Drive System Flashcards
Primary function of the drive system
To transmit torque from the engines to the proprotors
Secondary functions of the drive system
- Provides synchronization of the proprotors and single engine operation of the proprotor system through the Interconnect Drive System (ICDS)2. Provides a drive for electrical, pneumatic, and hydraulic power generation.
PRGB
Proprotor Gearbox - Transmit power and provide a speed reduction from the engine to the proprotor mast
PRGB Overrunning Clutch
Transmits engine torque during normal operation and permits overrunning during single engine operation, autorotation, or if engine speeds are not matched
Total reduction of PRGB
Reduces 15,000 RPM engine input speed to 397 RPM (100% Nr) at the proprotor shaft
Pressure regulating bypass valve in PRGB Lubrication System
Protects the system by returning excess high pressure oil back to the inlet side of the pump
How many debris sensors are there on each PRGB and where are they located?
3; No. 1 sensor is on the air/oil separator, No. 2 sensor is on the front of each PRGB, No. 3 sensor is below the air/oil separator
What provides cooling for the PRGB lubrication system
Nacelle heat exchangers. Airflow through the heat exchangers is provided by the TAGB driven blowers
Nacelle heat exchanger thermostatic bypass valve
Directs a percentage of oil flow around the heat exchanger when oil temperature is below approx. 82 degrees C
ELS
Emergency Lubrication System - Provides automatic backup lubrication to either PRGB in the event of a primary lubrication system failure to allow the postponement of an otherwise immediate requirement for landing.
When is the ELS activated? When is it deactivated?
Any time primary lubrication pressure drops below 30 psi. it is deactivated if pressure fluctuates back up to 35 psi or more
ELS has capability to supply oil at a reduced rate for___. How should timing be managed in the event ELS is operated?
30 min. Timing should commense at first indication of PRGB PRESS LOST and should be maintained without interruption until landing and shutdown regardless of whether there is a temporary suspension of ELS.
Functions of the TAGB
- Change the angle of drive2. Transmit power from the same side PRGB to the MWGB3. Reduce input shaft speed to the ICDS
TAGB gear reduction
Reduces 11,905 RPM input shaft speed to 6574 RPM output to the interconnecting drive shafts
During single engine operations the additional stress placed on operating side TAGB will result in ___
increased oil temperature
5 components mounted on and driven by the TAGB accessory section
- Generator 2. Gearbox oil pump3. Dual-stage oil filter assembly4. Hydraulic Pump5. Nacelle Blower Driveshaft
How many debris sensors are in the TAGB and where are they located
2; No. 1 is on the sump and No. 2 is on the air/oil separator
What provides cooling for the TAGB lubrication system
Nacelle heat exchangers
MWGB
Midwing Gearbox - Multiple output unit that transmits power between the left and right interconnect driveshafts without changing speed or direction of rotation.
What components are mounted on and interact with the MWGB
APU, Rotor Positioning Unit (RPU), and rotor brake
Which way do the proprotors turn?
The right proprotor turns clockwise as seen from the aft of the aircraft and the left proprotor turns counterclockwise
what causes the proprotors to turn in opposite directions
An extra idler gear in the first stage gear train of the left PRGB causes the left proprotor to turn counterclockwise.
Major Components of the drive system
- Proprotor gearbox (PRGB)2. Pylon support assembly 3. Tilt axis gearbox (TAGB) 4. Interconnect Drive System (ICDS)5. Midwing gearbox (MWGB)
Input Quill Assembly
Mounted on the lower aft portion of the PRGB. Provides the forward engine mount where the engine output shaft drives the first stage input gear train through an overrunning clutch.
Pylon Driveshaft Quill
The pylon driveshaft is connected to the pylon driveshaft quill and connects the PRGB to the TAGB.
Overrunning Clutch
Allows overrunning during single engine operation, autorotation, or if engine speeds are not matched. During single engine operations, it disengages the PRGB from the failed engine allowing the input quill to freewheel
Nacelle Heat Exchanger
Divided into 3 sections which provide oil/hydraulic fluid cooling for: The PRGB, TAGB/Generator, Hydraulic Pump
DSIU
Drive System Interface Unit - located in the midwing forward equipment shelf.
Functions of the DSIU
- Monitors for oil debris in PRGBs, TAGBs, and MWGB and reports all debris to the MCs2. Monitors and controls the ELS and reports ELS status to MCs.
What automatically occurs when the DSIU detects debris on PRGB, TAGB, or MWGB sensors
The DSIU automatically initiates up to 3 attempts to electrically burn off the debris
How many debris sensors are in the TAGB
2
What activates the ELS
The DSIU
When should ELS endurance timing be commenced
At the first indication of PRGB PRESS LOST and should be maintained without interruption until landing and shutdown.
Pylon Support Assembly
Primary load bearing structure between the wings and nacelles and functions as a pivot point for converting the nacelles
During single engine operation the additional stress placed on the operating engine side TAGB will result in ____
increased oil temperature
Difference in high temperature warning limit on the TAGB during single engine operations
121 degrees C during single engine operations versus 132 degrees C during normal operations
Difference in low pressure warning limit on the TAGB during single engine operations
50 psi versus 30 psi during normal operations
With respect to generators the left TAGB drives ___ and the right TAGB drives ____
left drives VFG No. 3right drives CFG No. 2
With respect to hydraulic pumps the left TAGB drives ___ and the right TAGB drives
left drives No. 1 Hydraulic System pumpright drives No. 2 Hydraulic System pump
ICDS
Interconnect Drive System - Purpose is to synchronize the proprotors and transfer power between the proprotor systems and all accessory equipment which also enables single engine operation.