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02 – Lifting System EC135 Classic

B1
Training Manual

Chapter 02
Lifting System

For instruction only Iss. August 2018 02 – 1

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02 – Lifting System EC135 Classic
B1
Training Manual

Table of contents
2.1 General Description of the Lifting System .................... 4 2.6 Rotor Brake System ...................................................... 38
2.2 Main Rotor Drive .............................................................. 6 2.6.1 Rotor Brake Indication System ........................................ 40
2.2.1 Driveshafts ......................................................................... 6 2.7 Main Transmission Mounts........................................... 42
2.3 Main Transmission .......................................................... 8 2.7.1 General ............................................................................ 42
2.3.1 General .............................................................................. 8 2.7.2 ARIS Anti Resonance Isolation System ........................... 46
2.3.2 LH and RH Drives ............................................................ 10 2.7.3 General System Description ............................................ 48
2.3.3 Tail Rotor Output Drive .................................................... 12 2.7.4 Clearance ........................................................................ 50
2.3.4 Main Transmission .......................................................... 14 2.8 Oscillation Damper ........................................................ 52
2.3.5 Lubrication System .......................................................... 18 2.9 Main Rotor System ........................................................ 54
2.3.6 XMSN Oil Temperature Indication ................................... 20 2.9.1 General ............................................................................ 54
2.3.7 XMSN Oil Pressure Indication ......................................... 20 2.9.2 Main Rotor Blade ............................................................. 56
2.3.8 XMSN High Oil Temperature Caution .............................. 20 2.9.3 Blade Root ....................................................................... 58
2.3.9 XMSN Oil Chip Caution ................................................... 20 2.9.4 Blade Fitting Area ............................................................ 60
2.3.10 XMSN Low Oil Pressure Caution / Warning .................... 22 2.9.5 Airfoil Section ................................................................... 62
2.3.11 Oil Distribution System .................................................... 24 2.9.6 Erosion Protection ........................................................... 64
2.3.12 Main Transmission Oil Service ........................................ 26 2.10 Main Rotor Blade P3 / T3 Version................................. 66
2.3.13 Accessory Gearbox ......................................................... 28 2.10.1 Rotor Blade Adjustments ................................................. 70
2.4 Oil Cooling System ........................................................ 30
2.5 Main Rotor Hub Shaft .................................................... 32
2.5.1 Main Rotor Hub Shaft - General ...................................... 32
2.5.2 Mast Moment Indication System...................................... 34
2.5.3 Mast Moment Indication CDS .......................................... 36
2.5.4 Mast Moment Indication CPDS........................................ 36

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02 – Lifting System EC135 Classic
B1
Training Manual

This training document comprises the following ATA chapters:

General Description of the Lifting System ATA 63
Main Rotor Drive ATA 63
Main Transmission ATA 63
Oil Cooling System ATA 63
Main Rotor Hub Shaft ATA 63
Rotor Brake System ATA 63
Main Transmission Mounts ATA 63
Oscillation Damper ATA 18
Main Rotor System ATA 62
Main Rotor Blade P3 / T3 Version ATA 62

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02 – Lifting System EC135 Classic
2.1 General Description of the Lifting System B1
Training Manual

2.1 General Description of the Lifting System

General Rotor Brake System

The lifting System of the EC135 is located in the transmission The rotor brake system permits stopping of the main– and tail rotor,
compartment on top of the transmission deck, within the center-of- after the engines have been shut down.
gravity area. It's main components are: It mainly consists of:
– Main rotor drive – cockpit mounted brake lever
– rotor brake system – bowden cable
– main rotor system – brake cylinder
– monitoring system – brake caliper
– brake disk
Main Rotor Drive
The main rotor drive system transmits power from both engines to the Main Rotor System
main– and tail rotor as well as to two cooling fans and two hydraulic
The main rotor system generates the lift and thrust of the helicopter.
pumps.
In conjunction with the tail rotor system, it provides directional control
It mainly consists of: of the helicopter in flight.
– 2 driveshafts
– main transmission Monitoring System
– main transmission mounts. For the important parameters (e.g. rotor RPM, oil pressure and oil
temperature) several sensors are installed. The signals are transmitted
to the cockpit in order to trigger cautions and warnings and supply the
indicating instruments.

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02 – Lifting System EC135 Classic
2.1 General Description of the Lifting System B1
Training Manual

Lifting System - General Arrangement

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02 – Lifting System EC135 Classic
2.2 Main Rotor Drive B1
2.2.1 Driveshafts Training Manual

2.2 Main Rotor Drive

General
The main rotor drive transmits power from both engines to the main
rotor, tail rotor and to the auxiliary units. Additionally it is a structural
component of the helicopter and also transmits all static and dynamic
loads between the main rotor system and the fuselage.

Components of Main Rotor Drive

The main rotor drive consists of:
– 2 driveshafts
– main transmission
– main transmission mounts
– main rotor drive monitoring system.

2.2.1 Driveshafts

General
Two driveshafts connect the engines to the freewheel units of the
main transmission. They transfer the power of the engines to the main
transmission. In addition, they correct any misalignment between the
engine outputs and the main transmission inputs. For this purpose two
flexible diaphragms are attached to each end.
A compensation in length is done by the engine output flange.

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2.2 Main Rotor Drive B1
2.2.1 Driveshafts Training Manual

Engine Drive Shaft

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2.3 Main Transmission B1
2.3.1 General Training Manual

2.3 Main Transmission

Tab. 02-1: Leading Particulars Main Transmission
2.3.1 General
Mass approx. 143.5 kg
The main transmission transfers the power from both engines
to the main rotor system, tail rotor and the accessory drives. All Gear reduction Main rotor 14.923
mounting points, attachment fittings and oil lines are integral with the Tail rotor 1.183
transmission casing. Two freewheel units incorporated in the input Speed Drive 5898
drives allow power to be transmitted only from the engines to the main
Main rotor 385
transmission.
Tail rotor output 4986
2.3.1.1 Components Oil quantity approx. 10.0 l
The main transmission is of modular design. It mainly consists of: AirGO 3001 for EC135 T2+ / P2+ and P3 / T3
– LH and RH input drives Oil types alternatively: 0–156; MIL–L–23699 C for all
– tail rotor drive other EC 135
– main gearbox Material Aluminium alloy
– lubrication and cooling system
♦ NOTE Airbus Helicopters recommends AirGo 3001 for all
– LH and RH accessory drives
EC135.

