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Re: Europa-List: Electrics- Help requested for Electrics Bill of Materia

Subject: Re: Europa-List: Electrics- Help requested for Electrics Bill of Material
From: Frans Veldman <frans@privatepilots.nl>
Date: Sat, 15 May 2010 13:59:22

On 05/15/2010 12:21 PM, jglazener wrote:

> Having finished the bottom fuselage I am now starting work on the
> top. This brings me in contact with something I have managed to avoid
> so far- electrics.

Well, that's the fun part! :-D No sticky, allergy provocing stuff, just
connecting some wires.

> Not knowing where to start I have request. Does anyone have, or would
> be able to make, a rough Bill of Material for the stuff I would need,

It largely depends on how you want to connect everything.
Do you want to crimp? Then get decent crimping tools. Do you want to
solder? Then get the appropriate tools for that. How do you want to fuse
everything? Car-style fuse, or circuit breakers? Fuse each single item,
or just "instrument panel", "fuel pump", and "flying controls"?

At least you need cutters, a decent stripper (teflon wire is a nightmare
to strip if using the inappropriate tools), heat shrink tube in various
diameters, a heat gun, and if you are over 40, reading glasses.

First make a plan. Map each item that needs to be wired. Plan where you
locate your "ground". Near the engine is an obvious choice (I used a
bolt through the firewall for that, so on both sides I can add ring
connectors for various items requiring a ground). I also used another
common ground behind the cockpit, because I have lots of other items
located in that area.

Then plan the diameters of the wires. Data/signal wires can be the
smallest size, the other sizes depends on the fuses you are going to
use: If you use a 3 Amp fuse for something, the wire has to be able to
withstand 3 Amp's at least (otherwise the wire will protect the fuse).
You can find tables on the internet for this. (If you plan to buy wires
---From an American source, be prepared for the confusing fact that if the
number increases, the diameter gets smaller). For ground cables, use at
least the same diameter as the power cable, add the amount of amps
together if you share the ground cable over various items. I like to
keep the ground cable at least 1 step thicker than required.

Then, after you have carefully planned the routing of the cables,
calculate the length of wires you need, and increase that with 50%. Oh,
and keep your antenna cables and strobe cables out of the way of data
cables as much as possible, plan a different routing for these.
I would recommend to use teflon insulated wires. ACS sells these.

For every single item, look at its connection possibilities. Some
devices have a connector already attached to it, so it is a no-brainer.
Just get the opposite sex in the desired variant (crimp or solder). For
other things, like the trim servo, I would suggest to solder wires
directly to them. Connectors are a common fault source, and why use a
connector for something you don't plan to take out regularly? I even cut
off connectors from some items that came with a connector, and hard
wired them.

For bundling the wires, use tie wraps. I bought the "cobra" type from
ACS, as they don't have the sharp ends that tend to scratch you whenever
you reach behind a cable. They sold them only by a lot of 1000, so I
still have plenty of these. I can send you some if you want.
But in the beginning I would use "scrap" quality of tie wraps, as you
will find yourself adding new wires regularly. Leave the final wrapping
until the very end!

And forget to order everything at once, but plan to do this in stages,
as when you are progressing you will change plans often.

If you really get stuck, call for help.

Frans



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