This article describes the process I went through
to replace the flying wires and turnbuckles on my Fly Baby in
July 2022. While this is about re-rigging an operational
aircraft, there's plenty of detail that'll help those who are
building their planes and need to rig it for the first time.
Before hieing off into the nuts and bolts of my re-rigging,
let's review some basics. Aviation cables come in two
basic varieties, galvanized and stainless steel.
Stainless is more resistant to corrosion, although in some
applications it isn't as strong.
Aviation cables are twisted (or "laid") using between seven
and 133 individual wires. Very thin wires are often
combined into sub-elements that are twisted together
first. If you see below, a 1x7 cable consists of
seven LARGE wires, wrapped around each other. For 7x19
wires, nineteen sets of wires are twisted together, then seven
of those subgroups are then wrapped around each other.
Years ago, when I was in the flying club operating N500F, we upgraded the front flying wires to 5/32". I thought that was a good idea; 5/32 1x19 cable is rated at 3300 pounds, vice the 2200 pounds the standard 1/8" 1x19 cable.
So, I bought 5/32" 1x19 stainless cable to make new flying
wires from, plus turnbuckles rated at 3300 pounds instead of
the standard 1600-pound units.
And...problems arose, as the picture at the right
shows. The 1x19 cable could not be bent in a tight
enough loop to form the eyes for attachment. I could not
get it to lie smoothly around the thimble, not without getting
Remember the descriptor for 1x19 cable:
"Non-flexible"? Yep, it was biting me in the tail.
When the group did the re-rigging of N500F with 5/32" cable
in the '80s, they must have used 7x19 cables. 7x19 5/32"
cables in stainless are rated at only 2400 pounds, vs. the
3300 pounds of 1x19.
So, I scaled back to 7x19 5/32" stainless cables for my
forward flying wires.
At this point, I was going to use two 5/32" cables and two 1/8" cables on the -80 shackle.
Being the cautious guy I am, I did another mockup of
the shackle area. And it STILL wasn't
The two pictures with the red backgrounds show sample
sections of the cable looped around the -61 and -80
shackle. See....they STILL don't lie
right. Notice on both how the cable loops are
riding up over each other. This is an obviously
source of stress and problems, so I wasn't willing to
As of this point, I decided to go with the stock
system: four 1/8" 1x19 cables on each shackle.
The image on the right is interesting...it shows one
wing's shackle and cables that I removed from the
aircraft this summer. Four 1/8" cables and
thimbles DID fit on the shackle!
...but it is the -61 shackle, not the -80
shackle. And not the arrow, showing where the
stress on the cable actually bent it a bit. Not
a nominal situation.
So...the decision is made: Rig the airplane
dead stock, with 1/8" 1x19 cables.
The decision did relieve one other aspect.
Turnbuckles to go with 1/8" cable have a fork that takes
3/16" clevis pins, those for 5/16" cable take a 1/4"
clevis pins. So, just drill the holes in my anchor
plates to 1/4"?
No can do, amigo. The centerpoint of holes must be
at least twice the diameter of the hole from the edge of
the metal. And my anchor plates were drilled for
3/16" holes, with the edge margin to match.
Going to a 5/32" cable setup would have required new
anchor plates, at least in the front. I toyed with
this, thinking I could upgrade the plates to 0.125" steel
vs. the stock 0.090". As it happens, my old
horizontal/vertical bandsaw (bought about 40 years ago)
can't handle 0.125" 4130 steel. Finally decided to
use the stock plates.
Yeah, but my plates were drilled for THREE
turnbuckles. Wouldn't it look funny leaving one spot
I'm the fourth owner of my Fly Baby, and the previous
builder had done the three-turnbuckle conversion.
When I bought the plane, he gave me the OLD plates he had
removed. I rummaged through my drawer of old Fly
Baby stuff and found the old plates.
Clean 'em off, repaint, and reuse. While I was at
it, I did the same to the aft plates as well.
Selecting turnbuckles was interesting. Earlier this year, when I had been planning to use 5/32" cables, I needed turnbuckles to match. This, normally, would have meant buying AN130-32S turnbuckles, rated at 3200 pounds, instead of the -16S turnbuckles on the stock bird. However, I hate wrapping safety wire around turnbuckles. I decided to use the MS2125X series turnbuckles, which use a small clip to safety, instead.
