AMT 2103: Aircraft Fuels and Lubricants - Midterms

Air Cooling

 What type of cooling system uses air from the atmosphere to cool the engine?

Hot water

In a convection heating system, what rises to the top?

Additives

What property helps reciprocating engine lubricants resist oxidation?

 Centrifugal Pump

 What device is used to circulate water in a cooling system?

Weight of a substance to distilled water

 What does specific gravity compare?

Viscosity

 What does oil's ability to hold particles in suspension refer to?

    Rubbing of surfaces

 What is friction?

Resistance to flow

What is viscosity?

Acts as a cushion

 What does lubricant do between metal parts?

Thickness of oil

What does viscosity grade indicate?

Temperature effect on viscosity

 What does the viscosity index number indicate?

Viscosimeter

 What instrument measures viscosity?

Flexibility in temperature

 What is a benefit of multi-grade oils?

 Kinetic Friction

 What type of friction must lubricants withstand extreme loads?

Society of Automotive Engineers

What does SAE stand for?

To reduce friction

What is the primary purpose of lubricant?

To reduce friction

What is the primary purpose of lubricants in aviation?

Thermal stability

Which characteristic of aviation lubricants helps them perform well at high altitudes?

Additives

What property of lubricants helps them protect against corrosion in aircraft engines?

To maintain performance in cold temperatures

Why is it important for aviation lubricants to have a low freezing point?

Low viscosity

What characteristic ensures that aviation lubricants can flow easily during start-up?

They must reduce friction

What is the primary requirement for aviation reciprocating engine lubricants?

 To prevent breakdown at high temperatures

Why must lubricants for reciprocating engines have good thermal stability?

Low viscosity

Which characteristic is important for lubricants to maintain proper flow during cold starts?

To protect engine components from wear

Why is it essential for reciprocating engine lubricants to have good anti-wear properties?

True

The best oil for most purposes is one that maintains a constant viscosity throughout temperature changes  

True

Higher temperatures also lower the volumetric efficiency of the engine

False

AirCooled Engines Produce less aerodynamic noise  

True

Cooling system should be capable of removing about % of the heat generated in the combustion chamber while maintaining the optimum temp of the engine under all operating conditions of the engine  

True

The viscosity of the oil is affected by temperature  

False

W used in end of the grade or weight number that indicates the oil is of the ashless dispersant type  

False

The oil becomes thick at high temperatures and thin at low temperatures  

True

At temperatures below  °F, preheating of the engine and oil supply tank is normally required regardless of the type of oil used  

True

Approved preservative lubricating oil should be removed at end of the first  hours of operation  

True

Oil cooling can account for up to  percent of the total engine cooling and is an excellent medium to transfer the heat from the engine to the oil cooler  

True

Lubrication forms an oil film between two moving surfaces  

True

SAE ratings are not purely arbitrary and bear direct relationship to the Saybolt or other ratings  

True

The oil that flows slowly is viscous or has a high viscosity; if it flows freely, it has a low viscosity  

False

Cloud point and Pour point are established for engine oils to determine that they can withstand the high temperatures encountered in an engine  

True

The first additives incorporated in straight mineral piston engine oils were based on the metallic salts of barium and calcium