Chapter 4 - Hydraulic principles (18-07-18) Flashcards
What are some typical uses for hydraulic in large A/C?
Gear and wheel brakes
noise wheel steering
Primary flight controls
Spoilers
Flaps
Speed brakes
Engine thrust reversers
In terms of hydraulic response, what does an incompressible fluid allow for?
An immediate response to an input.
What can be said about the static pressure at different locations in a fluid when a load is being applied to it?
It is the same everywhere in the fluid.
What 2 equations are used to work out the displacement of an output piston from the input piston in a hydraulic system?
W = F x d
F = P x A
What is a passive hydraulic system?
One that uses human power to raise pressure
What is an active hydraulic system?
One that uses one or more pumps
What properties must a hydraulic fluid possess?
Low viscosity
resistance to foaming
good lubricator
corrosion resistant
thermal stability
high boiling point & low freezing point
Chemically inert
non flammable with flash point above 100degC
good storage properties
What are the 2 different oil types and when can they be mixed?
Synthetic (purple)
Mineral (Red)
THEY MUST NEVER BE MIXED
What should a person do when handling oil for hydraulic systems and why?
Wear protective clothing to avoid direct contact due to the corrosive nature of the oil
What are the advantages of a hydraulic system?
Excellent for providing large amounts of power
little energy lost in the transmission process
leaks are easy to spot
reduced weight compared to mechanical system
What are the disadvantages of a hydraulic system?
The fluid is highly corrosive
forces generated can require strong structures
large systems can be heavy
susceptible to fluid contamination
damage to hydraulic lines
hydraulic fluid is a health risk and environmentally hazardous
What are the basic components of an elementary hydraulic system?
Pump
Pipes
Valves
Fluid
resevior
accumulator
actuators
