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HSM-72 HAC > NATOPS 2- Powerplant And HMU > Flashcards

NATOPS 2- Powerplant And HMU Flashcards

1
Q

Five sections of engine

A

Intake, compressor, combustor, turbine, and exhaust

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2
Q

Compressor stages

A

Five stage axial and single stage centrifugal, rotor/stater assembly

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3
Q

Combustion section consists of

A

Flow through, annular combustion chamber, two igniters, 12 fuel injectors and receives fuel from the ODV

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4
Q

what is the Gas generator turbine and what does it drive?

A

Two stage, air cooled, high-performance axial design

The compressor and accessory gearbox.

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5
Q

Define the Power Turbine

A

2 stage, coaxial

Shaft connects to the high speed shaft which connects to the input module

TGT is sensed between the two turbines

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6
Q

what is 30% and 70% of Engine airflow used for?

A

30% used for the combustion process, 70% for:

  • compressor inlet temperature (T2) air
  • Compressor discharge pressure (P3) air
  • Combustor and turbine cooling
  • Engine oil seal pressurization
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7
Q

What does the HMU provide?

RANNAF (RANN Away Fast)

A
  • rapid engine transient response through collective compensation
  • automatic fuel scheduling for engine start
  • NG overspeed protection
  • NG governing
  • Acceleration limiting
  • Flameout and compressor stall prevention
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8
Q

NG overspeed protection:

A

HMU mechanically limits NG to 110 +- 2 %

Reaches the position corresponding to an overspeed, a spring loaded valve secures fuel flow the engine.

Once the overspeed condition has passed the valve will open and allow normal operation

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9
Q

The DECU trims ________

A

The HMU to

  • satisfy the requirements of the power turbine load and
  • reduce pilot workload
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10
Q

PCL positions

A

OFF- PAS mechanically shuts off fuel at the shut off valve in the HMU

IDLE- the HMU automatically controls start sequence fuel flow

FLY - that’s the maximum level of power that can be supplied

LOCKOUT - Manually controls NP and NG.
- loses TGT limiting, NP governing, load sharing

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11
Q

Collective is to ________ as PCL is to _________

A

Load demand spindle (LDS)

Power Available spindle (PAS)

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12
Q

Engine-driven fuel boost pump does what:

A
  • Provide reliable suction feed from the aircraft fuel tank to the engine, minimizing fire hazard in the event of damaged fuel lines
  • provides discharge pressure to satisfy the min inlet pressure requirement of the HMU or High-pressure fuel pump
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13
Q

Fuel is tapped off in the HMU for what?

A

1) positions a metering valve to ensure proper fuel flow
2) positions a servo piston actuates variable geometry vane servo and start bleed valve
3) amplifies T2, P3, Ng that influence fuel flow and variable geometry servo position

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14
Q

HMU responds to: 3 things

A 
2 mechanical (LDS, PAS)
1 electrical (DECU) - actuates torque motor servo to trim NG speed
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15
Q

HMU responds to PCL for:

A
  • fuel shutoff
  • Setting engine start fuel flow with automatic acceleration to ground idle
  • Setting permissible NG up to maximum
  • Fuel priming
  • DECU override capability (LOCKOUT)
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16
Q

The HMU provides feedback to the DECU via the _________.

A

Linear variable displacement transducer (LVDT)

17
Q

Why is the engine power in the FLY position more that what is normally required?

A
  • Fail-safe to high power = in case of the loss of the torque motor electrical current
  • Power available with OEI = The operating engine’s gas generator can increase power sufficiently up to its limit to carry the load at the given LDS setting
18
Q

Overspeed and Drain Valve functions:

PPTR

A
  • provides fuel flow to the 12 fuel injectors
  • purges the main fuel manifold to prevent coking of the fuel injectors
  • traps fuel upstream so that priming is not required
  • Return fuel back to the HMU if np overspend or DECU hot start prevention is activated
19
Q

IPS is driven by

A

The AGB

20
Q

SHP of engines?
Continuous?
Intermediate?
Contingency?

A

1662

1800 for 30 min

1940 for 2.5 min

21
Q

Flow of air into Inlet section of engine

A

Air enters, hits swirl vanes, goes through the IPS and -either blown over board by blower assembly- or - hits the deswirl vanes and into the compressor.

22
Q

What type of Engine do we have?

A

T700-GE-401C front-drive turboshaft engine

23
Q

What is the waterwash manifold an integral part of?

A

the swirl frame

24
Q

What does the HMU respond to with the PCL in FLY?

A

collective position through a Load Demand Spindle (LDS)

25
Q

The engine fuel system consists of what?

A

Engine-driven fuel boost pump, fuel filter, HMU, and ODV

26
Q

Engine fuel filter does not filter what?

A

water

27
Q

What routes fuel to the Engine fuel filter?

Where does it go after?

A

Engine-driven fuel boost pump

routed to the HMU High-pressure fuel pump

28
Q

What does the HMU contain?

A
  • High-pressure Fuel pump
  • NG governor
  • Metering Valve
  • LVDT
  • torque motor servo
  • variable geometry vane servo
  • vapor vent
  • shutoff valve
29
Q

HMU Mechanical Linkage: The LDS directly coordinates __ speeds to the approximate power required by the rotor system based on collective position

A

Ng

30
Q

What 3 inputs does the HMU receive to aid it in controlling variable stator vanes and anti-ice/start bleed valve position?

What does this reduce the chance of?

A

T2, P3, and Ng

Compressor stall

31
Q

What trims the metering valve when it is scheduling engine fuel flow commensurate to current power demand?

A

The Torque motor servo in response to DECU signals

32
Q

How does the HMU provide Ng Governing?

A

The HMU receives T2, P3, and Ng inputs from their respective sensors, which are used to schedule fuel for minimum flow, maximum flow, and variable geometry vane control

33
Q

How does the HMU provide Acceleration Limiting?

A

The Ng governor ensures that any PCL motion will result in safe engine operation and will not cause engine damage or an inadvertent shutdown.

34
Q

What are the two types of Engine Limiting?

A
  1. TGT Limiting - defined by reaching either IRP or CRP functions within the DECU/(C)EDECU
  2. HMU-fuel flow limiting - due to the physical dimensions of the fuel lines
    - also is designed to protect the compressor section by limiting fuel flow as a function of Ng and ambient temperature
35
Q

What will happen if you are Engine Limited and increase the collective?

A

The rotors will droop

36
Q

What does the Alternator power?

A
  • ignitor assembly
  • DECU
  • Ng signal to the vertical instruments
37
Q

Two things engine driven fuel boost pump is designed for

A
  1. Provide reliable suction feed from the aircraft fuel tank to the engine, minimizing vulnerabilities in event of damaged fuel lines
  2. Provide discharge pressure to satisfy the minimum inlet pressure requirement of HMU or high px fuel pump

HSM-72 HAC (47 decks)

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