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Chinook CH-47D > Powertrain > Flashcards

Powertrain Flashcards

1
Q

There are nine sync shafts. What does each shaft “assembly” consist of? What are they made of?

A

Each shaft assembly consists of a bearing assembly, flexible coupling, plate assembly and the shaft, which are supported by two rubber and metal mounts. (lord mounts)

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2
Q

The forward transmission changes the direction of drive by how much? Also what is the tilt of the forward rotor system?

A

Changes the direction of power input 99 degrees to the vertical position, inducing a nine degree forward tilt.

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3
Q

What does the forward and aft transmissions consist of?

A

Consists of a reservoir, gearbox, and cooler assembly

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4
Q

How many degrees of change does the aft transmission provide between the input and output drivetrains? What is the tilt of the aft system?

A

Changes the direction of power input 86 degrees to the vertical position, inducing a four degreed forward tilt.

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5
Q

What does the aft shaft assembly consist of?

A

Consists of a thrust bearing (ball type bearing for vertical loads), and shaft assembly.

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6
Q

What does the quill shaft do?

A

Connects the engine power output shaft to the engine transmission.

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7
Q

What is unique about the first and seventh sync shafts?

A

Shaft number one (forward trans) is a short shaft with a flexible adapter on the aft end.
Shaft number seven is a shaft assembly without a flexible adapter.
Those in between are interchangeable.

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8
Q

What is the difference between sync shaft 8 and 9?

A

Shaft number eight is a shaft with a flexible adapter on the aft end and number nine is a shaft assembly without a flexible adapter and is used to phase the aircrafts rotor system.

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9
Q

What supports the aft shaft?

A

A thrust bearing and housing assembly is bolted to the AFT PYLON structure at waterline +119 and is used to support the shaft.

The bearing is inside the housing assembly and receives oil from the aft transmission main oil system.

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10
Q

What is also included on the housing assembly for the aft shaft?

A

Oil inlet filter, chip detector, pressure switch

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11
Q

What triggers the XMSN OIL PRESS caution light on the Aft shaft?

A

When the pressure in the thrust bearing housing drops below 10 PSI the “XMSN OIL PRESS” master caution light and the “AFT SHAFT” main oil pressure light on the maintenance panel will illuminate.

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12
Q

When is phasing of the rotor system required?

A

Phasing of the rotor system is required whenever the synchronizing shafting is disconnected or one of the three main transmissions, aft vertical shaft, or a synchronizing shaft is removed.
The No.9 synchronizing shaft is removed to facilitate the phasing.

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13
Q

What metal is the engine transmission made of?

A

The housing for the engine transmission is cast from magnesium alloy.

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14
Q

How is power output shaft connected to the engine transmission? Where does the sprag clutch sit?

A

By way of the quill shaft, which drives the spiral bevel pinion gear.

That spiral pinion gear drives a second spiral pinion gear and the transmission output shaft assembly where the direction of torque is changed approximately 90 degrees towards the combining transmission.

A sprag clutch fits between the spiral gear internal diameter and the transmission output shaft.

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15
Q

Why is it important that the sprags engage on start-up?

A

When/if they do suddenly engage, it would apply a significant amount of torque to both the transmission and the engine drive shaft, resulting in a engine drive shaft twisting in half or engine transmission damage.

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16
Q

Engine oil system capacity (for 1 engine)

A

The total single system capacity is 11.1 quarts.

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17
Q

Single engine oil reservoir capacity

A

6 qts

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18
Q

When to check engine transmission oil level

A

Fluid level is checked within 30 minutes after shutdown.

It should be approximately in the middle of the reservoir sight glass.

If it has been longer than 30 minutes the aircraft should be run for 5 minutes if the transmission oil level is suspected to be low.

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19
Q

What does the engine transmission temp probe/switch do/activate?

A

Transmits the oil temperature from the reservoir to the indicator via the selector switch in the cockpit.

Also Connected to the LEFT or RIGHT transmission OVERTEMP latch on the maintenance panel and the XMSN OIL HOT caution light on the master caution/advisory panel which is activated at 140°C.

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20
Q

When will the combining transmission oil filter LRB pop?
Does hot weather effect this?
Can it be reset?

A

A filter bypass visual indicator will extend when the pressure difference across the filter is 15-18 PSID.

*The bypass indicator has a thermionic lockout that prevents the bypass indicator from activating when the temperature of the oil is 46º ± 5ºC.
*The indicator has a ball that prevents the filter button from being reset after the bypass indicator has extended.

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21
Q

Sequence of oil cooler assembly?

A

Combining transmission cooler on bottom
#1 in middle
#2 on top

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22
Q

Each cooler has a temperature/pressure bypass valve that will allow the oil to bypass the cooler assembly when?

A

The temperature is at or below 71º ±4ºC.

The pressure difference exceeds 30 ±5 PSI.

