REFLECTOR: Oil lines and ground wire.

Douglas Holub doug.holub at comcast.net
Sat Sep 3 21:39:14 CDT 2005


.127" would be the radius. The diameter would be .254", or about 2 AWG.

I personally shudder at the thought of running electricity through an oil
line. I know oil is a good insulator, and transformers are filled with oil
sometimes, but oil is flammable, and a spark at the wrong time would be a
disaster. For example, if the oil line should become disconnected while the
power was on, there could be intermittent sparks. Hot oil gushing into the
airplane is a bad enough problem without it also catching on fire. Or maybe
you're doing some maintenance in the hangar and disconnect the oil line
while the power is on.

I'm sure it could be done safely, but I think it's asking for trouble.

Doug Holub

----- Original Message -----
From: "Laurence Coen" <lwcoen at hotmail.com>
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Sent: Saturday, September 03, 2005 11:19 AM
Subject: Re: REFLECTOR: Oil lines and ground wire.


> Scott,
>
> As far as using the aluminum oil lines for a ground return, don't.  Their
> ability to conduct electricity is a function of cross sectional area and
the
> material.  Aluminum has four times the resistance of copper for the same
> cross section.  1/2" aluminum tubing has a wall thickness of 0.035".  I
> calculated the cross sectional area and it is equivalent to a wire of
about
> 0.12" dia.  That's far too small even if it were copper.
>
> The other question about up one side and down the other has been discussed
> before and as a result I chose to do it that way.  I believe that someone
at
> the factory took measurements of temperature at both ends of both oil
lines.
> The lines were in the same duct.  The oil flowing foreword lost 20 deg. F
> but the return oil was reheated 15 deg. F.  The two lines together were
> acting as a counter flow heat exchanger.  At least in theory, moving the
> return line to the other duct should make the oil entering the oil cooler
15
> deg. warmer thus increasing its' efficiency and getting perhaps another 5
> deg. drop in the return line.  I've never had my oil lines in the same
duct
> so I am unable to test the theory.
>
> Larry Coen
> N136LC
>
> ----- Original Message -----
> From: "Scott Derrick" <scott at tnstaafl.net>
> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
> Sent: Saturday, September 03, 2005 10:04 AM
> Subject: REFLECTOR: Oil lines and ground wire.
>
>
> > My plane came with high pressure hoses for oil lines. Both ran in the
> > pilot side duct.  I noticed that the manual calls for 1/2 " aluminum
> > lines.   I was considering replacing the high pressure rubber/steel flex
> > lines with aluminum.  Much lighter and smaller, those hydraulic lines
are
> > huge and heavy.
> >
> > I was also considering running one up the pilot side and the other down
> > the copilot side to take advantage of the additional cooling benefits.
> > Has anybody done the comparison of running both in one duct and one in
> > each to see if there really is an advantage?
> >
> > Then I got to thinking about using the oil lines for my ground return
path
> > from the battery to the engine?  Aluminum is a pretty good conductor,
and
> > having two lines would seem to provide a substantial return path if I
> > bonded both tubes at both ends?
> > Anybody do this?
> >
> > Scott
> > _______________________________________________
> > To change your email address, visit
> > http://www.tvbf.org/mailman/listinfo/reflector
> >
> > Visit the gallery!  www.tvbf.org/gallery
> > user:pw = tvbf:jamaicangoose
> > Check new archives: www.tvbf.org/pipermail
> > Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
> >
> _______________________________________________
> To change your email address, visit
http://www.tvbf.org/mailman/listinfo/reflector
>
> Visit the gallery!  www.tvbf.org/gallery
> user:pw = tvbf:jamaicangoose
> Check new archives: www.tvbf.org/pipermail
> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
>




More information about the Reflector mailing list