Reciprocating engines

Question 1

How are conventional reciprocating engines classified

Answer 1

According to cylinder arrangement with respect to the crankshaft

In line, V-type, radio, and opposed

Method of cooling is liquid cooled, or air cooled

Question 2

What are the different types of piston rings

Answer 2

Compression rings, oil control rings, and scraper rings

Question 3

What are the main causes of a cylinder having low compression

Answer 3

Broken piston ring, rings that are not sealing properly, burnt valves, and poorly seating valves

Question 4

What is the purpose of the oil control rings

Answer 4

They are used to control the thickness of the oil film on the cylinder walls

Question 5

What may be the result of installing piston rings incorrectly

Answer 5

Excessive oil consumption

Question 6

What type of piston rod are commonly found in radial engines

Answer 6

Master and articulating rod assembly’s

Question 7

What type of bearings are in general use in reciprocating engines

Answer 7

Plane, roller, and ball bearings

Plane bearings are generally used for crankshaft, camshaft and connecting rods

Roller bearings are used primarily as crankshaft main bearings

And ball bearings are used for supercharger impeller shaft bearings and crankshaft Russ bearings on large radial engines

Question 8

What is the indication of valve blow by

Answer 8

Indicated by hissing or whistling when pulling the propeller through by hand.

Hey cylinder compression check should be completed to identify the faulty cylinder

Question 9

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

Answer 9

Valve springs will resonate at certain energy speeds. If only one spring is used, the valve will float as a spring surges. To illuminate this problem, two springs are installed on each valve

Question 10

What is the purpose of valve overlap

Answer 10

Valve overlap permits better volumetric efficiency And lowers the cylinder operating temperatures

Question 11

Describe the inspection you would give the valve springs during engine overhaul

Answer 11

Clean thoroughly, visually inspect for evidence of overheating, cracks, broken ends, and compression strength

Question 12

What is the purpose of using valves with sodium filled stems

Answer 12

Sodium is used because it is an excellent he conductor

The sodium melts at a relatively low temperature, and as the valve moves up and down the sodium is circulated, carrying the heat from the valve head to the stem. Then the heat is dissipated to the cylinder head

Question 13

What causes engine sudden stoppage

Answer 13

Striking an object or engine seizure Due to internal damage

Question 14

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

Answer 14

Most manufacturers require a complete engine tear down and inspection

Question 15

What is the purpose of crankshaft dynamic dampers used an aircraft engine

Answer 15

Dampers are used to overcome forces which caused the flexion of the crankshaft and torsional vibration.

Crankshaft vibrations are reduced by placing floating dampeners weights in a counterweight assembly, particularly in a single throw type crankshaft

Question 16

How would you make a run out check on the crankshaft that is still installed on an engine

Answer 16

Remove the propeller from the crankshaft and attach a dial indicator gauge to the front of the crankshaft. Adjust the piston of the gauge needle so that is touching the shaft. Rotate the crankshaft and check for misalignment

Question 17

What is detonation

Answer 17

All fuels have a critical limit of temperature and compression, beyond this limit they will ignite spontaneously and burn with excessive violence

Question 18

What cylinder is engine to magneto timing based on

Answer 18

The number one cylinder

It is usually set for around 30° before top dead center on the compression stroke

Question 19

What is the engine sudden speed reduction

Answer 19

This occurs when a propeller strokes and object but continues to run

Question 20

What can be learned about the condition of an engine by studying the result of a compression check

Answer 20

You can determine if the valves, piston rings, and Pistons are adequately sealing the combustion chamber

Question 21

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

Answer 21

Magic wand or a more modern infrared laser thermometer

Question 22

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

Answer 22

A dial indicator, telescopic gauge and outside micrometer or inside micrometer

Question 23

What would a cold cylinder indicate

Answer 23

No combustion inside the cylinder, normally do to know ignition or clogged fuel nozzle

Question 24

Where is a crack most likely to occur in a piston

Answer 24

Where the piston pin/wrist pin Connects

Question 25

What should be done to a Nose wheel airplane before removing the engine

Answer 25

Support the tail of the airplane