6.10 Flashcards
What’s 6 advantages of cables ?
- Strong
- Light weight
- Flexible
- High mechanical efficiency
- Can be setup without backlash
- Vibration doesn’t effect cables
3 disadvantages of cables ?
- Tension must be adjusted regularly
- Prone to wear at points of contact ( pulleys etc )
- Tension varies with temp changes
Whats the construction process of a cable ?
Number of wires braided together forming a strand, number of strands are braided together to form a cable
Whats an opposite direction twist called ?
Regular lay - twisting wire and strands in opposite directions reduces the cables tendency to uncoil
( cables either have left or right regular lay )
What “lay” is it called if you twist the stands around the central core ?
Lang lay
Whats the 4 common types of steel cable used for aircraft ?
- Non flexible 1x7
- Non flexible 1x19
- Flexible 7x7
- Extra flexible 7x19
How many wires and strands are the non flexible 1x7 cable made from ?
1 strand and 7 wires
Where are non flexible cables only aloud to be used ?
Straight runs where the cable doesn’t pass over any pulleys.
Where are flexible cables used ?
Straight runs, or where large pulleys are being used.
Where are extra flexible cables used ?
Used where cables must change direction over small diameter pulleys ( flight controls / trim systems )
Whats the 4 cable end fittings ?
- Terminals
- Thimbles
- Bushings
- Shackles
Whats the 4 types of terminal fittings ?
- Threaded
- Fork ends
- Eye ends
- Single/double shank ball ends
What 3 terminals are used to connect a cable to a turnbuckle and bell cranks ?
Threaded
Fork
Eye
What are the ball terminals used to attach cables to ?
Quadrants
Where are the single shank and double shank ball ends used ?
Single shank - end of cable
Double shank - end of cable or in centre of cable run
Why would you use lock clad cables ?
To eliminate sagging and wear in long cables.
Whats a lock clad cable made up of ?
Swaged aluminium tubing around steel cable
What does the swaged aluminium tubing on lock clad cables do ?
Prevents abrasion of outer wire when pain through bulkheads / other obstructions in the aircraft.
Whats a turnbuckle ?
Mechanical screw device which can make minor adjustments I cable length and tension
How can the left hand thread side of turn buckle be identified ?
Has a groove at end
When screwing turnbuckle onto cable, how many threads should be left exposed at either side of the turn buckle ?
Not more than 3 threads
Whats the two ways of locking a turnbuckle ?
- Lock wire
- Special clips
Why is a cable tension regulator used ?
When the cable tension changes due to expansion and contraction of the aircraft’s structure and cables I flight.
Why are pulleys used ?
To guide cables and change their direction.
( pulleys require no further lubrication during use )
Why must pulleys have guards ?
To prevent cable jumping out of the grooves when there is lack in the cable
When should you use a fair lead ?
When there is a possibility of the cable contacting the aircraft’s structure.
Why are control rods used ?
Used in flight control systems to give push pull motion.
What can happen to control rods which are fitted with a bearing ?
Can become loose or disconnected due to failure of swaging that retains ball races.
What can happen if there is wear where the bell crank connects to the control rod ?
Cause a delay in response to the system it is connecting to.
Where is a torque tube used ?
Where there is a twisting motion in a control system.
Whats the two most common flexible control systems ?
- Bowden cables
- Teleflex control cables
What do small light aircraft use Bowden cables for ?
Throttle or fuel mixture control
What could cause Bowden cables to fail to function smoothly ?
If water or contaminants enter housing
What controls on modern day aircraft do teleflex cables operate ?
- Engine controls
- Propeller controls
- Trimming controls
Whats the 3 types of teleflex cables ?
- DS 23/2
- DS 380
- DS 169330
Where is a sliding end fitting used ?
Where there is no need to convert the push-pull movement of the cable to rotary.
When do you use a quick break unit ?
To facilitate the removal of components without disturbing the control.
