V2500 LINE AND BASE MAINTENANCE

Engine Construction

CHAPTER 4
ENGINE CONSTRUCTION
ATA 72

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OBJECTIVES

1. Recognize basic engine specifications.

2. Locate engine features shown below.
• Bearings
• Modules
• Internal cooling and sealing airflow components
3. Identify Line Replaceable Units (LRUs).

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OVERVIEW

The V2500 is composed of the following sections:

• Low Pressure Compressor (LPC) fan

• LPC booster

• High Pressure Compressor HPC

• Diffuser and combustor

• High Pressure Turbine HPT

• Low Pressure Turbine LPT

• Turbine Exhaust Case TEC.

The engine also features a fan case-mounted Main Gearbox (MGB)

to drive engine and aircraft accessories. The MGB is also known as
the Accessory Gearbox. The external gearbox assembly consists of
both the Angle Gearbox (AGB) and the MGB.

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ENGINE MODULES

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ENGINE MAIN BEARINGS

No. Type Capability
Bearings support the weight of engine parts and permit one surface
to roll over another with minimal friction and wear. The weight of the
• Takes thrust loads of the LP stub shaft
parts is transmitted through balls or rollers.
1 Ball • Provides axial and radial support for the
Bearings are designed from materials that can withstand extreme LP stub shaft and LPC rotor
pressure, since they must absorb the axial and radial loads of
rotating assemblies. An axial load is transmitted parallel to the
bearing shaft, and a radial load is applied perpendicular to the shaft. Roller, oil • Provides radial support for front of the LPT
2
dampened shaft and rear of LP stub shaft
Bearings are lubricated, cooled, and cleaned by oil.

The five single-race bearings are located in three bearing • Takes thrust loads of the HPC
compartments. Ball, oil
3 • Provides axial and radial support for front
dampened
of HPC
• The front bearing compartment, located at the center of the
intermediate case, houses bearing nos. 1–3. Bearing nos. 1 and
3 provide axial location support. Bearing No. 3 centers by a
• Provides radial support for rear of HPC
series of spring rods. 4 Roller
shaft
• The center bearing compartment, located in the
Diffuser/Combustor Case, houses the No. 4 Bearing.
Roller, oil • Provides radial support for rear of LPT
5
• The rear bearing compartment, located in the Turbine Exhaust dampened shaft
Case (TEC), houses the No. 5 Bearing.

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ENGINE MAIN BEARINGS

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BEARING COMPARTMENTS

Front Bearing Compartment

The front bearing compartment houses bearing nos. 1, 2, and 3 and

is located in the intermediate case.

The compartment is sealed by two carbon seals, one at the front of

the No. 1 Bearing and another at the rear of the No. 3 Bearing.

Low Pressure Compressor (LPC) Stage 2.5 air supports both

carbon seals while High Pressure Compressor (HPC) Stage 8 air
supports the hydraulic seal.

No. 1 Bearing

The No. 1 Bearing is a split inner race ball bearing. It is secured to

the No. 1 Bearing support by a bolted flange on its outer race. This
bearing provides radial and axial support for the front of the LP stub
shaft and LPC rotor. It also provides axial location for the Low
Pressure Turbine (LPT).

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FRONT BEARING COMPARTMENT

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BEARING COMPARTMENTS

Front Bearing Compartment (Cont.)

No. 2 Bearing

The No. 2 Bearing is a cylindrical roller bearing with a shouldered

outer race. This bearing provides radial support for the rear of the
LP stub shaft and the front of the LPT shaft. The outer race
incorporates squeeze film oil dampening to reduce rotor vibration.

No. 3 Bearing

The No. 3 Bearing is a split inner race ball bearing. The outer race
is secured to the No. 3 Bearing housing by a bolted flange. The
bearing housing is centered by 18 spring rods. Any radial
movement is dampened by oil pressure fed to an annulus around
the bearing outer race. The No. 3 Bearing provides axial and radial
location for the HPC rotor and also supports the internal drive gear.

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Engine Construction

BEARING NOs. 2 AND 3

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BEARING COMPARTMENTS (Cont.)

No. 4 (Center) Bearing Compartment

The No. 4 center bearing compartment houses the No. 4 Bearing. No. 4 Bearing

The compartment is located in a high temperature and pressure The No. 4 Bearing is a roller bearing that provides radial support to
environment at the center of the combustion section. the rear of the HPC shaft. The inner race has shoulders that guide
the rollers in the race. The outer race, installed in the No.4 Bearing
The compartment is protected from radiated heat by a heat shield support assembly, is machined elliptically so the bearing rollers
and an insulating supply of cooling air. This supply of cooled Stage cannot skid.
12 air, called buffer air, enters the space between the chamber and
first heat shield.

