Power Plants Flashcards
C2A Power Plant type
Two Allison T56-A-425
Power section
Compressor - Combustion - Turbine
Torquemeter
Connect the power section to the RGB.
*Provides a means to measure shaft horsepower.
R.G.B
Reduction gear box
Coverts high speed (13,820) low torque to low speed (1106) high torque prop output.
RGB contains?
G enerator H ydraulic O il pumps S tarter T ach generator
Where is the Accessories drive housing located?
On the bottom of the Compressor section
Major assemblies of Accessories drive housing
Fuel control
Speed sense control
Speed sense valve
Engine control
Power levers
Condition levers
Coordinator
Safety device (RGB)
Negative torque signal (NTS)
Safety coupling
NTS - Negative torque signal
Prevent excessive prop drag if the engine is not developing sufficient power.
Safety coupling
Auto disengages the RGB from the power section if negative torque reach 1450 shaft horsepower (SHP).
Prop brake
Released by starter - above 22% RGB oil pressure.
Applied - rpm less than 20%
Locked - when prop attempts to turn backwards
Auto feathers (Auto FX)
Auto feather armed
Power lever above 75 degrees
Prop thrust below 500 lbs
LSGI
Low speed ground idle
LSGI operational characteristic
Reduce engine RPM to 70%
Active between 7-24 degree PLA
The switch located above master caution panel.
During LGSI, engine air is available for ECS and hyd reservoir press 14sec after engine accelerate past?
61 +/- 2%
What is Alpha ana Beta range?
Alpha - flight 100% Speed
Beta - ground ops / taxi
Major functional prop component?
Spinner Prop hub Counterweight blades Pump housing assembly (PCA) Pitch change actuator (EPC) Digital electronic prop control (IOC) Integrated oil control (AVM) Actuator valve module (EVH) Electronic valve housing
Prop control?
Non rotating assembly mounted on the aft extension of prop hub.
Prop control contains?
Oil reservoir
Pumps
Valves
Control devices with hyd power
Spinner
Fiberglass assembly, provide air flow around the prop, ram air to cool prop oil control. Electric heating to provide anti ice when selected.
Prop blades consist of
Fiberglass shell
Graphite spar
Nickel sheath (prevent erosion)
Rubber heating pads (anti ice)
Prop pitch?
Determined by power lever position, maintain the prop and engine at a constant speed.
Prop pitch ops
Can only occur at blade angels of 63 to 19 degrees
Prevent decrease of blade angel
Engine instruments
Torque indicators TIT indicators Tachometers RGB oil press Power oil press Oil temp
Torque indicators
Receives input from the torque-meter.
Graduated 0-6000 horsepower
TIT indicators
18 thermocouples are used to sense engine tempt in the combustion section in degree centigrade 100 - 1200.
Tachometers
Indicate engine speed RPM % 100-13820. Electrical power
RGB oil press
The outlet of RGB pumps
0-300 psi
Power unit oil
Outlet of each power unit oil filter
0-100 psi
Oil temp
Received from temp bulb in the oil line.
Calibrate -70 to 150 degree
Fuel flow
0-2500 in 50 pounds per hours (PPH).
Fuel quantity
Co pilot side, 0-6500 lbs in 100 lbs increments.
Fire detection system
Both engine have fire detection circuits, monitor & indicate fire conditions.
If the warning light do not illuminate when tested, a failure of the detection system is indicated.
Fire extinguish system
Pulling the T-handle expose the fire button.
Pushing the switch detonates the 6.5 lbs of bromotrifluoromethane container. 350-750 psi
Engine fuel system
Contain 912 gal tank each wing.
Primary fuel JP5/F44
Engine driven fuel pump
Located in the accessories drive housing.
Deliver to fuel control unit.
Series and parallel
Series
The out put of secondary pump feed the inlet of the primary.
0-16% rpm no light and 65-100% no light.
If no primary pump light between 16-65% sec pump fail.
Parallel
Primary and sec pump auto transferred between 16-65%rmp primary pump light illuminate.
If the light illuminate above 65% primary fail to close.
Which engine driven fuel pump is use for flight ops?
Secondary pump is the primary pump for flight ops.
Cross flow valve differential?
4 psi
Fuel boost pumps
Two electrically operated are submerged in each fuel tank, one forward and aft.
Down to approximately 1% fuel remaining.
Which pump provides a sustained fuel flow during period of negative G?
Aft boost pump.
In what altitude engine driven fuel pumps can supply fuel flow for engine ops?
Below 6000ft, with all boost pump inoperative.
How many boost pump enough to sustain both engine above 6000ft?
