Aileron Cables

Ailerons installed with slave struts

We have functional ailerons!  This past week, I got all the cables made and installed.

Ribs drilled for cables

One of the first things I had to do was figure out where to drill holes in the ribs for the cables to pass thru.  I took some careful measurement and used a string line to mark the capstrips, then projected these measurements up to the hole location.  

Fit-up cable

I then made some quick and dirty fit-up cables from some left over stainless cable and Nicopress sleeves.  These made sure I got the lengths right prior to making the good ones.

I've got a bunch of stainless cable that I use for this purpose only and don't use it for actual control cables.  Not only is it un-original (galvanized is original) in these vintage aircraft, but can break without the owner even being aware.  I teach an assembly and rigging class at Rock Valley College and we spend a lot of time on control cables.  Many folks think that they can put stainless cables in their aircraft and never worry about them again.  Unfortunately, there have been several commuter and airliner accidents caused by broken stainless cables.  These cables actually wear on the inside and cause internal strands to break due to the galling of the metal as the cable flexes.  These broken strands are invisible during inspection unless the tension is removed and the cable bent into a U-shape.  Galvanized cable, on the other hand, has natural lubricity due to the galvanizing that does not cause galling when flexed.  Yes, it will eventually rust, but will last many, many years.  So there you go - probably more than you ever cared to know about cable!!


Here are some misc. pictures of the final assembly

Lower aileron attachment

Lower aileron pulley

Balance cable attachment in upper wing

Upper aileron attachment

Attachment at control stick

Once I had the cables installed and tensioned, I realized I had to add a few things:  a couple of fairleads in several locations to make sure the cable does not contact anything in the wings, and some pulleys near the control stick.

Fairlead

Here's a pic of one of the fairleads I made.  Basically a tube welded to a bracket that attaches to the rib, with a split phenolic tube inserted and safety wired in place.

Pulley installed

 I'm still not quite sure how the cables were originally run so they did not contact any tubing in the fuselage.  Probably, there were some wear blocks taped or attached to the tubing, but I wasn't comfortable with this due to the change in cable angle.  So I welded in some brackets to attach pulleys.  This was just the ticket - no clearance issues and the whole system operates very smoothly.

You can see the pulley to the right in the picture just tack-welded in place.  I need to finish weld it after the wings are removed.

Next are the rudder cables, but need to make the floor first.  The rudder pedals are attached to the floor.  And (sob, sob) my break from school is done - I start classes again on Monday, which should be interesting.  We just moved into a newly built, 40,000 square foot facility on the west side of the Greater Rockford Airport. I'll be facing 40 new green-horns that will have that classic "deer in the headlights" look!