The buffer air is then exhausted from the cooling spaces close to
the upstream side of the carbon seals, creating an area of cooler air
from which the sealing function is obtained. This results in an
acceptable air temperature flowing across the face of the carbon
seals into the bearing compartment.

A scavenge valve on the vent side of the cooling air passage

controls buffer air flow rates.

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NO. 4 (CENTER) BEARING COMPARTMENT

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BEARING COMPARTMENTS (Cont.)

No. 5 (Rear) Bearing Compartment

No. 5 Bearing
The No. 5 rear bearing compartment houses the No. 5 Bearing,
which supports the LPT rotor.
The No. 5 Bearing is a cylindrical roller bearing that provides radial
support to the rear of the LPT shaft. Oil is fed to an annulus
The rear bearing compartment is located in the center of the LPT
between the outer race and bearing support to dampen vibration.
module, at the rear of the LPT shaft.

A single carbon seal, supported by Stage 8 air, seals the

compartment at the front end. At the rear, a simple cover plate with
an O-ring type seal is secured by 12 bolts.

Inside the compartment, the LPT shaft end is sealed by a small

disk-type plug, with a spring-supported jacket cup ring seal. This is
secured by a double helix spring clip. Air and oil will not flow down
the LPT shaft.

Pressure supply and scavenge oil pipes are covered by an

insulating heat shield material.

Separate venting is not necessary for this compartment because

the airflow inducted by the scavenge pump provides the required
pressure drop across the seal.

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NO. 5 (REAR) BEARING COMPARTMENT

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ENGINE INTERNAL COOLING AND SEALING AIRFLOWS

Sealing airflows provide positive air pressure to the bearing

chambers to prevent oil loss.

Cooling airflows provide cooling air for the engine’s internal

components, keeping them within designed operating temperatures.
Stage Purpose

Air used for internal cooling and sealing is taken from the LPC • Seals hydraulic seal between the LP/HP shaft
Stage 2.5 and HPC stages 6 (early A1 only), 8, 10, and 12. The fan HPC 8 in the front bearing compartment and the single
bypass provides external cooling air. carbon seal of the No. 5 Bearing compartment

• Provides airflow control for compressor stability

Stage Purpose and aircraft bleed services supply
• Provides “make up” air supply for the HPT
• Provides cooling air for: HPC 10 Stage 1 disk rear face, HPT Stage 2 disk front
o Air Cooled Oil Cooler (ACOC) face and HPT 2 blades
o Active Clearance Control (ACC), which • Supplies cooling air for the HPT Stage 2 Nozzle
Fan
controls turbine blade tip clearance Guide Vane (NGV) Assemblies
o Air Cooled Air Cooler (ACAC), used for Stage
12 air or buffer air • Provides cooling for combustion chamber,
HPT Stage 1 blades and NGVs
HPC 12 • Supplies cooled 12th stage ACAC air to the No.
• Seals the front and rear carbon seals of the
LPC 2.5 4 Bearing compartment to cool, seal, pressurize
front bearing compartment
and scavenge

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ENGINE INTERNAL COOLING AND SEALING AIRFLOWS

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ENGINE MODULES

The engine module design allows for fast, efficient module changes No. Module Name
with minimum down time.
31 Fan
Modular construction has the advantages listed below.

• Lower overall maintenance costs 32 LPC/Intermediate case

• Maximum life achieved from each module 40 HP system

• Reduced turn-around time for engine repair 41 HPC

• Reduced spare engine holdings

42 Diffuser and combustor
• Ease of transportation and storage
44 Stage 1 turbine NGV assembly
• Rapid module change with minimum ground running
45 HPT
• Easy hot section inspection
50 LPT
• Vertical/horizontal build strip

• Split engine transportation 60 External gearbox

• Compressors/turbines independently balanced.

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ENGINE MODULES

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ENGINE MODULES (Cont.)

Fan

Purpose: A rubber de-icing tip is bonded to the front of the inlet cone. If ice
begins to form on the rubber tip, it is thrown slightly out of balance
The fan module compresses air which flows into the engine through and begins to vibrate. The vibration causes the ice to be shed from
the nacelle intake cowl and core gaspaths. the inlet cone.

