ENGINE COOLING

1. Which of the following results in a decrease in volumetric efficiency?

A. Cylinder head temperature too low.

B. Part-throttle operation.

C. Short intake pipes of large diameter.

B. Part-throttle operation.

2. The most common method and generally the best conduction of heat from the inside of a cylinder barrel to the cooling air is accomplished by

A. Machining fins directly on the outside of the barrel.

B. Shrinking on a jacket or muff of aluminum cooling fins around a steel cylinder sleeve.

C. Machining fins directly on the outside of the barrel and shrinking on a jacket or muff of aluminum cooling fins around a steel cylinder sleeve (on different areas of the barrel).

A. Machining fins directly on the outside of the barrel.

1) Some aircraft exhaust systems include an augmenter system to draw additional air over the engine for cooling.

(2) Augmenter systems are used to create a low pressure area at the lower rear of the aircraft engine cowling. Regarding the above statements,

A. Only No. 1 is true.

B. Only No. 2 is true.

C. Both No. 1 and No. 2 are true.

C. Both No. 1 and No. 2 are true.

4. High cylinder head temperatures are likely to result from

A. Fouled spark plugs.

B. A very lean mixture at high power settings.

C. A very rich mixture at high power settings.

B. A very lean mixture at high power settings.

5. Which of the following should a mechanic consult to determine the maximum amount of cylinder cooling fin that could be removed when cracks are found?

A. Engine structure repair manual.

B. AC 43.13-1A.

C. Engine manufacturer's service or overhaul manual.

C. Engine manufacturer's service or overhaul manual.

6. Which statement is true regarding the air passing through the combustion section of a jet engine?

A. Most is used for engine cooling.

B. A small percentage is frequently bled off at this point to be used for air-conditioning and/or other pneumatic powered systems.

