid takes the shape of it’s container. Any substance which would yield to any force tending to alter it’s shape, having freedom of movement without separation from its mass & will take the shape of it’s container. (both gasses and liquids can be defined as fluids)
Definition of a Liquid?
Do liquids expand wth heat?
any fluid having a definite volume and is non-compressible.
However, liquids do expand with heat.
Hydrostatic Paradox:
It doesn’t matter how big a container is, it only matters how much weight is on top. Volume size shape don’t matter, it just matters what type of fluid is.
Pascal’s Law
When is a force is exerted anywhere on a body of confined liquid, the pressure is transmitted AT ONCE and UNDIMINISHED & ALWAYS ACTS AT RIGHT ANGLES to the area of walls of the container.
How large is a transmitted pressure? To answer this you need what?
(NEED PSI and FORCE)
If you have two equal sized areas pushing it’ll push _______ amount of force
The SAME
Hydraulic Fluid:
What is it’s viscosity
What temperatures does it operate to?
Can other components use it?
Details about A5606 which we use.
• Low Viscosity
• Goes to temperature extremes (120C – 248F)
• Compatible with other components
• AS 5606 (hydraulic fluid)
o Mineral Based
o Flammable
o Non-Corrosive
o Red (arrow, Seminole)
o Foams upHydraulic reservoir
What does it do?
What does it serve as ?
What is often done to the reservoir and why ?
What does it prevent?
- Stores hydraulic fluid
- Serves as an expansion fluid
- Often pressurized to prevent foaming
What does the hydraulic pump do?
• Provides necessary fluid movement.
Typical Hydraulic Systems: Pressure
HIGH
MEDIUM
LOW
ARROW PRESSURE?
- High (3000PSI)
- Medium (1500 PSI)
- Low (400-800 PSI)
- Arrow Landing Gear Up (1300 PSI)
Hydraulic Acccumulator:
What does it act as?
What does it do?
What does it utilize sometimes
What’s it’s purpose?
- Acts as a shock absorber
- Stores hydraulic fluid under pressure
- Utilizes compressible fluid (nitrogen) to maintain pressure
• Purpose:
o Dampens surges
o Backup pressure source
o Avoids back pressure shock
Check Valves:
What do they do?
What are the three valves and what is their basic idea?
Make sure that fluid doesn’t back up
• Ball Check Valve
(one way flow, a ball piston and spring, ball plugs it and spring and piston hold it)
- Cone Check Valve (same concept)
- Swing Check Valve
Relief Valve
How does it work?
• When the pressure reaches a predetermined value, allows fluid from the pressure side of system to be relieved into relief valve. Avoids over pressurization of the hydraulic system.
Hydraulic Actuator :
What does it do?
What does it convert?
Can be two types what are they?
DOES THE WORK
- Converts hydraulic pressure & Flow into mechanical work
- Can be linear or rotary
Filter
What does it do?
• Traps dirt and other sediment
Seals: What doe they do?
: make sure we don’t lose our hydraulic fluid.
Lines : What do they do?
Trasmit fluid and pressure throughout the system.
could be a 2 inch line or a 20 inch line, can still transmit same pressure