Location: The fairing provides an aerodynamic flow over the annulus fillers
and into the LPC.
The fan module is located in the front of the engine, contained
within the fan case. Operation:

Description: The LPC fan pressurizes air, which flows into the engine through
the nacelle intake cowl.
Twenty-two hollow fan blades are retained in the fan disk radially by
dovetail roots and axially by front and rear retaining rings. Twenty- The larger part of the compressed air goes through the fan duct,
two annulus fillers are installed between adjacent blades, forming a which provides the primary part of the engine thrust. The smaller
platform between each blade. These fillers form the fan inner part is compressed again when it goes through the LP and HP
annulus. A rubber seal is bonded to each side of the annulus fillers compressor stages.
to prevent air leakage between each blade and filler.

The inlet cone and fairing smooth the airflow into the fan. The fairing
is made of metal.

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FAN MODULE

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ENGINE MODULES (Cont.)

LPC/Intermediate Case

Purpose: The fan case is installed on the mounting pads on each outer strut
end of the intermediate structure (fan frame) with bolts.
The LPC/intermediate case module houses the front bearing
compartment, internal gearbox, and the LPC system to form part of The intermediate case module includes an internal gearbox that
the bypass ducting. contains a driven gear assembly.

Location:

This module is located in the front of the engine between the fan
module and the HP module.

Description:

The LPC/intermediate case module includes the fan case and

intermediate structure (fan frame), which are the two primary
components that make the case module.

The intermediate structure (fan frame) is a one-piece welded

structure with 10 inner and outer struts. The inner struts hold the
LPC booster stage assembly and the components to make the front
bearing compartment.

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LPC/INTERMEDIATE CASE MODULE

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ENGINE MODULES

LPC/Intermediate Case (Cont.)

Internal Gearbox

The gear-driven assembly engages an internal drive gear located

on the HP stub shaft. This action transmits torque from the HPC to
drive the Main and Angle gearboxes via the tower shaft and angle
gearbox.

The internal gearbox acts as a support for the No. 2 Bearing.

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INTERNAL GEARBOX

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ENGINE MODULES The disk for stages 1.5, 2, 2.3 and 2.5 is a welded titanium
assembly that contains axial dovetail slots for the attachment of the
LPC/Intermediate Case (Cont.) four stages of rotor blades.

LPC/Booster Rotor blades for stages 1.5, 2, 2.3 and 2.5 are made of titanium and
are mounted into the dovetail slots of their respective disks.
Purpose:
Stator vanes for stages 1.5, 2 and 2.3 are made of titanium.
The LPC/booster compresses the air received from the fan module The vanes are bonded to inner rings by a silicone rubber compound
and delivers it at a suitable pressure level to the HPC. and secured to the LPC case by bolts.

Location: Stator vanes for stage 2.5 is made of aluminum and are secured to
an inner ring by bolts and bonded to an outer ring by a silicone
The LPC/booster is located in the center of the intermediate case rubber compound.
structure (fan frame).
Operation:
Description:
Air is delivered into the LPC by the fan module. The air then passes
The LPC/booster consists of the following. through each rotor and stator stage and is compressed at a suitable
pressure before it is delivered to the HPC.
• Rotor blades and disk for stages 1.5, 2, 2.3, and 2.5
NOTE
• LPC front and rear cases
The V2500-A1 has an LPC/booster with three stages (1.5, 2 and
• Stator vanes for stages 1.5, 2 and 2.3 2.5). The V2500-A5 has four stages (1.5, 2, 2.3 and 2.5).

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LOW PRESSURE COMPRESSOR/BOOSTER

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ENGINE MODULES (Cont.)

High Pressure Compressor (HPC)

Purpose: • rear inner and outer case which forms the bleed

The High Pressure Compressor (HPC) supplies the required amount • manifolds and contains the fixed stators.
of pressurized air for all combustion and aircraft needs. It continues to
increase the pressure of the air supplied by the LPC. HPC stages are numbered 3-12.

Location: Operation:

The HPC is located between the intermediate case module and the The compressed air from the LPC goes into the HPC through the
diffuser/combustor assembly. Variable Inlet Guide Vanes (VIGVs).

