Hydraulic And Pneumatic Power Systems Flashcards
What are three types of hydraulic fluids?
Vegetal, Mineral and Phosphate Esters.
Which color mineral base and phosphate-ester hydraulic fluids have?
Mineral -Red / Phosphate ester - Light purple.
What happens to plastic resins, vinyl compositions, lacqers, and oil base paints if exposed to a phosphate ester base hydraulic fluid such as skydrol?
Damaged, softened and/or peeled.
What precautions should be taken to minimize contamination during replacement of a hydraulic unit?
All lines should be plugged or capped after disconnecting.
What would cause a hydraulic filter to go into open by-pass, allowing unfiltred fluid into the system?
clogged filter.
What are two types of engine-driven hydraulic pumps?
Constant - delivery and Variable - delivery.
How does a gear-type power pump operate?
Two meshed gears are driven by a power unit rotate in a housing.
Fluid is carried around the outside of the gears and delivered to the outlet side as the gears rotate.
What feature is built into a hydraulic pump-drive system to prevent engine damage in the event of pump seizure or overload?
A shear action in the pump drive shaft occurs.
What is the purpose of a pressure relief valve?
To limit the amount of pressure, preventing failure of the system components.
What is the purpose of a pressure regulator?
To manage the output of the pump to maintain system pressure and allow the pump to turn without resistance(unloading).
What is used in some hydraulic systems to supplement the power pump when several units are operated at the same time? (High demand)
An accumulator
What are the different types of accumulators?
Piston, Diaphragm and Bladder.
What must be accomplished with any accumulator prior to disassembling?
Make sure that the air or preload has been discharged.
For what purposes are pneumatic systems used in some aircrafts?
To operate brakes, doors, drive pumps and engine starting.
What are sources of pneumatic power?
Storage bottles, vane-type pumps, and turbine engine compressor.
What happens to excessive pressure in a pneumatic system?
A Relief Valve will bleed it to the atmosphere.
What is the purpose of restrictors that are used in aircraft pneumatic systems?
To control the rate of flow.
Why should a pneumatic system be purged periodically?
To remove contamination and moisture.
What are the results of exposing lacquers, oil-baised paint, plastic resins and vynil compounds to phosphate ester based hydraulic fluid?
The materials will be damaged and/or softened or the paint will peel.
Name several sources used to develop hydraulic pressure:
Hand pumps, engine-driven pumps and electrically driven pumps.
What types of components or systems are pneumatically operated in some aircraft?
Landing Gear, Brakes, Flaps and other mechanic actuators.
Name several sources of pneumatic power:
Storage bottles, engine bleed air, engine-driven compressor or vane-type pumps.
