The Murphy Builders Site

Anyone out there using a header tank with fuel return lines AND a fuel
flow turbine? My LOM is fuel injected. I have two options as I see it
(I am open to others):

1. Run the return line through a 6 port / 3 position selector which
directs the return flow into the originating tank. Place the fuel flow
turbine after the selector. Drawbacks -> The turbine will be
inaccurate all the time and the fuel return lines add complexity.

2. Use a header tank with the selector before the header tank. The
return line comes back to the header tank and the flow turbine is placed
up stream of the header tank. Drawbacks -> Header tank adds complexity
& weight and the return line might induce bubbles in the fuel line.

So, does anyone out there use a header tank with a fuel return line into
it? Does the fuel injector return line cause any air bubbles to be
introduced in the fuel supply line?

--
Best Regards,

Scott Hibbs
hibbs@pacifier.com


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Have seen both configurations - using return lines to the tanks is
the most common arrangement. Have heard of a few problems with header
tanks getting too warm, introducing bubbles, etc.

The return outlet into the wing tank should NOT be at the top -
it is better near the bottom. Apparently the falling fuel can build
up a static charge ...

Header tank should be mounted high, with an air vent line running
up to the wing tanks, to get rid of any bubbles - more complexity! :-(
Lost a friend because the header tank split in a crash & sprayed fuel
everywhere...

Have also heard several horror stories about fuel flow turbines
causing serious flow problems - only heard of one that worked well....
possibly a good arguement for KIS ! Just use the sight guages and
calculate fuel consumption - it should never be THAT critical for
range.

The return line can go to a simple valve that points to left or
right tank. A separate selector can be used for feed. It's too bad
the fuel pump is on the engine - I REALLY liked Geert's arrangement.
He used Subaru fuel pumps submerged in the fuel tanks, just like the
cars. This meant that you don't need valves at all - just turn on
the pump you want to use !

Don't LOM supply a suggested fuel system configuration ?? You
might be able to find a ZLIN and check to see how they do it ...

....bobp

-------------------------orig.------------------------------------------
At 08:30 PM 4/5/00 -0700, you wrote:

Anyone out there using a header tank with fuel return lines AND a fuel
flow turbine? My LOM is fuel injected. I have two options as I see it
(I am open to others):

1. Run the return line through a 6 port / 3 position selector which
directs the return flow into the originating tank. Place the fuel flow
turbine after the selector. Drawbacks -> The turbine will be
inaccurate all the time and the fuel return lines add complexity.

2. Use a header tank with the selector before the header tank. The
return line comes back to the header tank and the flow turbine is placed
up stream of the header tank. Drawbacks -> Header tank adds complexity
& weight and the return line might induce bubbles in the fuel line.

So, does anyone out there use a header tank with a fuel return line into
it? Does the fuel injector return line cause any air bubbles to be
introduced in the fuel supply line?

--
Best Regards,

Scott Hibbs
hibbs@pacifier.com


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Archives located at:
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*--------------------------------------------------------------------------

---------*

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The Murphy Rebel Builders List is for the discussion
between builders and owners of Murphy Rebel aircraft.
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*-----------------------------------------------------------------------------------*




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You might be able to add a tube to the inside of the tank fitting,
to lower the outlet ....

Sorry, I don't recall - not sure if it was actually a turbine, or
some other kind of device. Seem to recall it was plumbed into a bypass
pipe, so full flow went past it .... Will try to see what the SR is
using for that digital flow meter.

Finding a Zlin might still be a good option.

Good luck !
.....bobp

-------------------------------orig.---------------------------------------
At 09:49 PM 4/6/00 -0700, you wrote:

Bob, thanks for the advice. I had not heard about the static issue with

falling fuel. I wish I

had known about that before I placed the return fittings in the tank. You

mention that only one

flow turbine worked well, do you remember the name? The LOM manual only

specifies a return line,

does not recommend how to plumb it, besides, this is 1/3 of the fun.

--
Best Regards,

Scott Hibbs
hibbs@pacifier.com

3: Re: Header tanks and injector return lines.....
by Bob Patterson <bob.patterson@canrem.com>

The return outlet into the wing tank should NOT be at the top -
it is better near the bottom. Apparently the falling fuel can build
up a static charge ...

Have also heard several horror stories about fuel flow turbines
causing serious flow problems - only heard of one that worked well....


Don't LOM supply a suggested fuel system configuration ?? You
might be able to find a ZLIN and check to see how they do it ...

....bobp

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The Murphy Rebel Builders List is for the discussion
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Archives located at:
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*--------------------------------------------------------------------------

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The Murphy Rebel Builders List is for the discussion
between builders and owners of Murphy Rebel aircraft.
Archives located at:
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*-----------------------------------------------------------------------------------*




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