04 - System: Engine Flashcards

1
Q

Engine: How is the engine mounted to the helicopter?

A
  • Forward coupling to the gearbox
  • To the rear structure via two rubber anti-vibration mounts

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.2)

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2
Q

Engine: What kind of compartment is the power plant mounted in?

A

In a fire-proof compartment

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.2)

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3
Q

Engine: How is the engine bearing and gears lubricated?

A

By oil circulation under pressure

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.3.1)

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4
Q

Engine: What is the purpose of the Thermostatic Valve?

A

Returns oil directly to the tank without passing through the cooling system.

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.3.3)

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5
Q

Engine: At which temperatures are the Thermostatic Valve operated?

A
  • < 74°: The valve is wide open, and the oil therefore returns directly to the tank
  • ≥ 86°: The valve is fully closed and all the oil flows through the oil cooler

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.3.3)

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6
Q

Engine: Where is the oil cooler located?

A

Forward of the MGB.

  • Engine oil cooling: To the left when looking through the oil cooler air intake (larger portion of the oil cooler)
  • MGB oil cooling: To the right when looking through the oil cooler air intake (smaller portion of the oil cooler)

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.3.5)

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7
Q

Engine: What provides the cooling effect of the engine oil in forward flight?

A

Ram air passing through the oil cooler

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.3.3)

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8
Q

Engine: What provides the cooling effect of the engine oil in hover flight?

A

The cooling air flow is provided by the motor-driven fan

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.3.3)

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9
Q

Engine: Where is the thermal switch operating the motor-driven fan located?

A

Within the oil tank

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.3.3)

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10
Q

Engine: At which temperatures are the motor-driven fan operated?

A
  • > 77°: The fan motor starts
  • < 68°: The fan motor stops

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.3.3)

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11
Q

Engine: What are the two functional parameters of a lubrication system, as for the engine?

A

Temperature and Pressure

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.3.4)

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12
Q

Engine: Which components are used to monitor the engine oil system?

A
  • Temperature indicator located in the oil tank
  • Pressure indicator located after the pressure pumps and oil filter
  • A low pressure warning light (<ENG P>) which illuminates below 1.3 bar
  • A chip detector (<ENG CHIP>) fitted on the scavange pump

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.3.4)

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13
Q

Engine: Which mechanical controls act on the engine?

A
  • Fuel flow control
    • Twist grip - operated by the pilot
    • Consider it as “Power available”
  • Engine governor
    • Coupled with the collective pitch
    • Consider it as “Power demand”

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.4.1.)

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14
Q

Engine: What is the function of the governor?

A
  • Meters fuel quantity
  • Maintains constant NTL

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.4.1)

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15
Q

Engine: What is static droop?

A

The small NR variations which occours when power demand is increased or decreased.

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.4.1)

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16
Q

Engine: What causes static droop?

A

The flyweight inability to quickly react to sudden power changes - due to the centrifugal forces lack in response time.

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.4.1)

17
Q

Engine: How is static droop compensated?

A

By the collective pitch/governor (anticipator) coupling, which changes the tension of the spring in the flyweight centrifugal governor.

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.4.1)

18
Q

Engine: What does the collective pitch/governor (anticipator) prevent?

A

Compensates for static droop and thereby prevents:

  • Surging on sudden accelerations
  • Flame-out on sudden decelerations

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.4.1)

19
Q

Engine: Which valves does the fuel flow control lever acts on?

A
  • Main valve
  • Emergency valve

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.4.1)

20
Q

Engine: During starting, with the twist grip in starting range, how is fuel supplied to the engine?

A
  • Main valve partly open
    • Fuel metering is determined by the position of the twist grip
  • Starting solenoid valve open (due to pilot pressing starter)
  • Bleed valve closed (controlled by fuel pressure)

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.4.2.1)

21
Q

Engine: How is fuel flow controlled with the twist grip in flight position?

A
  • Main valve is fully open
  • NG governor
    • meters fuel based on NTL
    • controls accel/decel with anticipator
  • Starting solenoid is closed
  • Bleed valve open

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.4.2.1)

22
Q

Engine: How is fuel supplied to the engine with the twist grip in emergency range?

