Today's Message Index:
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1. 07:43 AM - Re: Fuel Flow thru Facet pump (mikeperkins)
2. 08:29 AM - Re: Re: Fuel Flow thru Facet pump (SWeidemann@aol.com)
3. 08:50 AM - Re: Fuel Flow thru Facet pump (mikeperkins)
Message 1
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| Subject: | Re: Fuel Flow thru Facet pump |
Mike,
All header tanks are installed with the same intention: insure fuel flow in 1)
a dive, or 2) with one tank empty and the other tank unported due to a slip or
skid.
Once upon a time, in the Model 1 and 2 days, fuel lines were commonly being routed
uphill, over top of the door and then down between the windshield and the
door, then back up to a firewall-mounted header tank. The biggest problem with
this installation was requiring the fuel to go uphill over the doors because
of the extremely low head pressure, or even negative head pressure, at that point
in the system. Pulling fuel like this with a pump leads to vapor lock. Vapor
lock is often associated with high temperatures, so thinking of it as an expanding
"gas bubble" might be a better way to look at it. Anyway, to get around
the problem of unreliable fuel flow, folks were resorting to installing primer
bulbs over the doors, which had their own problems, and the whole thing was
getting messy.
The switchover to the rear-mounted header tank arrangement occurred about 1990.
The intention was to encourage routing that kept the fuel constantly going downhill
immediately after leaving the wing tanks to prevent vapor lock. I switched
my system over from the old way to the new way after it had all been plumbed
but not flown. When I installed the rear-mounted header tank, I also added
a valve just above the seat between each wing tank and the header tank. And I
installed a main shutoff just forward and below the left door. The system has
worked well for 400 hours.
--------
Mike Perkins
Havana, Illinois
Model I, 532, B gearbox, GSC prop
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=408004#408004
Message 2
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| Subject: | Re: Fuel Flow thru Facet pump |
I agree with Mike's question. Why is a header tank necessary for such a
system (Kitfox with low behind the seat header tank) where gravity should
take care of ALL your fuel pressure needs? I have an ancient Luscombe with
wing tanks that uses Mother Nature's Gravity System and has no fuel pump
anywhere.
Sko
Message 3
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| Subject: | Re: Fuel Flow thru Facet pump |
The Luscombe's updraft carb is located much farther below the wing tanks than the
the Kitfox's side-draft carbs. So the Luscombe's head pressure at the carb
is going to be a lot higher, and so will the gravity fuel flow rate. That's my
guess anyway.
--------
Mike Perkins
Havana, Illinois
Model I, 532, B gearbox, GSC prop
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=408012#408012
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