Description: The angular position of the VIGVs and Variable Guide Vanes
(VGVs) is automatically adjusted to give the air flow the correct
The HPC is a 10-stage axial flow compressor made up of the direction through the compressor.
following:
As the air goes through the compressor, each stage compresses it
• drum rotor assembly more. The pressurized air is then delivered to the combustion
chamber.
• front case which contains variable stator vanes
Air is ducted from the HPC stages 7-10 to supply air for aircraft
o 5 vanes – A1 engine services. Additionally, more air is bled off at stages 7 and 10 to
improve engine starting and to prevent compressor surge under
o 4 vanes – A5 engine certain operating conditions.

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HIGH PRESSURE COMPRESSOR

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ENGINE MODULES

HPC (Cont.)

Rotor Assembly

The rotor assembly has five sub-assemblies.

• Vortex reducer ring

• HPC shaft

• HPC rotating air seal

• Stages 3 to 8 HPC drum

• Stages 9 to 12 HPC drum

The five sub-assemblies are bolted together to make the rotor. Stages
3 to 5 compressor blades are attached in axial dovetail slots. Stages 6
to 12 compressor blades are installed in slots around the
circumference of the disks through an axial loading slot.

The two rotor drums are bolted together with a vortex reducer installed
between the 8th and 9th stages. The vortex reducer straightens the
Stage 8 air flow, which passes to the center of the engine for the
internal cooling and sealing.

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HIGH PRESSURE COMPRESSOR ROTOR ASSEMBLY

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ENGINE MODULES

HPC (Cont.)

HPC Blades

The compressor blades in stages 3–5 are attached to the disks in

axial dovetail slots and secured by lock plates. Rubber strips
bonded to the underside of the platform seal gaps between the
blades.

Blades in stages 6–12 are installed in a slot around the

circumference of the disks. Each disk has one axial loading slot to
enable the blades to be installed onto the disk.

Four lock blades are installed on each disk, two on each side of the
loading slot, and are secured by two lock nuts and two jackscrews
per circumferential stage.

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HIGH PRESSURE COMPRESSOR BLADES

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ENGINE MODULES (Cont.)

Diffuser and Combustor

Purpose: • combustor chamber assembly

The diffuser and combustor group has four primary functions listed • No. 4 Bearing compartment.
below.
The inner and outer liner are manufactured from sheet metal with
• Straighten the flow of air from the HPC 100 separate ceramic coated liner segments attached to their inner
surface (50 tiles on each liner). The tiles can be independently
• Reduce the velocity of the air to get the best speed and replaced during engine overhaul.
pressure for combustion Operation:
• Mix fuel with the air and supply ignition to make fuel burn 1. Air velocity is decreased in the diffuser case, converting the
• Hold the No. 4 Bearing in position speed energy into pressure.

Location: 2. Fuel is mixed with the air in the combustion chamber and
then burned.
The diffuser and combustor module is located between the HPC
module and the HPT module. 3. The hot expanding gases exiting the combustion chamber
are directed back toward the turbine NGV assembly.
Description:
The diffuser and combustor module includes:
• diffuser case assembly

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DIFFUSER/COMBUSTOR SYSTEM

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ENGINE MODULES

Diffuser and Combustor (Cont.)

Diffuser Case Assembly

The diffuser case is considered a main structural part of the engine.

It houses and supports the loads of the No. 4 Bearing compartment.

The diameter of the diffuser section is larger at the rear than at the
front. This diameter difference decreases the speed of the air and
changes the velocity energy into increased pressure.

The diffuser case has 20 mounting pads, where the fuel injectors
are installed, and two mounting pads where the igniter plugs are
installed. The diffuser case also includes five mounting pads for the
combustion chamber outer alignment pins.

Outlet guide vanes, bolted at the front of the diffuser, straighten the
air coming from the HPC. The air enters the diffuser portion of the
diffuser case prior to entering the combustion chamber.

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DIFFUSER CASE ASSEMBLY

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ENGINE MODULES

Diffuser and Combustor (Cont.)

Combustion Chamber Assembly

The annular type combustor consists of an outer liner assembly and

an inner liner assembly.

The outer liner is secured by five locating pins which pass through
the diffuser casing. The combustion chamber outer liner assembly
has 20 fuel nozzle guides.

The inner combustion liner is attached to the Stage 1 turbine NGV

assembly.

Air that surrounds the combustor is used in the combustion process

for dilution and exit temperature control of the combustion gases
and for cooling of the combustor liners.

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COMBUSTOR CROSS SECTION

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ENGINE MODULES (Cont.)

Turbine Nozzle Guide Vane (NGV) Assembly The vanes are attached to the Stage 1 HPT cooling duct assembly
with bolts. Each hollow vane has internal baffles and cooling holes
Purpose: in the airfoil. Vane airfoils also have a heat-resistant coating.

