NIFE Engines 3-8-1 Lubrication Systems

Question 1

Describe the functions of lubricants

Answer 1

Purpose is to reduce friction caused by metal-to-metal contact.

Question 2

Describe the characteristics of synthetic lubricants

Answer 2

• Not all synthetic oils are derived from the same base. Therefore, synthetic oils by different manufacturers should never be mixed. Synthetics are also not compatible with mineral or petroleum base oils.
• Less coking deposits
• Stronger chemical stability at higher temps
• Is very corrosive
• 3 year shelf life

Question 3

Define viscosity

Answer 3

The property of a fluid that resists the force tending to cause the fluid to flow.

Question 4

Describe a basic aircraft lubrication system

Answer 4

Function is to provide an adequate supply of clean oil to the bearings and gears at the proper pressure and temp. remove heat from the engine, and remove contaminates from the system.

Question 5

Wet sump system

Answer 5

Oil stored internally to engine.

Disadvantages: Oil supply is limited to sump capacity, hard to cool, not adaptable to unusual flight attitudes.

Question 6

Dry sump system

Answer 6

The oil supply is carried in a tank located in the airframe or mounted on the engine.
Carries a large amount of oil and the temp of the oil can be controlled.
Allows axial flow engines to maintain their small shape

Question 7

Dry sump subsystems

Answer 7

1. Pressure subsystem
2. Scavenge Subsystem
3. Breather pressurizing subsystem

Question 8

Oil tank

Answer 8

Stores system supply oil.

Designed to provide a constant supply of oil to the engine any any aircraft attitude.

Question 9

Oil pump

Answer 9

supplies oil under pressure to the parts of the engine that must have lubrication

Question 10

Oil pressure relief valve

Answer 10

Limits max pressure

Redirect oil if needed.

Question 11

Scavenge subsystem

Answer 11

removes oil from the main bearing compartments and accessory gear drives

Question 12

magnetic chip detector

Answer 12

detects metal fragments in the scavenged oil path

Question 13

Air Oil cooler

Answer 13

Reduce the temp of the oil for re-circulation.

Question 14

Oil temp regulating valve

Answer 14

Located at the oil entrance to the fuel-oil heat exchanger. Directs the flow of return oil into the fuel-oil hx to allow cooling to occur

Question 15

Fuel temperature sensing switch

Answer 15

located in the fuel outline line of the fuel-oil heat exchanger, senses the exiting fuel’s temperature - when temps are excessive, a switch sends actuates the air-oil cooler doors

Question 16

Breather pressurizing subsystem functions

Answer 16

• Minimizes internal oil leakage by encasing oil sumps with pressurized air
• Ensures proper spray patterns of oil across the bearing