A

Directly through the emergency valve - the pilot has to adjust the opening af the valve according to the collective pitch

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.4.2.1)

23
Q

Engine: The thresholds for power limitations are set in order protect which components?

A
  • Engine protection
    • T4
    • Ng
  • MGB protection
    • Torque

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.5.1)

24
Q

Engine: Where is the Ng transmitter located?

A

In the accessory gearbox

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.5.2)

25
Q

Engine: Where is T4 measured?

A

At the free turbine inlet

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.5.3)

26
Q

Engine: How is torque measured?

A

At the engine reduction gear

The intermediate pinion is displaced as torque is increased, causing oil flow to increase, which in turn is converted to a torque reading

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.5.4)

27
Q

Engine: What is the difference between the >Starter SwitchCrank

A

Starter switch

  • Fuel injection via the starting solenoid-valve
  • Ignition
  • Accelerates the starter/generator (NG)

Crank

  • Accelerates the starter/generator (NG)
    • ​Cool and dry the gas stream
    • Evacuate potentially trapped fuel
  • Does Not
    • Inject fuel
    • Engage igniters

(Instruction Manual - Basic 1 - Main Systems, Chapter 14, Paragraph 14.6.2.)

28
Q

Engine: What are the main modules of the engine?

A

(Turbomeca Training Notes, Arriel 1, page 3.5)

29
Q

Engine: How is air compressed before entering the combustion chamber?

A
  • Axial compressor (1st stage)
  • Centrifugal compressor (2nd stage)

(Turbomeca Training Notes, Arriel 1, page 3.6 - 3.9)

30
Q

Engine: How is the compressed air distributed in the combustion chamber?

A
  • Primary air:
    • Mixed with the fuel for combustion
  • Secondary air:
    • Calibrated to obtain flame stability
    • Cooling of the gas
    • Distribution of temperature on the turbine

(Turbomeca Training Notes, Arriel 1, page 3.10)

31
Q

Engine: Which components are driven by the accesory gearbox?

A

B-O-S 1-1-2-2

  • Breather (seperates oil from air/oil mist and vents the system)
  • Oil pump
  • Starter-generator
  • N1 tachometer generator
  • N1 governor
  • N2 tachometer generator
  • N2 governor

(Turbomeca Training Notes, Arriel 1, page 3.20)

32
Q

Engine: Which oil pumps does the oil system contains?

A
  • One pressure pump
  • Three scavange pumps

(Turbomeca Training Notes, Arriel 1, page 4.4)

33
Q

Engine: Does the input for ENG P light and Oil Pressure Indicator originate from the same transmitter?

A

No

  • ENG P: Low oil pressure switch
  • Oil Pressure Indicator: Pressure transmitter

(Turbomeca Training Notes, Arriel 1, page 4.16)

34
Q

Engine: What are the functions of the different air systems in the engine?

A
  • P0 - Internal Air System - also called “secondary air system” (P-C-B)
    • Pressurises the labyrinth seals
    • Cools certain internal engine parts
    • Balances the forces on the rotating assemblies
  • P1 - Compressor Bleed Valve
    • Closes when Ng reaches 96%
    • Opens when Ng decreases below 94%
  • P2 - Air Tappings (S-H-A-G B)
    • Start injector ventilation
    • Heater/Demister
    • Air intake (Sandfilter)
    • Governor (used during metering of fuel)
    • Bleed valve operation

(Turbomeca Training Notes, Arriel 1, page 5.2 - 5.6)

35
Q

Engine: How many fire detector are mounted on the engine?

A

6

  • 3 in cold area (In front of combustion)
    • One at the axial compressor (200°C)
    • Two at the accessory gearbox (200°C)
  • 3 in hot area (Aft of combustion)
    • One at T4 (400°C)
    • One at exhaust (400°C)
    • One at the reduction gearbox (300°C)

(Turbomeca Training Notes, Arriel 1, page 11.21)

(Instruction Manual - Basic 1 - Main Systems, Chapter 13, Paragraph 13.4.1)

36
Q

Engine: Principle sketch of how the governor meters fuel

A

(Turbomeca Training Notes, Arriel 1, page 3.5)