The Turbine Nozzle Guide Vane (NGV) Assembly delivers the The 1st Stage HPT cooling duct is installed on the rear-inner flange
exiting gases from the combustion chamber at the right speed and of the diffuser case.
pressure to the 1st Stage HPT blades. When assembled with the outer combustion chamber liner
assembly, the combustion chamber inner liner creates a chamber
Location: for burning the mixture of fuel and air.

The Turbine NGV Assembly is located between the rear of the Operation:
diffuser case and the front of the HPT. The ring of guide vanes creates a series of nozzles which increase
the velocity of the gases from the combustion chamber. The vanes
Description: point the gases at the optimum angle onto the Stage 1 turbine
blades.
Primary parts of the NGV assembly include:
The internal vane baffles and airfoil cooling holes permit cool air
• Stage 1 HPT vane cluster assemblies from the diffuser case to go through the vane and over the external
airfoil to decrease metal temperature. Sheet metal seals between
• Stage 1 HPT cooling duct assembly adjacent vane platforms decrease leakage of the cool air.
The Stage 1 HPT cooling duct assembly carries HPC discharge air
• Combustion chamber inner liner from the diffuser case, and sends it through the metered nozzle
known as the Tangential Outboard Injector (TOBI) duct. The air is
used to cool the front face of the Stage 1 turbine rotor and Stage 1
turbine blades.

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TURBINE NOZZLE GUIDE VANE ASSEMBLY

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ENGINE MODULES (Cont.)

High Pressure Turbine (HPT)

Purpose: • blades (64)

The High Pressure Turbine (HPT) module converts energy from the • Stage 1 rear HPT air seal.
combustion gases to turn the HPC.
Primary parts of the Stage 2 rotor assembly include:
Location:
• Stage 2 turbine hub
The HPT is connected to the rear HPC shaft, between the Turbine
• blades (72)
NGV Assembly and the LPT.
• Stage 2 blade retaining plate
Description:
• Stage 2 HPT air seal.
Primary parts of this module include:
Primary parts of the HPT case assembly include:
• HP rotor assemblies (stages 1 and 2)
• HPT duct segments for stages 1 and 2
• HPT case and 2nd Stage vane assembly.
• HPT 2nd stage NGVs
The HPT rotor assemblies are two stages of turbine hubs with
single-crystal, nickel-alloy blades installed in slots on the hub. • Stage 2 HPT support assembly.
Primary parts of the Stage 1 rotary assembly include:
• Stage 1 turbine hub
• inner and outer HPT air seals

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Engine Construction

HIGH PRESSURE TURBINE ASSEMBLY (1 OF 2)

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V2500 LINE AND BASE MAINTENANCE
Engine Construction

ENGINE MODULES

HPT (Cont.)

Operation:

The HPT uses the energy of the combustion gases to supply

movement to the HPC.

Honeycomb seals on the inner diameter (ID) end of the Stage 2

vane platform are aligned with knife-edge seals on the Stage 1 HPT
(rear) air seal and Stage 2 HPT air seal to prevent gaspath leakage.

HPT airfoils are cooled by airflow.

The Stage 1 HPT blades are cooled by the HPC discharge air
which flows through the Stage 1 HPT cooling duct assembly. The
Stage 2 vane clusters are cooled by Stage 10 compressor air that
flows in through the center of the vanes.

Stage 2 HPT blade cooling air is a mixture of HPC discharge air

and Stage 10 compressor air. This air moves through holes in the
Stage 1 HPT (front inner) air seal and the Stage 1 turbine hub into
the area between the hubs. The air then goes into the Stage 2
blade root and out the trailing-edge cooling holes.

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V2500 LINE AND BASE MAINTENANCE
Engine Construction

HIGH PRESSURE TURBINE ASSEMBLY (2 OF 2)

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544 APRIL 2016
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V2500 LINE AND BASE MAINTENANCE
Engine Construction

ENGINE MODULES (Cont.)