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2.3 Main Transmission B1
2.3.1 General Training Manual

Main Transmission - Modules

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2.3 Main Transmission B1
2.3.2 LH and RH Drives Training Manual

2.3.2 LH and RH Drives Freewheel Unit

The engines drive the input drive shafts in clockwise direction. In
Assembly this direction, the freewheel clutches are interlocking the driving and
The drive consists of: driven parts.
– freewheel housing The functions of the freewheel clutches are as follows:
– freewheel unit – Starting the engines: Only one engine drives initially and the
– seal housing with seal freewheel clutch to the other drive is overrun. It will lock if
both engines are running at the same RPM.
– ball bearing and roller bearing
– One engine becomes inoperative: It’s freeweel clutch is
– drive pinion.
overrun and prevents the engine from being driven by the
main transmission.
Function – Both engines become inoperative: Both freewheel clutches
The driveshaft connecting the engine to the main transmission is are overrun and the main rotor can turn without any additional
attached to the triangular flange of the freewheel shaft. The bevel gear friction from the engines (autorotation).
of the drive pinion meshes with the bevel gear of the intermediate
shaft. The correct gear mesh (gear backlash and gear tooth pattern)
is ensured by a shim of the appropriate thickness between the ball
bearing and transmission casing. The shaft seal in the cover seals off
the rotating freewheel shaft at its outboard end.

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2.3.2 LH and RH Drives Training Manual

Freewheel Assembly

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2.3 Main Transmission B1
2.3.3 Tail Rotor Output Drive Training Manual

2.3.3 Tail Rotor Output Drive

General
The tail rotor consists of:
– connecting flange
– spacer
– seal housing with shaft seal
– output shaft

Assembly
The connecting flange provides the attachment point for the rotor brake
disc adapter and the tail rotor driveshaft. The splined output shaft
meshes with the splines of the connecting flange. The correct position
of the connecting flange is adjusted by the gearbox manufacturer with
the help of a spacer. The shaft seal in the seal housing seals off the
rotating connecting flange at its outboard end.

♦ NOTE During the reinstallation of the connecting flange it

must be ensured that the axial position relative to
the output shaft is correct.
That means that the connecting flange must be in
contact with the spacer. Otherwise an axial play of
the output shaft is given. The actual position of the
flange has an influence to the relative position of the
rotor brake disc to the rotor brake calliper.

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2.3.3 Tail Rotor Output Drive Training Manual

Tail Rotor Output Drive

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2.3 Main Transmission B1
2.3.4 Main Transmission Training Manual

2.3.4 Main Transmission Collector Stage

The collector stage is the center part of the main transmission. The
General collector stage is driven by two intermediate gears. It transmits:
The transmission concept was designed by ZF (Zahnradfabrik – the combined engine power to the main rotor system and to
Friedrichshafen). The transmission is driven by two engines and the tail rotor system
drives the main rotor, the tail rotor and the accessories. – the lifting forces into the transmission housing
The main transmission reduces the input RPM of the two engines – dynamic and static forces from the lifting system.
to the required output RPM for the main rotor, the tail rotor and the
accessories. The transmission is divided into the following stages:
– input stage Accessory Drives
– freewheel clutches Accessory drives are installed to drive the oil cooler fans and the
hydraulic pumps. They are located at the LH and RH forward side of
– collector stage
the main transmission and are driven by the intermediate gears.
– accessory drives.

Input Stage
The LH and RH side engine input drive shafts are installed in the
lower housing assembly. They are provided with freewheel clutches
to prevent a reverse power flow from the main transmission to the
engines. The two vertical intermediate gears change the power flow
by 90° and pass it to the collector helical gear of the collector stage.
Additionally, the intermediate shafts drive the oil pumps.

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2.3.4 Main Transmission Training Manual

Main Gearbox - Geartrain and RPM (at 100%)

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2.3.4 Main Transmission Training Manual

Main Gearbox, Lateral Cut, View against Flight Direction

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2.3.4 Main Transmission Training Manual

Main Gearbox, Longitudinal Cut

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2.3 Main Transmission B1
2.3.5 Lubrication System Training Manual

2.3.5 Lubrication System Oil Filter

An oil filter located in the central oil passage separates the contaminants
General from the oil. The housing of the oil filter is fitted with a bypass valve (∆p
The main transmission is provided with a wet sump oil system for 3.5 bar) and a mechanical filter contamination indicator (∆p 2.1 bar).
lubrication and cooling. Because of redundancy, the lubrication system This means that this pop–out is a preclogging indicator. If the filter
comprises two oil pumps located in the lower casing of the gearbox. becomes clogged, the oil will be rerouted through the bypass valve
The main components of the system are: thereby maintaining the proper supply of oil to the system.
– filler neck An oil pressure transducer measures the oil pressure in the central oil
– oil filter passage. Visual indication of the pressure is provided in the cockpit.
The oil is conveyed to both oil coolers and from there to the lubricating
– spray tubes
points through the integral oil passages in the casing. Installed at
– LH and RH oil pumps these lubricating points and accessible from the outside are spray
– oil sight glass tubes which provide for optimum lubrication of the components.
Oil is added to the system via the filler neck. The oil level is indicated The oil filter can be cleaned in an ultrasonic bath.
by the oil sight glass. Oil is drained off through a valve which houses
the chip detector. Oil Cooler
The oil coolers are mounted to the RH and LH side of the main
Oil Pumps transmission. They are split into two sections. The smaller section
The main transmission is equipped with a redundant lubrication of each cooler, which is connected directly to the main transmission,
system comprising two oil pumps located in the lower casing of the serves for cooling the main transmission oil.
gearbox. These pumps are driven by the intermediate shafts through For this, ambient air is drawn by the cooling fans and forced through
interconnected driveshafts. There is a predetermined breaking point the oil coolers via air ducts. From there, the air is directed overboard
integrated in these shafts. via outlet ducts (see also chapter “Power Plant”, Oil Cooling System).
The oil pumps draw oil from the oil sump and convey it through a
central oil passage. If either pump should fail, the remaining pump is
able to convey enough oil to meet system demands. Failure of an oil
pump is detected by a low–pressure switch and is visually indicated in
the cockpit. In the central oil passage, an oil temperature transducer
measures the oil temperature and an oil temperature switch monitors
the max. permissible oil temperature. The associated indicators are
located in the cockpit.

