15.10, 15.7, 15.9 Flashcards
Describe a heat pump
Gas drive gear and a driven gear ( most common )
Filter clog indicator
“Pop out” on filter housing
Difference in cold tank and hot tank
Cold= scavenge lines Hot= pressure lines
What’s used to detect ferrous debris in oil system
Magnetic chip detector
3 sub systems of lubrication system
- supply and pressure
- scavenge
- vent systems
3 oil pumps
Vane , gear , gerator
What way does oil in a filter flow
“ out to in”
Where are chip detectors located
Before the inlet to each scavenge pump
Or in oil tank
Cooling medium used for oil coolers
Air or fuel or both
Purpose of a vent system
Ensure proper flow to bearings
Pressure and velocity in convergent duct
Pressure increase velocity decrease
Main parts of the exhaust
Exhaust cone, tailpipe , exhaust nozzle
Purpose of exhaust cone
Collects gas from turbine and passes it through its converging structure which decreases the airflow velocity but increases pressure , it also protects the rear face of turbine disc from high temperatures
What engines have shorter exhaust ducts
Turbo fan engines
Exhaust ducts used in supersonic aircraft
CD duct used
How is noise in exhaust reduced
Multi lobe nozzles
Corrugated type nozzles
2 types of hot stream thrust reverser operation
Clamshell , bucket doors
Operation of cold stream reverser
6 actuators open blocker doors and direct airflow forward
Purpose of exhaust struts
Protect the rear face of turbine discs from excessive temp and also help straighten out the whirl in the gas flow as it leaves the turbine
Purpose of convergent exhaust nozzles
Changes pressure energy in the exhaust gases into max velocity energy as gases or ass into the atmosphere
When would variable area nozzle be used
Supersonic military aircraft
3 sources of noise from engines
Compressor , turbine , exhaust
Nozzles used to quieten engine
Multi lobe nozzles
Corrugated type nozzles
2 types of thrust reverser systems
Hot stream reversal ( bucket doors )
Cold steam reversal
Requirements for lubrication
Low volatility, anti foaming , high flash point , high viscosity, good film strength, wide temp range
Requirements of fuel
Plumpability, high calorific value , good lubricity, high flash point , low corrosive
What is a synthetic oil
Oil made by chemical synthesis of a mineral , animal or vegetable base
2 common types of lubrication
Low viscosity synthetic oil ( modern engines )
Slightly higher viscosity oil( turbo prop)
Pour point of an oil
Lowest temp at which oil will flow
Contaminants found in fuel
Dissolved water , microbiodial
When is water most likely to enter a fuel
When it’s warmer.