Low Pressure Turbine (LPT)

Purpose: The LPT rotor is installed in the LPT case where it is in alignment
with the LPT stators. The LPT case is made from high-heat-
The Low Pressure Turbine (LPT) supplies the necessary power to resistant nickel alloy and is a one-part, welded assembly.
turn the LPC and fan.
The five LPT disks are made from high-heat-resistant nickel alloy
Location: and are axially installed and assembled together with nuts and
bolts.
The turbine is located aft of the HPT at the rear of the engine.
The LPT blades are also made from nickel alloy and are attached to
the disks by fir-tree roots. The blades are held in axial position on
Description:
the disk by the rotating air seals (knife edge). The rotating air seals
Primary parts of the LPT module include the following. are in line with stationary abradable seals installed on the LPT
stator vanes.
• LPT five-stage rotor
The LPT shaft is attached to the rotor by 20 nuts and bolts on the
• LPT five-stage stator vanes 6th stage disk.
• Air seals
Operation:
• LPT case
The hot, expanding gases blow through the five stages of the LPT.
• Inner and outer duct
The remaining energy from the combustion gases is extracted to
• LPT shaft provide the necessary power to turn the LPC through the LPT shaft.
• TEC

FOR TRAINING PURPOSES ONLY Subject to export and disclosure limitations on the page “About This Guide” P&W PROPRIETARY INFORMATION
544 APRIL 2016
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V2500 LINE AND BASE MAINTENANCE
Engine Construction

LOW PRESSURE TURBINE (LPT)

FOR TRAINING PURPOSES ONLY Subject to export and disclosure limitations on the page “About This Guide” P&W PROPRIETARY INFORMATION
544 APRIL 2016
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V2500 LINE AND BASE MAINTENANCE
Engine Construction

ENGINE MODULES

LPT (Cont.)

Turbine Exhaust Case (TEC)

The TEC provides support for the No. 5 Bearing and mounting
provisions for the Combined Nozzle Assembly (CNA), exhaust plug,
and rear mount.

The TEC assembly contains the LP rotor rear (No. 5) bearing and
support structure. The loads are transmitted to the outer case by
struts.

The TEC has mounts for the airframe-supplied tail cone and the
CNA. This case also includes the engine rear mount and rear
ground handling mount points.

The Exhaust Gas Temperature (EGT) probes are installed in the

case struts to measure the total temperature using T4.9
temperature probes. The total pressure is measured by P4.9
pressure probes, which are integral with the case struts.

FOR TRAINING PURPOSES ONLY Subject to export and disclosure limitations on the page “About This Guide” P&W PROPRIETARY INFORMATION
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V2500 LINE AND BASE MAINTENANCE
Engine Construction

TURBINE EXHAUST CASE

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V2500 LINE AND BASE MAINTENANCE
Engine Construction

ENGINE MODULES (Cont.)

Mount
Accessory Unit
External Gearbox Assembly Face
Purpose: • Deoiler
• Pneumatic starter
The external gearbox assembly transmits power from the engine to
provide drives for the accessories mounted on the gearbox front Front • Dedicated generator
and rear faces. • Hydraulic pump
• Oil pressure pump and filter
Location:

The external gearbox assembly is installed at the bottom of the

• Fuel Pump and Metering Unit FMU
intermediate module.
Rear • Oil scavenge pumps unit
Description: • Integrated Drive Generator System IDGS
The external gearbox assembly includes the Main Gearbox (MGB)
and the Angle Gearbox (AGB). The assembly is a cast aluminum
housing that has individually replaceable drive units and magnetic Oil sealing for the gearbox accessory drives is provided by a
chips detectors located on the main and angle gearboxes. combination of spring-supported carbon seals and O-rings. Carbon
seals and O-rings are Line Replaceable Units (LRUs).
The MBG is installed to the intermediate case flange by three
mounting links and the AGB support is attached by one mounting A manual HP system crank (turning port) is located on the front face
link. of the gearbox between the starter and the dedicated alternator.

The AGB support is a casting that houses the lay shaft and rigidly
connects the angle gearbox to the main gearbox.

FOR TRAINING PURPOSES ONLY Subject to export and disclosure limitations on the page “About This Guide” P&W PROPRIETARY INFORMATION
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V2500 LINE AND BASE MAINTENANCE
Engine Construction

EXTERNAL GEARBOX ASSEMBLY

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V2500 LINE AND BASE MAINTENANCE
Engine Construction

ENGINE MODULES

External Gearbox (Cont.)

Operation:

At engine run conditions, the external gearbox transmits the power

from the tower shaft to the accessories installed on the MGB.

At starter conditions, the external gearbox transmits power from the

starter to the engine through the tower shaft.

The external gearbox supplies the necessary speeds and torques

for the accessories to perform their various functions.

FOR TRAINING PURPOSES ONLY Subject to export and disclosure limitations on the page “About This Guide” P&W PROPRIETARY INFORMATION
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