Reciprocating and Induction and Engine Cooling Systems

Question 1

Where is the heat taken from that is used to heat the induction air in a reciprocating engine?

Answer 1

From a muff that is installed around some part of the exhaust system.

Question 2

Where does the alternate air come from that is used with a pressure carburetor or a fuel injection system?

Answer 2

From inside the engine cowling.

Question 3

Where does carburetor ice normally form in a carburetor?

Answer 3

In the throat of the carburetor, on and around the throttle valve.

Question 4

Does the application of carburetor heat cause the air-fuel mixture to become richer or to become leaner?

Answer 4

Heated air causes the air-fuel mixture to become richer.

Question 5

What is used to drive most of the external superchargers used on modern reciprocating engines?

Answer 5

Exhaust gasses.

Question 6

What controls the speed of a turbocharger compressor?

Answer 6

The amount of exhaust gas that is forced to flow through the turbine. This is controlled by the position of the waste gate.

Question 7

What is the danger of operating an aircraft reciprocating engine with too high a carburetor air temperature?

Answer 7

Too high a carburetor air inlet temperature can cause the air-fuel mixture to reach its critical temperature and detonate.

Question 8

What is usually installed in a large reciprocating engine between the turbo supercharger and the carburetor?

Answer 8

An intercooler. This is an air-to-air heat exchanger.

Question 9

In what position should the carburetor heat control be placed when starting a reciprocating engine?

Answer 9

In the COLD position.

Question 10

How does an engine air inlet vortex destroyer help prevent foreign object damage to the engine?

Answer 10

A high-velocity stream of compressor bleed air is blown out in front of the engine to break up the vortices that form in front of the engine when it is operating at high power on the ground.

Question 11

What is meant by pressure cooling of an aircraft engine?

Answer 11

Air cooling in which air is forced to flow through baffles and cylinder fins by a pressure differential across the engine.

Question 12

What is the purpose of an augmentor tube in the cooling system of an aircraft reciprocating engine?

Answer 12

The augmentor tube uses the velocity of the exhaust gasses to produce a low pressure on one side of the engine that helps pull cooling air through it.

Question 13

Where is the highest temperature located in a turbine engine?

Answer 13

At the inlet to the high-pressure turbine.

Question 14

How are the turbine inlet guide vanes and the first-stage turbine blades in some turbine engines cooled?

Answer 14

High-pressure compressor bleed air flows through the hollow guide vanes and hollow turbine blades.

Question 15

Which side of an air-cooled engine cylinder has the greatest amount of cooling fins?

Answer 15

The side of the cylinder in which the exhaust valve is located.

Question 16

What should be done to repair a bent cooling fin in a cast aluminum cylinder head?

Answer 16

It is normally best to leave a bent cast fin alone if it does not restrict the flow of air. Cast fins are brittle and could break off.

Question 17

What is used in a helicopter to increase the amount of cooling air that flows over the engine cylinders?

Answer 17

A belt-driven fan.

Question 18

What should be the position of the cowl flaps on a reciprocating engine when it is run on the ground?

Answer 18

They should be wide open when operating the engine on the ground.

Question 19

What is the function of the majority of the air that passes through a turbine engine?

Answer 19

Most of the air is used for cooling.

Question 20

How does metallic sodium in an exhaust valve aid in transferring heat?

Answer 20

The sodium melts when the engine is running, and it sloshes up and down as the valve operates. The sodium picks up heat from the valve head and carries it into the stem so it can be transferred to the cylinder head and dissipated into the air.

Question 21

How is the structure around a turbine engine protected from excessive heat from the engine?

Answer 21

An insulating blanket protects the structure from excessive heat.

Question 22

What is the function of blast tubes that are installed in a pressure cooling system of a reciprocating engine?

Answer 22

These blast tubes direct cooling air to the magnetos and the generator.

Question 23

Of what material is the insulation blanket made that is used to protect the aircraft structure from the heat produced by a turbine engine?

Answer 23

Fiberglass sandwiched between sheets of metal foil.