S Hydraulic System Principals

Question 1

What is the purpose of hydraulic systems?

Answer 1

To operate systems that would require a high physical effort

Question 2

What is fluid static pressure?

Answer 2

The resulting energy of the fluid (temperature) and the force of its own weight

Question 3

Where is static pressure constant?

Answer 3

Along a depth line

Question 4

Pressure equation

Answer 4

P = F/A

Question 5

What happens if you increase the output forces?

Answer 5

You increase the piston area and reduce the output stroke

Question 6

What is the equation for hydraulic piston stroke?

Answer 6

Input force x input stroke = output force x output stroke

Question 7

What is a passive hydraulic system?

Answer 7

Hydraulic systems powered by human effort

Question 8

What is an active hydraulic system?

Answer 8

A powered system, driven by a hydraulic pump

Question 9

What are the 2 types of active systems?

Answer 9

1. Close centred

2. Open centred

Question 10

What is a closed centred system?

Answer 10

Constant pressure all the time

Question 11

What is an open centred system?

Answer 11

Pressure only when demanded

Question 12

What is the pressure of a typical airliners hydraulic system?

Answer 12

3000-4000psi

Question 13

What are the 9 desired properties of hydraulic fluid?

Answer 13

Question 14

What are the 2 types of hydraulic fluid?

Answer 14

Mineral and synthetic

Question 15

What colour is mineral hydraulic fluid?

Answer 15

Red

Question 16

What colour is synthetic hydraulic fluid?

Answer 16

Purple

Question 17

Why should hydraulic fluid types not be mixed?

Answer 17

The wrong fluid may seriously damage parts of the system, especially seals

Question 18

What precautions should be taken when handling hydraulic fluid?

Answer 18

It is very corrosive, wear gloves and eye protection

Question 19

5 main advantages of a hydraulic system?

Answer 19

1. Provide large amounts of power to remote services
2. Little energy loss in the transmission of power
3. Leaks are easy to spot
4. Lighter than equivalent mechanical system
5. Provide power advantages for operation of heavy services

Question 20

5 main disadvantages of hydraulic systems?

Answer 20

1. Highly corrosive
2. Forces generated require strong structures
3. Can still be quite heavy
4. Susceptible to fluid contamination and damaged lines
5. Fluid is a health and environmental hazard