>>The PFA approved the fitting of two filters one in each outlet from the
tank,
so you have a new one available in flight whatever the problem with the
first,. and the use of sealed car type filters which cannot be assembled
with
a leak. The Purolator can "by design", due to those 0 rings sitting on a
rounded end. The car ones have bigger surface area too. <<
The most important point of this is that a limited displacement pump like
the Facet cannot deliver enough fuel in a pumped system like ours if even a
tiny amount of air leaks in upstream of the pump. The air expands and
displaces fuel on the suction side so that the pump does not fill properly.
A slightly different problem occurs with Ellison throttle body
carburetters, (excellent devices correctly installed), fed by these same
Facet pumps. If the fuel line is empty, such as after running one side of
the tank dry, it will take something like TWO MINUTES to pump all the air
out because the air has to be pushed through tiny #80 size holes, at part
throttle not many of them. Rate of sink must be at least 650 fpm which is
not much time when you need to find your field and all the other things
necessary in that situation.
Graham
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