6:10 Control Cables Flashcards
What is the main advantage of control cables over other mechanical means such as actuators or shafts and chains
Weight saving
Is handling, checking and adjusting control cables easy or hard
Relatively easy
In aircraft construction what is the minimum tensile strength for individual cables
1200nm squared at a breaking elongation of 2-7%
How are cables made up (3 step)
Wires-strands-cables
How are the wires and strands twisted
The the wires are twisted one way and the strands another
What are non flexible cables normally used for
Purposes such as drag or anti drag wires or bracing
When would extra flexible cables be used
Over primary flight controls or when the operation over w pulley is frequent
How would you check the tension of large aircraft cables
By using a tensiometer
How are end connections attached to cables
By swaging
What are the different cable terminal types
- Ball (single or double shank)
- Stud end
- Fork end
- Eye end
What are fairleads
Fairleads are used to guide control cables to prevent contact with the aircraft structure
What are pressure seals
Pressure seals are like fairleads but are used when a cable passes through a pressure bulkhead
What is the purpose of pulleys
Pulleys are used in cable runs to effect a change in direction
What is the purpose of a turnbuckle
Turnbuckles are a mechanical screw device. They are used in cable control runs to make minor adjustments to cable length or cable tension
What type of threads do turnbuckles have
One end has a right hand thread and the other has a left hand thread
What ways can turnbuckles be locked
Normally a clip type lock is used
What is a cable tension regulator
A mechanical device used in aircraft to maintain cable tension even through changes in temperature
What must be done to cable tension regulators when they need to be disconnected from cable runs
They must be locked or snubbed (can be very dangerous if they are not
What is the major advantage of cable and conduit over other methods
Relatively light and installation is simple
What are two examples of cable and conduit control run
Teleflex and Bowden
What type of transmissions can teleflex cables operate
Push and pull
When are sliding end fittings used
Where it is not necessary to convert a pull-push movement in to a rotary movement
What is used to take up angular movement in control runs
Swivel joints
What is the rotary travel limited to in a single entry unit and what what angle of engagement must be maintained between the gear wheel and the teeth of the cable
Limited to 270° and a minimum of 40° of engagement
Why would a double entry unit be required over a single entry unit
When a greater amount of travel is required
When would swivel joints be installed
Where rotary movement of the control lever at the receiving end does not exceed 90°
What is the purpose of quick break units
They are installed in control runs to facilitate the removal of a component with out disturbing the run
What must rigid conduit be
Clean, free from dents and deformation and reasonably straight
Can damage to rigid conduit be repaired
It can be repaired by inserting a new length of conduit and by using a connector to connect both ends together
When tightening a nipple type connector why should two spanner’s be used
To prevent damaging the conduit
How do Bowden cable runs operate
They operate as pull only and the return is acted by a spring
What is the purpose of a junction box
A junction box is used to connect a single cable to two others where two components are to be operated by a single control
What is the minimum bend radius for Bowden cable conduit
12x diameter of the conduit
If a Bowden conduit is damaged must it be renewed or can it be repaired
It must be replaced
For Bowden controls longer than 2ft, how often should the run be supported
Every 12 inches
What must a Bowden cable be lubricated with
Graphited synthetic grease applied at room temperature (60-70°f)
