From: "R & A Colebrook" <rossann@azstarnet.com>
To: <lancair.list@olsusa.com>
Subject: FACET PUMPS
Date: Thu, 31 Dec 1998 21:47:18 -0700
Message-ID: <01be3541$eea83520$fc24c5a9@rossann.olympus.net>
Mime-Version: 1.0

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Some comments Facet pumps and fuel system design.


My 235 is built with no cowl tank.  Fuel feeds directly to the engine

from the wing tanks.  I put a Facet pump in each wheel well as close to

the tank as possible all plumbed with 3/8 line.  I put a line around

each pump with a check valve to insure free flow to the engine.  The

selector valve has left, right and both but I never use the both

position for the reason previously mentioned that with one tank dry the

engine pump would suck air.  A valve with just left and right would be

better choice.  I think this is the simplest system with most

redundancy.  As long as one of the three pumps (2 electric, 1 engine

driven) is operable there is fuel to the engine.  The electric pumps are

on the essential electric bus which can be powered directly from the

battery in case of failure of the master solenoid.


My kit came with Facet pumps with 1/8 inch pipe thread ports but Neico

swapped them for bigger port pumps at no cost.


This system does introduce two items of concern.  As previously

mentioned by someone, an electric pump must be on to get the primer to

work.  Also the pump must be on to get a fuel sample from the

gascolator.  My Facet pumps put up 6 psi. You get a snappy fuel sample.

But I have determined that if the primer is unlocked 6 psi on the system

will push enough gas through the primer line that the engine will hardly

run.  I have therefore added a small ball valve in the primer line under

the panel where I can reach it, as a  back up to the O ring seal in the

primer pump.  My pre-takeoff check` list includes verifying that the

ball valve is closed.


I have only 70 hours on the airplane but so far this system has been

trouble free.


Ross W. Colebrook