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nuckollsr(at)cox.net
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 Posted: Fri Jan 19, 2007 8:24 am Post subject: Starting points redux |
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Here's a reprint on a reply I crafted for a builder some years
ago dealing with some of the issues faced by a neophyte builder
in coming to grips with a new task . . . configure and fabricate
an aircraft electrical system.
------------------****************-------------------
At 05:44 PM 10/27/2002 -0500, you wrote
| Quote: | Thanks for your reply and I do appreciate the time you have
spent.
|
No problem. It's what I do . . .
| Quote: | *IF* I knew anything about this subject I wouldn't have asked
for help with *specifics*. I don't have the time to experiment
and see who is right (or wrong). You are generally regarded as
a guru in your discipline and I had hoped there would be a
"reasonable, definitive and irrefutable answer", Since I have
not been shown anything (by anyone), I guess I need to choose
what seems to be the safest course of direction.
I am not trying to argue or diminish your knowledge on the
subject in any form or fashion. I simply need a document that
will be an accurate guide and keep me out of trouble. The 43-13
is generally regarded as the "accepted" methodology, not
withstanding an heretofore unseen document that would supersede
the 43-13 handbook.
You mention that you could sit down and write some. Let me
tell you that would be welcomed with open arms throughout
the experimental community. I have read a lot of what you
have wrote and it makes a lot of sense. A document about
wiring in an vibrating environment would be a great asset
to our community. "To Solder or Not to Solder". <g>
|
----------------------------------------------------------------
Okay. Here are the "rules" by which Bob Nuckolls would
wire his own airplane:
----------------------------------------------------------------
RULE 1: First choice for joining/terminating any wires up
through 22 through 12AWG are PIDG style terminals as described in
http://www.aeroelectric.com/articles/terminal.pdf
using tools like
http://www.aeroelectric.com/Catalog/tools/tools.html#rct-1
or better.
---------------------------
RULE 2: Where there is a choice, I would select fast-ons over
threaded fasteners in the 22 to 12 AWG range using
terminals like
http://www.aeroelectric.com/Catalog/wiring/wiring.html#faston
with features as explained in
http://www.aeroelectric.com/articles/faston3.pdf
---------------------------
RULE 3: When I have to live with a treaded fastener then
these terminals are in order . . .
http://www.aeroelectric.com/Catalog/wiring/wiring.html#s816p
----------------------------
RULE 4: For wires larger than 12AWG, then I would solder and heatshrink
joints as described in . .
http://www.aeroelectric.com/articles/big_term.pdf
Using materials like . . .
http://www.aeroelectric.com/Catalog/wiring/s812.jpg
which are supplied with double-wall heatshrink for finishing.
-------------------------------
RULE 5A: Permanent splicing of single conductors to be accomplished
with butt splices like . . .
http://www.aeroelectric.com/Catalog/wiring/s816.jpg
-------------------------------
RULE 5B: but if it was deemed desirable to break the
splice open for future convenience, a knife splice and heat
shrink would be used thusly . . .
http://www.aeroelectric.com/Catalog/wiring/ksplc2.jpg
-------------------------------
RULE 6: When the accessory items are supplied with
nylon connectors like AMP Mate-n-Lock or Molex, pins
are installed with a tool like . . .
http://www.aeroelectric.com/Catalog/tools/tools.html#bct-1
used thusly . . .
http://216.55.140.222/articles/matenlok/matenlok.html
These connectors would only be used as an accommodation
for the use of an accessory that comes with them already
installed. They are not my connector style of choice for any
other applications.
------------------------------------
RULE 7A: When working with accessories supplied with
D-sub connectors, the first choice of mating connectors
is the removable pin variety that will accept machined
pins like . .
http://www.aeroelectric.com/Catalog/connect/connect.html#S604
installed with a tool like
http://www.aeroelectric.com/Catalog/tools/tools.html#rct-3
and removed with a tool like . . .
http://www.aeroelectric.com/Catalog/tools/tools.html#dse-1
---------------------------------------
RULE 7B: if for any reason the crimped-pin mating d-sub is
not available, then soldering is my second choice using
techniques described in . . .
http://www.aeroelectric.com/articles/dsubs/d_solder.html
and tools like
http://www.aeroelectric.com/Catalog/tools/tools.html#s101_1
or better
-----------------------------------------
RULE 7C: If options 7A and 7B are not practical, then the
lowest order choice for working with d-subs is open barrel
crimped pins installed with a tools and techniques like
those described in RULE 6.
