Systems Flashcards
What type of rotor system?
Starflex semi-rigid 3 bladed
Describe the MGB Modules?
1: epicyclic reduction gear
2: bevel gear
3: lubrication gear
Which engines are used?
B4: Arriel 2B1
T2: Arriel 2D
How tall is the rotor system?
10.96’
How long is the aircraft?
41.47’
How wide is the aircraft?
7.57’
What are the three datum references?
X is longitudinal
Y is lateral
Z is horizontal
How do the skids try to prevent ground resonance?
Mustache shape and three point fitting with elastomer bearings
How many suspension bars support the MGB?
4
Why does the MGB need suspension?
Due to rigid attachment to rotor
How is the MGB secured to the airframe?
4 rigid bars at the top of airframe
4 suspension bars at MGB
How are the MGB vibrations absorbed?
Laminated pads which are flexible in shear and stiff in compression
What’s the purpose of flex couplings?
To absorb small misalignments
Where is the MGB low pres switch?
Left side of MGB Mod 2
Where is the MGB chip switch?
- Drain plug on MGB mod 1 next to sight glass
2. Top of MGB
Where is the MGB temp switch?
Next to chip detector / sight glass / mod 1
What is the max / rec / company rotor brake speeds?
170 / 140 / 100
How is each blade identified?
Colored adhesive tape
When does the main rotor system require servicing?
Never
What is a starflex?
A rotor hub which is star shaped (3 arms) and flexible in flapping direction.
What’s the “heart” of the starflex?
Spherical Thrust Bearings
Describe a Spherical Thrust Bearing?
A bearing flexible in torsion, flapping and drag but rigid in compression.
What’s the purpose of a frequency adaptor?
In-plane dragwise dampening and rigidity. Dampening to limit oscillations and stiffness to adjust the natural frequency.
What absorbs the in-plane dragwise movements?
Frequency Adaptor
Can you misassemble a starflex hub?
No, every part is either identical or foolproofed.
Which trim tabs can be adjusted on the MR Blades?
Inner 2 tabs
How is the MR RPM acquired?
A magnetic rate sensor (phonetic sensor) placed in front of a slotted wheel (ring gear)
Which PCB processes the aural warning for RRPM?
PCB 1 in ASU
What’s the ASU?
Then ancillary system unit ensures helicopters electrical ancillary functions.
What functions are provided by the ASU?
Visual and Aural warnings, Nr signal for VEMD and EBCAU functions
What’s an EBCAU?
Engine Backup Control Ancillary Unit.
Provides back up engine management
What reduces cabin vibrations?
Cabin resonators
What’s a cabin resonator?
A series of weights attached to the cabin to counteract main rotor vibrations
How does the rotor hub vibration absorber work?
It uses a weight on a set of springs to counteract loads exerted on the rotor hub.
How many shafts make up the tail rotor drive shaft?
- Short, intermediate and rear shaft
What’s the tail rotor short shaft made out of and why?
Steel, due to exhaust heat.
How many couplings support the tail rotor shaft?
4 flex couplings
How is the tail rotor lubricated?
Splash lubrication
Which way should the tail rotor “mickey mouse ears” face?
Backwards / Aft
How are pedal inputs transferred to the tail rotor?
Flex ball cable
What degrees are the fenestron blades mounted?
45° / 32.5° / 25 °
What’s the TR RPM
3568 RPMs
What’s the purpose of the boss weights?
To generate a moment counteracting the blade zero pitch return moment so that the air foil is stabilized at a set pitch
What’s unique about the swashplate?
Uniball / Teflon design
Where is the starter/generator mounted?
Right side of engine on the bottom
When does the starter become a generator?
When it produces more than 0.5V difference to the busbar.
What type of servos are used?
Double rotary distributor design
Where are the servos anchored?
To the bell housing of the MGB
What’s the purpose of a double rotary distributor valve?
Prevents flight controls from being jammed if a valve seizes.
How does the double distributor valve work?
It leverages a locking spring, which when freed actuates a microswitch for notification of a failure and bypasses the main valve for continued operation.
Where is the limit sensor
Toward the top on the right side of the rotor system.
Why is the limit sensor on the right side?
It’s the point with the most flapping and this best indicator of load.
How much pressure is in the hydraulic system?
35 bar
How is the upper hydraulic system powered?
MGB
How is the lower hydraulic system powered?
V belt
When does the limit light come on?
Exceeding loading limits on rotor
Indicated failure of upper hydraulics
Cyclic outside 10-88° quadrant
When does the fuel filter light come on?
Fuel pressure at or below 0.7 bar
