7.13 Controll Cabkes Flashcards
Kearney swager
Form of cold roll forging.
Engages the terminal onto the cable so that the terminal cannot be separated.
Cables up to 3/8 in diameter can be swaged.
Select the match pair of roll dies suited for the cable.
Over swaging will cause work hardening and may lead to embrittlement.
Never more than 4 passes.
Hydraulic/pneumatic press swaging
Quicker means of swaging.
Cable testing
Loaded to 60% of its breaking strength.
Load applied gradually for at least 3 minutes using a swaged terminal pull tester.
Nicopress
Uses a copper sleeve, mechanically pressed.
Extremely strong.
Witness marks used to ensure for any slippage.
Inspection of control cables
Recommend that an annual or 100-hour inspection of all control cables is performed for broken wire strands.
Any cable with one broken wire or strand in critical fatigue areas must be replaced.
Critical fatigue areas:
- any section where the cable is flexed, rubbed or worked
- any point within 12 inches of a swaged on fitting
- pulley, sleeve , fair-lead.
Close inspection must be made by passing a cloth over the area to snag on brocken wires.
Pulley inspection
Must be aligned.
Must be free to rotate through their full travel.
Inspection for :
- roughness
- sharp edges
- presence of FOD
Inspect bearings.
Fairleads
At any point where the cable is likely to contact the structure it is run through a fairlead.
Cable tensioning
Pre-stretch load i.a.w. Manual. Applied with steady speed for 5 mins.
Ambient temp is important
Tension evenly throughout the system.
Turnbuckles are locked by either wire locking, lock nuts or locking clips.
Cable tension measuring
A tensioner is used.
A tensioner has an accuracy of 98%
Uses arbitrary units.
Compensate for temperature
For long cables use an average of 2 or 3 readings.
Rigging pins, gust locks can be used I.a.w AMM
Bowden cables used for?
Engine controls, propeller pitch controls, throttle/power controls, landing gear emergency extensions.
Bowden cables
Pull only.
Movement of a cable inside a conduit.
What are the two most common materials used for construction of control cables
Carbon steel and stainless steel
Teleflex cable systems.
Can pull + push
Typical use might be a throttle lever.
Stronger than Bowden.
Can be moved incrementally and locked in position.
Chance of seizing due to FOD or freezing.
Inner cables are regularly removed, cleaned, lubricated.
Teleflex end fittings.
Single entry - has to have a wrap of at least 40 degrees.
Double entry - wrap of 180.
Most common area for damage is at bends.
Cables inspected annually
Always check foe full free movement.