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2.3.5 Lubrication System Training Manual

Main Transmission - Oil System

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2.3 Main Transmission B1
2.3.6 XMSN Oil Temperature Indication Training Manual

2.3.6 XMSN Oil Temperature Indication 2.3.9 XMSN Oil Chip Caution

General General
The oil temperature of the main gearbox is measured by a transducer For the detection of magnetic chips in the oil system, a chip detector is
mounted to the gearbox at the oil filter housing. The temperature is fitted in the common suction line of both oil pumps. It is installed by a
indicated in the cockpit on the analog oil temperature and pressure bayonet connection in the XMSN oil drain plug (a check valve closes
indication or on the VEMD in °C. when the chip detector is removed).
Accumulation of particles bridge a contact gap of the detector magnet
2.3.7 XMSN Oil Pressure Indication and close the circuit to the CDS / CPDS.
The indication at the MISC CAUTION display will be:
General
– XMSN CHIP
The oil pressure is measured by a transducer mounted to the gearbox
in the central oil passage. The pressure is indicated in the cockpit on
the analog oil temperature and pressure indication or on the VEMD
in bar.
Tab. 02-2: Oil Pressure

Minimum 0.5 bar

Continuous operation 0.5 to 7.8 bar

2.3.8 XMSN High Oil Temperature Caution

General
The oil temperature caution caption is triggered by an oil temperature
switch installed at the main transmission oil filter housing. The switch
closes the circuit to the CDS / CPDS at a temperature of approx.
115 °C.
The indication at the MISC CAUTION display will be:
– XMSN OIL T

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2.3.9 XMSN Oil Chip Caution Training Manual

Main Transmission - Monitoring

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2.3 Main Transmission B1
2.3.10 XMSN Low Oil Pressure Caution / Warning Training Manual

2.3.10 XMSN Low Oil Pressure Caution / Warning

General
To warn the pilot in case of low oil pressure in each of the XMSN
lubrication systems, two pressure switches are installed downstream
of the oil pumps. The switches are installed at the lower front side of
the main transmission.

2.3.10.1 Low Oil Pressure Caution

Each oil pressure switch closes when the pressure at the associated
pump outlet is below 0.5 bar.
The associated indication are as follows:
– XMSN OIL P Caution SYS I or II on CDS / CPDS

2.3.10.2 Low Oil Pressure Warning

In case of low oil pressure in both XMSN lubrication systems (both
pump outlet pressure switches sense a pressure below 0.5 bar) a low
pressure warning will be sent additionally to the CDS / CPDS caution
captions.
The associated indications are as follows:
– XMSN OIL P Cautions SYS I and II on CDS / CPDS
– XMSN OIL P Warning on the warning unit
– gong in the headset with 3 seconds intervals.

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2.3.10 XMSN Low Oil Pressure Caution / Warning Training Manual

Main Transmission - Oil Pressure Switches

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2.3 Main Transmission B1
2.3.11 Oil Distribution System Training Manual

2.3.11 Oil Distribution System

General
The distribution system delivers oil to all bearings and gears in the
main gearbox as well as to the accessory drives and the freewheel
clutches. The system mainly consists of bores in the gearbox housing
and spray nozzles, screwed into the gearbox housing. After lubricating
the gears and bearings, the oil flows into the oil sump in the lower
housing by gravity.

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2.3.11 Oil Distribution System Training Manual

Main Transmission - Components of Lubrication System

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2.3 Main Transmission B1
2.3.12 Main Transmission Oil Service Training Manual

2.3.12 Main Transmission Oil Service

The following oil type is approved for the main transmission:
– MIL-L-23699
– AirGO 3001 for EC135 T2, T2+, P2, P2+
The oil quantity is approx. 10.0 liters.

2.3.12.1 Oil Level Sight Glass

The main transmission oil level can be checked by a sight glass,
located at the RH rear side of the main transmission.
The “MAX” and “MIN” marks indicate the upper and the lower oil level
limits.

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2.3.12 Main Transmission Oil Service Training Manual

Main Transmission - Oil Service

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2.3 Main Transmission B1
2.3.13 Accessory Gearbox Training Manual

2.3.13 Accessory Gearbox

General
A fan drive gearbox consists of:
– gearbox housing
– idler gear witch ball bearing
– driveshaft with bevel gear and bearings
– output pinion gear with ball bearings.

Configuration and Function

The intermediate shaft of the main gearbox drives the idler gear and
the driveshaft of the accessory gearbox. The driveshaft is splined to
the hydraulic pump. The flange for the hydraulic pump encases the
driveshaft seal. The bevel gear of the driveshaft drives the output
pinion gear of the fan. The fan bearings are lubricated with main
gearbox oil.

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2.3.13 Accessory Gearbox Training Manual

Accessory Gearbox

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2.4 Oil Cooling System B1
2.3.13 Accessory Gearbox Training Manual

2.4 Oil Cooling System

General Oil Cooler

Both engines as well as the main transmission of the helicopter The oil coolers are mounted at the RH and LH side of the main
are equipped with internal, independent oil circuits. These ensure transmission. They are split into two sections. The smaller section
permanent lubrication and cooling of highly stressed components of each cooler, which is connected to the main transmission by feed
under all operating conditions. To keep the oil temperature within tubes directly, serves for cooling the main transmission oil.
limits, a oil cooling system is installed in the helicopter. The larger section of each cooler is connected to the associated
Independant cooling circuits are availble for the: engine by oil hoses. This section serves for cooling the engine oil.
– LH engine
– RH engine Cooling Air Flow
– main transmission. Ambient air which enters the air intakes is drawn by the cooling fans
and forced through the oil coolers via the inlet air ducts. From there
the air is directed overboard by the outlet ducts.
Components
The oil cooling system consists of the following:
– 2 cooling fans
– 2 inlet airducts
– 2 outlet airducts
– 2 dual section oil coolers (engine / main transmission)
– 2 thermal controlled bypass valves in the engine circuits
– severeal hoses and connectors

Cooling Fans
The cooling fans aremounted at the front side of the main transmission
RH and LH. They are driven by the main transmission geartrain (12666
RPM at 100 %).