One
Which boost pump is the only one power by left engine generator?
Port aft boost pump.
Fuel control
Located port side each engine
Varies fuel flow, coordinated with prop angel and speed
Protecting from overspeed con
Overspeed governor limits engine speed to?
104-108 % rpm
Temp datum valve
Meter fuel flow (startup & accelerate)
Overspeed protection
Control in reverse
Permit total shutoff (manually or electrically)
Coordinator
Coordinate fuel control, prop, electronic fuel trim system.
Calibrate 0-90 degree
Located behind the fuel control
Fuel dump system
Both tanks down to 20% fuel remaining (12115lbs per tank) at 1300 lbs/min
Electronic fuel trim
20% more fuel required for engine ops.
Temp limiting 0-60 degree coordinator (ground)
Temp controlling 60-100 (flight)
In temp limiting, what degree of TIT limiting temp to shutdown the engine. Preventing engine fire.
850 degree
Temp datum control
Temp datum valve responds to signals sent by temp datum. Trim the necessary amount of fuel during start and when engine speed reach 94%.
Manifold drain valve
Drain at shutdown, below 9psi.
Close by speed sense control through the ignition relay at 16% rpm during start
Held close by fuel press
Fuel enrichment
Provide increase fuel flow and extreme cold condition.
Fuel enrichment by?
Switch on
Engine speed above 16%
Fuel manifold below 50 psi
Engine oil system
Provide the power section and the RGB with sufficient oil lubrication and cooling.
Engine oil tank
12 gal Service to 8 6.2 gal useable Below 4.3 oil low light 3.3 gal 8sec neg g baffle
The engine oil system consist of three section:
Pressure, scavenge, and breather sections.
What the scavenge do?
Collects the used oil, cools it, and returns it to the oil tank.
The maximum allowable oil consumption is?
0.35 GPH
MIL-L-7808
Cold oil
Metal chip detector system
Two per engine on the RGB and the power section of each engine oil system
Engine controls
Power levers
Condition levers
Power levers
0-90 degree
Beta range 0-34
Alpha range 34-90
Condition levers
Overrides all power lever commands
Air start
Run
Ground stop
Feather
Flight idle stop solenoid
Prevents power lever movement below flight idle in flight
How many interconnected liner in the combustion section?
6
Spark igniters located in # ___ & # ___ combustion liners.
2:5
Fifth and tenth stage bleed air system
Nickel and dime
Bleed air valves are installed to prevent compressor stall during start
Open until 94 percent during start
Compressor bleed air system
14 stage bleed air in the compressor section
14 stage bleed air used for?
Cross bleed air Oil cooler ejector Hyd reservoir press 45+/-5(head press) Deicing Defogging AC/ECS Pressurization
Engine anti icing
From 14 stage bleed air
De fueling will terminate with ____ gal remaining.
4 gal / 1%
Type of oil
MIL-L-23699
Oil servicing should be accomplished with in ____ min, past that ____ min penalty run to heat up the oil.
10 : 30
Propeller servicing
MIL-PRF-83282
Engine fire extinguisher contains
6.1/2 bromotrifluoromethane
35-75 Psi
Dump fuel approximately
1300 lb/min
The fuel dump system permit jettisoning fuel from both tanks to approximately ____ %fuel remaining.
20% (1215 lb)
The engine has?
Reduction gear assembly
14 stage axial flow compressor
6 interconnected combustion liners
4 stage turbine
What used to crank the engine during normal starting?
A pneumatic starter
What fire the fuel air mixture in no. 2 and no. 5 combustion liner?
The igniter plugs
The fuel air mixture in the other four liners is ignited through what?
Crossover tubes
What the coordinator do?
Coordinates the operation of the fuel control, propeller, and the electronic fuel trimming system.
What are the main units of engine fuel system?
Engine driven fuel pump
Fuel control unit
Electronic fuel trim system
What are the three pump assembly elements?
Centrifugal boost pump
Spur-gear-type prim&sec
What control by the electronic fuel trim system?
TIT, thereby controlling engine power output.
Power lever is less than 0-66 degrees coordinator position?
Above 66-90 degrees?
(Engine speed rises above 94% rpm)
Temp limiting
Temp controling
The datum control is fed the TIT data from where?
The engine thermocouples and a reference temp valve (datum).
What the temp datum do?
To control fuel flow allowing the electronic fuel trim system to bring the temp back on schedule by .
What power the temp datum control (electronic amplifier)
Essential AC bus no.1
MEDB ROW 2 a and b
The 5 forces acting on the prop are?
Centrifugal force, centrifugal twist, aerodynamic twist, thrust bending and torque bending
