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!

Cable Splices

Got a good start on making cables today.  All the splices are the wrapped and soldered style.  Started out making a couple of practice ones first.  As I mentioned in a previous post, they don't conform to any standards I've seen, but decided to make them like the original ones anyway - that was how the airplane was type-certificated.  I was a little concerned how easy they would be to make.  2 strands of wire are looped through the thimble, then all 4 ends wrapped around the cable simultaneously.  I wasn't sure how easy it would be to keep all 4 strands tight and nested without criss-crossing them, but it actually turned out to be  easier than what it may seem.

The elevator cables are made from 1/8" 1X19 and the rest from 1/8" 7X19.  This is a drawing to show how they were made.

Here's a sequence of pictures and a description of the process.

 This is what you'll need:

• A fixture to hold the cable and thimble (easy to make if you don't have one)
• Cable cutter
• Heavy-duty soldering iron
• .035" galvanized wire to wrap the cable
• Non-acid liquid soldering flux
• 1/8", 50/50 solder

 The cable I used had a lot of grease in it from the manufacturing process that "cooked" out when heated with the soldering iron.  I made this tube that is filled with lacquer thinner to clean the ends.  Worked good, although it looks like a stick of TNT!

 To begin, the cable and thimble is put into the fixture.  I used the vise grip with rubber tubing over the jaws to pinch the cable tightly to the thimble as I started wrapping.

Note:  typically, the little tangs on the end of the thimble are bent up prior to wrapping.  The original cables did not have these tangs bent up, which is how I made them.

This is how the wrapping starts.  2 strands looped thru the thimble, then all 4 strands laying side-by-side and wrapped tightly around the 2 cables. 

Sorry for the picture being out of focus...

 Wrapping continues up to the first inspection gap - a gap in the wrapping about 1/8" wide that allows the cable to be visually inspected for slipping.  These cables have 2 inspection gaps about 1 3/4" apart.

 Here you can see the wrap is nearly complete with 2 inspection gaps.  In this photo I'm trimming the end at an angle to allow the wrap to gradually taper down.  It worked easier to make this cut now than at the beginning - I could make sure the length was right, and that the taper was in the correct direction.  I used a cut-off wheel, but notice I put in a piece of scrap steel to keep from nicking the good side of the cable.

 Here it is, ready to be soldered which is actually the easiest part.  You'll need a big, heavy-duty soldering iron.  I believe mine is 150 watts, which is about perfect.  I work from inspection gap to inspection gap.  Start by brushing on the flux, heat the area, and apply the solder.  The solder flows nicely once everything gets heated up.  It will look kind of nasty at first, some of the oils from the cable will still leach out.  Just take a cloth and wipe it while it is still hot, and it will make it all bright and shiny.  I highly recommend using nothing more than a soldering iron, i.e. no torch.  You don't want to heat the cable up to the point that it will weaken it.

Once completed, scrub it with soap and water to clean off any remaining flux.






Voila!  Here's a finished one (top) with an original on the bottom.

I had to make 4 elevator cables.  Lincoln-Page doubled them up: 2 on the top of the bell crank and 2 on the bottom.  Still need to make the rudder cables (2 that go back to the rudder, and a couple of balance cables) then the ones for the ailerons (3, one to each lower aileron and a long balance cable in the upper wing).

More to come....

August 4 Update - Lots of Misc. Stuff

This being my first post since EAA, I hope everyone that went had a nice time.  We did, although the weather was a little hotter than I like, but most people I talked to were not complaining.  

The Travel Air I flew up from the Kelch Museum got a lot of attention.  It was featured Monday during the Vintage in Review, and then we were interviewed for a future article in Vintage Magazine.  Great exposure for the museum.

We also trained about 600 people on how to hand-prop an airplane.  A workshop we performed twice a day near the Red Barn in the Vintage area.

Once back home, I didn't waste any time getting back in the shop.  I have a couple weeks off yet before I have to be back in school, so I wanted to take advantage of this time.  As the title of this post reads - I got a lot of misc. stuff done:

Magneto Switch

Original magneto switch out of the airplane

This is the original magneto switch out of the airplane that I finally finished.  The switch was fine, just needed cleaning and paint, but the handle was cracked and unusable.  The switch is a Clum - the same used in Model T's although the Model T handle is different.  So I took a Model T handle, added some brass in places and machined it to look like the original.  I then had it nickel plated.  Very happy with how it came out!  Note it only has "OFF" and "ON" - the Curtiss OX-5 is a single magneto engine.





Tail Surfaces

Forming new elevator trailing edge

Aligning ribs and attaching trailing edge

 I thought (or at least hoped) little was going to be required with the tail surfaces.  Closer examination showed the trailing edges had enough corrosion to warrant replacing, plus they weren't very straight.  What bugged me the most, though, was the rib alignment between the horizontal stab and elevator.  They were installed rather haphazardly and crooked as well.  I typically don't like to alter "factory" things like this for authenticity and originality, but I worked so hard with the wings, etc to have everything straight and lined up, that I just couldn't let this go.  That meant cutting welds on ribs and lining everything up with a large square.  It all came out great in the end, just a lot more work than I originally thought.

The new trailing edges were also worth the extra effort.  They are now all very straight and symmetrical.  Plus, the 4130 tubing will be stronger than the original mild steel tubing that was used.

Aligning new trailing edge on rudder

Tail surfaces all finished and mounted for check of fit

Pitch trim control

Misc. Controls

While I had the horizontal stab on, I wanted to check fit and function of the trim.  The pitch trim is a rather heavy-duty set of controls.  It has a ratcheting lever in the rear cockpit, with a push/pull tube that mounts to a bell crank type lever that pushes the leading edge of the stab up or down to change trim.  This picture shows it mounted (prior to restoration) to make sure everything worked properly - which it did.

Trim mounting on horizontal stab

Rudder pedals and throttle levers

I also got out the rudder pedals as I will need those installed to make/run control cables.  Here you can see all the bits and pieces as well as the throttle levers.  As you an see, the airplane is meant for a one-legged pilot.  (OK, that's a bad joke.  Actually one is missing and I'll have to make it).  They don't get much simpler - just some round tubing welded together and no brakes.






Aileron Slave Struts

Completed slave strut

 And finally, I got the slave struts done.  They really weren't that difficult to make, but I had to wait for the AN 665 terminals I ordered to arrive.  The pictures pretty much tell the story.

Upper end

Lower, adjustable end

Shown mounted to aileron

What's next on the old agenda?  Well, it's time to start making all the control cables.  You can refer to my previous post as I talk about how they were originally made.  They will all be wrapped and soldered splices, but I am going to do them the "Lincoln-Page" way.  This method does not conform to any standard such as in CAM 18, but that was how the airplane was originally type-certificated.  Stay tuned, all this should be in my next post...