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2.4 Oil Cooling System B1
Training Manual

Oil Cooling System - General Arrangement

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2.5 Main Rotor Hub Shaft B1
2.5.1 Main Rotor Hub Shaft - General Training Manual

2.5 Main Rotor Hub Shaft

2.5.1 Main Rotor Hub Shaft - General Bonding Jumper

The main rotor hub shaft transmits the driving moment to the main Four bonding jumpers are screwed onto the hub cap support with
rotor blades which are connected to the hub. In doing so, it also one end and to bonding studs at the rotor blades. This allows static
performs the function of a rotor head. discharge of the rotorblades.
The main rotor hub shaft assembly consists of the following
components: Hub Cap Support
– rotor hub shaft with integral flanges The hub cap support, which is manufactured from aluminum alloy,
– hub cap support is attached by screws to the upper hub flange of the main rotor hub
shaft, and seals off the open end of the hub shaft.
– rotor hub cap.
The helicopter can be lifted by a hoisting device attached to the hub
cap support.
Configuration
The main rotor hub shaft, which is hollow and is formed with two hub Rotor Hub Cap
flanges at its upper end, is a one–piece forged part made of steel For aerodynamic reasons, a rotor hub cap is installed. It is a composite
alloy. In between the two flanges the rotor blades are fixed. construction which can be delivered in two different types:
The two fixation points for the scissors assembly are forged to the – standard rotor hub cap
shaft. On the lower end of the shaft are the seating surfaces for the – quick–removable rotor hub cap for blade folding system
mast bearings and the mast spline which meshes with the main (optional).
transmission.
The upper hub flange is marked with the numbers 1 through 4 at the The hub caps are attached to the support by screws in the case of the
blade attachment areas, with the numbers counted in the clockwise standard hub cap and by bayonet connections and safety screws in
direction. This identification is important for relating the blade the case of the quick–removable hub cap.
attachment areas to their respective blades.

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2.5 Main Rotor Hub Shaft B1
2.5.1 Main Rotor Hub Shaft - General Training Manual

Main Rotor Hub Shaft

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2.5 Main Rotor Hub Shaft B1
2.5.2 Mast Moment Indication System Training Manual

2.5.2 Mast Moment Indication System ♦ NOTE The signal processing unit can be installed under
the transmission deck or above the avionics deck in
General the rear of the helicopter.
The mast moment indication system is used to measure and indicate
any bending moments, which occur on the rotor mast.
The system mainly consists of:
– strain gauge bridge
– sensor amplifier unit
– induction transmitter (stator and rotor)
– signal processing unit
– indication at the CDS / CPDS.

Function
The signal processing unit (SPU) produces a certain frequency which
is transmitted to the signal amplifier unit (SAU).
The signal is transferred via stator, attached to the lower gearbox cover
in the oil sump, and rotor of the induction transmitter. The SAU sends
a signal (carrier frequency) to the strain gauge bridges, bonded into
the rotor mast. Due to shaft bending, the resistance of the strain gauge
bridge changes thus modulating the amplitude of the carrier frequency.
The SAU amplifies the SGB signal and converts it to a frequency
signal (25 kHz ±10 kHz). 25 kHz corresponds to 0% mast moment
(MM) resp. 0V SGB signal. This frequency signal is modulated on a
13.56MHz carrier frequency. This 13.65 MHz frequency is generated
by the SPU and also supplies the SAU with power. The modulated
signal is transmitted back from the SAU via the induction transmitter
to the SPU. The signal processing unit generates a voltage signal
proportional to the bending moment. This voltage signal is sent to the
CDS / CPDS for mast moment indication.

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2.5.2 Mast Moment Indication System Training Manual

Mast Moment Indication System

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2.5 Main Rotor Hub Shaft B1
2.5.3 Mast Moment Indication CDS Training Manual

2.5.3 Mast Moment Indication CDS 2.5.4 Mast Moment Indication CPDS
The CDS mounted mast moment indicator consists of a green, a The mast moment indication at the VEMD consists of a white marking
yellow and a red bar and an additional red “limit light”. with different ranges. The following ranges are allocated to single
Tab. 02-3: Mast Moment Indication CDS colors:
Normal range up to 50 % green Tab. 02-4: Mast Moment Indication CPDS

Caution range 50 % to 78 % yellow Normal range up to 50 % no color

Maximum 78 % to 100 % red Caution range 50 % to 66 % yellow
When the mast moment exceeds 63.15 % and is below 77.80 %, the Maximum > 66 % red
red limit light flashes at approx. 3 flashes / second. When the mast
moment is reduced to less than 63.15 %, the limit light extinguishes. ♦ NOTE 50 % equal 9500 Nm bending moment.
When the mast moment exceeds 77.80 %, the limit light is turned on
continuously. It remains on until a CDS cold start occurs. The actual
cumulated counter value is stored in 200 ms steps in the CDS memory
and can be displayed in the advisory display by turning the rotary knob
to the “M” position. (Example: 0017 = 17 x 200 ms = 3.4 s)

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2.5.4 Mast Moment Indication CPDS Training Manual

Mast Moment Indication System

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2.6 Rotor Brake System B1
2.5.3 Mast Moment Indication CDS Training Manual

2.6 Rotor Brake System

General Function
The hydro-mechanical rotor brake system enables the main and tail The rotor brake is actuated by a brake lever. Before it can be operated,
rotors to be brought to a standstill, and locks them against further the brake lever must be released from its detent by actuating a
rotation for a limited period of time. With the brake lever applied locking pawl which allows the brake lever to be pulled downward until
and locked, the hydraulic pressure in the rotor brake system will be it engages. The maximum force is limited by the damper spring. To
maintained for some time before slowly dissipating. An electrical release the brake lever, the locking pawl on the brake lever must be
switch lights up a caption in the cockpit indicating system that the rotor pressed.
brake has been engaged.
♦ NOTE The fluid reservoir must be filled with brake fluid
♦ NOTE The rotor brake may only be operated under the DOT–4 only.
following conditions: the engines have been shut
down or the rotor speed is down to 50 % of its
nominal speed

System Components
The rotor brake system mainly consists of:
– brake lever (located in the cockpit)
– bowdenflex cable
– damper (force limiter spring)
– brake cylinder with fluid reservoir
– brake caliper
– brake disk
– micro switch for CDS/CPDS caution ROTOR BRK.

