LESSON 2
PRACTICE EXERCISE
ANSWER KEY AND FEEDBACK
Item
Correct Answer and Feedback
1.
C.
Retract and extend.
The piston of a double-action actuating cylinder can move in either direction, depending on
which of the two ports has pressure applied. (Page 27)
2.
D.
Irreversible valve.
The irreversible valve prevents the shock and vibration of the rotor blades from feeding
back to the pilot's hands through the control stick. (Page 36)
3.
A.
Relief valve.
A relief valve does just what the name implies. It releases pressure at a predetermined
pressure level. (Page 33)
4.
D.
Selector valve.
The selector valve determines the flow of fluid. (Page 34)
5.
B.
Check valve.
A check valve basically allows fluid to flow only in one direction. When fluid flow tries to
reverse its direction, the reverse direction of fluid pushes a ball against its seat and shuts off
any reverse fluid flow. (Page 38)
6.
B.
Priority valve.
Allows flow of fluid to nonessential parts as long as the pressure remains normal. As soon
as there is a pressure drop, it immediately reduces pressure to any nonessential
components. (Page 41)
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