Hydraulic applications, capability and theory of operation
How efficient are hydraulic system operations
100%
in a power pack system where are most of the major components located
in a self-contained unit
what is an Electro-hydrostatic actuator
power pack system includes all the major components in a self-contained unit. Thisincludes the actuator and the pump.
What colour is vegetable based hyd fluid?
Blue
what are air valves used for?
to charge accumulators
what is mechanical advantage
obtained by using a piston with a small area to force fluid into acylinder with a larger piston.
Name 5 components in a basic hydraulic system
reservoir, engine driven pump, selector, check valves, accumulator, unloading valve, filter, hand pump
The hydraulic fluid reservoir holds excess hydraulic fluid to accommodate volume changes from
Cylinder extension and contraction
Temperature-driven expansion and contraction
Leaks.
Red Hyd fluid mil spec is
MIL-H-5606
What are hydraulic pumps driven by
Engine, electric, pneumatic, ram air
Define a closed hydraulic system
a system that returns the fluid to a reservoir for further use
What is used in a hydraulic system to dampen pressure surges
Accumulator
What is a stand pipe?
A standpipe outlet feeds the engine-driven pump. In the event of a break in the system that causes the engine pump to lose all its fluid, the hand pump can still pick up enough fluid to lower the landing gear and flaps and actuate the brakes.
What is one of the disadvantages of Skydrol
It is quite susceptible to contamination by water fromthe atmosphere
What is the purpose of a hydraulic pump
to supply a flow of fluid to a hydraulic system
What is a open circuit hydraulic system
Open centre circuits use pumps which supply a constant-volume flow. The flow is returned to thetank through the control valve's open centre, that is, when the control valve is centred. It provides anopen return path to the tank and the fluid is not pumped to a high pressure
What does the unloading valve do?
opens a path from the pump to the reservoir so the pump does not use energy to create pressure when it is not needed
Where is the air drawn from to pressurise the reservoir?
pneumatic systems or APU
What seals and hoses are used with MIL-H-5606
Neoprene
How is pressure created in a hydraulic system
by restricting fluid flow
How are the control valves connected in a closed circuit hydraulic system?
in parallel
what aircraft would use a pressurised reservoir and why
Aircraft that fly at high altitudes. to maintain fluid at the pump inlet to stop cavitation
What are the three types of Accumulator?
Piston, diaphragm and bladder
Skydrol hydraulic systems are flushed with?
Trichloroethylene
During pump operation, some of the hydraulic fluid is deliberately internally leaked from the pumping section to provide.....
pressure lubrication to the pump moving parts and to assist cooling