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2.6 Rotor Brake System B1
Training Manual

Rotor Brake System

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2.6 Rotor Brake System B1
2.6.1 Rotor Brake Indication System Training Manual

2.6.1 Rotor Brake Indication System

General
A micro switch that is installed on the brake caliper mounting slideway
will indicate an engaged rotor brake an the rotor brake indicating
system. The slide itself is installed on the rotor brake support in a way
that it can move laterally against a spring by approximately 1 mm. Two
springs (one on each slide bolt) press the slide to the right (seen in
flight direction). The force to move the slide can be adjusted by shims
(also on left hand side).
If the rotor brake is engaged and the brake disk starts turning, the
brake caliper will move together with the slide against the spring and
depress the microswitch.
The indication on the CDS/CPDS MISC caution display will be:
– ROTOR BRK

♦ NOTE With an engaged rotor brake and a stillstanding

rotor, the caution ROTOR BRK is not triggered.
With an engaged brake the caution will come on the
moment the rotor starts turning.

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2.6.1 Rotor Brake Indication System Training Manual

Rotor Brake Indication System

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2.7 Main Transmission Mounts B1
2.7.1 General Training Manual

2.7 Main Transmission Mounts

2.7.1 General
The main transmission is attached to the airframe by four ARIS (Anti
Resonance Isolation System) dampers, one side load strut (Y-Strut)
and two torque struts.
The components of the main transmission mounting serve to transmit
the main rotor forces and moments into the helicopter airframe.

Gearbox Struts
One (titanium) side load strut (Y–strut) carries all forces in lateral (Y)
direction. The side load strut is attached to the airframe via a combined
torque / Y–load bracket on the LH side of the transmission deck.
The strut is attached to the main transmission accesscover by means
of two screws.
Two titanium torque struts carry the main rotor reaction torque and all
forces created by the main rotor system in longitudinal (X) direction.
The torque struts are attached to the airframe and to the main
transmission by bolts. Spherical bearings are integrated in the torque
struts.
In case of a torque strut failure the emergency stop keeps the gear
box in position and prevent a total failure of the ARIS mounts.

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2.7 Main Transmission Mounts B1
2.7.1 General Training Manual

Main Gearbox - Attachment

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2.7 Main Transmission Mounts B1
2.7.1 General Training Manual

INTENTIONALLy LEFT BLANK

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2.7 Main Transmission Mounts B1
2.7.1 General Training Manual

Gearbox Struts

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2.7 Main Transmission Mounts B1
2.7.2 ARIS Anti Resonance Isolation System Training Manual

2.7.2 ARIS Anti Resonance Isolation System

Principle
In order to isolate a vibration between the rotor system and the aircraft
fuselage a spring/mass damper is used.
The spring rate and the mass weight have to be defined in such a way
that the main rotor frequency induces the anti resonance oscillation in
the spring/mass system. Thus the H/C rotor system and the damping
mass vibrate with the same frequency, with phase shift of 180°.
Therefore, the forces generated by the rotor system in downward
direction are compensated by the forces created by the dampingmass
in upward direction and vice versa.
This system is only effective in the vertical axis (z–direction) and
towards the adjusted frequency.

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2.7.2 ARIS Anti Resonance Isolation System Training Manual

Principle of Passive Anti–Resonance Vibration Isolation

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2.7 Main Transmission Mounts B1
2.7.3 General System Description Training Manual

2.7.3 General System Description A pre–loaded compression spring together with the secondary
The system consists of 4 uniaxial hydro-mechanical vibration isolaters. bellows produce an operating pressure within the self-contained unit
They carry all weight and lifting forces transmitted by the main of approx. 6 to 7 bar, thereby ensuring the functional integrity of the
transmission. They are attached to the airframe with 4 bolts each and vibration isolator for all operating conditions.
to the main transmission by a special spherical bearing and one bolt The emergency stop which is formed in the shape of a cylindrical pot
each. For “fail safe” purposes an emergency stop is mounted above fits over the corrugated portion of the primary bellows and is attached
each damper. to the transmission deck of the fuselage with screws.
The purpose of the system is to reduce the loads and vibrations If the primary bellows of the vibration isolator should fail, the
generated by the main rotor to the helicopter fuselage. transmission will be supported either by the emergency stop or the
detachable emergency stop rings.
Function
The vibrations generated by the main rotor cause periodic movements
of the main transmission relative to the fuselage which in turn causes
axial movement of the primary bellows.
In response to the travel of the primary bellows, the secondary bellows
produce a bigger stroke as determined by the ratio of their respective
cross-section areas. The resultant inertia forces (force generator)
cause the pressure of the glycol solution in the vibration isolator to
fluctuate. The spring and pressure forces at the isolator attachment
point on the fuselage overlap each other. Therefore, vibrations are
reduced at the anti–resonance frequency.
The primary bellows are provided with an adapter at the bottom end
for connecting them to the fuselage, while at the top end they are
formed with a forked lug for connecting them to the main transmission.
The forked lug is fitted with bushings. Above the bellows section, the
primary bellows are formed with an integral ring above which there is
an annular groove which accomodates a split emergency stop ring.
At the upper end of the secondary bellows there is a mass jacket. A
pendulum rod acting as a guide for the mass is attached to this jacket.

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2.7.3 General System Description Training Manual

ARIS - Vibration Isolators

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2.7 Main Transmission Mounts B1
2.7.4 Clearance Training Manual

2.7.4 Clearance
The clearance between stop ring and emergency stop must have a
certain value. For measuring this clearence, a feeler gauge is used at
four places 90° apart and the mean value has to be calculated.
The clearance is adjusted with shims to the nominal value 0.7 to
1.0 mm during installation.

♦ NOTE The clearance will change with the temperature and

therefore can’t be used for failure detection.

