Paul,

    As you have seen, the recommendation is two fuel pumps.  One fuel pump
even with a "lifetime" warranty and guaranteed never to "wear out" is not a
good bet.  First, all that guarantee really means is the manufacture
believes that he will acquire more profit in  additional sales with the
"lifetime" warranty than it will cost him to honor "failure returns".  It
tells you absolutely nothing about the inherent design and material
reliability of the product itself.  Guaranteed never to "wear out" is also
not the same as "guaranteed not to fail".  I believe you can only count on
products that have a favorable history of failure in use.  Even prolong
manufacture tests frequently fail to duplicate the real world failure rates.

  The evaluation criteria in my mind is -  what is the cost to ensure
redundancy in a critical system Vs the potential down side if that component
fails.  I need not tell you the down side of a single fuel pump failing.

I designed my fuel feed with two independent feeds from my header tank to
each of my two fuel pumps.  Then each pump has its own high pressure
filter - I recommend a separate filter  for each pump - if you have both
feeding the same filter and the filter plugs up, well, you can figure the
rest.  I then use a "Y" to bring the two high pressure fuel lines together
going to the fuel rails.

Regarding activation.  The simplest thing might be to have your CPU system
control your primary pump through its relay and simple use a manual toggle
switch to turn on the secondary pump.  I only have my secondary pump on for
take off and landing and its not hard to put a reminder in your check list
to turn on the secondary pump for those phases of flight.

The MSD fuel pumps and the models Tracy Crook sells will put out approx. 80
psi with no flow and no regulator.  So you do need a regulator to stabilize
your fuel pressure at around 43 psi for good consistent fuel injection.

my 0.02 worth

Ed


Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
From: "sqpilot@earthlink" <sqpilot@earthlink.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Tuesday, February 17, 2004 7:38 PM
Subject: [FlyRotary] fuel pumps


> I am nearing the end of my 13b engine installaon...Are most of you using
two
> fuel pumps, or do you feel that the pumps are reliable enough to run only
> one?  I have the MSD fuel pump. Also, I assume that most high pressure
fuel
> pumps (45psi) can be mounted either vertically or horizontally?  Thanks
for
> any and all suggestions.  Paul Conner, 13b powered SQ2000
>
>
>
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