Page 1 of 1

murphy-rebel Digest for 1 Feb 2001

Posted: Fri Feb 17, 2012 8:40 pm
by phil stubley
re:fuel lines
Rick,
When you are planning your fuel lines think of when (not if) you get an
air bubble in the line, and how it will get out.
If you have a RISE as in your plan, the air will be trapped. It may even
be trapped if there is a level section of small diameter such as a
restriction at your isolation valve. The result is that there will be a
small flow allowed past the air bubble, enough to start and idle, and
enough in the float bowl to do your runup. But when you ask for full
power you may get it for only 30 seconds. Just enough to get you into
some serious trouble. (Been there, done that)
Wayne's comments are the same, just a different way of looking at it.
Hope that helps.
Phil Stubley

And Wayne, re grease. While you were sunning youself I found some
grease, Aeroshell 22, which Shell recommended over their (cheaper)
trailer grease. At $10 per tube it is not a prohibitive cost, less than
one tube per wheel.Thanks for your input.
Phil.

list-server wrote:
Subject: fuel lines

Hello everyone,
I need some comments on my approach to my proposed fuel line
routing. My plan is to run the main lines along the outside bottom of
the fuselage root ribs (FUS-27 L&R) and then either down the side (the
narrow side facing the center of the A/C) or down the back(the wide side
facing the rear of the A/C) of the front door post uprights(FUS-4). I
could also run the first portion inside along the bottom of the root
ribs and jump inside and down the door post. When the line gets to the
main square tubes it will run downhill to the center of the A/C. At this
point I will tee the two lines (one from each side) together and also
have a sump drain there. Now one line will run up to the firewall and
gascolator. These lines could be enclosed in a cover arrangement to
avoid damage. Stainless steel line is also an option for these. One
other possibility for line material (5/16" i.d.) is high pressure teflon
hose that is enclosed in a braided stainless steel jacket. The braided
hose assemblies are about $30.00 each for a six foot long hose.Available
from McMacter-Carr. These hoses are typically used for oil pressure
lines and other high pressure applications.
Feel free to bombard me will all of your comments.
Thanks,
Rick D.

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5 Message:0005 5
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From: "Wayne G. O'Shea" <oifa@irishfield.on.ca>
To: "Murphy Rebel Builders List" <murphy-rebel@dcsol.com>
Subject: Re: fuel lines

Rick, DO NOT run the fuel lines forward and then down (unless you are
running an electric fuel pump)!!!! When low on fuel, with the A/C at a high
angle of attack, the fuel is being supplied by "siphon" action to the carb,
as there is no longer any "head" pressure available from the tank. If you
happen to drop a wing (especially if only running on one tank) the siphon
will be broken (as the fuel goes away from the inlet) and most likely you
will be unable to get the siphon going again. The engine will run for a
short while, until the carb bowl and immediate line goes empty, then you're
a GLIDER! If you run the lines back and then down as shown in the manual,
the only way you will have fuel problems will be if you hold a VERY steep
dive for a VERY long time, or if you run the tanks dry!

Just my 2 cents, but of course it is your Rebel, so the choice is ALWAYS
yours!!

Regards,
Wayne G. O'Shea
www.irishfield.on.ca

----- Original Message -----
From: "Richard DeCiero" <rsdec1@star.net>
To: "Rebel Builders" <murphy-rebel@dcsol.com>
Sent: Thursday, February 01, 2001 9:15 PM
Subject: fuel lines
Hello everyone,
I need some comments on my approach to my proposed fuel line
routing. My plan is to run the main lines along the outside bottom of
the fuselage root ribs (FUS-27 L&R) and then either down the side (the
narrow side facing the center of the A/C) or down the back(the wide side
facing the rear of the A/C) of the front door post uprights(FUS-4). I
could also run the first portion inside along the bottom of the root
ribs and jump inside and down the door post. When the line gets to the
main square tubes it will run downhill to the center of the A/C. At this
point I will tee the two lines (one from each side) together and also
have a sump drain there. Now one line will run up to the firewall and
gascolator. These lines could be enclosed in a cover arrangement to
avoid damage. Stainless steel line is also an option for these. One
other possibility for line material (5/16" i.d.) is high pressure teflon
hose that is enclosed in a braided stainless steel jacket. The braided
hose assemblies are about $30.00 each for a six foot long hose.Available
from McMacter-Carr. These hoses are typically used for oil pressure
lines and other high pressure applications.
Feel free to bombard me will all of your comments.
Thanks,
Rick D.

