Airframe Flashcards
Length
42.45 ft (12.94 m) from main-rotor tip to the upper tip of the vertical stabilizer.
From nose to tail, the airframe is 35.86 ft (10.93 m)
Height
Top of the Starflex main-rotor hub is a half an inch shy of 11 ft tall (3.34 m)
Engine
Safran Turbomeca Arriel 2B1
- Free-turbine engine (clutchless drive) with integral freewheel
- Modular design
- Cooling system and externally fitted oil tank
- 847 shp Take-off
- 732 shp Max cont
Main Rotor Hub (MRH)
Starflex semi-rigid
Bearingless hub (laminated glass-resin star) without a drag damper
No grease nipples
Modular, fail-safe design
1 - Laminated spherical stop, - Thrust Bearing - which is flexible in torsion, flapping and drag but rigid in compression. It is the “heart” of the hub as it absorbs all the loads and displacements.
2 - Star arm (star made of “glass resin” laminate). Fabrics molded and oven-cured.
3 - Sleeves : Glass resin yarn roving.
4 - Elastomer blocks - Frequency Adaptor - distorting shearwise (in-plane dragwise damping and rigidity).
5 - Self-lubricating balljoint, centering the sleeve at the end of the star arm.
Main Rotor Blades
- Spar made of fiberglass roving
- Glass fabric skin and foam core
- Fail- safe design
Main Rotor Mast
- Removable subassemblies
- Mast casing attached by 4 suspension bars which “support” the helicopter
- Includes the servo actuators
Main Gearbox
- Modular design (3 Modules)
- Module 1 (Epicyclic Reduction Gear) Stationary Ring Gear, 5 Planet Gears, Sun Gear
- Module 2 Bevel Gear, Ring Gear
- Module 3 Lubricating Pump
- Attached by flexible bidirectional suspension
- Two reduction gear stages (1 bevel gear drive, 1 epicylic gear train)
- Pressure lubrication with oil cooling system
- Includes rotor brake and hydraulic pump drive
Structural Subassemblies
A FEW WORDS ABOUT THESE NEW MATERIALS
They are synthetic resins divided into 2 main classes:
- Thermoplastics which soften when heated and harden when cooled, e.g. polyamides (Nylon, Rilsan), polycarbonates, etc.
- Thermosetting resins which, under the combined action of heat and a hardener, hot-cure irreversibly to form a new product, e.g. epoxy resins, silicone, etc. Laminates and laminated honeycomb are reinforced plastics with very good mechanical strength properties. Laminated materials are produced from thermosetting resins and reinforcing materials (glass, carbon, graphite, boron or other fibers).
Tail Rotor
- Hingeless, greaseless seesaw rotor with glass roving spar
- Pitch change by spar twisting
- Fail-safe design
- Symmetrical
Tail Rotor Gearbox (TGB)
Angle reduction gear with splash lubrication
Tail Guard
Protects the ventral fin
Vertical Fins
Dorsal (upper)
Ventral (lower)
- In cruise flight, the asymmetric NACA airfoil of the dorsal fin generates an aerodynamic force that opposes the main rotor’s counter torque and thus reinforces the tail rotor thrust.
- In B3 version, a step on the RH side of the upper fin improve this phenomenon.
- The ventral fin has a symmetric NACA airfoil to stabilize the helicopter about its yaw axis.
Horizontal Stabilizer
An asymmetric NACA airfoil, set at negative angle to the horizontal datum; creates nose-up moment with a relative wind
Landing Gear
Supports the helicopter
Protects the airframe on landing
Damps out vibration when the helicopter is on the ground with the rotor spinning
The landing gear assembly comprises:
- front and rear cross tubes
- two skids
- two hydraulic shock absorbers
Flexible Steel Strip behind Skid
A flexible steel strip bent downwards behind the skid increases the landing gear stiffness and changes its natural frequency so that ground resonance can never occur.
