Cable Tracker

One of the more troublesome aspects of aviation electrical work is the
fact our wires are usually NOT color-coded. That means you can have a
bundle of twenty wires and before you can do any useful work you will
need to figure out which one of the twenty at the equipment rack is
the frayed one you've spotted behind the instrument panel.

How to do it? The good ol' fashioned way, which I described in an
article some time ago, is to use a continuity tester. That is, a
hunka wire long enough to run from here to there, a couple of
flashlight batteries, and a flashlight bulb. You know you've found
the correct lead when the bulb lights up. I even described a do-it-
yourself tester based on an old-style Navy flashlight.

Alas, while 3 volts ain't all that much, that's what you are
connecting to your wires when you use a continuity-check as I
described in my article. If you're dealing with a real mess, such as
a bundle of wires that have been chopped with an ax (!) ...you could
be connecting those 'unimportant' three volts to a meter-circuit that
blows it's top at two volts.

Whatcha REALLY want is a cable tracker.

A cable track is a little oscillator that puts a warbling TONE on the
wire under test, which you can then 'hear' by waving a matching
receiver at the other end of the wire.

Harbor Freight's gottem. Item #94181 about $20 US, probably less if
you can find a Sale. (But Santa brought me this one :-) I'll
probably do a little write-up, put it on my blog so you can see what
it looks like. But not this year.

Was it a good year? Of course it was; they're all good years. Some
are just better than others.

Time for my Ten O'Clock pills. I'll see you guys next year.

-R.S.Hoover

On Jan 1, 1:17*am, " wrote:
One of the more troublesome aspects of aviation electrical work is the
fact our wires are usually NOT color-coded. *That means you can have a
bundle of twenty wires and before you can do any useful work you will
need to figure out which one of the twenty at the equipment rack is
the frayed one you've spotted behind the instrument panel.

How to do it? *The good ol' fashioned way, which I described in an
article some time ago, is to use a continuity tester. *That is, a
hunka wire long enough to run from here to there, a couple of
flashlight batteries, and a flashlight bulb. *You know you've found
the correct lead when the bulb lights up. *I even described a do-it-
yourself tester based on an old-style Navy flashlight.

Alas, while 3 volts ain't all that much, that's what you are
connecting to your wires when you use a continuity-check as I
described in my article. *If you're dealing with a real mess, such as
a bundle of wires that have been chopped with an ax (!) ...you could
be connecting those 'unimportant' three volts to a meter-circuit that
blows it's top at two volts.

Whatcha REALLY want is a cable tracker.

A cable track is a little oscillator that puts a warbling TONE on the
wire under test, which you can then 'hear' by waving a matching
receiver at the other end of the wire.

Harbor Freight's gottem. *Item #94181 about $20 US, probably less if
you can find a Sale. *(But Santa brought me this one :-) *I'll
probably do a little write-up, put it on my blog so you can see what
it looks like. *But not this year.

Was it a good year? *Of course it was; they're all good years. *Some
are just better than others.

Time for my Ten O'Clock pills. *I'll see you guys next year.

-R.S.Hoover

I just put that on my list for my yearly Harbor Freight run on Friday.
Hope it's in stock.
Thanks
Karl

On Jan 1, 1:17*am, " wrote:
....you could
be connecting those 'unimportant' three volts to a meter-circuit that
blows it's top at two volts.

yep


A cable track is a little oscillator that puts a warbling TONE on the
wire under test, which you can then 'hear' by waving a matching
receiver at the other end of the wire.

good tip. thanks.

-R.S.Hoover

Mark

..
..
And it takes about 20% more time to do the wiring on a NEW airplane or a
COMPLETE REBUILD on an old one to get the good old aviation white wire
insulation and down to Staples for 9 marking pens; black, brown, red,
orange, yellow, green, blue, violet, and gray. (0, 1, 2, 3, 4, 5, 6, 7, 8,
and 9) Assign each wire in the aircraft a number in accordance with a
little thought about what the numbers really mean. With three digits you
can have about 800 wires, with four digits 8000. Above that, you are making
a 747.