Adjustment
A main rotor speed of 100 % nR means that the main rotor rotates at
6.6 rounds per second. This results in a 4/rev vibration frequency of
26.3 Hz. The natural vibration frequency of the ARIS is adjusted to
this figure.

Failure Detection
At +20 °C the pendulum rod will protrude. The protrusion varies with
the ambient temperature, but generally it can be stated, that as long
as the pendulum rod protrudes the ARIS is still serviceable.
In case of pressure drop (e.g. crack in one of the bellows) the internal
spring and the inner bellows expand and the pendulum rod will
disappear.

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2.7.4 Clearance Training Manual

ARIS - Measurement of Clearance

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2.8 Oscillation Damper B1
2.7.4 Clearance Training Manual

2.8 Oscillation Damper

General of 26.7 Hz. The natural vibration frequency of the y damper is adjusted
The aircraft is equipped with a mass / spring damper to reduce lateral to this figure.
vibrations (y direction). It is mounted to the fuselage and compensates
for lateral vibrations created by the main rotor system. ♦ NOTE If the H/C flies permanently in higher altitudes, the
efficiency of the damper can be adjusted by removing
a certain amount of tuning sheets (according service
Location and Assembly
engineering information).
The y–damper is mounted to the stringer below the LH floor panel.
The damper assembly consists of two weights bolted to the springs.
The location of the weights on the springs is adjustable. On each
weight it is possible to attach up to 6 tuning sheets. The springs, with
the weights attached, are mounted to a common support.

Function
The damper is energized by lateral oscillations of the fuselage. The
natural frequency of the damper can be adjusted by adjusting the
weights of the mass or moving the weights on the springs. If the
damper frequency is tuned to the same frequency as the fuselage
oscillations, it will vibrate in exact opposition to the fuselage vibrations.
Those induced vibrations of the damper will react in direct opposition
to the fuselage vibrations and will cause a reduction in fuselage lateral
vibrations.
The y–damper is adjusted to give the lowest level of vibrations at
101.5 % NR instead of 100 % NR. This is in order to achieve the best
compromise of vibration levels when the rotor speed increases to 104
% NR at high density altitudes.
A main rotor speed of 101.5 % NRR means that the main rotor rotates at
6.7 revolutions per second. This results in a 4/rev vibration frequency

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2.8 Oscillation Damper B1
Training Manual

y–Damper

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02 – Lifting System EC135 Classic
2.9 Main Rotor System B1
2.9.1 General Training Manual

2.9 Main Rotor System

2.9.1 General Swash Plate

The main rotor system consists of a bearingless, hingeless 4–blade The swashplate is the connecting link between the rotating rotor and
main rotor, main rotor shaft with integral hub, control elements, and the stationary components of the control system. It is mounted on a
the rotor-related indicators. By using modern composite materials, sliding sleeve which slides on a main gearbox mounted support tube.
this rotor system provides the flapping, lead–lag and blade pitch
change functions without the installation of complicated ball and Rotating Control Rods
elastomeric bearings. This type of construction is beneficial in terms The four rotating control rods transmit the control inputs from the
of maintenance, cost and weight. swashplate to the main rotor blades. For flight control adjustment
(track and balance), the control rods are length–adjustable.
System Components
The components of the main Rotor systems are: Driving Unit
– four main rotor blades Two scissors assemblies provide for synchronous rotation of the
– main rotor hub shaft swashplate bearing ring with the rotor mast.
– swash plate
– four rotating control rods
– scissors assembly (driving unit)

Main Rotor Blades

The four main rotor blades generate the lift and propulsion required for
flight. Each blade is attached to the hub-shaft by two identical bolts.

Main Rotor Hub-Shaft

The main rotor hub–shaft transmits the driving torque from the main
transmission to the main rotor blades. It also takes up rotor forces and
moments and passes them to the main transmission.

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2.9 Main Rotor System B1
2.9.1 General Training Manual

Main Rotor System

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2.9 Main Rotor System B1
2.9.2 Main Rotor Blade Training Manual

2.9.2 Main Rotor Blade bench) for the pitch link, so called “pre track value” can be changed.
This reference of the blade 1 ensures the basic rotor adjustment (min.
General and max. pitch angle). The settings of the blades 2, 3 and 4 are also
The main rotor blade is manufactured from fiber composite materials. set to the manufacturers basic settings (“pre track value”). Additionally
A blade root having low bending stiffness (Flex Beam) performs the blades 2,3 and 4 are individually adjusted (pitch link length and
the functions of the flap and lead-lag hinges. Because of the weak trim tab position) according the results of the track and balance run. All
torsional stiffness of the FlexBeam, the angle of attack of the blade blades can be replaced individually due to the manufacturers' basic
can be changed. settings. The numbers and colour codes for the blades 2, 3 and 4 are
mainly used as a reference for the track and balance equipment.
A pitch control cuff is integrated in the blade skin to provide a rigid
connection with the airfoil section of the blade. The pitch angle of ♦ NOTE If the basic adjustment is changed, the relationship
the main rotor blade is changed through a pitch horn on the pitch between the rotor thrust and the collective pitch
control cuff. During this feathering motion, the pitch control cuff is kept lever position will be out of tolerance. Depending
centered about the blade root by a bearing support and a spherical on the amount of deviation, the autorotation RPM
bearing. and the general helicopter performance will be
Two elastomeric lead–lag dampers provide sufficient in-plane damping influenced.
of the main rotor blade to prevent ground and air resonance.
The surface of the main rotor blade is provided with a protective coat ♦ NOTE The main rotor blades can be replaced individually
of PUR lacquer to protect the composite materials from solar radiation due to the adjustments at the manufacturers' test
and environmental and weather influences. stand.

