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2AX5X Vol 2 Unit 3

111 Self Test Questions

QuestionAnswer
Define matter. Any substance that occupies space and has weight.
Since liquids and gases have many properties in common, how are they frequently classified? As fluids.
All matter is made up of what? Molecules.
Which matter has the property of resisting changes in shape when a force is applied? Solid.
When sufficient force to a solid causes distortion, the solid is said to have exceeded what? Its elastic limit.
Which factors affect the amount of expansion and contraction of a solid? The amount of temperature change and the expansion characteristics of the solid.
What are the most outstanding characteristics of a liquid? Its ability to conform to the shape of its containing vessel and that it has a free surface.
For a liquid to transmit a pushing force, what condition must exist first? It must be completely enclosed in a container.
What would cause a cylinder of air to increase in pressure when placed in the sun? The air (gas) expands as its temperature increases, and since it is confined by the cylinder, its pressure will increase
What is one of the main differences in the characteristics of gases when compared to liquids? Gases are compressible while liquids are not
The measurement of a surface expressed in square inches Area
The amount of push or pull exerted on an object expressed in pounds Force
The amount of force acting on a unit of area expressed in psi Pressure
A substance that is a liquid or a gas Fluid
A measure of quantity expressed in cubic inches Volume
The amount of distance an object moved expressed in inches Stroke
The movement of a fluid cause by pressure difference Flow
State the basic principle of Pascal's Law. When a fluid is confined and force is applied, this force (pressure) is transmitted equally to all points in the system
Under what conditions does Pascal's Law not apply to fluids? Pascal's Law does not apply to fluids in motion
State the basic principle of Boyle's Law. If the pressure on a confined gas varies, its volume will vary inversely in the same proportion as long as the temperature does not change
Using Charles's Law, explain the effect of heating a gas in a cylinder that has a movable piston. Heating a confined gas will cause an expansion (volume increase) in direct proportion to its temperature change, thus causing the piston to move
What is another name for the Boyle's-Charles's law? General Gas Law
How is force calculated? (F)orce = (P)ressure x (A)rea
What is the mechanical advantage ratio if a 60-pound force is used to raise a 240-pound weight? 4:01
What is the mechanical advantage ratio if a 3-pound force used to raise 99 pounds? 33:01
A 150-pound weight is placed on a 10-square-inch piston and is then lifted by a force applied to a 2-square-inch piston. What force is required on the small piston, and what is the mechanical advantage? 30 pounds of force, 5:1
A 20-pound force on a 3-square-inch piston can lift how much weight on a 12-square-inch piston? What is the mechanical advantage? 80 pounds weight, 4:1
What is the pressure (psi) on a surface 12 square inches in area and supporting a weight of 216 pounds? 18 psi
How far will an 8-square-inch piston move if a 2-square-inch piston moves 8 inches? 2 inches
What characteristic of a fluid determines its resistance to flow? Viscosity
What effect does an orifice have on fluid-flow when compared to a venturi? An orifice will cause more turbulence and thus more energy loss than a venturi because it is not streamlined
How can resistance to flow be reduced? By streamlining the flow
What pressure difference can be observed during fluid-flow through a venturi? There is a pressure drop at the narrow opening (throat) of a venturi as the rate of flow of the fluid increases at this point The pressure will increase again after passing through the throat
How much fluid should a reservoir hold? Enough fluid to supply the normal operating needs of the system, along with an additional amount to replace fluid lost through minor leakage
Why do non-pressurized reservoirs have space above the fluid? To allow the fluid to purge itself of air bubbles that are picked up from the system
What prevents foreign material from entering the reservoir during servicing? A wire screen
What are the two main reasons for pressurizing a reservoir? First, it stops the fluid from foaming at high altitudes; second, it ensures a positive supply of fluid to the pumps.
How do you service a pressurized hydraulic reservoir with fluid? Use a portable servicing cart.
What unit in the pressurized hydraulic reservoir pressurizes the hydraulic fluid to 5 psi? A piston spring
To service or perform maintenance on an air-pressurized reservoir, what is the first thing you must do? Depressurize the reservoir
Name three functions of the air-pressurized reservoir pressure regulator. It regulates the pressure to the reservoir, acts like a relief valve, and has a differential valve to allow equalization of pressures between outside air and air inside the reservoir
How are pumps classified? By their displacement (volume) output
What two purposes does the hand pump serve? It can be used as an emergency source of pressure or as an auxiliary source of pressure for ground-checking the operation of the system units
When the hand pump handle is on the retraction stroke, which check valve is closed? The inlet check valve
What indicates that either check valve inside the hand pump has malfunctioned? The hand pump will become completely inoperative
If a third check valve is installed, what could be the problem if fluid is only sent into the system on the extension stroke? The inlet check valve is malfunctioning
What is a drawback of a constant-volume pump? As long as the pump rotates, the fluid-flow it produces will eventually build up pressure high enough in the confined area to burst the lines and container
What is the thinned portion on the drive shaft of a gear-type pump called? Shear section
On a vane-type pump, what keeps the vanes against the housing wall? Springs
In the constant-volume piston pump, what drives the cylinder block? Universal link
Why does a constant-volume piston pump always have a constant intake and output of fluid? There are always pistons somewhere between the upper and lower position
What does the suction boost pump do for engine-driven pumps? Ensures the engine pumps get an adequate supply of fluid
What regulates pressure in a variable-volume pump? An integral flow control valve (compensator)
What is the main difference between a Vickers stroke-reduction pump and a constant-volume pump? The angle between the drive shaft and the cylinder block
What position is the Vickers pump's cylinder block and yoke in when the system is at 0 psi? The extreme angle position, full flow
Do the pistons have a stroke when the Vickers pump reaches the zero flow point? No
What are the two major component groups of the Kellogg pump? The rotating group and the pressure-compensating group
What determines the length of the Kellogg pump's piston stroke? The angle setting of the cam plate
What is the purpose of the creep plates in Stratopower pumps? Cooler operation
Describe the pistons of the Stratopower pump. The pistons have fairly large hollow centers connected with cross-drilled holes
Which way would you turn the adjusting screw on the Stratopower pump to increase pressure? Clockwise
What is the purpose of a hydraulic motor? To convert hydraulic pressure into rotary mechanical motion
What can be used to control the speed of a hydraulic motor? Flow control valve
Explain the principle of a jackscrew. The screw remains stationary and the nut turns
What is the purpose of an accumulator in a hydraulic system? To store a volume of fluid under pressure, provide space for thermal expansion, and act as a cushion against pressure surges.
