Control Cables Flashcards
Control cables
Weight saving
Can be mended and routed any where
What is cable made off
Individual cable wire
Pre streghted from manufacture
The steel wires are twisted into strands and these are twisted into cables.
the wires are twisted in one direction and strands the opposite
What is a 7 x 7 cable
7 strains x 7 wires per strand
7 strains tired together, then 7 of them are tied together
What is the diameter of a 7 x 7 cable
3/32 inch
What is the diameter of a 7 x 19 cable
1/8
Cable tension
Due to temperature changes
Large aircraft have a complex automatic cable tensioning system to maintain tension relative as the aircraft expands and contracts due to ambient air temperatures.
Small aircraft cable tensions are set up as a compromise as they do not have this automatic system.
Check it is calibrated
Cable tensiometer is used ans adjusted via a turnbuckle
Fair leads
Fairleads are used to guide control cables to prevent contact with the aircraft structure.
Pressure seals
Where control cables pass through pressure bulkheads, pressure seals are used. The seals are filled with grease and allow the cable to pass freely whilst preventing the loss of pressurisation air.
Pulleys
Pulleys are used in control cable runs to effect a change in direction.
Guard pin stops from coming out
Gagging pin
Put in regulator to prevent it from moving
What is a turn buckle
mechanical screw device consisting of two threaded terminals and a threaded barrel. Turnbuckles are fitted in the cable assembly for the purpose of making minor adjustments in cable length and for adjusting cable tension
Never lubricated
Threads must be equally engaged
Locking
Clip type
When the tension is correctly adjusted, the two-piece clips are inserted into
a groove in the turnbuckle body and the terminal end on the cable. The two pieces are then clipped together through the hole in the barrel.
Compensation devices
A cable tension regulator is a mechanical device which, when fitted in a
cable system, allows the cables under all conditions of temperature change and structural deflection to take up and let out equally on each side of the circuit, thus maintaining uniform tension
Flexible remote cable systems
Manually operated from flight desk operating such things as trim tabs brake control vales engine controls
Can be bent
Types of cable and control method
Teleflex
Bowden
Teleflex
Cable
Pull and punch
Helix raped around cable engaging with gear teeth on control wheels
Can be left or right hand winding
Types of teleflex
DS 23/2 has a left hand flex winding
DS 380 has a right hand flex winding
DS 169330 has a left and flex winding , can be used in hot areas
End fitting single entry
Limited to 270 degrees of travel
Minimum of 40 degrees engagement at all times
Double entry unit
Greater travel can be made
Angles 90 , 120 or 180 travel angle
Anti torsion
Waisted
Prevent cable from twisting during operation
Straight lead unit
Support
Not suited for heavy load
Junction box
Used to reverse the direction of travel of the control cable
Branch a run control to operate two components
Sliding end fittings
Used in lieu of wheel units when it is not necessary to covert pull / push movement
End fittings
Guide tube in fork eye ball joint internal or existing threaded fitting
Attached my collet attachment or a spring and plug
Swivel joint
Installed where the rotery movement of the control lever at the receiving end dose not exceed 90
Consists of a ball and Scocket connection inside the housing
Distributed box
Cables to teleflex to screw jacks
Rotary to linear for trim tabs in conjunction with a torsion drive
Conduit connectors
Nipples types connector
Clamp connector
Similar to all-meal couplings but without and olive
Quick break unit
Various types installed in control systems
Facilitate the removal of components without disturbing the control
Bowden cables
Cable pull only Light loads Return via a spring Housed within a conduit Close coil wire Cotton braided Waterproof coating
Cable nipples
Brass nipples soldered or staged to cable
Spherical
Trunnions
Plain
End fittings are transmitting end of the cable
The rotate end passes through an adjustable stop
Spring loaded to return at either end
Adjustable stops
Remote end of cable passses through a plain stop
Hexagonal headed screw drilled to allow the cable to pass
Each screw is counter bound to receive the potential gap
Stop fitting to remote end of cable
Connectors
Cable connector -cant use with a conduit
Control connector - used for joining Bowen controls
