Reciprocating Engines

Question 1

1. How are conventional reciprocating engines classified?

Answer 1

By cylinder arrangement. (V-type, in line, opposed)

Question 2

2. What are the different types of piston rings?

Answer 2

Compression rings
Oil control Rings
Scraper Rings

Question 3

3. What are the main causes of a cylinder having low compression?

Answer 3

Broken piston rings
Rings not seated
Burnt valves
Poorly seated valves

Question 4

4. What is the purpose of the oil control rings?

Answer 4

Controls thickness of pool film on cylinder wall

Question 5

5. What may be the result of installing piston rings incorrectly?

Answer 5

Excessive oil consumption

Question 6

6. What types of piston rods are commonly found in radial engines?

Answer 6

Master & articulating rod assembly

Question 7

7. What type of bearings are general use in reciprocating engines?

Answer 7

Plain
Roller
Ball Bearings

Question 8

8. What is the indication of valve blow by?

Answer 8

Hissing or whistle while pulling propeller around

Question 9

9. What is the purpose of using more than one spring for valve closing?

Answer 9

Prevent valve surging

Question 10

10. What is the purpose of valve overlap?

Answer 10

Better volumetric efficiency & lowers the cylinder operating temps

Question 11

11. Describe the inspection you would give the valve springs during engine overhaul?

Answer 11

Cleaned
Inspected for overheating,cracks, broken ends, & compression strength

Question 12

12. What is the purpose of using valves with sodium filled stems?

Answer 12

Excellent heat conductor, once melts, sodium is circulated carrying heat from the valve head to the stem

Question 13

13. What causes ending sudden stoppage?

Answer 13

Sticking an object or engine seizure from internal damage

Question 14

14. What type of inspection must be made after sudden stoppage of an engine?

Answer 14

Tear down & inspection

Question 15

15. What is the purpose of the crankshaft dynamic dampers used in aircraft engines?

Answer 15

Reduce vibrations from pistons

Question 16

16. How would you make a “runout” check on a crankshaft that is still installed on the engine?

Answer 16

Remove propeller
Attach dial indicator to front of engine crankcase position needle on crankshaft
Check specs

Question 17

17. What is detonation?

Answer 17

Uneven fuel - air mixture & critical fuel temperature & compression will cause explosive spontaneous ignition

Question 18

18. What’s cylinder is engine to magneto timing based on?

Answer 18

1 Cylinder

Question 19

19. What is engine sudden speed reduction?

Answer 19

Propeller strike but engine continues to run

Question 20

20. What can be learned about the condition of an engine by studying the results of a compression check?

Answer 20

If valves, piston rings, pistons are adequately sealing combustion chamber

Question 21

21. How can a cold cylinder be located on a double row radial engine?

Answer 21

Infrared laser thermometer

Question 22

22. What instrument can be used to check bore for out of roundness?

Answer 22

Dial indicator
Telescopic gauge
Outside micrometer
Inside micrometer

Question 23

23. What would a cold cylinder indicate?

Answer 23

No combustion

Question 24

24. Where is a crack most likely to occur on a piston?

Answer 24

Piston pin connects

Question 25

25. What should be done to a nose wheel airplane before removing the engine?

Answer 25

Support the tail

Question 26

26. What is the running valve clearance on engines equipped with hydraulic lifters?

Answer 26

Zero