Message text written by Brian Rauchfuss - PCD
>Do you use two gascolators for the parallel system? I was thinking of
a modification of it which would still automatically bring up a reserve
side pump if the fuel pressure drops, but would join the two sides (using
a 1-way value to prevent backflow) and bring only a single hose through a
gascolator and to the engine.
This affords most of the benefits of the parallel system without the
weight and cost of two gascolators.<
I have 2 gascolators with an NRV (non return valve) at present. This is
because, as I am at present using the mechanical pump, the two sides cannot
be joined before the engine compartment. Having proved my system works,
your suggestion, using two electric pumps is my next step. Provided the
electrical system is set up correctly there should be very little risk of
both pumps failing simultaneously enabling the removal of the mechanical
pump with all the pipework across the engine. To achieve this, one of the
pumps should not receive its power from the main panel fuse and to guard
against total electrical failure a overvoltage 'crowbar' unit should be
installed if this is not already the case.
I have discussed my plans with Francis Donaldson and he is happy to allow
me to proceed as a trial on my aircraft. If it proves satisfactory it might
become an acceptable mod. Obviously this restriction affects UK owners
only.
Nigel Charles
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