11.11 Hydrualic Power Flashcards
(45 cards)
How do you calculate pressure?
Force/ Area
What pressure do civil aircraft hydraulic systems work at?
3000psi or 207 bar
What are the two types of hydraulic pressure?
. Hydrostatic pressure
. Hydrodynamic pressure
100KPa = ?
1DN/cm2
1 bar = ? Psi
14 psi
3000 psi = ? Bar
207 bar
What are the two types of hydraulic fluids?
Mineral oil
Synthetic oil
What colour is mineral oil?
Red
What colour is synthetic oil?
Violet
Can mineral and synthetic oil be mixed?
No
What is the specification for mineral and synthetic oil?
MIL-H 5606
What prefix’s do Boeing and airbus use?
Boeing = BMS
AIRBUS = NSA
What are the advatanges of hydraulic fluids?
. Low flammability
. Good lubricatuon
. Resistance to freeze
. Non evaporating
. Non foaming
. Chemical stability
What is the disadvantage of hydraulic fluid?
Hydroscopic quality
(Tendency to absorb water)
Which oil is better, mineral or synthetic?
Synthetic
What is the purpose of packing (back up ring)?
. Prevent leaks
. Separates the different fluid pressures
In high pressure areas, one seal may not be enough, so what would you use?
A backup ring
What are seals and back up rings made from?
Seals = rubber
Backup ring = Teflon
What are the two purposes of hydraulic reservoir?
. Compensate for variations in amount of hyduakid fluid needed from systems
. Keeps reserve of hydraulic fluid incase of a leaks
Where would you use static seals?
Static seal - used to seal against steady or pulsating pressures
What is used to prevent hyduakic fluid moving upwards if regret is a sudden loss of pressure?
(Stops sloshing)
A sheet metal baffle
When is the drain valve located on resivour?
Lowest part to allow emptying
Why is the hydraulic reservoir pressurised?
To ensure a positive supply of hydualic fluid always reaches the pumps
Prevents, foaming, evaporation, cavitation
What colour hydraulic system does electrical pump produce?
Blue hydraulic system