I was looking for a small flexible piece of tubing to run servo wires through and I think I found it..

It's drinking straws.. Not just any straw will do.. The Double Big Gulp straw from 7-11 will do the trick..
They are 13" log and 5/16 OD.. When did straws get so big?

I like the straws for wiring tubes.. they are small enough to fit through most places in a wing.
Flexible so they will make mild turns and twists..

For this setup the tubes twist under and around one of the wing spars.. Try that with paper or cardboard tubes.

So on to the howto..

I needed about 15" tubes so I had to put 2 straws together..

It's an easy trick.. Just flair one straw with whatever you have laying around.. A punch did the job in this case.. Be ready to put the straws together quickly as it will shrink back to it's original shape fast.

Once they are in it holds together quite well.

After the straws were put together I used a forstner bit to drill holes in the ribs and run the tubes through..

Now for the wires.. remove the plug from one end of the servo lead, run them through the tubes and re-install the plugs.

That's all..