-----------------------------------------
RULE 8: Installation of connectors on coaxial cables to
antennas are installed per
http://www.aeroelectric.com/articles/bnccrimp.pdf
using tool . .
http://www.aeroelectric.com/Catalog/tools/tools.html#rct-2
and wire . . .
http://www.aeroelectric.com/Catalog/antenna/antenna.html#rg-400
and connectors . . .
http://www.aeroelectric.com/Catalog/antenna/antenna.html
-------------------------------------------
RULE 9: A single point ground system shall be established behind
the instrument panel with sufficient attach points for all
accessories in the cockpit area. In deference to RULE 2,
a forest-of-fast-on-tabs ground block similar to . . .
http://www.aeroelectric.com/Catalog/wiring/wiring.html#gndblk
The threaded stud on the ground block assembly would penetrate
the firewall and be used to terminate battery (-) leads on
either side of firewall and the crankcase ground strap on
the engine side of the firewall.
In the case of canard pushers with the battery up front,
the ground bus would be mounted forward of the instrument
panel. If the airplane's firewall is metalic, then a
brass bolt and appropriate washers and nuts would be used
to provide an engine compartment ground stud and connection
of the ground lead to the firewall. A ground strap like . . .
http://www.aeroelectric.com/Catalog/wiring/wiring.html#bbs
. . . will be used to connect the crankcase to the firewall
ground stud.
Any ground straps provided around the rubber biscuits of
an engine mount will be removed. Engine mounts are for holding
engines on airplanes and not use for any part of the electrical
system.
-------------------------------------------
RULE 10: Tefzel wire used throughout with the exception of
cranking circuit fat wires where 4AWG or 2AWG welding cable
would be used. An alternative FAT wire could be one of the
new copper-clad aluminum wires. These new materials are as
solderable and crimpable as pure copper conductors.
Caution
To get the same electrical performance, you need to use about
2AWG steps larger wire than for copper but the installed wire
will still be lighter.
-------------------------------------------------------------------
Here endeth the reading of the rules. In parallel universes
there are differing rules which may well prove to be as useful
or perhaps even better than those cited in Bob's universe.
Given what Bob has learned up to and including Sunday,
October 27, 2003 the rules cited above are his personal
choices for practical, solid techniques using moderately
priced materials, and tools. Adherence to these rules is likely
to produce an electrical system where (1) component wear-out
and failure are the sole causes for maintenance and
(2) the wiring can be expected to perform as intended over
the lifetime of the airplane.
-------------------------------------------------------------------
| Quote: | Here is how I perceive the question, "When can you use solder on
a #2 wire?" Answer, "Well, that depends!". I can't deal with that
kind of an answer. Unfortunately that is all I have been getting
from our canard community rank and file.
|
Yes, it does depend . . . on only one thing. Whether or
not YOU want to solder wires. If any of the rank and file
disagree with this, please invite them to bring the facts
as they perceive them over to the AeroElectric-List. If
I'm unaware of some critical information on the matter,
I and several hundred others are intently interested
in knowing what it is.
This isn't a battle of wills or a turf war. We need to
be constantly evolving the art and science of building
airplanes based on physics. If I am in error, nobody is
more interested in knowing about it than I am.
> Let's take any war story you find "believable" and do a
| Quote: | > critical analysis of facts cited to see how they add value
> to our deliberations.
Bob, you are getting picky here, I must have hit a nerve, I
didn't mean to. Take my word for it however, there have been
recent posts of this and breaking because they were soldered.
I just am not going to find them at this time as most were
bad work anyway. One fellow emailed me and stated a bad crimp
is just as bad a bad solder. Hummmmm?
|
You brought up war stories as having an influence on your
deliberations. I've written many times and with extreme
disfavor on consideration of what I call "Dark and stormy
night" stories as useful data for the design and fabrication
of an electrical system. I'll suggest that most
of those stories came about due to a lack of
understanding on the part of pilots, manufacturers and
bureaucrats as to what it takes to produce a reliable
flight system.
See chapter 17 of the AeroElectric Connection.
Our easy-to-achieve goals for having airplanes that stand
above the spam-cans is (1) design for failure tolerance
and (2) take on the responsibility to learn how to use
ANY chosen assembly technique effectively. There will ALWAYS
be failures of one kind or another in ANY system. Yeah,
you might even burn a soldered terminal off the end of
a wire cause you didn't put it on right . . . but you might
burn a crimped terminal off too for EXACTLY THE SAME
REASON.
| Quote: | You mentioned $120.00 for a tool. To me that is not an
outrageous price. I'll look into them shortly. I suspect I
will need several. Perhaps you could recommend one.
|
Not $120 per tool but the WHOLE SET of tools
. . . see citations in list of rules above.
| Quote: | When I amuse my wife she becomes exuberant and happy. I hope
I have effected you in the same manner. <g> If you consider that
no other document has been offered, except the 43-13, to answer
my specific question, I guess it accurately fits the description.