Color Marking Color to Number Code Relationship

Each of the four main rotor blades is identified with a different color. – Yellow = number 1
The upper hub flange of the main rotor hub–shaft is coded with the
– Green = number 2
numbers 1 thru 4 on the blade attachment areas. In order to avoid
readjusting the control settings and the blade track when removing – Blue = number 3
or installing the same main rotor blades, these main rotor blades are – Red = number 4
reinstalled so that their respective colors are paired correctly with
number codes on the hub flange.
Blade number 1 (yellow colour code) is the reference blade. On the
blade 1 (yellow) only the settings determined by the manufacturer (test

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2.9.2 Main Rotor Blade Training Manual

Main Rotor Blade

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2.9 Main Rotor System B1
2.9.3 Blade Root Training Manual

2.9.3 Blade Root To prevent denting of the pitch control cuff – especially on the less
The blade root has the following functional areas: curved upper and lower surfaces – it incorporates a sandwich structure
and a hard foam filler core.
Blade fitting area (1)
Two drain holes are provided on the underside of the pitch contol cuff
Serves to attach the main rotor blade to the rotor hub of the main rotor
at the outboard end adjacent to the blade airfoil section. These serve
shaft and is fitted for this purpose with two Teflon–coated bushings.
to vent the pitch control cuff and to allow water which has condensed
Soft flapping section (2) in or penetrated the pitch control cuff to drain off.
This area enables the main rotor blade to flap up and down. The integration (transition area) of the pitch control cuff to the blade
Soft torsion section (3) body provides a force transmitting connection which transmits the
Enables the main rotor blade to twist about its feathering axis to control inputs to the aerodynamic portion of the blade. A part of the
change the blade pitch angle. forces andmoments generated by the main rotor blade are transmitted
Soft lead-lag section (4) through this connection to the pitch control cuff.
Enables in-plane motion of the main rotor blade. A positive twist of +16° built into the blade in the region where the
pitch control cuff joins the airfoil section provides the airfoil section
with a corresponding preset pitch angle and brings the flexbeam into
Pitch Control Cuff
an unloaded (untwisted) mid position.
The pitch control cuff is provided with a transition area where it is
integrated with the aerodynamic portion of the blade, and with a
damper connection at its open end. The pitch control cuff, which
permits neither torsional nor lead–lag movements, surrounds the
blade root and is rigidly connected to the adjacent airfoil section.
Torsional stiffness is required so that the control inputs can be
transmitted through the pitch control cuff to the airfoil section of the
blade.
The in–plane rigidity of the pitch control cuff is obtained through the
unidirectional orientation of its carbon fibers in the trailing and leading
edge of the control cuff. Lead–lag rigidity is necessary to enable lead-
lag movements of the main rotor blade to be transmitted directly to the
lead-lag dampers without significant losses.

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2.9.3 Blade Root Training Manual

Main Rotor Blade - Control Cuff

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2.9 Main Rotor System B1
2.9.4 Blade Fitting Area Training Manual

2.9.4 Blade Fitting Area

A composite damper connection is integrated in the fiber structure
of the pitch control cuff. In the areas where it connects to the lead-
lag dampers, it is constructed with extreme stiffness to withstand
compression loads. This is necessary because the lead-lad dampers
have to be axially preloaded during installation.
The damper connection is tilted 15° relative to the blade fitting plane
in the direction of the pitch horn.
The pitch control cuff is supported at the blade fitting end by the
damper installation consisting of the elastomeric lead-lag dampers
and the bearing support which provides pivotal and tilting movements.
When control inputs are made, the pitch control cuff rotates about this
pivot point. Simultaneously, the flexbeam twists to feather the main
rotor blade about its longitudinal axis and provide the required pitch
angle.
The pitch control cuff provides the following functions:
– transmits control inputs to the aerodynamic portion of the
blade to change the blade pitch angle
– transmits in-plane movements of the main rotor blade to the
lead-lag dampers
– provides the blade root with an aerodynamic fairing.

♦ NOTE The blade bolt bushings are tilted 2.5° against the
rotor blade longitudinal axis in order to cone up
the blade. Thus the forces in the blade fitting are
reduced when the rotor is turning.

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2.9.4 Blade Fitting Area Training Manual

Main Rotor Blade - Blade Fitting Area and Pitch Control

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2.9 Main Rotor System B1
2.9.5 Airfoil Section Training Manual

2.9.5 Airfoil Section Blade skin

The airfoil section generates the main rotor blade lifting force. It has The blade skin, which is made of GRP plies, surrounds the spar, lead
a rectangular blade geometry with a parabolic swept-back tip and a rod and blade core. It ensures that the aerodynamic portion of the
negative 2° twist per meter. The blade airfoil consists of: blade is provided with the necessary torsional stiffness. The skin plies
– a homogenous section comprising the DM-H4 airfoil up to on the upper and lower surfaces of the blade converge at the blade
trailing edge where they are squeezed together to complete a torsion
R = 4500 mm
box.
– a transition area between airfoil DM-H4 and airfoil DM-H3
between R = 4500 and R = 4800 mm
– the blade tip comprising the DM-H3 airfoil between R = 4800
and R = 5100 mm.

Blade Core
The hard-foam blade core provides the supporting structure for the
blade contour and stabilizes the blade skin.

Blade Spar
The blade spar consists of glassfiber rovings. They run from the blade
tip to the blade root, around the bushings in the blade fitting area, and
back to the tip. They absorb the tension and bending forces.

Lead Rod
The lead rod in the blade leading edge determines the required
position of the blade center of gravity (CG)in chordwise direction.

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2.9.5 Airfoil Section Training Manual

Main Rotor Blade - Airfoil Section

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2.9 Main Rotor System B1
2.9.6 Erosion Protection Training Manual

2.9.6 Erosion Protection Blade Tip Mass and Tuning Mass

An erosion protection is bonded on the entire length of the blade The blade tip mass increases the rotor inertia and stabilizes the rotor
leading edge. Between the blade tip and approx. the middle of the RPM (e. g. autorotation). The tuning mass changes the resonance
homogenous airfoil section, the erosion protection is composed of frequency of the rotor blade in order to stay clear of other main
nickel alloy or aluminum alloy on old-type blades. The surface of the frequencies in the rotor system.
aluminum alloy erosion protection is hardened. In the area adjacent to
the erosion protection, where there is less risk of erosion, an erosion Trim Tabs
protective tape (one or two parts) made of polyurethane (PU) is Two metal trim tabs and one FRP tab are bonded and, in addition,
integrated in the blade skin. A PU erosion protective film is bonded riveted to the trailing edge near the blade tip. The trim tabs enable the
on the paint coat covering the butt joints between parts of the erosion track of the main rotor blades to be adjusted so that they all fly in the
protection and the forward edge of the pitch control cuff. same tip path plane. Both metal trim tabs may be bent to make track
adjustments.
Balance Chamber
A balance chamber is incorporated in the main rotor blade near the Dynamic Balancing Washers
blade tip. Preliminary settings made in the balance chamber by the The balance washers for dynamic balancing are attached to the pitch
manufacturer ensure that the blades can be replaced individually. control cuff under a cover.
These presettings must not be changed by the customer.