Each wire starts off with a double stripe of the lead digit. Then one
stripe on the insulation for the second digit, and so on. FOr example, wire
#234 would start off with two thin red stripes around the circumference of
one end of the wire, then a single orange stripe, then a yellow stripe.
THen a CLEAR shrink sleeve around the whole "number". Repeat at the far
end.

Or, get yourself some colored shrink and do the whole job with about half
the time. Same drill, but this time the first digit is twice as wide as the
rest of them.

Jim

--
"It is the mark of an educated mind to be able to entertain a thought
without accepting it."
--Aristotle


wrote in message
...


One of the more troublesome aspects of aviation electrical work is the
fact our wires are usually NOT color-coded.

On Jan 1, 10:53*am, "RST Engineering" wrote:
.
.
And it takes about 20% more time to do the wiring on a NEW airplane or a
COMPLETE REBUILD on an old one . . . . .
-----------------------------------------------------------------------------------------------------

An along about there Mr. Newbie shakes his head and sez, "Well, I can't see any way that you'd EVER need to re-wire some of them ol' birds," with the clear implication that, as a new owner of an old airplane he is liable to be practiced upon by one of them CERTIFIED fellers who are the only ones ALLOWED to touch his antique battle-damaged warbird.

He's wrong, of course.

Here... lookit this. It's what's left of a 1943 grommet. ("What IS
this stuff?" he asks.) Usta be rubber. No, not Neoprene -- RUBBER.
Came from a big plantation in AFRICA, not Brazil. Sixty years ago.
Sixty years, tucked into a hole in an aluminum bracket of a war-bird.
( This was a coupla years ago.) The 'rubber' is harder than a bride's
biscuits -- you can't even dent it with your thumb-nail. It dried
out, cracked, vibrated loose and left a small bundle of wires to
vibrate against the aluminum bracket, which they did for Heaven knows
how many hours... before it wore through the insulation, shorted out
and set the insulation on fire. Lotsa sixty year old white smoke but
that was about it, plus welding the wire to the bracket and blowing
the breaker. And no, this thing right here in my hand is NOT the
original grommet, it's the one next to it... there were about six of
them, all in this condition.

But here's the Lesson that goes with this little billy-dew: Almost
every piece of rubber in the whole damn plane is in similar condition.

(And here's another lesson: Where are you going to find someone to
rewire it? Because with that attitude of yours it sure as hell ain't
going to be me -- nor by any one I know, least ways not at this
airport :-)

-R.S.Hoover

PS -- Nope, I'm not an A&E. But neither are about 90% of the people
maintaining America's airplanes, from Piper 'Cubs' to Boeing 747's.
What they are, are guys working 'under instruction,' meaning there's a
certified Someone, somewhere out there on the hangar floor.
Bucking rivets, pulling wire, assembling an engine, replacing a
tire... all that sorta work. But don't expect to find 'Am Pan' on the
back of his coveralls nor anyone passing out 1099-R's neither.

"RST Engineering" wrote in message
m...
.
.
And it takes about 20% more time to do the wiring on a NEW airplane or a
COMPLETE REBUILD on an old one to get the good old aviation white wire
insulation and down to Staples for 9 marking pens; black, brown, red,
orange, yellow, green, blue, violet, and gray. (0, 1, 2, 3, 4, 5, 6, 7,
8, and 9) Assign each wire in the aircraft a number in accordance with a
little thought about what the numbers really mean. With three digits you
can have about 800 wires, with four digits 8000. Above that, you are
making a 747.

Each wire starts off with a double stripe of the lead digit. Then one
stripe on the insulation for the second digit, and so on. FOr example,
wire #234 would start off with two thin red stripes around the
circumference of one end of the wire, then a single orange stripe, then a
yellow stripe. THen a CLEAR shrink sleeve around the whole "number".
Repeat at the far end.

And skip wire #233, or any with repeating last digits. Otherwise you end up
with red-red-orange-orange. You couldn't distinguish that from wire #322.

