Wiring - some initial planning / learning

While working on the aft fuse construction, plans page 10-14 had the following note:

This got me looking at the ELT installation and also the installation of the tail light in the rudder, and the trim servo wiring in the elevator.

Wiring Diagram

In the spirit of and an attempt at professional wiring, i have decided to record all wire runs in a proper software program, and I've chosen a program called KiCAD for this purpose. The following screenshots come from that program.

Wire Book

In addition to the wiring diagram program, i have decided to keep a wire book. This is an excel based spreadsheet, which lays out details of all the wires in the aircraft, including their from and to locations, type, color and gauge. This also acts as a tabular pin out record for when i build the wire harnesses later on. Here is a screenshot - obviously a work in progress!

The wire details tab - where each single wire is recorded, including its label, type, color, from location pin and to location pin, as well as the planned lengths based on the Van's Common Fuselage Harness

The pinout diagram is planned to make pinning connectors a lot easier. 

Obviously, each wire in the wire book needs to be drawn into the wiring diagram, and is recorded as "drawn" if it is included in the diagram, and "installed" once installed in the aircraft.

Trim Motor Wiring

The Van's harness accounted for the trim wires by running a twisted 3 pair to the aft fuselage bulkhead, where these wires are broken by a Molex connector. The 2 white trim power wires run through this bulkhead and join the right side harness, for input at a later date to a Garmin Autopilot servo - if you use dynon, these go into the connector on one side, do a u-turn and come straight back out the same connector and then up to the panel! This seemed like a LOT of connectors, and each one gives 3 more potential failure points, so i have elected to simplify things somewhat.

Instead, i will run a single 5 core, jacketed, 24 AWG cable from the connector at the aft deck (see more on connectors below), all the way to the panel. If i need to break this open later, in order to send the trim wires to a Garmin servo, this is easy enough to do.

A screenshot from KiCAD showing the nomenclature of the wiring diagram. The cool part is each wire is traceable - if you click on it it is highlighted, and you can move between sheets and see where it goes and what it is connected to. 

Rudder Tail Light

I received the Van's tailcone left wiring harness with the empennage kit, which allows for the Suntail tail light - given that FlyLED's is from Australia, i think i would like to use them instead, meaning that the supplied wiring harness would need some modification. The supplied wires are also broken at the aft fuse bulkhead in the same MOLEX connector.

Instead, i have planned for a single cable running the length of the aircraft, unbroken from the rudder light all the way to the panel, where the FlyLeds Light Controller board will be located. This is a 2 Core, Shielded, 22AWG cable as per the FlyLEDS instructions.

ELT Installation

At this point i am unsure what ELT i will need to install, so i am hedging my bets and running a single 3 Core, 22AWG shielded wire. This will satisfy the power and GPS data requirements of both the ACK and the ARTEX ELT's. Who knows what will be available when i eventually install one! (i will also run the COAX for the antenna supplied in the kit, and the "Phone Cable" which Van's supplies for the ACK ELT remote).

Connectors

Understanding connectors has been fun! There are Dsub, CPC and Deutsch among others. I initially thought i would go for the dsub connectors, as i had a crimper for these already, but the i found out there are some CPC connectors which also take dsub pins (and some that do not!), and then i realised that the deutsch connector pins, while a different pin, are crimped with the same crimper as well!

Off to digikey i went and tried to find each of these items - but what a nightmare! (especially the CPC's). What was called for was a ready reference for the part numbers for each type of connector, so i went ahead and made one up. The latest version can be found here.

Time to order

So it was time to make an order! From Stein i ordered a bunch of wires and dsub connectors. From digikey i got some more dsubs, some CPC's and some Deutsch connectors to play with. I also ordered a bunch of fire resistant snap-in bushings and some caterpillar grommet from Domcar.

$800 worth of wire from Stein! 

Grommets from Domcar

For now i am storing the wiring in my filing box:

Elevator Trim Aft Deck wiring / Wire Labeling

I decided that the tiny little molex connectors that are located inside the elevator were no good, so i elected to follow an idea from a Stein video, and simply wire them using dsub pins connected together, and covered in heat shrink. At the other end, i wired them to a dsub connector which will mate with a dsub at the aft deck position, and go all the way to the panel.

dsub pins crimped to the end of the trim wires.

Dymo labels are printed using the "wire" template and wrapped around the wire...

...then they are covered in clear heatshrink.

a dsub is them made up.

The empty pin slots are left open. The connector is held together by the connector body.

The trim wires are connected to the extension (with the sdub plug on the other end) using a pin 2 pin connection.

Each pin is then covered in heat shrink, and the whole thing is covered in a larger head shrink. Next time i would stagger the pins, but this time i didn't have enough wire to do that (i didn't want to cut the wires coming from the trim motor itself any shorter). 

Deutsch Connectors

Looking online at the deutsch connectors, i feel that these are going to be better than dsub conenctors for my pusposes, so i have orderded some to see what they are like. They also work out a bit cheaper per connector. I will likely go ahead and replace the above dsub plug for the elevator trim with a deutsch connector in the future.