Wiring - aft wires run forward.

While waiting for the engine shop to have time to build my engine, i've been working on getting all the wiring from the wings, cabin and tail run to where i think i will locate the various boxes. I have found it impossible to blog each wire i run - it would be so tedious! Instead, this will serve as a general overview. 

This post is a half way mark of the wiring and a sort of signpost for how things are going. I will try and expand on parts which are interesting or noteworthy. 

This is quite an enjoyable task, but time consuming. Many hours just head scratching working out where and how to mount the various boxes. 

I created 2 fold down avionics shelves between the sub-panel and the firewall, which will hold the SDS ECU on the right hand side, and likely a remote COM radio, and a remote audio panel on the left hand side. In the centre section i created a couple of spanwise bars which will hold the EIS box, and there is room for one more box such as the GAD29 ARINC box. Details are here. 

I decided to start the wiring with all the wires aft of the panel first, then do the wires which are 'interpanel' last. 

So as a general overview, i ended up with 2 main runs along the centre tunnel, which then snake up the sides of the wiring channel to some ADEL calmps on either side. Various other ADEL clamps were placed around the area. This gave me essentially a 'highway' for all the wires to travel. They come up the sides of the wiring channel, then route to where they need to go. 

These two ADEL clamp locations are the main hubs of the "highway" - they route the wires coming up the sides of the wiring channel to where they need to go. 

ADEL clamps on the sides of the radio stack and under the sub-panel lip, allow routing forward to the panel and switches, as well as to the avionics shelf locations at the sides.

The avionics mounting bars in the centre section also get a bunch of ADEL clamps to help route wiring. These ones on the left hand side route to the left avoinics shelf, while the ones on the right hand side route to the grounding block.

Here is a general overview of the area under the forward access panels:

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Wing Root Connectors

The logical place to start was with the wing root connectors, as this is where the largest number of wires need to go. Having the aircraft on the rotisserie was essential. 

I started with the wires related to the autopilot such as Power and Ground as well as 'CWS - control wheel steering' (which is also autopilot disconnect). These need to be shared between the 2 auto-pilot servos, so needed some wires crimped together. I wanted these crimps to be accessible later, so placed some service loops in the centre tunnel for these wires.

One of many shielded cable terminations.

The wing root connectors are CPC. 

Each wing root connector got a small service loop so it can be pulled out above the floor for maintenance.

Every wire got a label at each end, and once pinned was marked in the wiring diagram with a pink "P" symbol. If one end of the wire was not pinned yet, it was run to it's final location, and left loose with it's mates for the same box. These were labelled with a yellow "R" meaning 'Roughed'. As always, the master Excel 'Wirebook' was updated with either "Pinned" (if both ends were pinned), or 'Roughed'. This serves as a checklist for where i am at in the process.

These 4 systems got a crimp / service loop in the centre tunnel

One of the autopilot crimps and service loops for the centre tunnel.

The service loops will be tied seperate from the main bundle for easy maintenance later. 

Smoke System Connector

An extra grommet was added to the right hand side, to accept the wires pertaining to the smoke system connector.

This connector is located in the floor behind the co-pilots seat. It has all the wires to interface with the smoke system.

Once again there was a large service loop so the connector can be accessed above the floors. It was tied off to remain clear of the rudder cable. 

Where i want to be able to remove a bundle for maintenance, it is tied off with a cable tie, as this can be cut and replaced more easily than a wax tie.

The smoke system contains a power and ground wire for a 'smoke solenoid' which sits in the oil supply line. This gets power and opens whenever the smoke system is activated, to allow smoke oil to flow. Ther ground wire for this gets routed to the bottom of the panel, then using a crimp gets extended to the grounding block. This will allow me to install a sky-typing box later at this crimp connection and have both access to the solenoid ground, and aircraft ground from that location.  

Fuel Pump and Pitot Power (and Relays)

The fuel pumps and the pitot heater are both powered through relays. The relay mount was previously made up, so i ran the wires for these. 

Wires were added to the fuel pumps, but terminated in temporary faston connectors, which will interface with the temporary box used to run the engine on the truck. They will eventually get Deutsch DT connectors.

The relays get a power source line, which then needs a tap off for the relay power. To do this, i twist the wire ends together, then crimp into one terminal. The relay holder are NARVA 68084, and the pins used are 56224 crimped with a standard MOLEX style crimper. The relays i will use are Narva 68048BL, rated at 30 amps on the NC contacts. 

Wires stripped and splayed

Held together with some homestats

Twisted together and tied with lacing cord.

The connector is crimped

Then the insulation is crimped. It recieved a heatshrink label over the top.

A small service loop allows the entire holder to me moved forward of the wiring channel.

The fuel pump system side wires were run and terminated in a DT style connector from the local Supercheap Auto. 

PITOT / AOA tube routing

I worked out that i would need to enlarge 2 grommet holes to run the PITOT and AOA hoses forward. My drill would not fit, so i had to get creative! 

Headset Jack Wiring

I worked out that i will probably use a remote audio panel located on the left hand fold down avionics shelf, so was able to install and run the headset jacks. I added some images i found online on how these are wired to the wiring diargram so i didn't stuff them up! The wires were roughed in, but left at a length that they would reach the centre panel, in the event i go with a panel mounted audio panel.

The wires were mechanically attached, then soldered, then covered in glue lined heatshrink.

Stick Wires

I had originally planned to use the Van's plug locations in the sticks for the designed MOLEX connectors. I purchased these but they are SIMPLY AWFUL! So bloody small. I tried crimping some on the bench, and can't imagine how someone would do that in-situ in the aeroplane. So i bit the bullet and filed out the sockets on the stick bases to fit a DSUB. These were then wired, and a service loop was added, just long enough to allow me to access the sockets later on, but also not to interfere with the stick or pushrod movement. 

For reference, these are the correct MOLEX part numbers to fit the Van's stock stick bases - but i would not recommend using these:

This is the service look length for the stick wires.

The stick bases were filed to fit the connector, and are just held in with cable ties.

That's all the interesting bits for the wiring done for now, and represnets all the wires which needed to be run forward from the cabin / wings to the panel.