How to take measurements for cables
We will cover two methods: (1) measure the original cable, and (2) measure the cable run.
If you are measuring the original cable, use the chart on the previous page as a guide.
You measure to the ends of threaded studs, and to the CL of any holes. The cable must be
straight, with no kinks, and taut, with about 12 pounds of pull.
You will also have to identify the ends. Turnbuckle studs come in two lengths, long and short.
The long studs mate with turnbuckle bodies that are 4 inches long, and the shorts use a body that is 2 1/2 inches long.
You will also have to identify the thread, Left Hand or Right Hand. If you are not sure about what you are looking
at, grab a bolt and hold it next to the stud thread. If the stud thread looks like the bolt, it is RH.
If it looks different (reversed or slopes the other way) it is a LH.
If you do not have the original cable, then you must measure the run. It is more work, but it will work.
You are going to run safety wire in place of the cable. If one end is to a turnbuckle body, then place the turnbuckle body
onto the mating cable and run it down until the last thread is just at the end of the body.
Secure your safety wire to the center hole in the body. Now string the safety wire in the cable run and secure it to whatever the cable attaches to.
Lets say it attaches to a rudder horn. Thread the wire thru to hole and pull it as tight as you can. Wrap it back on itself a few turns,
and the safety wire should now be installed just like the missing cable. Now you can release the wire by clipping it just where it wraps on itself,
and carefully remove. You can now measure this pseudo cable. The ends are going to be just where the wire makes a 90 degree turn.
When you lets us know the length, you MUST tell us how you measured the cable. If you used the safety wire routine, you MUST tell us
exactly what you attached the safety wire to as we will have to make adjustments to this length. Clearly, the turnbuckle stud should not
go to the center of the turnbuckle body, and the other end is a measurement to to edge of the hole, not the center.
A note about warbirds and cable charts:
You cannot presume that a cable chart in the maintenance manual is an accurate description of the cables in your aircraft.
Our experience has been that the charts are correct only about 50% of the time. You MUST verify the cable installed in the aircraft.
Link back to Cables page