Static Discharger
A static discharger is riveted to the blade trailing edge in the blade tip
area. It consists of an adapter, a threaded fitting and the discharger
rod. The static discharger enables the discharge of static electricity
from the helicopter. An electrical conducting strap is embedded in the
blade skin to electrically connect the static discharger to the bonding
jumper connecting point. The conducting strap runs along the erosion
protection from the static discharger to the pitch control cuff. A flexible
bonding jumper electrically connects the main rotor blade to the main
rotor hub-shaft.

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2.9.6 Erosion Protection Training Manual

Main Rotor Blade

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2.10 Main Rotor Blade P3 / T3 Version B1
2.9.6 Erosion Protection Training Manual

2.10 Main Rotor Blade P3 / T3 Version

General New Core and Impact Web

Basically the main rotor blade of the P3 / T3 Version is identically to Shape and size of foam core 6 and 7 has change to adapt the new
the P1 / T1 to PE / TE version from the blade root until blade station length and twist of the blade. To improve the skin impact stability at the
R4500. blade tip, a double–C impact web is integrated between foam core 6
and 7. The leading edge of foam core 7 is reinforced rovings.
Main Changes
The main changes are: Blade Tip Mass
– airfoil section lenght increased The new blade tip mass length is increased to 170 mm with a straight
shape and a weight of 1700 gr. Additonal retaining rovings are
– airfoil section twist change at R4500
integrated to keep the blade tip mass in position.
– airfoil section between R4500 to R5200 includes
– new foam cores and impact web Trim Tabs
– new blade tip mass To increase the effciency of the trim tabs, the installation position is
– trim tabs moved outboard moved 50 mm to the tip. The fixed trim tab is no longer installed.
– fixed trim tab removed

Airfoil Section
The airfoil section generates the main rotor blade lifting force. To
increase the efficency, the length of the airfoil section is increased by
100 mm. Between blade root and blade station R4500, the new blade
is identicall to the old blades.
At blade station R4500, the blade twist and the length is increased
with a parabolic sweep–back tip.
The Ni–Co erosion protection is elongated to new blade length.
There is no change in position, shape and size of the balancing
chamber.

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2.10 Main Rotor Blade P3 / T3 Version B1
Training Manual

Main Rotor Blade P3 / T3

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2.10 Main Rotor Blade P3 / T3 Version B1
2.9.6 Erosion Protection Training Manual

Lead Lag Dampers and Bearing Support

The lead-lag dampers are attached to the damper connection of the
pitch control cuff by screws installed through the bottom aluminum
plates. The top steel plates of the dampers are connected by nuts
to the ends of the bearing support, thereby connecting the lead-lag
dampers to each other through the bearing support. Both lead-lag
dampers are preloaded upon their connection to the bearing support.
This prevents tension loading of the elastomer material during control
inputs and blade flapping movements. Tension loads would greatly
reduce the service life of the lead-lag dampers.
The lead-lag dampers are installed tilted in relation to the rotor plane
due to the canted damper connection (see View V). This layout enables
a kinematic coupling to be obtained between the lead-lag motion and
the pitch angle of the main rotor blade. This coupling provides for a
large part of blade lead-lag damping during flight.
In the bearing support a spherical bearing is mounted which allows
pivoting and tilting movements. The bearing support together with the
lead-lag dampers support the open end of the pitch control cuff and
center it around the blade root.

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2.10 Main Rotor Blade P3 / T3 Version B1
Training Manual

Pitch Control Cuff and Blade Root

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2.10 Main Rotor Blade P3 / T3 Version B1
2.10.1 Rotor Blade Adjustments Training Manual

2.10.1 Rotor Blade Adjustments After the measurements on the rotor test stand weights can be shifted
forward and backward in order to achieve the master blade track
Manufacturer Adjustments level. The plastic spacers between the metallic weights allow a lateral
All four blades of the EC135 main rotor can be replaced individually. transfer of weight without influence on the longitudinal moment.
On a rotor test stand the deviation of the dynamic behaviour of the
master blade is detected and corrected. In order to stay within the Pretrack Value
manufacturer limits the following parameters have to be adjusted. For the first rotor blade adjustment the rotating pitch links normally
are set to a basic length. As a fine tuning towards the master blade
Longitudinal Moment (Static Spanwise Balancing) the basic length can be altered according the measurements on the
The longitudinal moment can be adjusted by changing weights in the rotor test stand. The pretrack value is a dimension in +/- [mm] for the
center of the balance chamber which is exactly in the center of gravity change of the basic pitch link length and is stamped on the respective
line the longitudinal axis. To determine the individual setting a special control cuff and the rotor blade log card. Thus the necessary flight
weighing equipment is necessary. time for the track and balance adjustment can be reduced.

♦ NOTE Any change of the longitudinal moment (e. g. ♦ NOTE Every time one or more rotor blades are replaced
application of paint in different radius stations of the pretrack value has to be adjusted at first, even
the rotor blade) will influence the blade behaviour for blade number 1 (yellow reference blade). For
significantly and abnormal vibrations can occur. any further track adjustment the pitch link length of
blade number 1 must not be changed.
Lateral Moment (Chordwise Balancing)
The lateral moment determines the lift and therefore the track level
of the rotor blade under different pitch angles. With the adjustment
of the lateral moment the characteristic of the master blade can be
transferred to all produced blades.
By shifting mass behind the longitudinal center of gravity line the
increase of the lateral moment creates more lift with a higher track
level and vice versa.When leaving the production line the balance
chamber normally is equipped with 12 weights (6 in front of, 6 behind
the center of gravity line). To harmonise production tolerances brass
or several combinations of brass and tungsten weights can be used.

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2.10.1 Rotor Blade Adjustments B1
Training Manual

Balance Chamber

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B1
Training Manual

INTENTIONALLy LEFT BLANK

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