Tail Rotor Flashcards
How is torque transmitted to the tail rotor?
3 Connected drive shafts and a gear box
1. Steel fwd drive shaft
2. Aluminum intermediate drive shaft (long)
3. Aluminum read drive shaft (short)
Why is the first TR drive shaft segment steel instead of aluminum?
to provide resistance to heat due to be located underneath the engine exhaust
What connects the segments of the TR drive shaft?
Flexible Thomas couplings
How many bearings support the intermediate drive shaft?
5 bearings
Bearing 1 is rigid to provide alignment and optimal axial vibration
Bearings 2-5 suport the center shaft and absorb vibrations. These are grease lubricated
Why is the diameter larger on the read TR drive shaft?
To increase efficient dynamic characteristics
What are the TR hover limits?
T2 ONLY
5 min hover limit:
1) OAT > 35C
2) Relative right xwind component (45-135degs)
3) 5kts or more
In order to precent overheating of fixed bearings of second drive shaft
Composition of the TR gearbox
- 2 Modules: Power and Control
- Torque transmitted from flex ball cable to TR control rod and gearbox lever
- 90deg Spiral Bevel Gear with one stage speed reduction
- Splash Lubricated
- Air cooled
- 1 chip detector
What component facilitates reotation of the fenestron body and movement in/out for pitch change?
The splined flange fixed to the hub
What is the pitch change spider?
- Mounted to the back side of the hub
- Changes pitch equally in all blades via swivel pins
- blades attached via tension/torsion straps
What do the ring weight do?
Reduce yaw loads by balancing the return moment of the blades ot the flat neutral position during a power failure
Is the fenestron hydraulically boosted?
No
Input control by flex ball cable and rod only
How many blades are in the fenestron?
10 asymmetrically spaced Aluminum blades
What are the fenestron blades made of?
Aluminum
What is the diameter of the fenestron?
39.37 inches
What is the weight will all blades installed?
18.69 lbs
