Message-Id: <3.0.3.32.19981012030730.00adbbe0@olsusa.com>
Date: Mon, 12 Oct 1998 03:07:30 -0400
To: lancair.list@olsusa.com
From: Bob <rab22@bigfoot.com> (by way of Marvin Kaye <marvkaye@olsusa.com>)
Subject: Re: 320 fuel system reply
Mime-Version: 1.0

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Funny this thread on unbalance would be here when I got home from
Copperstate.

Today on the way home, flying on the Navaid coupled to the GPS, the
plane began to turn slowly to the right.   Gosh what's wrong?, it never
did this before.  I turned off the AP and noticed I needed some left
aileron to stay level.  A quick blip on the aileron trim fixed that, and
the AP worked fine the rest of the trip.   I suspect the Navaid servo
had begun slipping when the amount of aileron force required got too
large.  I would emphasize that this was by no means an "automatic barrel
roll",  just a gentle turn.

I usually pump out of the left tank first when I'm flying alone.  I
would guess I had an imbalance of 8-9 gallons between the wing tanks.

In my 235, at least,  I think even left tank empty, right tank full,
would be easily controllable.  Has anyone tried this?

I also believe in a fuel return to reduce the chance of vapor lock, and
it is best if the return goes all the way into the header tank,  not
just back into the fuel line.   My return "leaks" about 5 gallons per hr
from a point just before the fuel flow transducer back into the header
tank.  Adding a new 1/4" inlet at the top of the header tank turned out
to be very easy.

header tank <---------------------------
                                       |
header----->boost --------->mech ------^->flow ---------->fuel
tank        pump            pump          xducer         controller


Like Tom Giddings,  I manage my own fuel transfer.  To help avoid
overflow,  I have a timer which shuts the pumps off after 10 mins.  To
help avoid underflow,  a radio shack count up/down timer which beeps
when it reaches zero is used.  Of course, you can't hear the beep,  so I
soldered a pair of wires across the pizeo-electric beeper in the timer
which are connected one of the unused "passenger microphone" inputs of
the  intercom.  This puts a sound in your ears which you can't ignore. 
This primitive system has been working well for over 200
hours.

Bob Belshe
N19BJ  235/320