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6 Message:0006 6
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From: Walter Klatt <Walter.Klatt@home.com>
To: " (Murphy Rebel Builders List)" <murphy-rebel@dcsol.com>
Subject: Re: fuel lines

Also, Rick, I don't know if you are using bungee gear or the new spring gear, but if it
is bungee, you should be aware of a possible hazard. I had a landing accident with my
plane where the rear drag strut pushed up through the rear fitting and into the floor
puncturing my fuel line. I ended up with fuel inside the cabin area, but fortunately
there was no fire. My lines were routed exactly as per MAM's manual, but if I did it
over, I would route them to the center of the floor to avoid the rear gear strut fitting.

"Wayne G. O'Shea" wrote:
Rick, DO NOT run the fuel lines forward and then down (unless you are
running an electric fuel pump)!!!! When low on fuel, with the A/C at a high
angle of attack, the fuel is being supplied by "siphon" action to the carb,
as there is no longer any "head" pressure available from the tank. If you
happen to drop a wing (especially if only running on one tank) the siphon
will be broken (as the fuel goes away from the inlet) and most likely you
will be unable to get the siphon going again. The engine will run for a
short while, until the carb bowl and immediate line goes empty, then you're
a GLIDER! If you run the lines back and then down as shown in the manual,
the only way you will have fuel problems will be if you hold a VERY steep
dive for a VERY long time, or if you run the tanks dry!

Just my 2 cents, but of course it is your Rebel, so the choice is ALWAYS
yours!!

Regards,
Wayne G. O'Shea
www.irishfield.on.ca

----- Original Message -----
From: "Richard DeCiero" <rsdec1@star.net>
To: "Rebel Builders" <murphy-rebel@dcsol.com>
Sent: Thursday, February 01, 2001 9:15 PM
Subject: fuel lines
Hello everyone,
I need some comments on my approach to my proposed fuel line
routing. My plan is to run the main lines along the outside bottom of
the fuselage root ribs (FUS-27 L&R) and then either down the side (the
narrow side facing the center of the A/C) or down the back(the wide side
facing the rear of the A/C) of the front door post uprights(FUS-4). I
could also run the first portion inside along the bottom of the root
ribs and jump inside and down the door post. When the line gets to the
main square tubes it will run downhill to the center of the A/C. At this
point I will tee the two lines (one from each side) together and also
have a sump drain there. Now one line will run up to the firewall and
gascolator. These lines could be enclosed in a cover arrangement to
avoid damage. Stainless steel line is also an option for these. One
other possibility for line material (5/16" i.d.) is high pressure teflon
hose that is enclosed in a braided stainless steel jacket. The braided
hose assemblies are about $30.00 each for a six foot long hose.Available
from McMacter-Carr. These hoses are typically used for oil pressure
lines and other high pressure applications.
Feel free to bombard me will all of your comments.
Thanks,
Rick D.

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7 Message:0007 7
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From: BILNEWKIRK@aol.com
Subject: Re: wooden prop
To: murphy-rebel@dcsol.com

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My question is what cruise and top-end speed I should expect from my O-290.
I have just received a new wooden Margie Warnke prop. It climbs at 1000 -
1100 fpm; cruises at 2400 rpm at 109 mph; and tops out at 2600 rpm and 118
mph.
She is willing to further refine it before putting on the final finish, but I
don't want to screww up a good thing.
Any words of wisdom?

Bill Newkirk
Rebel 376

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<HTML><FONT FACE=arial,helvetica><FONT SIZE=2>My question is what cruise and top-end speed I should expect from my O-290. &nbsp;
<BR>I have just received a new wooden Margie Warnke prop. &nbsp;It climbs at 1000 -
<BR>1100 fpm; cruises at 2400 rpm at 109 mph; and tops out at 2600 rpm and 118
<BR>mph.
<BR>She is willing to further refine it before putting on the final finish, but I
<BR>don't want to screww up a good thing.
<BR>Any words of wisdom?
<BR>
<BR>Bill Newkirk
<BR>Rebel 376</FONT></HTML>

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Contributors' page at:
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Visit the book store at:
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