CH.2B The Powerplant and Related Systems

Question 1

THE FOUR-STROKE OPERATING CYCLE

Answer 1

Reciprocating airplane engines- continuous energy-creating process 
INTAKE
COMPRESSION
POWER 
EXHAUST

Question 2

The continuous energycreating process in almost all reciprocating airplane engines is referred to as the four-stroke operating cycle - WHAT ARE THE STEPS?

Answer 2

INATKE of fuel/air mixture
COMPRESSION by teh piston
IGNITION and expansion of gases
VENTING of the burned gas

Question 3

How is the engine speed for aircraft equipped with fix-pitch propeller displayed?

Answer 3

Tachometer in revolutions per minute (RPM)

Question 4

What propeller is adjustable from cockpit?

Answer 4

Constant-speed propeller

Question 5

What is the manifold pressure gauge used for?

Answer 5

Used in constant-speed propeller AC to monitor engine output by displaying the pressure inside the engine in inches of mercury (Hg)

Question 6

What does the carburetor do?

Answer 6

Mixes incoming air with fuel and delivers it to the combustion chamer

Question 7

What does the mixture control do?

Answer 7

Adjusts fuel/air mixture

Question 8

What causes carburetor icing?

Answer 8

May be caused by fuel vaporization and decreasing air pressure in the venturi which causes a sharp temperature drop in the carburetor

Question 9

When does carburetor ice occur?

Answer 9

When temperatures are below 21 degrees C ( 70F) and relative humididty is above 80%.

Question 10

How do you combat effects of carb ice?

Answer 10

engines with float-type carburetors heat system which is designed to eliminate ice by routing air across a heat source before it enters the carburetor

Question 11

What is the ignition system made up of

Answer 11

magnetors, spark plugs, interconnecting wires, and the ignition switch

Question 12

When does detonation occur?

Answer 12

When the fuel in the cylinders explodes instead of burning smoothly

Question 13

When does preignition occur?

Answer 13

Preignition is a result of fuel/air mixture being ignited in advance of the normal timed ignition

Question 14

What is the main difference between fuel-pump and gravity-feed systems?

Answer 14

gravity systems do not include engine-driven or electric boost pumps or fuel pressure gauges

Question 15

Why is it a good practice to refuel tanks following the last flight of the day?

Answer 15

to help prevent moisture buildup

Question 16

What is a wet-sump system?

Answer 16

It uses an oil pump to draw oil from the sump and route it to the engine. Oil system operation can be monitored by referring to the oil pressure and temperature gauges

Question 17

How does the AC cool the engine?

Answer 17

Cooling air enters the engine compartment through an inlet behind the propeller hub where it is further directed to the hottest part of the engine by baffles

Question 18

How does the exhaust escape and how is it used?

Answer 18

Exhaust is normally directed out below the engine compartment through a muffler and tailpipe. Metal shrouds around the muffler capture heat which is used to defrost the windscreen and heat the cabin

Question 19

What does a constant-speed propeller control permit?

Answer 19

A constant-speed propeller permits you to select a blade angle, appropriate for flight. Propeller control regulates engine RPM as shown on tachometer, while the throttle controls engine power output, as indicated on the manifold pressure gauge

Question 20

What should you avoid with a constant-speed propeller

Answer 20

with a constant speed propeller you should avoid low RPM settings with high manifold pressure

Question 21

What do alternators produce?

Answer 21

Alternators produce alternating current (AC) first, and then convert it to direct current (DC) for use in the airplane electrical system

Question 22

As an airplane climbs, do you enrichen or lean the mixture to maintain an optimum fuel/air ratio?

Answer 22

LEAN the mixture

Question 23

What is your first indication of carburetor ice in an airplane equipped with a fixed -pitch propeller ?

Answer 23

Your first indication of carburetor icing in an airplane with a fixed-pitch propeller will be a decrease in engine RPM

Question 24

Explain why an engine equipped with a fuel injection system is less susceptible to induction icing than one equipped with a float-type carburetor

Answer 24

Sharp temp drop in a float-type carburetor due to fuel vaporization and decreasing air pressure in the venturi
If water vapor in the air condenses when the carburetor temp is at or below freezing, ice may form. Since engines equipped with a fuel injection system eliminate the carburetor, they are relatively free from the formation of induction icing.

Question 25

The uncontrolled, explosive ignition of the fuel/air mixture within the cylinder’s combustion chamber describes which type of abnormal combustion? What actions can you take while airborne to help correct for this problem?

Answer 25

DETONATION.
Detonation can occur when the engine overheats. If you suspect detonation while in flight you should attempt to lower the cylinder temp by:
Retarding the throttle
Enriching the fuel mixture
AND/OR
Lowering the nose to increase airspeed and the cooling airflow around the engine

Question 26

If the fuel grade specified for your airplane is not available, ca you use a lower/higher grade of fuel?

Answer 26

Sub with next higher grade, but only if approved by manufacturer.
Do not use lower fuel grade - can cause cylinder head and engine temp to exceed normal operating limits.

Question 27

Describe functions performed by the engine oil system

Answer 27

lubricating the engine’s moving parts

cooling the engine by reducing friction and removing some of the heat from the cylinders

providing a seal btwn the cylinder walls and pistons

carrying away contaminants which are removed as the oil passes through a filter

Question 28

If a constant-speed propeller is set to a high RPM with a blade pitch be high or low?

Answer 28

low

Question 29

Immediately after engine start you notice that the ammeter shows a discharge. Is this normal?

Answer 29

NO