"RST Engineering" wrote in message
m...
.
.
And it takes about 20% more time to do the wiring on a NEW airplane or a
COMPLETE REBUILD on an old one to get the good old aviation white wire
insulation and down to Staples for 9 marking pens; black, brown, red,
orange, yellow, green, blue, violet, and gray. (0, 1, 2, 3, 4, 5, 6, 7,
8, and 9) Assign each wire in the aircraft a number in accordance with a
little thought about what the numbers really mean. With three digits you
can have about 800 wires, with four digits 8000. Above that, you are
making a 747.

Each wire starts off with a double stripe of the lead digit. Then one
stripe on the insulation for the second digit, and so on. FOr example,
wire #234 would start off with two thin red stripes around the
circumference of one end of the wire, then a single orange stripe, then a
yellow stripe. THen a CLEAR shrink sleeve around the whole "number".
Repeat at the far end.

Or, get yourself some colored shrink and do the whole job with about half
the time. Same drill, but this time the first digit is twice as wide as
the rest of them.

Jim

--
"It is the mark of an educated mind to be able to entertain a thought
without accepting it."
--Aristotle


I really like this idea, especially the colored heat shrink version which
works just as well with Telfon and Tefzel which did not acept stamped
numbers very well--even when I had a stamping machine available.

The marking pen is most usefull on Mil-W-5086 and the older (PVC) version of
Mil-W-16878; and should also be kept away from sunlight; but the colored
shrink tube "rocks"!

Peter

On Jan 1, 4:24*pm, "Peter Dohm" wrote:

I really like this idea, especially the colored heat shrink version
----------------------------------------------------------------------------

Do you know a good source of small quantities of the required colors?

Writing on white (or at least, light colored) Heat Shrink is a pretty
good way of identifying the lead.

-Bob

wrote in message ...
On Jan 1, 4:24 pm, "Peter Dohm" wrote:

I really like this idea, especially the colored heat shrink version
----------------------------------------------------------------------------

Do you know a good source of small quantities of the required colors?

Writing on white (or at least, light colored) Heat Shrink is a pretty
good way of identifying the lead.

-Bob


Harbor freight?

wrote in message
...
On Jan 1, 4:24 pm, "Peter Dohm" wrote:

I really like this idea, especially the colored heat shrink version
----------------------------------------------------------------------------

Do you know a good source of small quantities of the required colors?

Writing on white (or at least, light colored) Heat Shrink is a pretty
good way of identifying the lead.

-Bob


That's a fair question, and I admit that I haven't had occasion to buy this
sort of thing in about a decade. Locally, in Florida, I used to buy heat
shrink from Electronic Equipment Company, Vance Baldwin Electronics and
occasionally Deanco (if I recall the name correctly) in the Orlando area.

I did a Google search using the keywords: color coded heat shrink tube
http://www.google.com/search?hl=en&q...earch&aq=f&oq=
which gave a lot of results, but most provide only a few of the colors.

The most promising for very small quantities, meaning only a couple of four
foot sticks of each color and size, is
http://www.justradios.com/heatshrinktubing.html and they appear to be set up
for completely automated ordering on line with very economical shipping.
Interestingly, they also look good for large quantities and spools are
shipped free.

I was curious, and also gave a phone call to Cable Specialties. They sell
in a minimum of 100 foot packages, so you would need to purchase 1000 feet
of the same size in addition to the clear and extra black; which is more
than most hobbyists would consider at one time. However, they appear to be
an excellent value for "shop" quantities, and carry a wide variety of types
by Mil-Spec.

Of course, those numbered Brady Labels, with a sleeve of clear heat shrink,
are another old stand by--in addition to your suggestion of writing on light
colored heat shrink, and possibly placing a clear sleeve over the result.

But anything other than a stamping machine will make you crazy if you try to
follow the Mil-Spec, or Boeing, workmanship standards to break wires out of
the resulting bundles!

I hope this helps.

Peter