Turbine Engine Lubrication Systems

These flashcards cover key concepts from the lecture notes on turbine engine lubrication systems, aiding in the review and understanding of important terms and their definitions.

What is the primary purpose of a lubricant in an engine?

To reduce friction between moving parts.

What type of lubrication is used universally in aircraft engines?

Liquid lubricants or oils.

What happens under ideal conditions of fluid lubrication?

Friction and wear are held to a minimum.

What is one of the key requirements for turbine engine lubricants?

Must have a high viscosity for load-carrying ability.

What is the significance of oil having low volatility in turbine engines?

Prevents loss by evaporation at high altitudes.

Why should turbine engine oil not foam?

Foaming can interfere with lubrication and cause damage.

What are synthetic oils developed for turbine engines known for?

Lower tendency to deposit lacquer and coke.

What is Type I turbine engine oil specification?

MIL-PRF-7808.

What is a common problem leading to excessive oil consumption?

Oil line leakage.

What are the three common oil pressure issues in turbine engines?

High, low, or erratic indicated oil pressure.

How is oil used to cool turbine engine bearings?

By circulating oil around the bearing to carry heat away.

What do wet-sump and dry-sump systems refer to?

Types of lubrication systems for turbine engines.

What is the main function of oil jets in turbine engines?

To deliver oil in an atomized spray to bearings.

What is the purpose of an oil filter in a lubrication system?

To remove foreign particles from the oil.

What type of valves are used to prevent oil from flowing back in the opposite direction?

Check valves.

How do thermostatic bypass valves maintain oil temperature?

By varying the flow of oil through the oil cooler.

What are the two basic types of oil coolers used in turbine engines?

Air-cooled and fuel-cooled oil coolers.

What does a deoiler do in turbine engine lubrication systems?

Removes oil from the breather air.

What is the role of magnetic chip detectors in the oil system?

To detect and capture ferrous particles within the oil.

Why is it critical to maintain proper oil pressure in turbine engines?

To ensure adequate lubrication and prevent engine damage.

What is the function of an oil pressure regulating valve?

To keep oil pressure fairly constant in the system.

What symptom indicates a clogged oil filter?

High differential pressure across the filter.

What is one function of the oil pressure relief valve?

To relieve excessive pressure in the oil system.

What can result from oil jets being clogged?

Bearing failure due to lack of lubrication.

How are oil pumps used in turbine engines?

To supply and circulate oil under pressure to lubricate engine parts.

Why is it important to use the correct grade of oil in turbines?

To prevent engine wear and ensure effective lubrication.

What happens when the oil vapor mixes with air in the breather system?

It is separated from oil and vented overboard.

What is the main advantage of synthetic oils over petroleum oils?

Less tendency to deposit solids at high temperatures.

What kind of bearings are present in turbine engines that influence lubricant choice?

Ball and roller bearings (antifriction bearings).

Why should oil in a turbine engine not be contaminated?

Contaminated oil can damage high-speed ball and roller bearings.

How is the oil cooler integrated into the lubrication system?

To cool the oil before it is recirculated through the engine.

What is one characteristic of dry-sump systems?

An external oil tank is used to hold the majority of the oil supply.

What safety feature is present in oil filters to prevent oil flow blockage?

Bypass valves that allow oil to flow if the filter is clogged.

What critical factor affects the choice of lubricant in turbine engines?

Operating temperature and altitude requirements.

What is the relationship between oil viscosity and engine speed in turbine engines?

Lower viscosity is needed for good flow at high speeds.

What maintenance action should be taken if metal particles are found on a chip detector?

Investigate to find the source of the metal particles.

What does a scavenge pump do in a lubrication system?

Removes used oil from the engine back to the oil tank.

How can breather systems affect the oil system?

They help maintain balanced pressure across various compartments.