Homebuilt Aircraft Wiring Tools and Techniques

Homebuilt Aircraft Wiring
Homebuilt
Aircraft Wiring
Tools and Techniques
q
Paul Kuntz
EAA 430
EAA 430
February 16, 2013
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AeroElectric Connection
Join the aircraft electric discussion forum, hosted on matronics.com
‐‐ http://www.matronics.com/email‐list/
– moderator is Bob Nuckolls
Get a copy of Bob Nuckolls’ book, The AeroElectric Connection, free as a PDF file from his web site http://www.aeroelectric.com/ Now at 12
his web site http://www.aeroelectric.com/
Now at 12th edition
or print copy for $20.00 plus $3.00 postage
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Wire
Aircraft‐grade wire
Color convention:
Red/Black – Current to device
Red/Black –
Current to device
White – Current from device to ground
Green – ground, not carrying current
Tefzel insulation –
insulation – tough, heat tolerant, tough heat tolerant
remains flexible for a very long time
19 individual strands, copper, each strand tinned.
Withstands vibration
Solders well
20 ga wire will carry 7 amps with 10 deg C temperature rise No need to go
C temperature rise. No need to go smaller. Resistance 10 ohms/1000 ft
(10 ft length = .01 ohms; .05 V drop at 5 amps)
14 ga – 15 amps
12 ga – 22 amps
4 ga – 72 amps
g – 100 amps
p
2 ga
For starter currents, use welding wire (small strands, very flexible)
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Soldering
Hakko 936 soldering station shown
The pros swear by Metcal – expensive new but affordable on eBay Uses
new, but affordable on eBay. Uses radio frequency power to heat only the tip.
Use 63/37 lead/tin solder (eutectic), not 60/40. Soldering station, Portable propane iron
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Soldering
Soldering station, Portable propane iron
With clothespins and instant glue, assemble simple jigs in a few seconds
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Wire Stripping & Solder Splicing
This type
Not this type
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Wire Stripping & Solder Splicing
Don’t forget the heat shrink!
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Pre‐Insulated Diamond Grip (PIDG or Fast‐on) Terminals
Lots of options
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PIDG (Fast‐on) Terminals
Aircraft grade terminals grip the insulation as well as the wire, for strain relief
strain relief.
Don’t use the automotive type!
FFold end of small‐gauge wire for ld d f
ll
i f
tight crimp in terminal
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Knife Splices & Butt Splices
Could be used for joins at wing root, but for the few times you’ll be taking the wings off just put a service loop in the
wings off, just put a service loop in the wire, cut it and splice it when necessary.
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Wire Labels
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Molex or AMP Mate‐N‐Lock Connecters
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Molex Connecters
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Molex Connecters
removal tool closes the barbs so that you can remove the connector 14
from the housing
D‐sub Connecters
Commonly available in crimped or soldered stamped sheet metal, but get the machined gold‐plated type.
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D‐sub Connecters
For small‐gauge wire, fold the end back insert folded end in the
back, insert folded end in the terminal and crimp
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D‐sub Connecters
Pin insertion and removal tool
I
Insertion rarely requires the tool
ti
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i th t l
FFor removal, insert from wire end, l i
f
i
d
grasp tool and wire, then extract 17
Shielded Wire
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Shielded Wire
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RG‐400 Coax
Suitable for VHF radio and transponder
RG‐400 superior to RG‐58 in every way
Observe bend radius. If you kink it, throw it away
throw it away
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Avionics Ground Bus
Note multiple wires to firewall ground for ample current capacity. Each pin can carry 5 amps.
Eliminate ground loops and associated hard‐to‐identify avionics noise issues by grounding all 21
avionics at a common point that collects all of the ground wires from avionics components.
D‐Sub pins as in‐line connectors
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Thermocouples
Thermocouples work by measuring very small voltages generated at the junction of dissimilar metals. So, every joint in the wire is another dissimilar metal junction. Therefore, make all junctions with the same type pin and same junction type (soldered, crimped). Minimize connections and keep junction pairs at the same temperature
connections and keep junction pairs at the same temperature.
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Fuses vs. Circuit Breakers
No glass fuses!
Fuses open at least as quickly as circuit breakers. Fuses are simple, robust and extremely reliable.
You can’t reset a fuse, but resetting a breaker in flight is a questionable
breaker in flight is a questionable practice.
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In Line Fuses
In‐Line Fuses
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Weather Proof Connectors
Weather‐Proof Connectors
Seal‐All connectors available from Aircraft Spruce
Seal
All connectors available from Aircraft Spruce
Use B‐crimp type connectors similar to Molex
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Wire Ties, Anchors, Lacing
Thomas & Betts wire ties have a metal locking tab and are rated to g
185 deg F
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Wire Ties, Anchors, Lacing
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Panel Legends
Brother p‐touch label printer
Label tapes available in various widths, tape colors, character colors
Examples are white letters on clear tape
Examples are white letters on clear tape.
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Bench Power Supply
Bench Power Supply
Provides DC power at regulated 13.8 V, emulating the alternator output g
g
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p
for testing avionics and wiring on the workbench or in your plane.
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Web Sites
http://www.matronics.com/email‐list/
htt
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/
il li t/ start here and join the AeroElectric‐List. t th
d j i th A El t i Li t
Participation is by email through aeroelectric‐[email protected]
http://www.aeroelectric.com/ Bob Nuckolls’ homebuilt aircraft electrical system d i
design and techniques
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http://www.aeroelectric.com/Reference_Docs/ useful reference cocuments
p //
/
/ many short articles on a variety of y
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http://www.aeroelectric.com/articles.html/
techniques
http://www.solder.net/technical‐info/soldering‐tip‐videos Soldering tips and short videos
http://www.digikey.com A comprehensive source of electrical parts & supplies
http://www.steinair.com/ Source for wire, coax, fuses, switches, terminal, etc.
http://www.bandc.biz/electrical‐supplies.aspx variety of electrical supplies & tools
http://www.mouser.com/ Likely to have just about anything you need, but the web site makes it nearly impossible to find what you are looking for, unless you are a
site makes it nearly impossible to find what you are looking for, unless you are a professional parts buyer. I bought a few things here, after exhausting other resources.
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