11.11 Hydraulics Flashcards
What ATA chapter number is hydraulics?
ATA 29
What is the unit for pressure
Pascal or NM
What is hydraulic pressure measured in?
Bar
What is 1 bar in psi
14.5psi
What pressure do most civil aircraft operate at?
3000psi or 207 bar
What sort of pressure does the A380 operate at?
5080psi or 350 bar
Why do aircraft like the A380 increase the pressure in their system rather than stick to 3000psi
To generate the required force with out having to increase the size of hydraulic components
What is the formula for force
F=PxA
Force = pressure x area
What are the two types of hydraulic pressure
Hydrostatic pressure and hydrodynamic pressure
What type of pressure is used on an aircraft hydraulic system
Hydrostatic pressure
What is hydrodynamic pressure
Pressure produced by moving liquids ideally with no internal friction
Is it possible to transport force by using solid, liquids and gasses?
No, just liquid and gas
What is more easily compressible liquid or gas?
Gas is more easily compressible
What substance pressurises more quickly, liquid or gas?
Liquid
What two types or hydraulic fluid are there
Mineral and synthetic
What colour is mineral oil usually
Red
Can mineral oils be mixed together
There are many suppliers of mineral oils but they can be mixed together
What colour is synthetic oil usually?
Violet or purple
Can synthetic oils be mixed
Yes the same grade of synthetic oils can be mixed
Can synthetic and mineral oils be mixed?
No
What are the 2 of the most common name of synthetic oil
Skydrol and hyjet
What are the prefix’s used by Boeing and Airbus for synthetic oils?
Boeing - BMS
Airbus - NSA
What do the oil specifications describe?
The oils ability to perform a certain standard through a range of changing conditions
What types of performance characteristics must minders aircraft oils have?
- Low Flammability
- Good lubricating quality
- Resistance to freezing
- Non evaporating
- Non foaming
- Chemical stability
- Hygroscopic quality