All I have seen are several multi page documents, although well
written, do not answer my original question regarding solder
in the vibrating arena.
|
I've made the statement numerous times and will repeat it
here. There is no significant difference in a properly
soldered versus properly crimped joint on a wire. Crimping
takes specialized tools and less skill; soldering uses
very in-expensive tools and takes some practice. I cannot
cite any reason for saying that one technique is better
than the other with respect to service life in your airplane.
> One of these days, I plan to do a "Layman's Guide to
> the use of AC43-13 Electrical Section" . . . it's
> going to be a big chore and I'm not looking forward to
> it.
| Quote: | It would appear that it is a badly needed document. Having
been inundated with just about every "war story" and Uncle
Herbs snake oil remedy for proper wiring, I would personally
be relieved to have in my possession such a document. All
kidding aside, you should dedicate it to me. I represent the
many who don't know but will admit it. <g>
|
I think you're making it more complicated than it
needs to be. This is the objection I have for the
way the EXP-Bus was sold at OSH last time I was there.
A guy behind the counter hands you this whippy
assembly that looks really complicated . . .
http://www.controlvision.com/pages/avionics_expbus.htm
. . .and it only costs $300! You hold the thing in your
hand an think, "Damn! I'd NEVER be able to figure out
something like this," while the guy behind the counter
tells you about all the whippy things it will do and
how much "time" it will save.
The question you don't know to ask and he doesn't offer
is "Does this product offer the simplest, lowest parts
count, equal or better performance result at the same
or lower cost of ownership." My answer to that
question is, "No, it does not."
When you pick up an English language dictionary, one
finds perhaps 100,000+ words contained therein of which
most literate adults use less than two percent
of the total. Yet I think we communicate very well.
AC43-13 is a similar document. It's a real piece of
work and LOOKS important because its got this
whippy government agency seal on the cover.
Like the EXP-Bus and the dictionary, there are a handful
of core facts and features around which 95% of your
system will be designed and built and I think I've
touched on most of them above.
| Quote: | > It's precisely this sort of quest for comfort in
> traditional techniques and/or bureaucratic decision
> making that has brought certified aviation to the point
> it is today . . .
>
> |---------------------------------------------|
> | Independence, Kansas . . . your #1 source |
> | factory fresh, 50-year old airplanes. |
> |---------------------------------------------|
You have a valid point. I only wish my Long will be around
as long and respected as the veritable DC-3.
|
No-biggie. Solar UV is going to rot the poor bugger
to dust before any of your wiring falls apart.
| Quote: | Again, thanks for your time. I do feel honored that someone
of your stature has taken the time to try and straighten me
out and be a help.
|
Another no-biggie. You've just fallen victim to a
veritable blizzard of non-information that provides
job-security for certain classes of worker citizens
in other aviation venues.
You're really better prepared than you think you are
but pouring over a document that's 95% floobydust will
only make the answers harder to find and understand.
Put down your copy of AC43-13 and let's get started
on your airplane. If questions come up along the way,
you'll get better answers TAILORED to your situation
off the list-servers than you'll get out of that
document.
By the way, my e-mail address at nuckolls(at)aeroelectric.com
is going away in a few days. 95% of what arrives there is
either spam or virus attacks. Use bob.nuckolls(at)cox.net
instead. There's an e-mail generator on the website at
http://aeroelectric.com/bob.nuckolls/ that will forward
to the Cox account. I'm trying to avoid publishing my
direct e-mail address on publicly accessed web pages
to keep from getting picked up by so many spam-bots.
Better yet, join the AeroElectric-List . . .
Bob . . .
------------------************-----------------
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nuckollsr(at)cox.net
Guest
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| Posted: Fri Jan 19, 2007 8:44 am Post subject: Starting points redux |
|
|
At 10:23 AM 1/19/2007 -0600, you wrote:
| Quote: |
<nuckollsr(at)cox.net>
Here's a reprint on a reply I crafted for a builder some years
ago dealing with some of the issues faced by a neophyte builder
in coming to grips with a new task . . . configure and fabricate
an aircraft electrical system.
------------------****************-------------------
At 05:44 PM 10/27/2002 -0500, you wrote
>Thanks for your reply and I do appreciate the time you have
>spent.
<snip>
My apologies folks. The links in this posting are
before the re-organization of the website that occurred
right after the message.
Dump this one and I'll see if I can sit down later today
and fix the links for a re-posting of the piece.
Bob . . .
|
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Bret Smith
Joined: 09 Jan 2006
Posts: 178
Location: Mineral Bluff, GA
|
| Posted: Fri Jan 19, 2007 9:44 am Post subject: Starting points redux |
|
|
Thank you for this...Looking forward to the redux
Bret Smith
---
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_________________
Bret Smith
RV-9A (Emp) |
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