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23
Q

Where is the jet protection screen assembly located and what else is it called?

A

Located behind the oil cooler assembly and known as last chance filter

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24
Q

The housing around the last chance filter provides what?

A

The housing is used to provide a SIGNAL PRESSURE to the pressure transducer.

Send a PRESSURE SIGNAL to the indicator via the selector switch in the cockpit.

The housing also contains a pressure switch which lights the XMSN OIL PRESS light on the master caution/advisory panel and the RIGHT or LEFT MAIN OIL PRESS light on the maintenance panel if the pressure in the housing drops below 20 PSI.

a. 7 PSI minimum at ground idle.

b. 20 PSI minimum at 100% RRPM.

c. 20 to 90 PSI for normal operation.

25
Q

Where is the engine transmission chip detector located? What signals does it provide?

A

It’s mounted on the bottom of the engine transmission.

Provide a signal for the ENG 1 or ENG 2 CHIP DETR master caution light and the LEFT or RIGHT CHIP DETECTOR latch on the maintenance panel.

Provide indication of metal particles in the transmission.

Inner probe and the outer housing are separated by a magnet which attracts the metal particles.

Protected by the fuzz burn off module.

26
Q

Where is the engine transmission temperature switch located and what does it do?

A

Mounted on the bottom of the transmission, pointing forward.

Connected to the ENG 1 or ENG 2 XMSN HOT master caution light.

Activated at 190°C

27
Q

Where is the engine transmission debris screen located?

A

Located on the combining transmission, just above the input point for the engine drive shaft.

28
Q

How does the engine transmission debris screen work?

A

All scavenge (return) oil is routed through the detector prior to being returned to the reservoir. There are 2 stainless steel screens, a positive and a negative, in each detector. Electrically conductive particles (in the return oil), bridging the positive to negative screen, activate the LEFT or RIGHT DEBRIS SCREEN latch indicators on the maintenance panel.

29
Q

Where are the transmission oil system vents located and what are their purpose?

A

Reservoirs for the engine transmission are vented by vents located on the top of combining transmission. These allow for air to flow into the reservoir chambers.

30
Q

How are the engine transmissions filled with oil?

A

Via the combining transmission (from the overflow of the combining transmission)

31
Q

How much oil does the c-box hold and when do you check it?

A

14 QTS
checked within 30 minutes after shutdown.

32
Q

Where is the temp/probe switch located on the combining transmission? What does it do?

A

Located below and to the left of the sight glass on the front of the combining transmission reservoir.

Transmits the oil temperature from the reservoir to the indicator via the selector switch in the cockpit.

Also Connected to the COMB transmission OVERTEMP latch on the maintenance panel and the XMSN OIL HOT caution light on the master caution/advisory panel which is activated at 140ºC.

33
Q

What is the order of the 3 pressure transducers behind the cooler assemblies

A

Mounted behind the cooler box assemblies, you have left engine transmission pressure transducer, combining transmission pressure transducer, and right engine transmission pressure transducer- (all sent to cockpit)

34
Q

Where is the combining main oil pressure switch located and what does it do?

A

Mounted on the top of the reservoir cover to the left of the main oil filter.

Lights the XMSN OIL PRESS light on the master caution/advisory panel and the MAIN OIL PRESS, COMB light on the maintenance panel if the pressure in the housing drops below 20 PSI.

35
Q

Where is the c box pressure switch located? What’s it do?

A

Mounted on the top of the reservoir cover to the left of the main oil filter.

Lights the XMSN OIL PRESS light on the master caution/advisory panel and the MAIN OIL PRESS, COMB light on the maintenance panel if the pressure in the housing drops below 20 PSI.

36
Q

Where is the c box chip detector and main and aux debris screens located?

A

Chip detector Mounted at the bottom center of the transmission. Provide a signal for the XMSN CHIP master caution light and the COMB CHIP DETECTOR latch on the maintenance panel.

Debris screen Located on the front of the combining transmission at the bottom of the gearbox, just below the #7 synchronizing drive shaft. This is also known as the LH and RH debris screens (AUX pump and aux debris screen on right side).

37
Q

When does the pressure relief valve on the combining transmission oil filter open?

A

Relieves the pressure at 48 to 50 PSI.

38
Q

How do the 3 cooler fans on the c box work?

A

They suck air. They are driven by a shaft via the combining transmission through a mounting pad on the back side.

Encased by a containment tube that will trap pieces of the fan shaft if it shears, keeping the pieces away from the No.8 synchronizing shaft.

39
Q

How much oil does the forward transmission main oil system hold?

A

The total system capacity is 27.9 quarts.

The reservoir has a capacity of 18 quarts.

40
Q

When should the oil level in the forward transmission be checked?

A

Fluid level is checked 30 minutes after shutdown. Should be middle of the sight glass.

41
Q

Where is the forward transmission temp/probe switch located?

