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Prewired harnesses?

Anybody used Dynon Network yet?

I was not yet very familiar with the Dynon but did discover they actually have an avionics system which works with pre fabricated wires, in 2023! After about any other industry uses pre manufactured cables probably for a century. I wish the certified avionics would come up with something similar. It should somehow be possible.

https://dynonavionics.com/skyview-network-cables.php

www.ing-golze.de
EDAZ

Dual RS-485 interconnections embedded in DB9 cables between the different main screens and Dynon proprietary peripherals. Plug, configure on the screen and just works. No CAN bus terminator complexities like on the Garmin G3X.

Belgium

Pre-fab harnesses have been used in GA, to the extent that one can measure up the lengths and build the harness on a bench. This is much easier than wiring in-situ.

I did some here

and I have seen some avionics shops do this. But otherwise, not much. I vaguely recall Socata were also making some harnesses on a big bench – probably for the TBM, 2008 or so.

Otherwise the obvious problem with pre-fab wires is that the length may not be right. Too long, you can coil it up somewhere, too short, it is useless. And for retrofits this is a problem. In the car business, everything is always in the same place but in GA the distances vary.

Regarding terminations, on RS485 (a part of my day job) you don’t need terminators if running at say 115200 baud and the reflections decay within the risetime of the signal, which with low slew rate chips (limited to 115k) tends to translate to about 300m distance. CAN bus can run much faster.

It must be one of the worst jobs ever to be wiring in-situ while crawling around some old plane, in an unheated hangar with -5C outside. Been there and seen it Found it hard to believe the workers were willing to do that job.

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

and I have seen some avionics shops do this. But otherwise, not much. I vaguely recall Socata were also making some harnesses on a big bench – probably for the TBM, 2008 or so.

I think all new aircraft avionics install is like that. There was an AvWeb video about Diamond (?), same story.
I’m surprised that more shops don’t do that – in theory it should be much easier – you measure everything up, pre-wire on the bench and then the installation should take significantly less time (reduced downtime).

EGTR

I agree.

The main problem with prewired harnesses is that you need a much bigger hole to feed the connector through

It is pretty obvious that the bulk of the wiring in the TB20 was done in-situ – because the holes in the airframe are far too small. In some cases you literally cannot get one more 4mm diameter shielded cable through a harness already 20mm diameter, because it is so tight. With their labour costs and working practices thrown into the pot, it doesn’t surprise me that Socata decided, in 2000, they could make much more money making €3M turboprops

Incidentally, they also did the wiring with the windscreen (front window) not yet fitted – which makes everything much easier.

Posts moved to an existing identical thread.

Administrator
Shoreham EGKA, United Kingdom

I’m using JCLPCB for 3D printing in SLS Nylon. Less hassle and much cheaper than Shapeways.

EGBW / KPRC, United Kingdom

Peter wrote:

€3M turboprops

Amazing times back then when €3M got you a new TBM.

always learning
LO__, Austria
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