The hub purge valve serves to relieve...

Question 1 / 205eccef9cbacbc34ba4d45a8a

Question 1 of 205eccef9cbacbc34ba4d45a8a

The hub purge valve serves to relieve pressure in the forward chamber of the servomotor cylinder in a CPP system when what situation occurs? See illustration GS-0172.

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Question 1 of 20

5eccef9cbacbc34ba4d45a8a

The hub purge valve serves to relieve pressure in the forward chamber of the servomotor cylinder in a CPP system when what situation occurs? See illustration GS-0172.

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🔍 Key Concepts

• Study how CPP (controllable‑pitch propeller) hub pistons move oil to change blade pitch (ahead vs astern). • Note which side of the servomotor piston is called the forward chamber in this drawing, and which direction of pitch that chamber controls. • Understand the purpose of a purge / relief valve in a hydraulic cylinder when the piston reaches a mechanical travel limit.

💭 Think About

• Looking at GS-0172, when the hub piston moves to command more pitch in one direction, which chamber is getting pressurized oil? Is that the forward chamber? • If the piston keeps trying to move after it hits its mechanical pitch stop, what happens to the oil trapped in that chamber unless there is a relief or purge valve? • Which of the listed choices actually involves the piston being forced against a travel limit in the direction controlled by the forward chamber, rather than just normal load or transient surge?

✅ Before You Answer

• Identify from the sketch which direction of pitch (ahead or astern) is associated with pressure in the forward servomotor chamber. • Confirm that a hub purge valve operates when the piston hits or tries to go past a mechanical pitch stop, not during ordinary thrust loading. • Eliminate any answers that do not clearly involve over‑stroking the piston in the direction controlled by the forward chamber.

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Question 1 of 20

The hub purge valve serves to relieve pressure in the forward chamber of the servomotor cylinder in a CPP system when what situation occurs? See illustration GS-0172.

The propeller is stroked beyond its full ahead pitch limits.

The propeller is stroked beyond its full astern limits.

During periods thrust loading.

During periods of high-pressure oil surge.

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Question 1 / 205eccef9cbacbc34ba4d45a8a

Question 1 of 205eccef9cbacbc34ba4d45a8a

The hub purge valve serves to relieve pressure in the forward chamber of the servomotor cylinder in a CPP system when what situation occurs? See illustration GS-0172.

Back

Question 1 of 20

5eccef9cbacbc34ba4d45a8a

The hub purge valve serves to relieve pressure in the forward chamber of the servomotor cylinder in a CPP system when what situation occurs? See illustration GS-0172.

No comments yet

Be the first to share your thoughts!

If the question has a related picture, it will appear here.

🔍 Key Concepts

💭 Think About

✅ Before You Answer

👋 Hi! I'm Genie, your AI study assistant. How can I help you with this question?

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