Oil lines as electrical ground return?

[Scott Derrick]

I accidently wrote my first post as a reply to another thread, so here
it is again on its own.

I have a pusher airplane with a nose oil cooler.

I am replacing the existing heavy hydraulic type(rubber/braided steel)
oil cooler lines with lighter metal lines. Either soft Aluminum or soft
copper 1/2 lines.

First question. I would like to use the lines as my ground return and
remove the 2 AWG wire I have now. Good idea?

Second question. Which would be better, or possibly which would be
worse and why? Copper or Aluminum.. Aluminum would be lighter but
copper offers a better ground return(less resistance). I have a big
engine and the starter needs all the current I can muster.

Scott

[COLIN LAMB]

First question. I would like to use the lines as my ground return and
remove the 2 AWG wire I have now. Good idea?

Second question. Which would be better, or possibly which would be worse
and why? Copper or Aluminum.. Aluminum would be lighter but copper offers
a better ground return(less resistance). I have a big engine and the
starter needs all the current I can muster.

I would not substitute the brake line for the #2 ground return. Beware of
corrosion that may occur in any connections that join copper and aluminum.
There is a potential difference, and the voltage created causes corrosion.
In some cases, the corrosion could continue until something bad happens -
including loss of electrical system. Any weight saving would be false
economy.

I would use copper rather than aluminum. Aluminum is less weight, but it
requires more preparation to connect. Keep everything in copper. If copper
touches aluminum, you will get electrolysis unless a special goop is used
with an approved connector.

Colin

[jerry wass]

Scott Derrick wrote:
> I accidently wrote my first post as a reply to another thread, so here
> it is again on its own.
>
> I have a pusher airplane with a nose oil cooler.
>
> I am replacing the existing heavy hydraulic type(rubber/braided steel)
> oil cooler lines with lighter metal lines. Either soft Aluminum or soft
> copper 1/2 lines.
>
> First question. I would like to use the lines as my ground return and
> remove the 2 AWG wire I have now. Good idea?
>
> Second question. Which would be better, or possibly which would be
> worse and why? Copper or Aluminum.. Aluminum would be lighter but
> copper offers a better ground return(less resistance). I have a big
> engine and the starter needs all the current I can muster.
>
> Scott
IF--you decide on the copper lines--do this--take a strip of bar copper
about 1/8" thick, 3/4" wide, and a couple of inches long..drill a 5/16"
hole in one end, form the other into a portion of a circle that is a
snug fit around the tubing---clean & silver solder the strap around the
tube..repeat at other end---This way if you get a loose connection, you
won't burn a hole in the tube.. Get a couple of MS-xxxx male flare
fittings--bore the other end out to a slip fit on the copper be sure &
leave the hex fitting on the adapter, so you can TIGHTEN the flex
hose.---Again, silver solder them on the tubing.
use SS braided Teflon lined hoses to complete the plumbing---allow for
expansion of the length of the tube..&&&& Jerry