What is the most common type of accumulator used? Cylindrical type
Which accumulator has a drilled passageway in the piston for lubrication? Piston
Where is the air-servicing valve located on the piston accumulator? At the bottom of the accumulator
What is the piston accumulator is serviced with? Dry air or nitrogen
Which accumulator has four separate chambers? Self-displacing accumulator
What is the only moving part of a self-displacing accumulator? The piston
In the self-displacing accumulator system, where is the relief valve located? Between the pressure line and return line
What are the three basic parts of a filter assembly? Head, element, and bowl
Which part of the filter assembly is mounted to the aircraft? Head
What does micron rating mean? The amount of dirt or contaminates that can be filtered out
What are the two ways fluids can usually flow through a filter assembly? Normal flow and bypass flow
How are hydraulic manifolds designed? To conserve space in the aircraft and permit ease of removing and replacing components
Why is it physically impossible to install the wrong valve in a manifold? Alignment pins make it physically impossible to install the wrong valve
What is the purpose of an actuating cylinder? To transform fluid pressure into a mechanical force
Brakes use what type of actuator? Single-acting
Commonly used on cargo door ramps and landing gear, this actuator is used when more force is required to move an object one way more than the other Double-acting unbalanced
What actuator has a piston rod that extends through both ends of the cylinder and is most commonly used on nose wheel steering? Double-acting balanced
Which actuator is commonly used on FLCS's to ensure operation by connecting to two separate hydraulic systems? Tandem acting
What does tandem mean? One behind the other
How many pistons are in a tandem actuator? Two
What is the purpose of the internal snubber actuator? To reduce damage to mechanisms by preventing the actuator from slamming into its end of travel with great force
Where is the main system relief valve normally installed in a hydraulic system? Between the pressure and return lines
What is the purpose of a selector valve? To control and direct the flow of hydraulic fluid
What is the advantage of a slide selector valve over the poppet type? Its ability to meter fluid
What is the purpose of a check valve? To allow free flow in one direction and no flow in the other direction
What are the different types of automatic check valves? Ball, cone, and flapper (gate) types
Which type of check valve is used primarily in low-pressure systems, such as the air pressurized reservoir system? Flapper check valve
What order of events do sequence valves set? Branches of hydraulic circuit
What is the purpose of the pressure regulator besides maintaining pressure within a predetermined range? Permit the pump to turn without resistance
What component is used in systems to limit the speed of movement of such items as wing flaps and landing gear? Restrictors
Where is a restrictor check valve usually installed? In the alternating line that carries fluid from the cylinder
What names are commonly used for the manually operated shutoff valves? Globe and needle
What are the parts of a motor-operated shutoff valve? An electric motor, a slide, valve body, limit switches, and an indicator
What is installed in the hydraulic system to prevent total fluid loss? A hydraulic fuse
How is internal leakage of a shuttle valve usually repaired? By removing the unit and flushing it with clean hydraulic fluid
What is another name for the supply section of a basic hydraulic system? Suction manifold
Which section of a basic hydraulic system contains all the lines and units starting with the pump to the selector valve? The pressure manifold
What are the four units of a hand pump system? A reservoir, hand pump, actuator, and a manual shutoff valve
How much pressure is required to lift 2,300 pounds using an actuator with 2 square inches of working area? 1,150 psi
What would happen to a constant-volume pump hydraulic system if there were no relief valves? The pressure would build up to the point where the tubing would rupture or damage system units
In order to properly design a hydraulic system, what must be considered? The pressure needed to operate the system
What is the disadvantage of a constant-volume pump hydraulic system, which has a relief valve but does not have any components to relieve the pump's workload? After a few hours of constant load, the pump would probably fail
What pressure does the pressure regulator and pressure switch maintain? The pressure between two designed pressure limits
Where does fluid-flow go when a regulator is kicked out? Returns to the reservoir through the regulator bypass
What does the term "operating range" mean? The difference between the two design limits
What is the main purpose of the accumulator in the regulator or pressure switch controlled system? Prevent rapid loss of pressure due to fluid leaks in the return lines, which would cause continuous kick in and kick out
Created by: Fah_Q