A small issue arose. The stock wing-bracing cables
on a Fly Baby are 1/8" 1x7, which are rated at 2100
pounds. However, the stock turnbuckles are
AN130-16S...which are rated at 1600 pounds, about 20%
less. I wanted turnbuckles to more-closely match the
rating of the cables.
For AN turnbuckles, this is impossible...you've got 1600
pound units, and 3200 pound units, and nothing in
between. Besides, as I mentioned in the last
section, the bigger turnbuckles would have required
brand-new anchor plates.
But...the MS series has a magical alternative. They
sell a fork end, rated at 2400 pounds, that uses a 3/16"
clevis pin AND is compatible with the -5 body (3200
One drawback of the MS series turnbuckles is that there
are not designation for "standard configuration"
turnbuckles. An AN130 turnbuckle has one fork end
and one cable end, and there's no equivalent designation
in the MS series. You have to order the specific
components to assemble your turnbuckle. Here's the
Now, here is where it gets fun.
Remember a few sections back, where I said it was
practically impossible to form cable eyes in the 5/32" 1x7
Turns out to be very difficult to form the eyes in 1/8"
1x19 cable, too. At least, just using your hands,
you can't form the cable tight enough to wrap around a
What the Sam Hill?
The obvious alternative is to use 7x19 cable
instead. It can easily form the eyes.
Biggest problem is strength. The 1x19 cable is
rated at 2100 pounds, the 7x19 cable at 1760 pounds.
Plus, the 7x19 cable is a bit stretchier...obviously not
the best solution for wing bracing. Pete even says,
"Control cable has considerable stretch to it and should
not be used for wing bracing." (Plans, Chapter 9, page
9-2/9-3 depending on version).
Yet Pete blithely specifies 1x19, with NO mention of how
to form the eyes.
Why? Because I think Pete had an easier time with
it, due to the availability of a specialized tool.
Pete lived most of his life in Seattle, a maritime town if
there ever was one. There was a specialized tool for
ship rigging, that would grip the cable and squeeze it
down to form the eye.
I was offered the loan of such a tool. Probably
would have made it easier. But, instead, I solicited
advice from various folks and used their information to
form the cable eyes.
First step was to form the cable eye that would include
the eye end for the turnbuckle. These eyes would
The basic solution required a vice and a "push
stick." I clamped the nicopress swage in the vice,
and tightened it down just enough to hold the nicopress
sleeve firmly without compressing it. Then, the
cable is led through the sleeve, a big eye is formed, the
thimble and turnbuckle cable eye is inserted. Then
grab the free end of the cable with one hand, pull like
crazy, and push the loop end of the cable with the push
stick until the thimble bottoms out on the sleeve.
Now comes the second-to-last act: Forming the
loop that goes over the shackle. At this
point, of course, the cable has to be at the exact
length (given the turnbuckle's ability to adjust for
One thing working in my favor was my decision to
not include thimbles on the shackle end. A
1/8" cable loop on its own will slide on over the
open end of the shackle, but a cable loop with a
thimble is too wide. So I didn't have to
continually attach more and more loops to the
shackle, and haul around the whole assembly for test
fitting. The cables could be done
individually, and slipped onto the shackle at the
So, how do you determine how long each cable has to be? I used a pretty simple system: I took a length of 20 gauge electrical wire, and crimped a 3/16" terminal on one end. Used a clevis pin to hold it to the anchor plate, drew the wire to the axle, passed one end down through it, pulled it tight, then twisted the wire around itself to form the approximate loop.
Before safetying the turnbuckles, I
needed to get the turnbuckles adjusted
so that both wings were at about the
First step was to adjust the landing
wires (the ones on TOP) of the wing so
that both wings had the same dihedral
angle. Simplest way of doing that,
I felt, was to pick a reference point on
both wingtips and adjust the landing
wires so that the two reference points
were the same height above the floor.
The MS series turnbuckles have grooves on the inside threads on the body, with matching grooves on the exterior threads of the turnbuckle ends.
Took the plane on a brief "crow hop" after the work
was done. Back to the hangar for a thorough
inspection, then take off for a single trip around
the pattern. Inspection, still no issues
Flew for a couple more hours, and realized the
plane was slightly right-wing-heavy. Undid the
safety clips for the aft turnbuckles on the right
wing, tightened the turnbuckles one and a half
turns, then re-safetied them. Perfect balance,