Message-ID: <000a01bfac20$681c9da0$ef6b1b3f@oemcomputer>
Reply-To: "dfs" <dfs@gateway.net>
From: "dfs" <dfs@gateway.net>
To: "Lancair List" <lancair.list@olsusa.com>
Subject: 235 Header Tank level sensor locations
Date: Fri, 21 Apr 2000 23:02:24 -0700
Mime-Version: 1.0

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This may not exactly answer Ed Sikora's questions about where to position
his tank sensors, but rather, I'm passing on some thoughts on the subject
that just might help the decision process.

The "Full" sensor is easy, it should be placed so that you get as much fuel
in the tank as possible without running go-juice out the overflow/vent. That
should be fairly easy to determine and isn't all that critical.

However, for the "Low" sensor, you need to consider that, should you suffer
a total electrical failure - or your transfer pump dies (I've had it happen
once) - ask yourself how much fuel you'e like to have in the header at any
time should such a scenario occur. I know I'd prefer to have the header
pretty close to full, giving me maximum range to find a place to land.

With this in mind, and after some thought on the subject, I elected to take
on the task of turning on the transfer pump switch whenever I saw the header
level get down to about 8-9 Gallons (my header holds a little over 11
gallons) and manuually turning it off when my "Full" sensor lit up. After
flying well over 500 hours with this system, it's become second nature to
keep the header full. It isn't much of a pilot work-load burden, I only have
to hit the switch about once every 20 minutes and in the beginning, I used a
simple twist-up timer that I set each time I turned the pump off, to help me
develop the habit of checking the sight gauge.

The one time I lost the transfer pump, I was da---- glad my header was full
as I was out in the Nevada boonies about an hour from an airport.
Incidentally, I've since installed a second pump, in series with the first
(fuel-wise) and wired in parallel (electrically) to the same switch. Since
the Facet pump is a "pump through" type, should one fail, the other will
still allow fuel to get to the header. (My selector valve is plumbed before
the pumps so I can still pump fuel from either wing tank, even with a single
pump failure). Anyone that wishes to may pooh-pooh redundancy, but in
critical systems, I can live with it!

Dan Schaefer

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