Reciprocating Engine Cooling Systems

Question 1

The Approximate percentage of heat converted into useful work in an internal combustion engine

Answer 1

30%

Question 2

In a non-supercharged engine the percentage of heat expelled as exhaust

Answer 2

45%

Question 3

The remaining percentage of heat absorbed by the oil and metal mass of the engine

Answer 3

25%

Question 4

The function of Cooling fins machined onto the cylinders

Answer 4

Provide large surface area for the transfer of heat to the surrounding airflow

Question 5

The NACA cowl produces lesser drag and is installed on _______ engines

Answer 5

Radial engines

Question 6

What The flared portion of the lower cowling on a horizontally opposed engine produces

Answer 6

Area of lower pressure to draw inlet air down and over the cylinders before exiting out of the bottom flare

Question 7

The two components located inside the piston engine which maximize the effectiveness of the cooling airflow

Answer 7

1. Baffles 2. Deflectors

Question 8

The term for the baffles installed between cylinders

Answer 8

Inter-cylinder baffles

Question 9

In a piston engine cowling, the pressure of the ram air entering the top of the cowling is ________ than the air leaving at the bottom of the cowling

Answer 9

higher

Question 10

The type of cooling produced by fast air being slowed down as it enters the top of the cowling

Answer 10

pressure cooling

Question 11

The three means of actuation of piston engine cowling flaps

Answer 11

1. Hydraulically 2. Electrically 3. Manually

Question 12

Describe an augmenter tube

Answer 12

Tubes that route exhaust gases from engine into a tube and out of the engine, while producing a high velocity, low pressure area inside the tube which draws air from the top of the cowling over the cylinders

Question 13

Describe blast tubes within a piston engine

Answer 13

Tubes that direct cooling air from cooling stream over magnetos and generators

Question 14

The main component of a cooling system for a helicopter is

Answer 14

a belt driven fan

Question 15

Operational principle of a a CHT thermo-couple

Answer 15

Two dissimilar metals. When a temperature difference exists between

Question 16

Where is the hot junction of a thermo-couple CHT circuit installed

Answer 16

inside the bayonet probe installed in the hottest cylinder

Question 17

Where is the cold junction of a thermo-couple CHT circuit installed

Answer 17

instrument case

Question 18

The 4 components to inspect in a piston engine cooling system 100 hour or annual inspection

Answer 18

1. Cowling 2. Cowling flaps 3. Baffles 4. Cylinder fins

Question 19

Anytime that excessive surface area of cylinder-fins are missing, what can be the affect

Answer 19

Excessive heat, which can lead to hot spots

Question 20

You can repair a damaged cylinder head fin as long as it

Answer 20

does not extend into the cylinder head

Question 21

How can a crack at the edge of a cylinder head fin be managed?

Answer 21

Stop drilled

Question 22

If the cooling fin on an aluminium cylinder head is inadvertently bent, what should be done and why

Answer 22

It should be left alone. Aluminium is fragile, atmepting to bend it back will cause it to break

Question 23

Work hardening in baffles and deflectors causes them to become

Answer 23

brittle and fatigue easier

Question 24

Burned paint found on a cylinder during the inspection can be indicative of

Answer 24

hot spot

Question 25

What are these?

Answer 25

Blast tubes

Question 26

Identify

Answer 26

1. Collector
2. Augmentor tube

Question 27

Identify

Answer 27

Bayonet Probe CHT thermocouple