A

Located on the No.2 side on the bottom of the sump, 3:00 position looking up.

  1. Transmits the oil temperature from the reservoir to the indicator via the selector switch in the cockpit.
  2. Connected to the FWD transmission OVERTEMP latch on the maintenance panel and the XMSN OIL HOT caution light on the master caution/advisory panel which is activated at 140ºC.
42
Q

What is the flow rate of the oil pump in the forward transmission? When does the LRB on the filter pop? Flow rate of AUX oil pump?

A

Pump is a gear type pump which produces a flow rate of 20 GPM.

A filter bypass visual indicator that will extend when the pressure difference across the filter is 15-18 PSID.

Aux pump is 1.5 GPM

43
Q

How does the oil cooler assembly work on the forward transmission? When does it bypass?

A

Driven by the forward transmission input adapter.

Draws air in from around the synchronizing shaft and forces it out through the cooler vanes.

Contains a bypass valve that allows the oil to bypass the cooler when the oil temperature is below 71ºC, or the pressure difference exceeds 30 ±5 PSI caused by a clogged cooler.

44
Q

Where is the pressure transducer for the forward transmission?

A

Mounted on the front side of forward transmission ―dog house‖ cowling.

Send a pressure signal to the indicator via the selector switch in the cockpit.

45
Q

Where is the forward transmission pressure switch located?

A

Mounted on the No.1 side of the gearbox assembly at the 8:00 position, above the main inlet screen

Lights the XMSN OIL PRESS light on the master caution/advisory panel and the MAIN OIL PRESS, FWD light on the maintenance panel if the pressure from the pump drops below 20 PSI.

46
Q

How long does the aux pump in the forward transmission operate if main oil pump becomes inoperative?

A

The auxiliary pump provides up to 2 hours of safe operation if the main lubrication system becomes inoperative.

47
Q

What’s the oil capacity of the Aft transmission?

A

The total system capacity is 44 quarts.

The reservoir has a capacity of 40 quarts.

48
Q

When should aft transmission oil level be checked?

A

Fluid level is checked 30 minutes after shutdown.

49
Q

Where is the aft transmission temp/probe switch and what is its function?

A

Located on the No.1 side of the sump, below the No.2 flight hydraulic pump.

Transmits the oil temperature from the reservoir to the indicator via the selector switch in the cockpit.

Connected to the AFT transmission OVERTEMP latch on the maintenance panel and the XMSN OIL HOT caution light on the master caution/advisory panel which is activated at 140ºC.

50
Q

Where is the oil pump assembly on the aft transmission located?

A

Located on the back side of the aft transmission gearbox, next to the main oil filter.

51
Q

What makes the aft transmission oil pump assembly different?

A

Consists of a pressure section and three oil return scavenge sections.

  1. Pump is a gear type pump which produces a flow rate of 29.5 GPM pressure and 5 GPM scavenge
  2. The scavenge sections are used to draw return oil from the generators through the generator return screen and return the oil to the sump.
52
Q

For transmission filters, when does the LRB pop and when does the filter bypass?

A

visual indicator will extend when the pressure difference across the filter is 15-18 PSID (unless the temperature of the oil is 46º ± 5ºC, then will bypass).

An internal bypass valve will only operate when there is a 25-30 PSID between the inside and the outside of the filter element.

Aft trans indicator must be within 30º of vertical at the top of the filter housing.

53
Q

Where is the aft transmission pressure switch located?

A

Mounted on the No.1 side of the gearbox assembly above the No.2 flight hydraulic pump and to the left of the main oil inlet screen.

Lights the XMSN OIL PRESS light on the master caution/advisory panel and the MAIN OIL PRESS, AFT light on the maintenance panel if the pressure from the pump drops below 20 PSI.

54
Q

What are the 4 elements on the combining transmission main and aux oil pumps?

A

Main Pump (front to rear): c-box scavenge, c box pressure, #1 pressure, #1 scavenge
Aux pump (front to rear): c-box scavenge, c box pressure, #2 pressure, #2 scavenge

55
Q

Aft Shaft pressure switch lights caution/mx panel at what pressure?

A

When pressure drops below 10 psi (different than other transmission switches that light when drops below 20 psi)

56
Q

If XMSN OIL PRESSURE master caution illuminates and there is no system on the selector switch indicating low pressure, what is assumed and WHY?

A

It is assumed it is the aft shaft because the aft shaft bearing has a pressure switch and not a transducer/transmitter.

57
Q

Do debris screens light the master caution panel?

A

No

58
Q

Is RH/LH xmsn oil hot an engine decision procedure?

A

Yes! RH/LH temp switch is located in the engine reservoir aft and below the sight glass. Latches over temp at 140 degrees and lights the xmsn oil hot caution on the caution panel. You rather get this light and land than wait to get the Eng trans hot light…

Chinook CH-47D (15 decks)

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