C. Most is used to support combustion.

A. Most is used for engine cooling.

7. The undersides of pistons are frequently finned. The principal reason is to

A. Provide for greater heat transfer to the engine oil.

B. Provide sludge chambers and sediment traps.

C. Support ring grooves and piston pins.

A. Provide for greater heat transfer to the engine oil.

8. Which of the following defects would likely cause a hot spot on a reciprocating engine cylinder?

A. Cowling air seal leakage.

B. A cracked cylinder baffle.

C. Too much cooling fin area broken off.

C. Too much cooling fin area broken off.

9. Cracks in cooling fins that do not extend into the cylinder head may be repaired by

A. Removing affected area and contour filing within limits.

B. Filling the extremities of crack with liquid metal.

C. Welding and then grinding or filing to original thickness.

A. Removing affected area and contour filing within limits.

10.  What part of an air-cooled cylinder assembly has the greatest fin area per square inch?

A. Cylinder barrel.

B. Rear of the cylinder head.

C. Exhaust valve port.

C. Exhaust valve port.

11.  The position of the cowl flaps during normal cruise flight conditions is

A. Open.

B. Closed.

C. One half open.

B. Closed.

12.  During ground operation of an engine, the cowl flaps should be in what position?

A. Fully closed.

B. Opened according to ambient conditions.

C. Fully open.

C. Fully open.

13.  What is the purpose of an augmenter used in some reciprocating engine exhaust systems?

A. To reduce exhaust back pressure.

B. To assist in displacing the exhaust gases.

C. To aid in cooling the engine.

C. To aid in cooling the engine.

14.  Reciprocating engines used in helicopters are cooled by

A. The downdraft from the main rotor.

B. A fan mounted on the engine.

C. Blast tubes on either side of the engine mount.

B. A fan mounted on the engine.

15.  The component/s in a turbine engine that operate/s at the highest temperatures is/are the

A. Exhaust cone.

B. Turbine disks.

C. First stage turbine nozzle guide vanes.

C. First stage turbine nozzle guide vanes.

16.  Where are cooling fins usually located on air-cooled engines?

A. Exhaust side of the cylinder head, inside the pistons, and connecting rods.

B. Cylinder head, cylinder walls, and inside the piston.

C. Cylinder head, cylinder barrel, and inside the piston.

C. Cylinder head, cylinder barrel, and inside the piston.

17.  A bent cooling fin on an aluminum cylinder head

A. Should be sawed off and filed smooth.

B. Should be stop-drilled or a small radius filed at the point of the bend.

C. Should be left alone if no crack has formed.

C. Should be left alone if no crack has formed.

18.  What is the position of the cowl flaps during engine starting and warmup operations under normal conditions?

A. Open for starting, closed for warmup.

B. Full open at all times.

C. Full closed at all times.

B. Full open at all times.

19.  Increased engine heat will cause volumetric efficiency to

A. Increase.

B. Decrease.

C. Remain the same.

B. Decrease.

20.  Cylinder head temperatures are measured by means of an indicator and a

A. Resistance bulb sensing device.

B. Wheatstone bridge sensing device.

C. Thermocouple sensing device.

C. Thermocouple sensing device.

21.  During an operational check of an electrically powered aircraft engine cowl flap system, the motor fails to operate. Which of the following is the first to be checked?

A. Flap actuator control switch.

B. Flap actuator motor circuit breaker.

C. Flap actuator motor.

B. Flap actuator motor circuit breaker.

22.  What is the function of a blast tube as found on aircraft engines?

A. A means of cooling the engine by utilizing the propeller backwash.

B. A device to cool an engine accessory.

C. A tube used to load a cartridge starter.

B. A device to cool an engine accessory.

23.  Generally, a small crack just started in a cylinder baffle

A. May be stop-drilled.

B. Requires no action unless it grows or is branched into two cracks.

C. Requires repair by reinforcing, such as installation of a doubler over the area.

A. May be stop-drilled.

24.  An engine becomes overheated due to excessive taxiing or improper ground runup. Prior to shutdown, operation must continue until cylinders have cooled, by running engine at

A. Idle RPM.

B. Low RPM with oil dilution system activated.

C. High RPM with mixture control in rich position.

A. Idle RPM.

25.  The purpose of an intercooler when used with a turbocharger is to cool the

A. Turbocharger bearings.

B. Exhaust gases before they come in contact with the turbo drive.

C. Air entering the carburetor from the turbocharger.

C. Air entering the carburetor from the turbocharger.

26.  A broken cooling fin on a cylinder head

A. Should be left alone.

B. Is cause for rejection of the head.

C. May be filed to smooth contours if damage and/or repair limits are not exceeded.

C. May be filed to smooth contours if damage and/or repair limits are not exceeded.

27.  The primary purpose of baffles and deflectors installed around cylinders of air-cooled aircraft engines is to

A. Create a low pressure area aft of the cylinders.

B. Force cooling air into close contact with all parts of the cylinders.

C. Increase the volume of air used to cool the engine.

B. Force cooling air into close contact with all parts of the cylinders.

28.  Prolonged idling of an engine will usually result in

A. Excessive cylinder head temperatures.

B. Increased oil consumption.

C. Foreign material buildup on spark plugs.

C. Foreign material buildup on spark plugs.

29.  How do cowl flaps aid in cooling a horizontally opposed aircraft engine?

A. Recirculates air through the engine cylinders.

B. Directs air through the engine cylinders.

C. Controls the amount of air flowing around the cylinders.

C. Controls the amount of air flowing around the cylinders.

30.  The greatest portion of heat generated by combustion in a typical aircraft reciprocating engine is

A. Dissipated through the cylinder walls and heads.

B. Converted into useful power.

C. Carried out with the exhaust gases.

C. Carried out with the exhaust gases.

31.  Which of the following assists in removing heat from the metal walls and fins of an air-cooled cylinder assembly?

A. A baffle and cowl arrangement.

B. An engine induction system.

C. An intercooler system.

A. A baffle and cowl arrangement.

32.  Aircraft reciprocating engine cylinder baffles and deflectors should be repaired as required to prevent loss of

A. Fin area.

B. Cooling.

C. Power.

B. Cooling.