TEST Flashcards
What are the three characteristics of the PT6A Engine?
Light weight free turbine reverse flow
What does Free Turbine mean?
An independent system that has no mechanical system and is only powered to driver the compressor turbines.
What does Reverse Flow mean?
Airflow is circled around 2 times inside the Gas section
hat is P3 in the engine?
compressor discharge
) What is P2.5 in the engine?
Interstage Air
What does black oil in the engine indicate?
It indicates that your carbon seal is deteriorating and depositing the dirt into the oil system. Change the seals
- Interface between power section and gas generator section
Flange C
- Power turbine vane assembly and power turbine
Flange D
CT Vane Assembly and shroud housing
Flange E
access to the compressor
Flange F
- AGB access
Flange G
Which of these flanges may be accessible by an overhaul shop only?
Flange A, B, F
) Name the type of bearings located from 1 - 6:
Ball Roller Roller Ball Roller Ball
) What type of loads do Ball Bearings take?
axial loads
What type of loads do Roller Bearings take?
Radial loads
) In what direction do the Compressor Turbines turn in?
CCW
In what direction does the Power Turbine turn in?
CW
What is the purpose of the master spline on the turbine disks?
Maintain balance with the shaft
At what percentage of Ng does bleed valve close at?
91%
What is the purpose and location of the Ng Tach Generator?
Purpose: Drives the the compressor in the Gas Generator Section (Gas Producer) - Location: Accessory Gearbox
What is the purpose and location of the Nf Tach Generator?
- Purpose: Drives the propeller through the RGB - Location: Reduction Gearbox (RGB)
What is the purpose and location of the Breather Impeller?
- Purpose: Vents breathed air overboard - Location: Accessory Gearbox
What is the purpose and location of the Fuel Heater?
Purpose: Pre-heats the fuel to prevent ice crystal formation - Location: Accessory Gearbox
What is the purpose and location of the Fuel Pump?
- Purpose: Boost fuel pressure to supply the fuel to the engine - Location: Inside FCU
What is the purpose and location of the Torque-Meter?
- Purpose: Measures torque of rotating shaft - Location: Reduction Gearbox
What is the purpose of the Accessory Gearbox?
- To drive the accessories mounted on it.
What is the purpose of the Reduction Gearbox?
To reduce the RPM for the propeller. It is reduced because of the airframe capacity to take such a speed/RPM
) How many stages are in this engine’s gearbox?
2 stages
What is the gear ratio at 100%?
Tach drive runs at 4200 RPM @ 100%
How many fuel nozzles are on a PT6? And what type?
- 10 Primary and 4 Secondary - Can be 7 and 7 as well - ALL ARE SIMPLEX
What is the job of Oil in the engine?
To cool, clean and lubricate the bearings and propeller systems of the engine
How much oil is consumed in the engine. Roughly
1 qt. In 10 hours of operation (MAXIMUM)
How much is the oil pressure in the system?
80 to 100 psi
What bearings have labyrinth seals on them?
1,2,3,4
What is the purpose of the ignition system?
To provide a heat source/ spark to ignite the air/fuel mixture for combustion
What are the 2 types of igniters?
Glow Plug - Spark Type
What do you do if igniters are dropped?
Throw them away and get a new one. Do not reuse as they can be damaged.
What must be done to the exciter while servicing?
Remove the exciter input lead before the high tension leads
What must be always done to the exciter box plugs while servicing?
Always cap them off to prevent anything from entering and damaging the box.
What is the purpose of the fuel system?
To supply clean fuel to the engine at a sufficient pressure to allow the burning in the combustor.
PT6 - power percentage divides on:
67% of power to drive compressor 33% of power to drive propeller
Engine two major sections:
- Gas generator section, also call [Gas producer Section] 2. Power Section
